Null HeVAL and local delete → crash

[perl5.git] / pp.c

/*    pp.c
 *
 *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
 *    2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 */

/*
 * 'It's a big house this, and very peculiar.  Always a bit more
 *  to discover, and no knowing what you'll find round a corner.
 *  And Elves, sir!'                            --Samwise Gamgee
 *
 *     [p.225 of _The Lord of the Rings_, II/i: "Many Meetings"]
 */

/* This file contains general pp ("push/pop") functions that execute the
 * opcodes that make up a perl program. A typical pp function expects to
 * find its arguments on the stack, and usually pushes its results onto
 * the stack, hence the 'pp' terminology. Each OP structure contains
 * a pointer to the relevant pp_foo() function.
 */

#include "EXTERN.h"
#define PERL_IN_PP_C
#include "perl.h"
#include "keywords.h"

#include "reentr.h"

/* XXX I can't imagine anyone who doesn't have this actually _needs_
   it, since pid_t is an integral type.
   --AD  2/20/1998
*/
#ifdef NEED_GETPID_PROTO
extern Pid_t getpid (void);
#endif

/*
 * Some BSDs and Cygwin default to POSIX math instead of IEEE.
 * This switches them over to IEEE.
 */
#if defined(LIBM_LIB_VERSION)
    _LIB_VERSION_TYPE _LIB_VERSION = _IEEE_;
#endif

/* variations on pp_null */

PP(pp_stub)
{
    dVAR;
    dSP;
    if (GIMME_V == G_SCALAR)
	XPUSHs(&PL_sv_undef);
    RETURN;
}

/* Pushy stuff. */

PP(pp_padav)
{
    dVAR; dSP; dTARGET;
    I32 gimme;
    assert(SvTYPE(TARG) == SVt_PVAV);
    if (PL_op->op_private & OPpLVAL_INTRO)
	if (!(PL_op->op_private & OPpPAD_STATE))
	    SAVECLEARSV(PAD_SVl(PL_op->op_targ));
    EXTEND(SP, 1);
    if (PL_op->op_flags & OPf_REF) {
	PUSHs(TARG);
	RETURN;
    } else if (PL_op->op_private & OPpMAYBE_LVSUB) {
       const I32 flags = is_lvalue_sub();
       if (flags && !(flags & OPpENTERSUB_INARGS)) {
	if (GIMME == G_SCALAR)
	    /* diag_listed_as: Can't return %s to lvalue scalar context */
	    Perl_croak(aTHX_ "Can't return array to lvalue scalar context");
	PUSHs(TARG);
	RETURN;
       }
    }
    gimme = GIMME_V;
    if (gimme == G_ARRAY) {
	const I32 maxarg = AvFILL(MUTABLE_AV(TARG)) + 1;
	EXTEND(SP, maxarg);
	if (SvMAGICAL(TARG)) {
	    U32 i;
	    for (i=0; i < (U32)maxarg; i++) {
		SV * const * const svp = av_fetch(MUTABLE_AV(TARG), i, FALSE);
		SP[i+1] = (svp) ? *svp : &PL_sv_undef;
	    }
	}
	else {
	    Copy(AvARRAY((const AV *)TARG), SP+1, maxarg, SV*);
	}
	SP += maxarg;
    }
    else if (gimme == G_SCALAR) {
	SV* const sv = sv_newmortal();
	const I32 maxarg = AvFILL(MUTABLE_AV(TARG)) + 1;
	sv_setiv(sv, maxarg);
	PUSHs(sv);
    }
    RETURN;
}

PP(pp_padhv)
{
    dVAR; dSP; dTARGET;
    I32 gimme;

    assert(SvTYPE(TARG) == SVt_PVHV);
    XPUSHs(TARG);
    if (PL_op->op_private & OPpLVAL_INTRO)
	if (!(PL_op->op_private & OPpPAD_STATE))
	    SAVECLEARSV(PAD_SVl(PL_op->op_targ));
    if (PL_op->op_flags & OPf_REF)
	RETURN;
    else if (PL_op->op_private & OPpMAYBE_LVSUB) {
      const I32 flags = is_lvalue_sub();
      if (flags && !(flags & OPpENTERSUB_INARGS)) {
	if (GIMME == G_SCALAR)
	    /* diag_listed_as: Can't return %s to lvalue scalar context */
	    Perl_croak(aTHX_ "Can't return hash to lvalue scalar context");
	RETURN;
      }
    }
    gimme = GIMME_V;
    if (gimme == G_ARRAY) {
	RETURNOP(Perl_do_kv(aTHX));
    }
    else if (gimme == G_SCALAR) {
	SV* const sv = Perl_hv_scalar(aTHX_ MUTABLE_HV(TARG));
	SETs(sv);
    }
    RETURN;
}

/* Translations. */

static const char S_no_symref_sv[] =
    "Can't use string (\"%" SVf32 "\"%s) as %s ref while \"strict refs\" in use";

/* In some cases this function inspects PL_op.  If this function is called
   for new op types, more bool parameters may need to be added in place of
   the checks.

   When noinit is true, the absence of a gv will cause a retval of undef.
   This is unrelated to the cv-to-gv assignment case.
*/

static SV *
S_rv2gv(pTHX_ SV *sv, const bool vivify_sv, const bool strict,
              const bool noinit)
{
    dVAR;
    if (!isGV(sv) || SvFAKE(sv)) SvGETMAGIC(sv);
    if (SvROK(sv)) {
	if (SvAMAGIC(sv)) {
	    sv = amagic_deref_call(sv, to_gv_amg);
	}
      wasref:
	sv = SvRV(sv);
	if (SvTYPE(sv) == SVt_PVIO) {
	    GV * const gv = MUTABLE_GV(sv_newmortal());
	    gv_init(gv, 0, "__ANONIO__", 10, 0);
	    GvIOp(gv) = MUTABLE_IO(sv);
	    SvREFCNT_inc_void_NN(sv);
	    sv = MUTABLE_SV(gv);
	}
	else if (!isGV_with_GP(sv))
	    return (SV *)Perl_die(aTHX_ "Not a GLOB reference");
    }
    else {
	if (!isGV_with_GP(sv)) {
	    if (!SvOK(sv)) {
		/* If this is a 'my' scalar and flag is set then vivify
		 * NI-S 1999/05/07
		 */
		if (vivify_sv && sv != &PL_sv_undef) {
		    GV *gv;
		    if (SvREADONLY(sv))
			Perl_croak_no_modify(aTHX);
		    if (cUNOP->op_targ) {
			SV * const namesv = PAD_SV(cUNOP->op_targ);
			gv = MUTABLE_GV(newSV(0));
			gv_init_sv(gv, CopSTASH(PL_curcop), namesv, 0);
		    }
		    else {
			const char * const name = CopSTASHPV(PL_curcop);
			gv = newGVgen_flags(name,
                                        HvNAMEUTF8(CopSTASH(PL_curcop)) ? SVf_UTF8 : 0 );
		    }
		    prepare_SV_for_RV(sv);
		    SvRV_set(sv, MUTABLE_SV(gv));
		    SvROK_on(sv);
		    SvSETMAGIC(sv);
		    goto wasref;
		}
		if (PL_op->op_flags & OPf_REF || strict)
		    return (SV *)Perl_die(aTHX_ PL_no_usym, "a symbol");
		if (ckWARN(WARN_UNINITIALIZED))
		    report_uninit(sv);
		return &PL_sv_undef;
	    }
	    if (noinit)
	    {
		if (!(sv = MUTABLE_SV(gv_fetchsv_nomg(
		           sv, GV_ADDMG, SVt_PVGV
		   ))))
		    return &PL_sv_undef;
	    }
	    else {
		if (strict)
		    return
		     (SV *)Perl_die(aTHX_
		            S_no_symref_sv,
		            sv,
		            (SvPOKp(sv) && SvCUR(sv)>32 ? "..." : ""),
		            "a symbol"
		           );
		if ((PL_op->op_private & (OPpLVAL_INTRO|OPpDONT_INIT_GV))
		    == OPpDONT_INIT_GV) {
		    /* We are the target of a coderef assignment.  Return
		       the scalar unchanged, and let pp_sasssign deal with
		       things.  */
		    return sv;
		}
		sv = MUTABLE_SV(gv_fetchsv_nomg(sv, GV_ADD, SVt_PVGV));
	    }
	    /* FAKE globs in the symbol table cause weird bugs (#77810) */
	    SvFAKE_off(sv);
	}
    }
    if (SvFAKE(sv) && !(PL_op->op_private & OPpALLOW_FAKE)) {
	SV *newsv = sv_newmortal();
	sv_setsv_flags(newsv, sv, 0);
	SvFAKE_off(newsv);
	sv = newsv;
    }
    return sv;
}

PP(pp_rv2gv)
{
    dVAR; dSP; dTOPss;

    sv = S_rv2gv(aTHX_
          sv, PL_op->op_private & OPpDEREF,
          PL_op->op_private & HINT_STRICT_REFS,
          ((PL_op->op_flags & OPf_SPECIAL) && !(PL_op->op_flags & OPf_MOD))
             || PL_op->op_type == OP_READLINE
         );
    if (PL_op->op_private & OPpLVAL_INTRO)
	save_gp(MUTABLE_GV(sv), !(PL_op->op_flags & OPf_SPECIAL));
    SETs(sv);
    RETURN;
}

/* Helper function for pp_rv2sv and pp_rv2av  */
GV *
Perl_softref2xv(pTHX_ SV *const sv, const char *const what,
		const svtype type, SV ***spp)
{
    dVAR;
    GV *gv;

    PERL_ARGS_ASSERT_SOFTREF2XV;

    if (PL_op->op_private & HINT_STRICT_REFS) {
	if (SvOK(sv))
	    Perl_die(aTHX_ S_no_symref_sv, sv,
		     (SvPOKp(sv) && SvCUR(sv)>32 ? "..." : ""), what);
	else
	    Perl_die(aTHX_ PL_no_usym, what);
    }
    if (!SvOK(sv)) {
	if (
	  PL_op->op_flags & OPf_REF &&
	  PL_op->op_next->op_type != OP_BOOLKEYS
	)
	    Perl_die(aTHX_ PL_no_usym, what);
	if (ckWARN(WARN_UNINITIALIZED))
	    report_uninit(sv);
	if (type != SVt_PV && GIMME_V == G_ARRAY) {
	    (*spp)--;
	    return NULL;
	}
	**spp = &PL_sv_undef;
	return NULL;
    }
    if ((PL_op->op_flags & OPf_SPECIAL) &&
	!(PL_op->op_flags & OPf_MOD))
	{
	    if (!(gv = gv_fetchsv_nomg(sv, GV_ADDMG, type)))
		{
		    **spp = &PL_sv_undef;
		    return NULL;
		}
	}
    else {
	gv = gv_fetchsv_nomg(sv, GV_ADD, type);
    }
    return gv;
}

PP(pp_rv2sv)
{
    dVAR; dSP; dTOPss;
    GV *gv = NULL;

    SvGETMAGIC(sv);
    if (SvROK(sv)) {
	if (SvAMAGIC(sv)) {
	    sv = amagic_deref_call(sv, to_sv_amg);
	}

	sv = SvRV(sv);
	switch (SvTYPE(sv)) {
	case SVt_PVAV:
	case SVt_PVHV:
	case SVt_PVCV:
	case SVt_PVFM:
	case SVt_PVIO:
	    DIE(aTHX_ "Not a SCALAR reference");
	default: NOOP;
	}
    }
    else {
	gv = MUTABLE_GV(sv);

	if (!isGV_with_GP(gv)) {
	    gv = Perl_softref2xv(aTHX_ sv, "a SCALAR", SVt_PV, &sp);
	    if (!gv)
		RETURN;
	}
	sv = GvSVn(gv);
    }
    if (PL_op->op_flags & OPf_MOD) {
	if (PL_op->op_private & OPpLVAL_INTRO) {
	    if (cUNOP->op_first->op_type == OP_NULL)
		sv = save_scalar(MUTABLE_GV(TOPs));
	    else if (gv)
		sv = save_scalar(gv);
	    else
		Perl_croak(aTHX_ "%s", PL_no_localize_ref);
	}
	else if (PL_op->op_private & OPpDEREF)
	    sv = vivify_ref(sv, PL_op->op_private & OPpDEREF);
    }
    SETs(sv);
    RETURN;
}

PP(pp_av2arylen)
{
    dVAR; dSP;
    AV * const av = MUTABLE_AV(TOPs);
    const I32 lvalue = PL_op->op_flags & OPf_MOD || LVRET;
    if (lvalue) {
	SV ** const sv = Perl_av_arylen_p(aTHX_ MUTABLE_AV(av));
	if (!*sv) {
	    *sv = newSV_type(SVt_PVMG);
	    sv_magic(*sv, MUTABLE_SV(av), PERL_MAGIC_arylen, NULL, 0);
	}
	SETs(*sv);
    } else {
	SETs(sv_2mortal(newSViv(AvFILL(MUTABLE_AV(av)))));
    }
    RETURN;
}

PP(pp_pos)
{
    dVAR; dSP; dPOPss;

    if (PL_op->op_flags & OPf_MOD || LVRET) {
	SV * const ret = sv_2mortal(newSV_type(SVt_PVLV));  /* Not TARG RT#67838 */
	sv_magic(ret, NULL, PERL_MAGIC_pos, NULL, 0);
	LvTYPE(ret) = '.';
	LvTARG(ret) = SvREFCNT_inc_simple(sv);
	PUSHs(ret);    /* no SvSETMAGIC */
	RETURN;
    }
    else {
	if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv)) {
	    const MAGIC * const mg = mg_find(sv, PERL_MAGIC_regex_global);
	    if (mg && mg->mg_len >= 0) {
		dTARGET;
		I32 i = mg->mg_len;
		if (DO_UTF8(sv))
		    sv_pos_b2u(sv, &i);
		PUSHi(i);
		RETURN;
	    }
	}
	RETPUSHUNDEF;
    }
}

PP(pp_rv2cv)
{
    dVAR; dSP;
    GV *gv;
    HV *stash_unused;
    const I32 flags = (PL_op->op_flags & OPf_SPECIAL)
	? GV_ADDMG
	: ((PL_op->op_private & (OPpLVAL_INTRO|OPpMAY_RETURN_CONSTANT)) == OPpMAY_RETURN_CONSTANT)
	    ? GV_ADD|GV_NOEXPAND
	    : GV_ADD;
    /* We usually try to add a non-existent subroutine in case of AUTOLOAD. */
    /* (But not in defined().) */

    CV *cv = sv_2cv(TOPs, &stash_unused, &gv, flags);
    if (cv) NOOP;
    else if ((flags == (GV_ADD|GV_NOEXPAND)) && gv && SvROK(gv)) {
	cv = MUTABLE_CV(gv);
    }    
    else
	cv = MUTABLE_CV(&PL_sv_undef);
    SETs(MUTABLE_SV(cv));
    RETURN;
}

PP(pp_prototype)
{
    dVAR; dSP;
    CV *cv;
    HV *stash;
    GV *gv;
    SV *ret = &PL_sv_undef;

    if (SvGMAGICAL(TOPs)) SETs(sv_mortalcopy(TOPs));
    if (SvPOK(TOPs) && SvCUR(TOPs) >= 7) {
	const char * s = SvPVX_const(TOPs);
	if (strnEQ(s, "CORE::", 6)) {
	    const int code = keyword(s + 6, SvCUR(TOPs) - 6, 1);
	    if (!code || code == -KEY_CORE)
		DIE(aTHX_ "Can't find an opnumber for \"%"SVf"\"",
		    SVfARG(newSVpvn_flags(
			s+6, SvCUR(TOPs)-6, SvFLAGS(TOPs) & SVf_UTF8
		    )));
	    {
		SV * const sv = core_prototype(NULL, s + 6, code, NULL);
		if (sv) ret = sv;
	    }
	    goto set;
	}
    }
    cv = sv_2cv(TOPs, &stash, &gv, 0);
    if (cv && SvPOK(cv))
	ret = newSVpvn_flags(
	    CvPROTO(cv), CvPROTOLEN(cv), SVs_TEMP | SvUTF8(cv)
	);
  set:
    SETs(ret);
    RETURN;
}

PP(pp_anoncode)
{
    dVAR; dSP;
    CV *cv = MUTABLE_CV(PAD_SV(PL_op->op_targ));
    if (CvCLONE(cv))
	cv = MUTABLE_CV(sv_2mortal(MUTABLE_SV(cv_clone(cv))));
    EXTEND(SP,1);
    PUSHs(MUTABLE_SV(cv));
    RETURN;
}

PP(pp_srefgen)
{
    dVAR; dSP;
    *SP = refto(*SP);
    RETURN;
}

PP(pp_refgen)
{
    dVAR; dSP; dMARK;
    if (GIMME != G_ARRAY) {
	if (++MARK <= SP)
	    *MARK = *SP;
	else
	    *MARK = &PL_sv_undef;
	*MARK = refto(*MARK);
	SP = MARK;
	RETURN;
    }
    EXTEND_MORTAL(SP - MARK);
    while (++MARK <= SP)
	*MARK = refto(*MARK);
    RETURN;
}

STATIC SV*
S_refto(pTHX_ SV *sv)
{
    dVAR;
    SV* rv;

    PERL_ARGS_ASSERT_REFTO;

    if (SvTYPE(sv) == SVt_PVLV && LvTYPE(sv) == 'y') {
	if (LvTARGLEN(sv))
	    vivify_defelem(sv);
	if (!(sv = LvTARG(sv)))
	    sv = &PL_sv_undef;
	else
	    SvREFCNT_inc_void_NN(sv);
    }
    else if (SvTYPE(sv) == SVt_PVAV) {
	if (!AvREAL((const AV *)sv) && AvREIFY((const AV *)sv))
	    av_reify(MUTABLE_AV(sv));
	SvTEMP_off(sv);
	SvREFCNT_inc_void_NN(sv);
    }
    else if (SvPADTMP(sv) && !IS_PADGV(sv))
        sv = newSVsv(sv);
    else {
	SvTEMP_off(sv);
	SvREFCNT_inc_void_NN(sv);
    }
    rv = sv_newmortal();
    sv_upgrade(rv, SVt_IV);
    SvRV_set(rv, sv);
    SvROK_on(rv);
    return rv;
}

PP(pp_ref)
{
    dVAR; dSP; dTARGET;
    SV * const sv = POPs;

    if (sv)
	SvGETMAGIC(sv);

    if (!sv || !SvROK(sv))
	RETPUSHNO;

    (void)sv_ref(TARG,SvRV(sv),TRUE);
    PUSHTARG;
    RETURN;
}

PP(pp_bless)
{
    dVAR; dSP;
    HV *stash;

    if (MAXARG == 1)
      curstash:
	stash = CopSTASH(PL_curcop);
    else {
	SV * const ssv = POPs;
	STRLEN len;
	const char *ptr;

	if (!ssv) goto curstash;
	if (!SvGMAGICAL(ssv) && !SvAMAGIC(ssv) && SvROK(ssv))
	    Perl_croak(aTHX_ "Attempt to bless into a reference");
	ptr = SvPV_const(ssv,len);
	if (len == 0)
	    Perl_ck_warner(aTHX_ packWARN(WARN_MISC),
			   "Explicit blessing to '' (assuming package main)");
	stash = gv_stashpvn(ptr, len, GV_ADD|SvUTF8(ssv));
    }

    (void)sv_bless(TOPs, stash);
    RETURN;
}

PP(pp_gelem)
{
    dVAR; dSP;

    SV *sv = POPs;
    STRLEN len;
    const char * const elem = SvPV_const(sv, len);
    GV * const gv = MUTABLE_GV(POPs);
    SV * tmpRef = NULL;

    sv = NULL;
    if (elem) {
	/* elem will always be NUL terminated.  */
	const char * const second_letter = elem + 1;
	switch (*elem) {
	case 'A':
	    if (len == 5 && strEQ(second_letter, "RRAY"))
		tmpRef = MUTABLE_SV(GvAV(gv));
	    break;
	case 'C':
	    if (len == 4 && strEQ(second_letter, "ODE"))
		tmpRef = MUTABLE_SV(GvCVu(gv));
	    break;
	case 'F':
	    if (len == 10 && strEQ(second_letter, "ILEHANDLE")) {
		/* finally deprecated in 5.8.0 */
		deprecate("*glob{FILEHANDLE}");
		tmpRef = MUTABLE_SV(GvIOp(gv));
	    }
	    else
		if (len == 6 && strEQ(second_letter, "ORMAT"))
		    tmpRef = MUTABLE_SV(GvFORM(gv));
	    break;
	case 'G':
	    if (len == 4 && strEQ(second_letter, "LOB"))
		tmpRef = MUTABLE_SV(gv);
	    break;
	case 'H':
	    if (len == 4 && strEQ(second_letter, "ASH"))
		tmpRef = MUTABLE_SV(GvHV(gv));
	    break;
	case 'I':
	    if (*second_letter == 'O' && !elem[2] && len == 2)
		tmpRef = MUTABLE_SV(GvIOp(gv));
	    break;
	case 'N':
	    if (len == 4 && strEQ(second_letter, "AME"))
		sv = newSVhek(GvNAME_HEK(gv));
	    break;
	case 'P':
	    if (len == 7 && strEQ(second_letter, "ACKAGE")) {
		const HV * const stash = GvSTASH(gv);
		const HEK * const hek = stash ? HvNAME_HEK(stash) : NULL;
		sv = hek ? newSVhek(hek) : newSVpvs("__ANON__");
	    }
	    break;
	case 'S':
	    if (len == 6 && strEQ(second_letter, "CALAR"))
		tmpRef = GvSVn(gv);
	    break;
	}
    }
    if (tmpRef)
	sv = newRV(tmpRef);
    if (sv)
	sv_2mortal(sv);
    else
	sv = &PL_sv_undef;
    XPUSHs(sv);
    RETURN;
}

/* Pattern matching */

PP(pp_study)
{
    dVAR; dSP; dPOPss;
    register unsigned char *s;
    STRLEN len;

    s = (unsigned char*)(SvPV(sv, len));
    if (len == 0 || len > I32_MAX || !SvPOK(sv) || SvUTF8(sv) || SvVALID(sv)) {
	/* Historically, study was skipped in these cases. */
	RETPUSHNO;
    }

    /* Make study a no-op. It's no longer useful and its existence
       complicates matters elsewhere. */
    RETPUSHYES;
}

PP(pp_trans)
{
    dVAR; dSP; dTARG;
    SV *sv;

    if (PL_op->op_flags & OPf_STACKED)
	sv = POPs;
    else if (PL_op->op_private & OPpTARGET_MY)
	sv = GETTARGET;
    else {
	sv = DEFSV;
	EXTEND(SP,1);
    }
    TARG = sv_newmortal();
    if(PL_op->op_type == OP_TRANSR) {
	STRLEN len;
	const char * const pv = SvPV(sv,len);
	SV * const newsv = newSVpvn_flags(pv, len, SVs_TEMP|SvUTF8(sv));
	do_trans(newsv);
	PUSHs(newsv);
    }
    else PUSHi(do_trans(sv));
    RETURN;
}

/* Lvalue operators. */

static void
S_do_chomp(pTHX_ SV *retval, SV *sv, bool chomping)
{
    dVAR;
    STRLEN len;
    char *s;

    PERL_ARGS_ASSERT_DO_CHOMP;

    if (chomping && (RsSNARF(PL_rs) || RsRECORD(PL_rs)))
	return;
    if (SvTYPE(sv) == SVt_PVAV) {
	I32 i;
	AV *const av = MUTABLE_AV(sv);
	const I32 max = AvFILL(av);

	for (i = 0; i <= max; i++) {
	    sv = MUTABLE_SV(av_fetch(av, i, FALSE));
	    if (sv && ((sv = *(SV**)sv), sv != &PL_sv_undef))
		do_chomp(retval, sv, chomping);
	}
        return;
    }
    else if (SvTYPE(sv) == SVt_PVHV) {
	HV* const hv = MUTABLE_HV(sv);
	HE* entry;
        (void)hv_iterinit(hv);
        while ((entry = hv_iternext(hv)))
            do_chomp(retval, hv_iterval(hv,entry), chomping);
	return;
    }
    else if (SvREADONLY(sv)) {
        if (SvFAKE(sv)) {
            /* SV is copy-on-write */
	    sv_force_normal_flags(sv, 0);
        }
        else
            Perl_croak_no_modify(aTHX);
    }

    if (PL_encoding) {
	if (!SvUTF8(sv)) {
	    /* XXX, here sv is utf8-ized as a side-effect!
	       If encoding.pm is used properly, almost string-generating
	       operations, including literal strings, chr(), input data, etc.
	       should have been utf8-ized already, right?
	    */
	    sv_recode_to_utf8(sv, PL_encoding);
	}
    }

    s = SvPV(sv, len);
    if (chomping) {
	char *temp_buffer = NULL;
	SV *svrecode = NULL;

	if (s && len) {
	    s += --len;
	    if (RsPARA(PL_rs)) {
		if (*s != '\n')
		    goto nope;
		++SvIVX(retval);
		while (len && s[-1] == '\n') {
		    --len;
		    --s;
		    ++SvIVX(retval);
		}
	    }
	    else {
		STRLEN rslen, rs_charlen;
		const char *rsptr = SvPV_const(PL_rs, rslen);

		rs_charlen = SvUTF8(PL_rs)
		    ? sv_len_utf8(PL_rs)
		    : rslen;

		if (SvUTF8(PL_rs) != SvUTF8(sv)) {
		    /* Assumption is that rs is shorter than the scalar.  */
		    if (SvUTF8(PL_rs)) {
			/* RS is utf8, scalar is 8 bit.  */
			bool is_utf8 = TRUE;
			temp_buffer = (char*)bytes_from_utf8((U8*)rsptr,
							     &rslen, &is_utf8);
			if (is_utf8) {
			    /* Cannot downgrade, therefore cannot possibly match
			     */
			    assert (temp_buffer == rsptr);
			    temp_buffer = NULL;
			    goto nope;
			}
			rsptr = temp_buffer;
		    }
		    else if (PL_encoding) {
			/* RS is 8 bit, encoding.pm is used.
			 * Do not recode PL_rs as a side-effect. */
			svrecode = newSVpvn(rsptr, rslen);
			sv_recode_to_utf8(svrecode, PL_encoding);
			rsptr = SvPV_const(svrecode, rslen);
			rs_charlen = sv_len_utf8(svrecode);
		    }
		    else {
			/* RS is 8 bit, scalar is utf8.  */
			temp_buffer = (char*)bytes_to_utf8((U8*)rsptr, &rslen);
			rsptr = temp_buffer;
		    }
		}
		if (rslen == 1) {
		    if (*s != *rsptr)
			goto nope;
		    ++SvIVX(retval);
		}
		else {
		    if (len < rslen - 1)
			goto nope;
		    len -= rslen - 1;
		    s -= rslen - 1;
		    if (memNE(s, rsptr, rslen))
			goto nope;
		    SvIVX(retval) += rs_charlen;
		}
	    }
	    s = SvPV_force_nomg_nolen(sv);
	    SvCUR_set(sv, len);
	    *SvEND(sv) = '\0';
	    SvNIOK_off(sv);
	    SvSETMAGIC(sv);
	}
    nope:

	SvREFCNT_dec(svrecode);

	Safefree(temp_buffer);
    } else {
	if (len && !SvPOK(sv))
	    s = SvPV_force_nomg(sv, len);
	if (DO_UTF8(sv)) {
	    if (s && len) {
		char * const send = s + len;
		char * const start = s;
		s = send - 1;
		while (s > start && UTF8_IS_CONTINUATION(*s))
		    s--;
		if (is_utf8_string((U8*)s, send - s)) {
		    sv_setpvn(retval, s, send - s);
		    *s = '\0';
		    SvCUR_set(sv, s - start);
		    SvNIOK_off(sv);
		    SvUTF8_on(retval);
		}
	    }
	    else
		sv_setpvs(retval, "");
	}
	else if (s && len) {
	    s += --len;
	    sv_setpvn(retval, s, 1);
	    *s = '\0';
	    SvCUR_set(sv, len);
	    SvUTF8_off(sv);
	    SvNIOK_off(sv);
	}
	else
	    sv_setpvs(retval, "");
	SvSETMAGIC(sv);
    }
}

PP(pp_schop)
{
    dVAR; dSP; dTARGET;
    const bool chomping = PL_op->op_type == OP_SCHOMP;

    if (chomping)
	sv_setiv(TARG, 0);
    do_chomp(TARG, TOPs, chomping);
    SETTARG;
    RETURN;
}

PP(pp_chop)
{
    dVAR; dSP; dMARK; dTARGET; dORIGMARK;
    const bool chomping = PL_op->op_type == OP_CHOMP;

    if (chomping)
	sv_setiv(TARG, 0);
    while (MARK < SP)
	do_chomp(TARG, *++MARK, chomping);
    SP = ORIGMARK;
    XPUSHTARG;
    RETURN;
}

PP(pp_undef)
{
    dVAR; dSP;
    SV *sv;

    if (!PL_op->op_private) {
	EXTEND(SP, 1);
	RETPUSHUNDEF;
    }

    sv = POPs;
    if (!sv)
	RETPUSHUNDEF;

    SV_CHECK_THINKFIRST_COW_DROP(sv);

    switch (SvTYPE(sv)) {
    case SVt_NULL:
	break;
    case SVt_PVAV:
	av_undef(MUTABLE_AV(sv));
	break;
    case SVt_PVHV:
	hv_undef(MUTABLE_HV(sv));
	break;
    case SVt_PVCV:
	if (cv_const_sv((const CV *)sv))
	    Perl_ck_warner(aTHX_ packWARN(WARN_MISC),
                          "Constant subroutine %"SVf" undefined",
			   SVfARG(CvANON((const CV *)sv)
                             ? newSVpvs_flags("(anonymous)", SVs_TEMP)
                             : sv_2mortal(newSVhek(GvENAME_HEK(CvGV((const CV *)sv))))));
	/* FALLTHROUGH */
    case SVt_PVFM:
	{
	    /* let user-undef'd sub keep its identity */
	    GV* const gv = CvGV((const CV *)sv);
	    cv_undef(MUTABLE_CV(sv));
	    CvGV_set(MUTABLE_CV(sv), gv);
	}
	break;
    case SVt_PVGV:
	if (SvFAKE(sv)) {
	    SvSetMagicSV(sv, &PL_sv_undef);
	    break;
	}
	else if (isGV_with_GP(sv)) {
	    GP *gp;
            HV *stash;

            /* undef *Pkg::meth_name ... */
            bool method_changed
             =   GvCVu((const GV *)sv) && (stash = GvSTASH((const GV *)sv))
	      && HvENAME_get(stash);
            /* undef *Foo:: */
            if((stash = GvHV((const GV *)sv))) {
                if(HvENAME_get(stash))
                    SvREFCNT_inc_simple_void_NN(sv_2mortal((SV *)stash));
                else stash = NULL;
            }

	    gp_free(MUTABLE_GV(sv));
	    Newxz(gp, 1, GP);
	    GvGP_set(sv, gp_ref(gp));
	    GvSV(sv) = newSV(0);
	    GvLINE(sv) = CopLINE(PL_curcop);
	    GvEGV(sv) = MUTABLE_GV(sv);
	    GvMULTI_on(sv);

            if(stash)
                mro_package_moved(NULL, stash, (const GV *)sv, 0);
            stash = NULL;
            /* undef *Foo::ISA */
            if( strEQ(GvNAME((const GV *)sv), "ISA")
             && (stash = GvSTASH((const GV *)sv))
             && (method_changed || HvENAME(stash)) )
                mro_isa_changed_in(stash);
            else if(method_changed)
                mro_method_changed_in(
                 GvSTASH((const GV *)sv)
                );

	    break;
	}
	/* FALL THROUGH */
    default:
	if (SvTYPE(sv) >= SVt_PV && SvPVX_const(sv) && SvLEN(sv)) {
	    SvPV_free(sv);
	    SvPV_set(sv, NULL);
	    SvLEN_set(sv, 0);
	}
	SvOK_off(sv);
	SvSETMAGIC(sv);
    }

    RETPUSHUNDEF;
}

PP(pp_postinc)
{
    dVAR; dSP; dTARGET;
    const bool inc =
	PL_op->op_type == OP_POSTINC || PL_op->op_type == OP_I_POSTINC;
    if (SvTYPE(TOPs) >= SVt_PVAV || (isGV_with_GP(TOPs) && !SvFAKE(TOPs)))
	Perl_croak_no_modify(aTHX);
    if (SvROK(TOPs))
	TARG = sv_newmortal();
    sv_setsv(TARG, TOPs);
    if (!SvREADONLY(TOPs) && SvIOK_notUV(TOPs) && !SvNOK(TOPs) && !SvPOK(TOPs)
        && SvIVX(TOPs) != (inc ? IV_MAX : IV_MIN))
    {
	SvIV_set(TOPs, SvIVX(TOPs) + (inc ? 1 : -1));
	SvFLAGS(TOPs) &= ~(SVp_NOK|SVp_POK);
    }
    else if (inc)
	sv_inc_nomg(TOPs);
    else sv_dec_nomg(TOPs);
    SvSETMAGIC(TOPs);
    /* special case for undef: see thread at 2003-03/msg00536.html in archive */
    if (inc && !SvOK(TARG))
	sv_setiv(TARG, 0);
    SETs(TARG);
    return NORMAL;
}

/* Ordinary operators. */

PP(pp_pow)
{
    dVAR; dSP; dATARGET; SV *svl, *svr;
#ifdef PERL_PRESERVE_IVUV
    bool is_int = 0;
#endif
    tryAMAGICbin_MG(pow_amg, AMGf_assign|AMGf_numeric);
    svr = TOPs;
    svl = TOPm1s;
#ifdef PERL_PRESERVE_IVUV
    /* For integer to integer power, we do the calculation by hand wherever
       we're sure it is safe; otherwise we call pow() and try to convert to
       integer afterwards. */
    if (SvIV_please_nomg(svr) && SvIV_please_nomg(svl)) {
		UV power;
		bool baseuok;
		UV baseuv;

		if (SvUOK(svr)) {
		    power = SvUVX(svr);
		} else {
		    const IV iv = SvIVX(svr);
		    if (iv >= 0) {
			power = iv;
		    } else {
			goto float_it; /* Can't do negative powers this way.  */
		    }
		}

		baseuok = SvUOK(svl);
		if (baseuok) {
		    baseuv = SvUVX(svl);
		} else {
		    const IV iv = SvIVX(svl);
		    if (iv >= 0) {
			baseuv = iv;
			baseuok = TRUE; /* effectively it's a UV now */
		    } else {
			baseuv = -iv; /* abs, baseuok == false records sign */
		    }
		}
                /* now we have integer ** positive integer. */
                is_int = 1;

                /* foo & (foo - 1) is zero only for a power of 2.  */
                if (!(baseuv & (baseuv - 1))) {
                    /* We are raising power-of-2 to a positive integer.
                       The logic here will work for any base (even non-integer
                       bases) but it can be less accurate than
                       pow (base,power) or exp (power * log (base)) when the
                       intermediate values start to spill out of the mantissa.
                       With powers of 2 we know this can't happen.
                       And powers of 2 are the favourite thing for perl
                       programmers to notice ** not doing what they mean. */
                    NV result = 1.0;
                    NV base = baseuok ? baseuv : -(NV)baseuv;

		    if (power & 1) {
			result *= base;
		    }
		    while (power >>= 1) {
			base *= base;
			if (power & 1) {
			    result *= base;
			}
		    }
                    SP--;
                    SETn( result );
                    SvIV_please_nomg(svr);
                    RETURN;
		} else {
		    register unsigned int highbit = 8 * sizeof(UV);
		    register unsigned int diff = 8 * sizeof(UV);
		    while (diff >>= 1) {
			highbit -= diff;
			if (baseuv >> highbit) {
			    highbit += diff;
			}
		    }
		    /* we now have baseuv < 2 ** highbit */
		    if (power * highbit <= 8 * sizeof(UV)) {
			/* result will definitely fit in UV, so use UV math
			   on same algorithm as above */
			register UV result = 1;
			register UV base = baseuv;
			const bool odd_power = cBOOL(power & 1);
			if (odd_power) {
			    result *= base;
			}
			while (power >>= 1) {
			    base *= base;
			    if (power & 1) {
				result *= base;
			    }
			}
			SP--;
			if (baseuok || !odd_power)
			    /* answer is positive */
			    SETu( result );
			else if (result <= (UV)IV_MAX)
			    /* answer negative, fits in IV */
			    SETi( -(IV)result );
			else if (result == (UV)IV_MIN) 
			    /* 2's complement assumption: special case IV_MIN */
			    SETi( IV_MIN );
			else
			    /* answer negative, doesn't fit */
			    SETn( -(NV)result );
			RETURN;
		    } 
		}
    }
  float_it:
#endif    
    {
	NV right = SvNV_nomg(svr);
	NV left  = SvNV_nomg(svl);
	(void)POPs;

#if defined(USE_LONG_DOUBLE) && defined(HAS_AIX_POWL_NEG_BASE_BUG)
    /*
    We are building perl with long double support and are on an AIX OS
    afflicted with a powl() function that wrongly returns NaNQ for any
    negative base.  This was reported to IBM as PMR #23047-379 on
    03/06/2006.  The problem exists in at least the following versions
    of AIX and the libm fileset, and no doubt others as well:

	AIX 4.3.3-ML10      bos.adt.libm 4.3.3.50
	AIX 5.1.0-ML04      bos.adt.libm 5.1.0.29
	AIX 5.2.0           bos.adt.libm 5.2.0.85

    So, until IBM fixes powl(), we provide the following workaround to
    handle the problem ourselves.  Our logic is as follows: for
    negative bases (left), we use fmod(right, 2) to check if the
    exponent is an odd or even integer:

	- if odd,  powl(left, right) == -powl(-left, right)
	- if even, powl(left, right) ==  powl(-left, right)

    If the exponent is not an integer, the result is rightly NaNQ, so
    we just return that (as NV_NAN).
    */

	if (left < 0.0) {
	    NV mod2 = Perl_fmod( right, 2.0 );
	    if (mod2 == 1.0 || mod2 == -1.0) {	/* odd integer */
		SETn( -Perl_pow( -left, right) );
	    } else if (mod2 == 0.0) {		/* even integer */
		SETn( Perl_pow( -left, right) );
	    } else {				/* fractional power */
		SETn( NV_NAN );
	    }
	} else {
	    SETn( Perl_pow( left, right) );
	}
#else
	SETn( Perl_pow( left, right) );
#endif  /* HAS_AIX_POWL_NEG_BASE_BUG */

#ifdef PERL_PRESERVE_IVUV
	if (is_int)
	    SvIV_please_nomg(svr);
#endif
	RETURN;
    }
}

PP(pp_multiply)
{
    dVAR; dSP; dATARGET; SV *svl, *svr;
    tryAMAGICbin_MG(mult_amg, AMGf_assign|AMGf_numeric);
    svr = TOPs;
    svl = TOPm1s;
#ifdef PERL_PRESERVE_IVUV
    if (SvIV_please_nomg(svr)) {
	/* Unless the left argument is integer in range we are going to have to
	   use NV maths. Hence only attempt to coerce the right argument if
	   we know the left is integer.  */
	/* Left operand is defined, so is it IV? */
	if (SvIV_please_nomg(svl)) {
	    bool auvok = SvUOK(svl);
	    bool buvok = SvUOK(svr);
	    const UV topmask = (~ (UV)0) << (4 * sizeof (UV));
	    const UV botmask = ~((~ (UV)0) << (4 * sizeof (UV)));
	    UV alow;
	    UV ahigh;
	    UV blow;
	    UV bhigh;

	    if (auvok) {
		alow = SvUVX(svl);
	    } else {
		const IV aiv = SvIVX(svl);
		if (aiv >= 0) {
		    alow = aiv;
		    auvok = TRUE; /* effectively it's a UV now */
		} else {
		    alow = -aiv; /* abs, auvok == false records sign */
		}
	    }
	    if (buvok) {
		blow = SvUVX(svr);
	    } else {
		const IV biv = SvIVX(svr);
		if (biv >= 0) {
		    blow = biv;
		    buvok = TRUE; /* effectively it's a UV now */
		} else {
		    blow = -biv; /* abs, buvok == false records sign */
		}
	    }

	    /* If this does sign extension on unsigned it's time for plan B  */
	    ahigh = alow >> (4 * sizeof (UV));
	    alow &= botmask;
	    bhigh = blow >> (4 * sizeof (UV));
	    blow &= botmask;
	    if (ahigh && bhigh) {
		NOOP;
		/* eg 32 bit is at least 0x10000 * 0x10000 == 0x100000000
		   which is overflow. Drop to NVs below.  */
	    } else if (!ahigh && !bhigh) {
		/* eg 32 bit is at most 0xFFFF * 0xFFFF == 0xFFFE0001
		   so the unsigned multiply cannot overflow.  */
		const UV product = alow * blow;
		if (auvok == buvok) {
		    /* -ve * -ve or +ve * +ve gives a +ve result.  */
		    SP--;
		    SETu( product );
		    RETURN;
		} else if (product <= (UV)IV_MIN) {
		    /* 2s complement assumption that (UV)-IV_MIN is correct.  */
		    /* -ve result, which could overflow an IV  */
		    SP--;
		    SETi( -(IV)product );
		    RETURN;
		} /* else drop to NVs below. */
	    } else {
		/* One operand is large, 1 small */
		UV product_middle;
		if (bhigh) {
		    /* swap the operands */
		    ahigh = bhigh;
		    bhigh = blow; /* bhigh now the temp var for the swap */
		    blow = alow;
		    alow = bhigh;
		}
		/* now, ((ahigh * blow) << half_UV_len) + (alow * blow)
		   multiplies can't overflow. shift can, add can, -ve can.  */
		product_middle = ahigh * blow;
		if (!(product_middle & topmask)) {
		    /* OK, (ahigh * blow) won't lose bits when we shift it.  */
		    UV product_low;
		    product_middle <<= (4 * sizeof (UV));
		    product_low = alow * blow;

		    /* as for pp_add, UV + something mustn't get smaller.
		       IIRC ANSI mandates this wrapping *behaviour* for
		       unsigned whatever the actual representation*/
		    product_low += product_middle;
		    if (product_low >= product_middle) {
			/* didn't overflow */
			if (auvok == buvok) {
			    /* -ve * -ve or +ve * +ve gives a +ve result.  */
			    SP--;
			    SETu( product_low );
			    RETURN;
			} else if (product_low <= (UV)IV_MIN) {
			    /* 2s complement assumption again  */
			    /* -ve result, which could overflow an IV  */
			    SP--;
			    SETi( -(IV)product_low );
			    RETURN;
			} /* else drop to NVs below. */
		    }
		} /* product_middle too large */
	    } /* ahigh && bhigh */
	} /* SvIOK(svl) */
    } /* SvIOK(svr) */
#endif
    {
      NV right = SvNV_nomg(svr);
      NV left  = SvNV_nomg(svl);
      (void)POPs;
      SETn( left * right );
      RETURN;
    }
}

PP(pp_divide)
{
    dVAR; dSP; dATARGET; SV *svl, *svr;
    tryAMAGICbin_MG(div_amg, AMGf_assign|AMGf_numeric);
    svr = TOPs;
    svl = TOPm1s;
    /* Only try to do UV divide first
       if ((SLOPPYDIVIDE is true) or
           (PERL_PRESERVE_IVUV is true and one or both SV is a UV too large
            to preserve))
       The assumption is that it is better to use floating point divide
       whenever possible, only doing integer divide first if we can't be sure.
       If NV_PRESERVES_UV is true then we know at compile time that no UV
       can be too large to preserve, so don't need to compile the code to
       test the size of UVs.  */

#ifdef SLOPPYDIVIDE
#  define PERL_TRY_UV_DIVIDE
    /* ensure that 20./5. == 4. */
#else
#  ifdef PERL_PRESERVE_IVUV
#    ifndef NV_PRESERVES_UV
#      define PERL_TRY_UV_DIVIDE
#    endif
#  endif
#endif

#ifdef PERL_TRY_UV_DIVIDE
    if (SvIV_please_nomg(svr) && SvIV_please_nomg(svl)) {
            bool left_non_neg = SvUOK(svl);
            bool right_non_neg = SvUOK(svr);
            UV left;
            UV right;

            if (right_non_neg) {
                right = SvUVX(svr);
            }
	    else {
		const IV biv = SvIVX(svr);
                if (biv >= 0) {
                    right = biv;
                    right_non_neg = TRUE; /* effectively it's a UV now */
                }
		else {
                    right = -biv;
                }
            }
            /* historically undef()/0 gives a "Use of uninitialized value"
               warning before dieing, hence this test goes here.
               If it were immediately before the second SvIV_please, then
               DIE() would be invoked before left was even inspected, so
               no inspection would give no warning.  */
            if (right == 0)
                DIE(aTHX_ "Illegal division by zero");

            if (left_non_neg) {
                left = SvUVX(svl);
            }
	    else {
		const IV aiv = SvIVX(svl);
                if (aiv >= 0) {
                    left = aiv;
                    left_non_neg = TRUE; /* effectively it's a UV now */
                }
		else {
                    left = -aiv;
                }
            }

            if (left >= right
#ifdef SLOPPYDIVIDE
                /* For sloppy divide we always attempt integer division.  */
#else
                /* Otherwise we only attempt it if either or both operands
                   would not be preserved by an NV.  If both fit in NVs
                   we fall through to the NV divide code below.  However,
                   as left >= right to ensure integer result here, we know that
                   we can skip the test on the right operand - right big
                   enough not to be preserved can't get here unless left is
                   also too big.  */

                && (left > ((UV)1 << NV_PRESERVES_UV_BITS))
#endif
                ) {
                /* Integer division can't overflow, but it can be imprecise.  */
		const UV result = left / right;
                if (result * right == left) {
                    SP--; /* result is valid */
                    if (left_non_neg == right_non_neg) {
                        /* signs identical, result is positive.  */
                        SETu( result );
                        RETURN;
                    }
                    /* 2s complement assumption */
                    if (result <= (UV)IV_MIN)
                        SETi( -(IV)result );
                    else {
                        /* It's exact but too negative for IV. */
                        SETn( -(NV)result );
                    }
                    RETURN;
                } /* tried integer divide but it was not an integer result */
            } /* else (PERL_ABS(result) < 1.0) or (both UVs in range for NV) */
    } /* one operand wasn't SvIOK */
#endif /* PERL_TRY_UV_DIVIDE */
    {
	NV right = SvNV_nomg(svr);
	NV left  = SvNV_nomg(svl);
	(void)POPs;(void)POPs;
#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
	if (! Perl_isnan(right) && right == 0.0)
#else
	if (right == 0.0)
#endif
	    DIE(aTHX_ "Illegal division by zero");
	PUSHn( left / right );
	RETURN;
    }
}

PP(pp_modulo)
{
    dVAR; dSP; dATARGET;
    tryAMAGICbin_MG(modulo_amg, AMGf_assign|AMGf_numeric);
    {
	UV left  = 0;
	UV right = 0;
	bool left_neg = FALSE;
	bool right_neg = FALSE;
	bool use_double = FALSE;
	bool dright_valid = FALSE;
	NV dright = 0.0;
	NV dleft  = 0.0;
	SV * const svr = TOPs;
	SV * const svl = TOPm1s;
        if (SvIV_please_nomg(svr)) {
            right_neg = !SvUOK(svr);
            if (!right_neg) {
                right = SvUVX(svr);
            } else {
		const IV biv = SvIVX(svr);
                if (biv >= 0) {
                    right = biv;
                    right_neg = FALSE; /* effectively it's a UV now */
                } else {
                    right = -biv;
                }
            }
        }
        else {
	    dright = SvNV_nomg(svr);
	    right_neg = dright < 0;
	    if (right_neg)
		dright = -dright;
            if (dright < UV_MAX_P1) {
                right = U_V(dright);
                dright_valid = TRUE; /* In case we need to use double below.  */
            } else {
                use_double = TRUE;
            }
	}

        /* At this point use_double is only true if right is out of range for
           a UV.  In range NV has been rounded down to nearest UV and
           use_double false.  */
	if (!use_double && SvIV_please_nomg(svl)) {
                left_neg = !SvUOK(svl);
                if (!left_neg) {
                    left = SvUVX(svl);
                } else {
		    const IV aiv = SvIVX(svl);
                    if (aiv >= 0) {
                        left = aiv;
                        left_neg = FALSE; /* effectively it's a UV now */
                    } else {
                        left = -aiv;
                    }
                }
        }
	else {
	    dleft = SvNV_nomg(svl);
	    left_neg = dleft < 0;
	    if (left_neg)
		dleft = -dleft;

            /* This should be exactly the 5.6 behaviour - if left and right are
               both in range for UV then use U_V() rather than floor.  */
	    if (!use_double) {
                if (dleft < UV_MAX_P1) {
                    /* right was in range, so is dleft, so use UVs not double.
                     */
                    left = U_V(dleft);
                }
                /* left is out of range for UV, right was in range, so promote
                   right (back) to double.  */
                else {
                    /* The +0.5 is used in 5.6 even though it is not strictly
                       consistent with the implicit +0 floor in the U_V()
                       inside the #if 1. */
                    dleft = Perl_floor(dleft + 0.5);
                    use_double = TRUE;
                    if (dright_valid)
                        dright = Perl_floor(dright + 0.5);
                    else
                        dright = right;
                }
            }
        }
	sp -= 2;
	if (use_double) {
	    NV dans;

	    if (!dright)
		DIE(aTHX_ "Illegal modulus zero");

	    dans = Perl_fmod(dleft, dright);
	    if ((left_neg != right_neg) && dans)
		dans = dright - dans;
	    if (right_neg)
		dans = -dans;
	    sv_setnv(TARG, dans);
	}
	else {
	    UV ans;

	    if (!right)
		DIE(aTHX_ "Illegal modulus zero");

	    ans = left % right;
	    if ((left_neg != right_neg) && ans)
		ans = right - ans;
	    if (right_neg) {
		/* XXX may warn: unary minus operator applied to unsigned type */
		/* could change -foo to be (~foo)+1 instead	*/
		if (ans <= ~((UV)IV_MAX)+1)
		    sv_setiv(TARG, ~ans+1);
		else
		    sv_setnv(TARG, -(NV)ans);
	    }
	    else
		sv_setuv(TARG, ans);
	}
	PUSHTARG;
	RETURN;
    }
}

PP(pp_repeat)
{
    dVAR; dSP; dATARGET;
    register IV count;
    SV *sv;

    if (GIMME == G_ARRAY && PL_op->op_private & OPpREPEAT_DOLIST) {
	/* TODO: think of some way of doing list-repeat overloading ??? */
	sv = POPs;
	SvGETMAGIC(sv);
    }
    else {
	tryAMAGICbin_MG(repeat_amg, AMGf_assign);
	sv = POPs;
    }

    if (SvIOKp(sv)) {
	 if (SvUOK(sv)) {
	      const UV uv = SvUV_nomg(sv);
	      if (uv > IV_MAX)
		   count = IV_MAX; /* The best we can do? */
	      else
		   count = uv;
	 } else {
	      const IV iv = SvIV_nomg(sv);
	      if (iv < 0)
		   count = 0;
	      else
		   count = iv;
	 }
    }
    else if (SvNOKp(sv)) {
	 const NV nv = SvNV_nomg(sv);
	 if (nv < 0.0)
	      count = 0;
	 else
	      count = (IV)nv;
    }
    else
	 count = SvIV_nomg(sv);

    if (GIMME == G_ARRAY && PL_op->op_private & OPpREPEAT_DOLIST) {
	dMARK;
	static const char oom_list_extend[] = "Out of memory during list extend";
	const I32 items = SP - MARK;
	const I32 max = items * count;

	MEM_WRAP_CHECK_1(max, SV*, oom_list_extend);
	/* Did the max computation overflow? */
	if (items > 0 && max > 0 && (max < items || max < count))
	   Perl_croak(aTHX_ oom_list_extend);
	MEXTEND(MARK, max);
	if (count > 1) {
	    while (SP > MARK) {
#if 0
	      /* This code was intended to fix 20010809.028:

	         $x = 'abcd';
		 for (($x =~ /./g) x 2) {
		     print chop; # "abcdabcd" expected as output.
		 }

	       * but that change (#11635) broke this code:

	       $x = [("foo")x2]; # only one "foo" ended up in the anonlist.

	       * I can't think of a better fix that doesn't introduce
	       * an efficiency hit by copying the SVs. The stack isn't
	       * refcounted, and mortalisation obviously doesn't
	       * Do The Right Thing when the stack has more than
	       * one pointer to the same mortal value.
	       * .robin.
	       */
		if (*SP) {
		    *SP = sv_2mortal(newSVsv(*SP));
		    SvREADONLY_on(*SP);
		}
#else
               if (*SP)
		   SvTEMP_off((*SP));
#endif
		SP--;
	    }
	    MARK++;
	    repeatcpy((char*)(MARK + items), (char*)MARK,
		items * sizeof(const SV *), count - 1);
	    SP += max;
	}
	else if (count <= 0)
	    SP -= items;
    }
    else {	/* Note: mark already snarfed by pp_list */
	SV * const tmpstr = POPs;
	STRLEN len;
	bool isutf;
	static const char oom_string_extend[] =
	  "Out of memory during string extend";

	if (TARG != tmpstr)
	    sv_setsv_nomg(TARG, tmpstr);
	SvPV_force_nomg(TARG, len);
	isutf = DO_UTF8(TARG);
	if (count != 1) {
	    if (count < 1)
		SvCUR_set(TARG, 0);
	    else {
		const STRLEN max = (UV)count * len;
		if (len > MEM_SIZE_MAX / count)
		     Perl_croak(aTHX_ oom_string_extend);
	        MEM_WRAP_CHECK_1(max, char, oom_string_extend);
		SvGROW(TARG, max + 1);
		repeatcpy(SvPVX(TARG) + len, SvPVX(TARG), len, count - 1);
		SvCUR_set(TARG, SvCUR(TARG) * count);
	    }
	    *SvEND(TARG) = '\0';
	}
	if (isutf)
	    (void)SvPOK_only_UTF8(TARG);
	else
	    (void)SvPOK_only(TARG);

	if (PL_op->op_private & OPpREPEAT_DOLIST) {
	    /* The parser saw this as a list repeat, and there
	       are probably several items on the stack. But we're
	       in scalar context, and there's no pp_list to save us
	       now. So drop the rest of the items -- robin@kitsite.com
	     */
	    dMARK;
	    SP = MARK;
	}
	PUSHTARG;
    }
    RETURN;
}

PP(pp_subtract)
{
    dVAR; dSP; dATARGET; bool useleft; SV *svl, *svr;
    tryAMAGICbin_MG(subtr_amg, AMGf_assign|AMGf_numeric);
    svr = TOPs;
    svl = TOPm1s;
    useleft = USE_LEFT(svl);
#ifdef PERL_PRESERVE_IVUV
    /* See comments in pp_add (in pp_hot.c) about Overflow, and how
       "bad things" happen if you rely on signed integers wrapping.  */
    if (SvIV_please_nomg(svr)) {
	/* Unless the left argument is integer in range we are going to have to
	   use NV maths. Hence only attempt to coerce the right argument if
	   we know the left is integer.  */
	register UV auv = 0;
	bool auvok = FALSE;
	bool a_valid = 0;

	if (!useleft) {
	    auv = 0;
	    a_valid = auvok = 1;
	    /* left operand is undef, treat as zero.  */
	} else {
	    /* Left operand is defined, so is it IV? */
	    if (SvIV_please_nomg(svl)) {
		if ((auvok = SvUOK(svl)))
		    auv = SvUVX(svl);
		else {
		    register const IV aiv = SvIVX(svl);
		    if (aiv >= 0) {
			auv = aiv;
			auvok = 1;	/* Now acting as a sign flag.  */
		    } else { /* 2s complement assumption for IV_MIN */
			auv = (UV)-aiv;
		    }
		}
		a_valid = 1;
	    }
	}
	if (a_valid) {
	    bool result_good = 0;
	    UV result;
	    register UV buv;
	    bool buvok = SvUOK(svr);
	
	    if (buvok)
		buv = SvUVX(svr);
	    else {
		register const IV biv = SvIVX(svr);
		if (biv >= 0) {
		    buv = biv;
		    buvok = 1;
		} else
		    buv = (UV)-biv;
	    }
	    /* ?uvok if value is >= 0. basically, flagged as UV if it's +ve,
	       else "IV" now, independent of how it came in.
	       if a, b represents positive, A, B negative, a maps to -A etc
	       a - b =>  (a - b)
	       A - b => -(a + b)
	       a - B =>  (a + b)
	       A - B => -(a - b)
	       all UV maths. negate result if A negative.
	       subtract if signs same, add if signs differ. */

	    if (auvok ^ buvok) {
		/* Signs differ.  */
		result = auv + buv;
		if (result >= auv)
		    result_good = 1;
	    } else {
		/* Signs same */
		if (auv >= buv) {
		    result = auv - buv;
		    /* Must get smaller */
		    if (result <= auv)
			result_good = 1;
		} else {
		    result = buv - auv;
		    if (result <= buv) {
			/* result really should be -(auv-buv). as its negation
			   of true value, need to swap our result flag  */
			auvok = !auvok;
			result_good = 1;
		    }
		}
	    }
	    if (result_good) {
		SP--;
		if (auvok)
		    SETu( result );
		else {
		    /* Negate result */
		    if (result <= (UV)IV_MIN)
			SETi( -(IV)result );
		    else {
			/* result valid, but out of range for IV.  */
			SETn( -(NV)result );
		    }
		}
		RETURN;
	    } /* Overflow, drop through to NVs.  */
	}
    }
#endif
    {
	NV value = SvNV_nomg(svr);
	(void)POPs;

	if (!useleft) {
	    /* left operand is undef, treat as zero - value */
	    SETn(-value);
	    RETURN;
	}
	SETn( SvNV_nomg(svl) - value );
	RETURN;
    }
}

PP(pp_left_shift)
{
    dVAR; dSP; dATARGET; SV *svl, *svr;
    tryAMAGICbin_MG(lshift_amg, AMGf_assign|AMGf_numeric);
    svr = POPs;
    svl = TOPs;
    {
      const IV shift = SvIV_nomg(svr);
      if (PL_op->op_private & HINT_INTEGER) {
	const IV i = SvIV_nomg(svl);
	SETi(i << shift);
      }
      else {
	const UV u = SvUV_nomg(svl);
	SETu(u << shift);
      }
      RETURN;
    }
}

PP(pp_right_shift)
{
    dVAR; dSP; dATARGET; SV *svl, *svr;
    tryAMAGICbin_MG(rshift_amg, AMGf_assign|AMGf_numeric);
    svr = POPs;
    svl = TOPs;
    {
      const IV shift = SvIV_nomg(svr);
      if (PL_op->op_private & HINT_INTEGER) {
	const IV i = SvIV_nomg(svl);
	SETi(i >> shift);
      }
      else {
	const UV u = SvUV_nomg(svl);
	SETu(u >> shift);
      }
      RETURN;
    }
}

PP(pp_lt)
{
    dVAR; dSP;
    SV *left, *right;

    tryAMAGICbin_MG(lt_amg, AMGf_set|AMGf_numeric);
    right = POPs;
    left  = TOPs;
    SETs(boolSV(
	(SvIOK_notUV(left) && SvIOK_notUV(right))
	? (SvIVX(left) < SvIVX(right))
	: (do_ncmp(left, right) == -1)
    ));
    RETURN;
}

PP(pp_gt)
{
    dVAR; dSP;
    SV *left, *right;

    tryAMAGICbin_MG(gt_amg, AMGf_set|AMGf_numeric);
    right = POPs;
    left  = TOPs;
    SETs(boolSV(
	(SvIOK_notUV(left) && SvIOK_notUV(right))
	? (SvIVX(left) > SvIVX(right))
	: (do_ncmp(left, right) == 1)
    ));
    RETURN;
}

PP(pp_le)
{
    dVAR; dSP;
    SV *left, *right;

    tryAMAGICbin_MG(le_amg, AMGf_set|AMGf_numeric);
    right = POPs;
    left  = TOPs;
    SETs(boolSV(
	(SvIOK_notUV(left) && SvIOK_notUV(right))
	? (SvIVX(left) <= SvIVX(right))
	: (do_ncmp(left, right) <= 0)
    ));
    RETURN;
}

PP(pp_ge)
{
    dVAR; dSP;
    SV *left, *right;

    tryAMAGICbin_MG(ge_amg, AMGf_set|AMGf_numeric);
    right = POPs;
    left  = TOPs;
    SETs(boolSV(
	(SvIOK_notUV(left) && SvIOK_notUV(right))
	? (SvIVX(left) >= SvIVX(right))
	: ( (do_ncmp(left, right) & 2) == 0)
    ));
    RETURN;
}

PP(pp_ne)
{
    dVAR; dSP;
    SV *left, *right;

    tryAMAGICbin_MG(ne_amg, AMGf_set|AMGf_numeric);
    right = POPs;
    left  = TOPs;
    SETs(boolSV(
	(SvIOK_notUV(left) && SvIOK_notUV(right))
	? (SvIVX(left) != SvIVX(right))
	: (do_ncmp(left, right) != 0)
    ));
    RETURN;
}

/* compare left and right SVs. Returns:
 * -1: <
 *  0: ==
 *  1: >
 *  2: left or right was a NaN
 */
I32
Perl_do_ncmp(pTHX_ SV* const left, SV * const right)
{
    dVAR;

    PERL_ARGS_ASSERT_DO_NCMP;
#ifdef PERL_PRESERVE_IVUV
    /* Fortunately it seems NaN isn't IOK */
    if (SvIV_please_nomg(right) && SvIV_please_nomg(left)) {
	    if (!SvUOK(left)) {
		const IV leftiv = SvIVX(left);
		if (!SvUOK(right)) {
		    /* ## IV <=> IV ## */
		    const IV rightiv = SvIVX(right);
		    return (leftiv > rightiv) - (leftiv < rightiv);
		}
		/* ## IV <=> UV ## */
		if (leftiv < 0)
		    /* As (b) is a UV, it's >=0, so it must be < */
		    return -1;
		{
		    const UV rightuv = SvUVX(right);
		    return ((UV)leftiv > rightuv) - ((UV)leftiv < rightuv);
		}
	    }

	    if (SvUOK(right)) {
		/* ## UV <=> UV ## */
		const UV leftuv = SvUVX(left);
		const UV rightuv = SvUVX(right);
		return (leftuv > rightuv) - (leftuv < rightuv);
	    }
	    /* ## UV <=> IV ## */
	    {
		const IV rightiv = SvIVX(right);
		if (rightiv < 0)
		    /* As (a) is a UV, it's >=0, so it cannot be < */
		    return 1;
		{
		    const UV leftuv = SvUVX(left);
		    return (leftuv > (UV)rightiv) - (leftuv < (UV)rightiv);
		}
	    }
	    assert(0); /* NOTREACHED */
    }
#endif
    {
      NV const rnv = SvNV_nomg(right);
      NV const lnv = SvNV_nomg(left);

#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
      if (Perl_isnan(lnv) || Perl_isnan(rnv)) {
	  return 2;
       }
      return (lnv > rnv) - (lnv < rnv);
#else
      if (lnv < rnv)
	return -1;
      if (lnv > rnv)
	return 1;
      if (lnv == rnv)
	return 0;
      return 2;
#endif
    }
}


PP(pp_ncmp)
{
    dVAR; dSP;
    SV *left, *right;
    I32 value;
    tryAMAGICbin_MG(ncmp_amg, AMGf_numeric);
    right = POPs;
    left  = TOPs;
    value = do_ncmp(left, right);
    if (value == 2) {
	SETs(&PL_sv_undef);
    }
    else {
	dTARGET;
	SETi(value);
    }
    RETURN;
}

PP(pp_sle)
{
    dVAR; dSP;

    int amg_type = sle_amg;
    int multiplier = 1;
    int rhs = 1;

    switch (PL_op->op_type) {
    case OP_SLT:
	amg_type = slt_amg;
	/* cmp < 0 */
	rhs = 0;
	break;
    case OP_SGT:
	amg_type = sgt_amg;
	/* cmp > 0 */
	multiplier = -1;
	rhs = 0;
	break;
    case OP_SGE:
	amg_type = sge_amg;
	/* cmp >= 0 */
	multiplier = -1;
	break;
    }

    tryAMAGICbin_MG(amg_type, AMGf_set);
    {
      dPOPTOPssrl;
      const int cmp = (IN_LOCALE_RUNTIME
		 ? sv_cmp_locale_flags(left, right, 0)
		 : sv_cmp_flags(left, right, 0));
      SETs(boolSV(cmp * multiplier < rhs));
      RETURN;
    }
}

PP(pp_seq)
{
    dVAR; dSP;
    tryAMAGICbin_MG(seq_amg, AMGf_set);
    {
      dPOPTOPssrl;
      SETs(boolSV(sv_eq_flags(left, right, 0)));
      RETURN;
    }
}

PP(pp_sne)
{
    dVAR; dSP;
    tryAMAGICbin_MG(sne_amg, AMGf_set);
    {
      dPOPTOPssrl;
      SETs(boolSV(!sv_eq_flags(left, right, 0)));
      RETURN;
    }
}

PP(pp_scmp)
{
    dVAR; dSP; dTARGET;
    tryAMAGICbin_MG(scmp_amg, 0);
    {
      dPOPTOPssrl;
      const int cmp = (IN_LOCALE_RUNTIME
		 ? sv_cmp_locale_flags(left, right, 0)
		 : sv_cmp_flags(left, right, 0));
      SETi( cmp );
      RETURN;
    }
}

PP(pp_bit_and)
{
    dVAR; dSP; dATARGET;
    tryAMAGICbin_MG(band_amg, AMGf_assign);
    {
      dPOPTOPssrl;
      if (SvNIOKp(left) || SvNIOKp(right)) {
	const bool left_ro_nonnum  = !SvNIOKp(left) && SvREADONLY(left);
	const bool right_ro_nonnum = !SvNIOKp(right) && SvREADONLY(right);
	if (PL_op->op_private & HINT_INTEGER) {
	  const IV i = SvIV_nomg(left) & SvIV_nomg(right);
	  SETi(i);
	}
	else {
	  const UV u = SvUV_nomg(left) & SvUV_nomg(right);
	  SETu(u);
	}
	if (left_ro_nonnum && left != TARG) SvNIOK_off(left);
	if (right_ro_nonnum) SvNIOK_off(right);
      }
      else {
	do_vop(PL_op->op_type, TARG, left, right);
	SETTARG;
      }
      RETURN;
    }
}

PP(pp_bit_or)
{
    dVAR; dSP; dATARGET;
    const int op_type = PL_op->op_type;

    tryAMAGICbin_MG((op_type == OP_BIT_OR ? bor_amg : bxor_amg), AMGf_assign);
    {
      dPOPTOPssrl;
      if (SvNIOKp(left) || SvNIOKp(right)) {
	const bool left_ro_nonnum  = !SvNIOKp(left) && SvREADONLY(left);
	const bool right_ro_nonnum = !SvNIOKp(right) && SvREADONLY(right);
	if (PL_op->op_private & HINT_INTEGER) {
	  const IV l = (USE_LEFT(left) ? SvIV_nomg(left) : 0);
	  const IV r = SvIV_nomg(right);
	  const IV result = op_type == OP_BIT_OR ? (l | r) : (l ^ r);
	  SETi(result);
	}
	else {
	  const UV l = (USE_LEFT(left) ? SvUV_nomg(left) : 0);
	  const UV r = SvUV_nomg(right);
	  const UV result = op_type == OP_BIT_OR ? (l | r) : (l ^ r);
	  SETu(result);
	}
	if (left_ro_nonnum && left != TARG) SvNIOK_off(left);
	if (right_ro_nonnum) SvNIOK_off(right);
      }
      else {
	do_vop(op_type, TARG, left, right);
	SETTARG;
      }
      RETURN;
    }
}

PP(pp_negate)
{
    dVAR; dSP; dTARGET;
    tryAMAGICun_MG(neg_amg, AMGf_numeric);
    {
	SV * const sv = TOPs;

	if (SvIOK(sv) || (SvGMAGICAL(sv) && SvIOKp(sv))) {
	    /* It's publicly an integer */
	oops_its_an_int:
	    if (SvIsUV(sv)) {
		if (SvIVX(sv) == IV_MIN) {
		    /* 2s complement assumption. */
		    SETi(SvIVX(sv));	/* special case: -((UV)IV_MAX+1) == IV_MIN */
		    RETURN;
		}
		else if (SvUVX(sv) <= IV_MAX) {
		    SETi(-SvIVX(sv));
		    RETURN;
		}
	    }
	    else if (SvIVX(sv) != IV_MIN) {
		SETi(-SvIVX(sv));
		RETURN;
	    }
#ifdef PERL_PRESERVE_IVUV
	    else {
		SETu((UV)IV_MIN);
		RETURN;
	    }
#endif
	}
	if (SvNIOKp(sv) && (SvNIOK(sv) || !SvPOK(sv)))
	    SETn(-SvNV_nomg(sv));
	else if (SvPOKp(sv)) {
	    STRLEN len;
	    const char * const s = SvPV_nomg_const(sv, len);
	    if (isIDFIRST(*s)) {
		sv_setpvs(TARG, "-");
		sv_catsv(TARG, sv);
	    }
	    else if (*s == '+' || (*s == '-' && !looks_like_number(sv))) {
		sv_setsv_nomg(TARG, sv);
		*SvPV_force_nomg(TARG, len) = *s == '-' ? '+' : '-';
	    }
	    else if (SvIV_please_nomg(sv))
		  goto oops_its_an_int;
	    else
		sv_setnv(TARG, -SvNV_nomg(sv));
	    SETTARG;
	}
	else
	    SETn(-SvNV_nomg(sv));
    }
    RETURN;
}

PP(pp_not)
{
    dVAR; dSP;
    tryAMAGICun_MG(not_amg, AMGf_set);
    *PL_stack_sp = boolSV(!SvTRUE_nomg(*PL_stack_sp));
    return NORMAL;
}

PP(pp_complement)
{
    dVAR; dSP; dTARGET;
    tryAMAGICun_MG(compl_amg, AMGf_numeric);
    {
      dTOPss;
      if (SvNIOKp(sv)) {
	if (PL_op->op_private & HINT_INTEGER) {
	  const IV i = ~SvIV_nomg(sv);
	  SETi(i);
	}
	else {
	  const UV u = ~SvUV_nomg(sv);
	  SETu(u);
	}
      }
      else {
	register U8 *tmps;
	register I32 anum;
	STRLEN len;

	(void)SvPV_nomg_const(sv,len); /* force check for uninit var */
	sv_setsv_nomg(TARG, sv);
	tmps = (U8*)SvPV_force_nomg(TARG, len);
	anum = len;
	if (SvUTF8(TARG)) {
	  /* Calculate exact length, let's not estimate. */
	  STRLEN targlen = 0;
	  STRLEN l;
	  UV nchar = 0;
	  UV nwide = 0;
	  U8 * const send = tmps + len;
	  U8 * const origtmps = tmps;
	  const UV utf8flags = UTF8_ALLOW_ANYUV;

	  while (tmps < send) {
	    const UV c = utf8n_to_uvchr(tmps, send-tmps, &l, utf8flags);
	    tmps += l;
	    targlen += UNISKIP(~c);
	    nchar++;
	    if (c > 0xff)
		nwide++;
	  }

	  /* Now rewind strings and write them. */
	  tmps = origtmps;

	  if (nwide) {
	      U8 *result;
	      U8 *p;

	      Newx(result, targlen + 1, U8);
	      p = result;
	      while (tmps < send) {
		  const UV c = utf8n_to_uvchr(tmps, send-tmps, &l, utf8flags);
		  tmps += l;
		  p = uvchr_to_utf8_flags(p, ~c, UNICODE_ALLOW_ANY);
	      }
	      *p = '\0';
	      sv_usepvn_flags(TARG, (char*)result, targlen,
			      SV_HAS_TRAILING_NUL);
	      SvUTF8_on(TARG);
	  }
	  else {
	      U8 *result;
	      U8 *p;

	      Newx(result, nchar + 1, U8);
	      p = result;
	      while (tmps < send) {
		  const U8 c = (U8)utf8n_to_uvchr(tmps, send-tmps, &l, utf8flags);
		  tmps += l;
		  *p++ = ~c;
	      }
	      *p = '\0';
	      sv_usepvn_flags(TARG, (char*)result, nchar, SV_HAS_TRAILING_NUL);
	      SvUTF8_off(TARG);
	  }
	  SETTARG;
	  RETURN;
	}
#ifdef LIBERAL
	{
	    register long *tmpl;
	    for ( ; anum && (unsigned long)tmps % sizeof(long); anum--, tmps++)
		*tmps = ~*tmps;
	    tmpl = (long*)tmps;
	    for ( ; anum >= (I32)sizeof(long); anum -= (I32)sizeof(long), tmpl++)
		*tmpl = ~*tmpl;
	    tmps = (U8*)tmpl;
	}
#endif
	for ( ; anum > 0; anum--, tmps++)
	    *tmps = ~*tmps;
	SETTARG;
      }
      RETURN;
    }
}

/* integer versions of some of the above */

PP(pp_i_multiply)
{
    dVAR; dSP; dATARGET;
    tryAMAGICbin_MG(mult_amg, AMGf_assign);
    {
      dPOPTOPiirl_nomg;
      SETi( left * right );
      RETURN;
    }
}

PP(pp_i_divide)
{
    IV num;
    dVAR; dSP; dATARGET;
    tryAMAGICbin_MG(div_amg, AMGf_assign);
    {
      dPOPTOPssrl;
      IV value = SvIV_nomg(right);
      if (value == 0)
	  DIE(aTHX_ "Illegal division by zero");
      num = SvIV_nomg(left);

      /* avoid FPE_INTOVF on some platforms when num is IV_MIN */
      if (value == -1)
          value = - num;
      else
          value = num / value;
      SETi(value);
      RETURN;
    }
}

#if defined(__GLIBC__) && IVSIZE == 8
STATIC
PP(pp_i_modulo_0)
#else
PP(pp_i_modulo)
#endif
{
     /* This is the vanilla old i_modulo. */
     dVAR; dSP; dATARGET;
     tryAMAGICbin_MG(modulo_amg, AMGf_assign);
     {
	  dPOPTOPiirl_nomg;
	  if (!right)
	       DIE(aTHX_ "Illegal modulus zero");
	  /* avoid FPE_INTOVF on some platforms when left is IV_MIN */
	  if (right == -1)
	      SETi( 0 );
	  else
	      SETi( left % right );
	  RETURN;
     }
}

#if defined(__GLIBC__) && IVSIZE == 8
STATIC
PP(pp_i_modulo_1)

{
     /* This is the i_modulo with the workaround for the _moddi3 bug
      * in (at least) glibc 2.2.5 (the PERL_ABS() the workaround).
      * See below for pp_i_modulo. */
     dVAR; dSP; dATARGET;
     tryAMAGICbin_MG(modulo_amg, AMGf_assign);
     {
	  dPOPTOPiirl_nomg;
	  if (!right)
	       DIE(aTHX_ "Illegal modulus zero");
	  /* avoid FPE_INTOVF on some platforms when left is IV_MIN */
	  if (right == -1)
	      SETi( 0 );
	  else
	      SETi( left % PERL_ABS(right) );
	  RETURN;
     }
}

PP(pp_i_modulo)
{
     dVAR; dSP; dATARGET;
     tryAMAGICbin_MG(modulo_amg, AMGf_assign);
     {
	  dPOPTOPiirl_nomg;
	  if (!right)
	       DIE(aTHX_ "Illegal modulus zero");
	  /* The assumption is to use hereafter the old vanilla version... */
	  PL_op->op_ppaddr =
	       PL_ppaddr[OP_I_MODULO] =
	           Perl_pp_i_modulo_0;
	  /* .. but if we have glibc, we might have a buggy _moddi3
	   * (at least glicb 2.2.5 is known to have this bug), in other
	   * words our integer modulus with negative quad as the second
	   * argument might be broken.  Test for this and re-patch the
	   * opcode dispatch table if that is the case, remembering to
	   * also apply the workaround so that this first round works
	   * right, too.  See [perl #9402] for more information. */
	  {
	       IV l =   3;
	       IV r = -10;
	       /* Cannot do this check with inlined IV constants since
		* that seems to work correctly even with the buggy glibc. */
	       if (l % r == -3) {
		    /* Yikes, we have the bug.
		     * Patch in the workaround version. */
		    PL_op->op_ppaddr =
			 PL_ppaddr[OP_I_MODULO] =
			     &Perl_pp_i_modulo_1;
		    /* Make certain we work right this time, too. */
		    right = PERL_ABS(right);
	       }
	  }
	  /* avoid FPE_INTOVF on some platforms when left is IV_MIN */
	  if (right == -1)
	      SETi( 0 );
	  else
	      SETi( left % right );
	  RETURN;
     }
}
#endif

PP(pp_i_add)
{
    dVAR; dSP; dATARGET;
    tryAMAGICbin_MG(add_amg, AMGf_assign);
    {
      dPOPTOPiirl_ul_nomg;
      SETi( left + right );
      RETURN;
    }
}

PP(pp_i_subtract)
{
    dVAR; dSP; dATARGET;
    tryAMAGICbin_MG(subtr_amg, AMGf_assign);
    {
      dPOPTOPiirl_ul_nomg;
      SETi( left - right );
      RETURN;
    }
}

PP(pp_i_lt)
{
    dVAR; dSP;
    tryAMAGICbin_MG(lt_amg, AMGf_set);
    {
      dPOPTOPiirl_nomg;
      SETs(boolSV(left < right));
      RETURN;
    }
}

PP(pp_i_gt)
{
    dVAR; dSP;
    tryAMAGICbin_MG(gt_amg, AMGf_set);
    {
      dPOPTOPiirl_nomg;
      SETs(boolSV(left > right));
      RETURN;
    }
}

PP(pp_i_le)
{
    dVAR; dSP;
    tryAMAGICbin_MG(le_amg, AMGf_set);
    {
      dPOPTOPiirl_nomg;
      SETs(boolSV(left <= right));
      RETURN;
    }
}

PP(pp_i_ge)
{
    dVAR; dSP;
    tryAMAGICbin_MG(ge_amg, AMGf_set);
    {
      dPOPTOPiirl_nomg;
      SETs(boolSV(left >= right));
      RETURN;
    }
}

PP(pp_i_eq)
{
    dVAR; dSP;
    tryAMAGICbin_MG(eq_amg, AMGf_set);
    {
      dPOPTOPiirl_nomg;
      SETs(boolSV(left == right));
      RETURN;
    }
}

PP(pp_i_ne)
{
    dVAR; dSP;
    tryAMAGICbin_MG(ne_amg, AMGf_set);
    {
      dPOPTOPiirl_nomg;
      SETs(boolSV(left != right));
      RETURN;
    }
}

PP(pp_i_ncmp)
{
    dVAR; dSP; dTARGET;
    tryAMAGICbin_MG(ncmp_amg, 0);
    {
      dPOPTOPiirl_nomg;
      I32 value;

      if (left > right)
	value = 1;
      else if (left < right)
	value = -1;
      else
	value = 0;
      SETi(value);
      RETURN;
    }
}

PP(pp_i_negate)
{
    dVAR; dSP; dTARGET;
    tryAMAGICun_MG(neg_amg, 0);
    {
	SV * const sv = TOPs;
	IV const i = SvIV_nomg(sv);
	SETi(-i);
	RETURN;
    }
}

/* High falutin' math. */

PP(pp_atan2)
{
    dVAR; dSP; dTARGET;
    tryAMAGICbin_MG(atan2_amg, 0);
    {
      dPOPTOPnnrl_nomg;
      SETn(Perl_atan2(left, right));
      RETURN;
    }
}

PP(pp_sin)
{
    dVAR; dSP; dTARGET;
    int amg_type = sin_amg;
    const char *neg_report = NULL;
    NV (*func)(NV) = Perl_sin;
    const int op_type = PL_op->op_type;

    switch (op_type) {
    case OP_COS:
	amg_type = cos_amg;
	func = Perl_cos;
	break;
    case OP_EXP:
	amg_type = exp_amg;
	func = Perl_exp;
	break;
    case OP_LOG:
	amg_type = log_amg;
	func = Perl_log;
	neg_report = "log";
	break;
    case OP_SQRT:
	amg_type = sqrt_amg;
	func = Perl_sqrt;
	neg_report = "sqrt";
	break;
    }


    tryAMAGICun_MG(amg_type, 0);
    {
      SV * const arg = POPs;
      const NV value = SvNV_nomg(arg);
      if (neg_report) {
	  if (op_type == OP_LOG ? (value <= 0.0) : (value < 0.0)) {
	      SET_NUMERIC_STANDARD();
	      /* diag_listed_as: Can't take log of %g */
	      DIE(aTHX_ "Can't take %s of %"NVgf, neg_report, value);
	  }
      }
      XPUSHn(func(value));
      RETURN;
    }
}

/* Support Configure command-line overrides for rand() functions.
   After 5.005, perhaps we should replace this by Configure support
   for drand48(), random(), or rand().  For 5.005, though, maintain
   compatibility by calling rand() but allow the user to override it.
   See INSTALL for details.  --Andy Dougherty  15 July 1998
*/
/* Now it's after 5.005, and Configure supports drand48() and random(),
   in addition to rand().  So the overrides should not be needed any more.
   --Jarkko Hietaniemi	27 September 1998
 */

#ifndef HAS_DRAND48_PROTO
extern double drand48 (void);
#endif

PP(pp_rand)
{
    dVAR; dSP; dTARGET;
    NV value;
    if (MAXARG < 1)
	value = 1.0;
    else if (!TOPs) {
	value = 1.0; (void)POPs;
    }
    else
	value = POPn;
    if (value == 0.0)
	value = 1.0;
    if (!PL_srand_called) {
	(void)seedDrand01((Rand_seed_t)seed());
	PL_srand_called = TRUE;
    }
    value *= Drand01();
    XPUSHn(value);
    RETURN;
}

PP(pp_srand)
{
    dVAR; dSP; dTARGET;
    UV anum;

    if (MAXARG >= 1 && (TOPs || POPs)) {
        SV *top;
        char *pv;
        STRLEN len;
        int flags;

        top = POPs;
        pv = SvPV(top, len);
        flags = grok_number(pv, len, &anum);

        if (!(flags & IS_NUMBER_IN_UV)) {
            Perl_ck_warner_d(aTHX_ packWARN(WARN_OVERFLOW),
                             "Integer overflow in srand");
            anum = UV_MAX;
        }
    }
    else {
        anum = seed();
    }

    (void)seedDrand01((Rand_seed_t)anum);
    PL_srand_called = TRUE;
    if (anum)
	XPUSHu(anum);
    else {
	/* Historically srand always returned true. We can avoid breaking
	   that like this:  */
	sv_setpvs(TARG, "0 but true");
	XPUSHTARG;
    }
    RETURN;
}

PP(pp_int)
{
    dVAR; dSP; dTARGET;
    tryAMAGICun_MG(int_amg, AMGf_numeric);
    {
      SV * const sv = TOPs;
      const IV iv = SvIV_nomg(sv);
      /* XXX it's arguable that compiler casting to IV might be subtly
	 different from modf (for numbers inside (IV_MIN,UV_MAX)) in which
	 else preferring IV has introduced a subtle behaviour change bug. OTOH
	 relying on floating point to be accurate is a bug.  */

      if (!SvOK(sv)) {
        SETu(0);
      }
      else if (SvIOK(sv)) {
	if (SvIsUV(sv))
	    SETu(SvUV_nomg(sv));
	else
	    SETi(iv);
      }
      else {
	  const NV value = SvNV_nomg(sv);
	  if (value >= 0.0) {
	      if (value < (NV)UV_MAX + 0.5) {
		  SETu(U_V(value));
	      } else {
		  SETn(Perl_floor(value));
	      }
	  }
	  else {
	      if (value > (NV)IV_MIN - 0.5) {
		  SETi(I_V(value));
	      } else {
		  SETn(Perl_ceil(value));
	      }
	  }
      }
    }
    RETURN;
}

PP(pp_abs)
{
    dVAR; dSP; dTARGET;
    tryAMAGICun_MG(abs_amg, AMGf_numeric);
    {
      SV * const sv = TOPs;
      /* This will cache the NV value if string isn't actually integer  */
      const IV iv = SvIV_nomg(sv);

      if (!SvOK(sv)) {
        SETu(0);
      }
      else if (SvIOK(sv)) {
	/* IVX is precise  */
	if (SvIsUV(sv)) {
	  SETu(SvUV_nomg(sv));	/* force it to be numeric only */
	} else {
	  if (iv >= 0) {
	    SETi(iv);
	  } else {
	    if (iv != IV_MIN) {
	      SETi(-iv);
	    } else {
	      /* 2s complement assumption. Also, not really needed as
		 IV_MIN and -IV_MIN should both be %100...00 and NV-able  */
	      SETu(IV_MIN);
	    }
	  }
	}
      } else{
	const NV value = SvNV_nomg(sv);
	if (value < 0.0)
	  SETn(-value);
	else
	  SETn(value);
      }
    }
    RETURN;
}

PP(pp_oct)
{
    dVAR; dSP; dTARGET;
    const char *tmps;
    I32 flags = PERL_SCAN_ALLOW_UNDERSCORES;
    STRLEN len;
    NV result_nv;
    UV result_uv;
    SV* const sv = POPs;

    tmps = (SvPV_const(sv, len));
    if (DO_UTF8(sv)) {
	 /* If Unicode, try to downgrade
	  * If not possible, croak. */
	 SV* const tsv = sv_2mortal(newSVsv(sv));
	
	 SvUTF8_on(tsv);
	 sv_utf8_downgrade(tsv, FALSE);
	 tmps = SvPV_const(tsv, len);
    }
    if (PL_op->op_type == OP_HEX)
	goto hex;

    while (*tmps && len && isSPACE(*tmps))
        tmps++, len--;
    if (*tmps == '0')
        tmps++, len--;
    if (*tmps == 'x' || *tmps == 'X') {
    hex:
        result_uv = grok_hex (tmps, &len, &flags, &result_nv);
    }
    else if (*tmps == 'b' || *tmps == 'B')
        result_uv = grok_bin (tmps, &len, &flags, &result_nv);
    else
        result_uv = grok_oct (tmps, &len, &flags, &result_nv);

    if (flags & PERL_SCAN_GREATER_THAN_UV_MAX) {
        XPUSHn(result_nv);
    }
    else {
        XPUSHu(result_uv);
    }
    RETURN;
}

/* String stuff. */

PP(pp_length)
{
    dVAR; dSP; dTARGET;
    SV * const sv = TOPs;

    if (SvGAMAGIC(sv)) {
	/* For an overloaded or magic scalar, we can't know in advance if
	   it's going to be UTF-8 or not. Also, we can't call sv_len_utf8 as
	   it likes to cache the length. Maybe that should be a documented
	   feature of it.
	*/
	STRLEN len;
	const char *const p
	    = sv_2pv_flags(sv, &len,
			   SV_UNDEF_RETURNS_NULL|SV_CONST_RETURN|SV_GMAGIC);

	if (!p) {
	    if (!SvPADTMP(TARG)) {
		sv_setsv(TARG, &PL_sv_undef);
		SETTARG;
	    }
	    SETs(&PL_sv_undef);
	}
	else if (DO_UTF8(sv)) {
	    SETi(utf8_length((U8*)p, (U8*)p + len));
	}
	else
	    SETi(len);
    } else if (SvOK(sv)) {
	/* Neither magic nor overloaded.  */
	if (DO_UTF8(sv))
	    SETi(sv_len_utf8(sv));
	else
	    SETi(sv_len(sv));
    } else {
	if (!SvPADTMP(TARG)) {
	    sv_setsv_nomg(TARG, &PL_sv_undef);
	    SETTARG;
	}
	SETs(&PL_sv_undef);
    }
    RETURN;
}

/* Returns false if substring is completely outside original string.
   No length is indicated by len_iv = 0 and len_is_uv = 0.  len_is_uv must
   always be true for an explicit 0.
*/
bool
Perl_translate_substr_offsets(pTHX_ STRLEN curlen, IV pos1_iv,
				    bool pos1_is_uv, IV len_iv,
				    bool len_is_uv, STRLEN *posp,
				    STRLEN *lenp)
{
    IV pos2_iv;
    int    pos2_is_uv;

    PERL_ARGS_ASSERT_TRANSLATE_SUBSTR_OFFSETS;

    if (!pos1_is_uv && pos1_iv < 0 && curlen) {
	pos1_is_uv = curlen-1 > ~(UV)pos1_iv;
	pos1_iv += curlen;
    }
    if ((pos1_is_uv || pos1_iv > 0) && (UV)pos1_iv > curlen)
	return FALSE;

    if (len_iv || len_is_uv) {
	if (!len_is_uv && len_iv < 0) {
	    pos2_iv = curlen + len_iv;
	    if (curlen)
		pos2_is_uv = curlen-1 > ~(UV)len_iv;
	    else
		pos2_is_uv = 0;
	} else {  /* len_iv >= 0 */
	    if (!pos1_is_uv && pos1_iv < 0) {
		pos2_iv = pos1_iv + len_iv;
		pos2_is_uv = (UV)len_iv > (UV)IV_MAX;
	    } else {
		if ((UV)len_iv > curlen-(UV)pos1_iv)
		    pos2_iv = curlen;
		else
		    pos2_iv = pos1_iv+len_iv;
		pos2_is_uv = 1;
	    }
	}
    }
    else {
	pos2_iv = curlen;
	pos2_is_uv = 1;
    }

    if (!pos2_is_uv && pos2_iv < 0) {
	if (!pos1_is_uv && pos1_iv < 0)
	    return FALSE;
	pos2_iv = 0;
    }
    else if (!pos1_is_uv && pos1_iv < 0)
	pos1_iv = 0;

    if ((UV)pos2_iv < (UV)pos1_iv)
	pos2_iv = pos1_iv;
    if ((UV)pos2_iv > curlen)
	pos2_iv = curlen;

    /* pos1_iv and pos2_iv both in 0..curlen, so the cast is safe */
    *posp = (STRLEN)( (UV)pos1_iv );
    *lenp = (STRLEN)( (UV)pos2_iv - (UV)pos1_iv );

    return TRUE;
}

PP(pp_substr)
{
    dVAR; dSP; dTARGET;
    SV *sv;
    STRLEN curlen;
    STRLEN utf8_curlen;
    SV *   pos_sv;
    IV     pos1_iv;
    int    pos1_is_uv;
    SV *   len_sv;
    IV     len_iv = 0;
    int    len_is_uv = 0;
    I32 lvalue = PL_op->op_flags & OPf_MOD || LVRET;
    const bool rvalue = (GIMME_V != G_VOID);
    const char *tmps;
    SV *repl_sv = NULL;
    const char *repl = NULL;
    STRLEN repl_len;
    int num_args = PL_op->op_private & 7;
    bool repl_need_utf8_upgrade = FALSE;
    bool repl_is_utf8 = FALSE;

    if (num_args > 2) {
	if (num_args > 3) {
	  if(!(repl_sv = POPs)) num_args--;
	}
	if ((len_sv = POPs)) {
	    len_iv    = SvIV(len_sv);
	    len_is_uv = len_iv ? SvIOK_UV(len_sv) : 1;
	}
	else num_args--;
    }
    pos_sv     = POPs;
    pos1_iv    = SvIV(pos_sv);
    pos1_is_uv = SvIOK_UV(pos_sv);
    sv = POPs;
    if (PL_op->op_private & OPpSUBSTR_REPL_FIRST) {
	assert(!repl_sv);
	repl_sv = POPs;
    }
    PUTBACK;
    if (repl_sv) {
	repl = SvPV_const(repl_sv, repl_len);
	repl_is_utf8 = DO_UTF8(repl_sv) && repl_len;
	if (repl_is_utf8) {
	    if (!DO_UTF8(sv))
		sv_utf8_upgrade(sv);
	}
	else if (DO_UTF8(sv))
	    repl_need_utf8_upgrade = TRUE;
    }
    else if (lvalue) {
	SV * ret;
	ret = sv_2mortal(newSV_type(SVt_PVLV));  /* Not TARG RT#67838 */
	sv_magic(ret, NULL, PERL_MAGIC_substr, NULL, 0);
	LvTYPE(ret) = 'x';
	LvTARG(ret) = SvREFCNT_inc_simple(sv);
	LvTARGOFF(ret) =
	    pos1_is_uv || pos1_iv >= 0
		? (STRLEN)(UV)pos1_iv
		: (LvFLAGS(ret) |= 1, (STRLEN)(UV)-pos1_iv);
	LvTARGLEN(ret) =
	    len_is_uv || len_iv > 0
		? (STRLEN)(UV)len_iv
		: (LvFLAGS(ret) |= 2, (STRLEN)(UV)-len_iv);

	SPAGAIN;
	PUSHs(ret);    /* avoid SvSETMAGIC here */
	RETURN;
    }
    tmps = SvPV_const(sv, curlen);
    if (DO_UTF8(sv)) {
        utf8_curlen = sv_len_utf8(sv);
	if (utf8_curlen == curlen)
	    utf8_curlen = 0;
	else
	    curlen = utf8_curlen;
    }
    else
	utf8_curlen = 0;

    {
	STRLEN pos, len, byte_len, byte_pos;

	if (!translate_substr_offsets(
		curlen, pos1_iv, pos1_is_uv, len_iv, len_is_uv, &pos, &len
	)) goto bound_fail;

	byte_len = len;
	byte_pos = utf8_curlen
	    ? sv_pos_u2b_flags(sv, pos, &byte_len, SV_CONST_RETURN) : pos;

	tmps += byte_pos;

	if (rvalue) {
	    SvTAINTED_off(TARG);			/* decontaminate */
	    SvUTF8_off(TARG);			/* decontaminate */
	    sv_setpvn(TARG, tmps, byte_len);
#ifdef USE_LOCALE_COLLATE
	    sv_unmagic(TARG, PERL_MAGIC_collxfrm);
#endif
	    if (utf8_curlen)
		SvUTF8_on(TARG);
	}

	if (repl) {
	    SV* repl_sv_copy = NULL;

	    if (repl_need_utf8_upgrade) {
		repl_sv_copy = newSVsv(repl_sv);
		sv_utf8_upgrade(repl_sv_copy);
		repl = SvPV_const(repl_sv_copy, repl_len);
		repl_is_utf8 = DO_UTF8(repl_sv_copy) && repl_len;
	    }
	    if (SvROK(sv))
		Perl_ck_warner(aTHX_ packWARN(WARN_SUBSTR),
			    "Attempt to use reference as lvalue in substr"
		);
	    if (!SvOK(sv))
		sv_setpvs(sv, "");
	    sv_insert_flags(sv, byte_pos, byte_len, repl, repl_len, 0);
	    if (repl_is_utf8)
		SvUTF8_on(sv);
	    SvREFCNT_dec(repl_sv_copy);
	}
    }
    SPAGAIN;
    if (rvalue) {
	SvSETMAGIC(TARG);
	PUSHs(TARG);
    }
    RETURN;

bound_fail:
    if (repl)
	Perl_croak(aTHX_ "substr outside of string");
    Perl_ck_warner(aTHX_ packWARN(WARN_SUBSTR), "substr outside of string");
    RETPUSHUNDEF;
}

PP(pp_vec)
{
    dVAR; dSP;
    register const IV size   = POPi;
    register const IV offset = POPi;
    register SV * const src = POPs;
    const I32 lvalue = PL_op->op_flags & OPf_MOD || LVRET;
    SV * ret;

    if (lvalue) {			/* it's an lvalue! */
	ret = sv_2mortal(newSV_type(SVt_PVLV));  /* Not TARG RT#67838 */
	sv_magic(ret, NULL, PERL_MAGIC_vec, NULL, 0);
	LvTYPE(ret) = 'v';
	LvTARG(ret) = SvREFCNT_inc_simple(src);
	LvTARGOFF(ret) = offset;
	LvTARGLEN(ret) = size;
    }
    else {
	dTARGET;
	SvTAINTED_off(TARG);		/* decontaminate */
	ret = TARG;
    }

    sv_setuv(ret, do_vecget(src, offset, size));
    PUSHs(ret);
    RETURN;
}

PP(pp_index)
{
    dVAR; dSP; dTARGET;
    SV *big;
    SV *little;
    SV *temp = NULL;
    STRLEN biglen;
    STRLEN llen = 0;
    I32 offset;
    I32 retval;
    const char *big_p;
    const char *little_p;
    bool big_utf8;
    bool little_utf8;
    const bool is_index = PL_op->op_type == OP_INDEX;
    const bool threeargs = MAXARG >= 3 && (TOPs || ((void)POPs,0));

    if (threeargs)
	offset = POPi;
    little = POPs;
    big = POPs;
    big_p = SvPV_const(big, biglen);
    little_p = SvPV_const(little, llen);

    big_utf8 = DO_UTF8(big);
    little_utf8 = DO_UTF8(little);
    if (big_utf8 ^ little_utf8) {
	/* One needs to be upgraded.  */
	if (little_utf8 && !PL_encoding) {
	    /* Well, maybe instead we might be able to downgrade the small
	       string?  */
	    char * const pv = (char*)bytes_from_utf8((U8 *)little_p, &llen,
						     &little_utf8);
	    if (little_utf8) {
		/* If the large string is ISO-8859-1, and it's not possible to
		   convert the small string to ISO-8859-1, then there is no
		   way that it could be found anywhere by index.  */
		retval = -1;
		goto fail;
	    }

	    /* At this point, pv is a malloc()ed string. So donate it to temp
	       to ensure it will get free()d  */
	    little = temp = newSV(0);
	    sv_usepvn(temp, pv, llen);
	    little_p = SvPVX(little);
	} else {
	    temp = little_utf8
		? newSVpvn(big_p, biglen) : newSVpvn(little_p, llen);

	    if (PL_encoding) {
		sv_recode_to_utf8(temp, PL_encoding);
	    } else {
		sv_utf8_upgrade(temp);
	    }
	    if (little_utf8) {
		big = temp;
		big_utf8 = TRUE;
		big_p = SvPV_const(big, biglen);
	    } else {
		little = temp;
		little_p = SvPV_const(little, llen);
	    }
	}
    }
    if (SvGAMAGIC(big)) {
	/* Life just becomes a lot easier if I use a temporary here.
	   Otherwise I need to avoid calls to sv_pos_u2b(), which (dangerously)
	   will trigger magic and overloading again, as will fbm_instr()
	*/
	big = newSVpvn_flags(big_p, biglen,
			     SVs_TEMP | (big_utf8 ? SVf_UTF8 : 0));
	big_p = SvPVX(big);
    }
    if (SvGAMAGIC(little) || (is_index && !SvOK(little))) {
	/* index && SvOK() is a hack. fbm_instr() calls SvPV_const, which will
	   warn on undef, and we've already triggered a warning with the
	   SvPV_const some lines above. We can't remove that, as we need to
	   call some SvPV to trigger overloading early and find out if the
	   string is UTF-8.
	   This is all getting to messy. The API isn't quite clean enough,
	   because data access has side effects.
	*/
	little = newSVpvn_flags(little_p, llen,
				SVs_TEMP | (little_utf8 ? SVf_UTF8 : 0));
	little_p = SvPVX(little);
    }

    if (!threeargs)
	offset = is_index ? 0 : biglen;
    else {
	if (big_utf8 && offset > 0)
	    sv_pos_u2b(big, &offset, 0);
	if (!is_index)
	    offset += llen;
    }
    if (offset < 0)
	offset = 0;
    else if (offset > (I32)biglen)
	offset = biglen;
    if (!(little_p = is_index
	  ? fbm_instr((unsigned char*)big_p + offset,
		      (unsigned char*)big_p + biglen, little, 0)
	  : rninstr(big_p,  big_p  + offset,
		    little_p, little_p + llen)))
	retval = -1;
    else {
	retval = little_p - big_p;
	if (retval > 0 && big_utf8)
	    sv_pos_b2u(big, &retval);
    }
    SvREFCNT_dec(temp);
 fail:
    PUSHi(retval);
    RETURN;
}

PP(pp_sprintf)
{
    dVAR; dSP; dMARK; dORIGMARK; dTARGET;
    SvTAINTED_off(TARG);
    do_sprintf(TARG, SP-MARK, MARK+1);
    TAINT_IF(SvTAINTED(TARG));
    SP = ORIGMARK;
    PUSHTARG;
    RETURN;
}

PP(pp_ord)
{
    dVAR; dSP; dTARGET;

    SV *argsv = POPs;
    STRLEN len;
    const U8 *s = (U8*)SvPV_const(argsv, len);

    if (PL_encoding && SvPOK(argsv) && !DO_UTF8(argsv)) {
        SV * const tmpsv = sv_2mortal(newSVsv(argsv));
        s = (U8*)sv_recode_to_utf8(tmpsv, PL_encoding);
        argsv = tmpsv;
    }

    XPUSHu(DO_UTF8(argsv) ?
	   utf8n_to_uvchr(s, UTF8_MAXBYTES, 0, UTF8_ALLOW_ANYUV) :
	   (UV)(*s & 0xff));

    RETURN;
}

PP(pp_chr)
{
    dVAR; dSP; dTARGET;
    char *tmps;
    UV value;
    SV *top = POPs;

    SvGETMAGIC(top);
    if (!IN_BYTES /* under bytes, chr(-1) eq chr(0xff), etc. */
     && ((SvIOKp(top) && !SvIsUV(top) && SvIV_nomg(top) < 0)
	 ||
	 ((SvNOKp(top) || (SvOK(top) && !SvIsUV(top)))
	  && SvNV_nomg(top) < 0.0))) {
	    if (ckWARN(WARN_UTF8)) {
		if (SvGMAGICAL(top)) {
		    SV *top2 = sv_newmortal();
		    sv_setsv_nomg(top2, top);
		    top = top2;
		}
		Perl_warner(aTHX_ packWARN(WARN_UTF8),
			   "Invalid negative number (%"SVf") in chr", top);
	    }
	    value = UNICODE_REPLACEMENT;
    } else {
	value = SvUV_nomg(top);
    }

    SvUPGRADE(TARG,SVt_PV);

    if (value > 255 && !IN_BYTES) {
	SvGROW(TARG, (STRLEN)UNISKIP(value)+1);
	tmps = (char*)uvchr_to_utf8_flags((U8*)SvPVX(TARG), value, 0);
	SvCUR_set(TARG, tmps - SvPVX_const(TARG));
	*tmps = '\0';
	(void)SvPOK_only(TARG);
	SvUTF8_on(TARG);
	XPUSHs(TARG);
	RETURN;
    }

    SvGROW(TARG,2);
    SvCUR_set(TARG, 1);
    tmps = SvPVX(TARG);
    *tmps++ = (char)value;
    *tmps = '\0';
    (void)SvPOK_only(TARG);

    if (PL_encoding && !IN_BYTES) {
        sv_recode_to_utf8(TARG, PL_encoding);
	tmps = SvPVX(TARG);
	if (SvCUR(TARG) == 0
	    || ! is_utf8_string((U8*)tmps, SvCUR(TARG))
	    || UTF8_IS_REPLACEMENT((U8*) tmps, (U8*) tmps + SvCUR(TARG)))
	{
	    SvGROW(TARG, 2);
	    tmps = SvPVX(TARG);
	    SvCUR_set(TARG, 1);
	    *tmps++ = (char)value;
	    *tmps = '\0';
	    SvUTF8_off(TARG);
	}
    }

    XPUSHs(TARG);
    RETURN;
}

PP(pp_crypt)
{
#ifdef HAS_CRYPT
    dVAR; dSP; dTARGET;
    dPOPTOPssrl;
    STRLEN len;
    const char *tmps = SvPV_const(left, len);

    if (DO_UTF8(left)) {
         /* If Unicode, try to downgrade.
	  * If not possible, croak.
	  * Yes, we made this up.  */
	 SV* const tsv = sv_2mortal(newSVsv(left));

	 SvUTF8_on(tsv);
	 sv_utf8_downgrade(tsv, FALSE);
	 tmps = SvPV_const(tsv, len);
    }
#   ifdef USE_ITHREADS
#     ifdef HAS_CRYPT_R
    if (!PL_reentrant_buffer->_crypt_struct_buffer) {
      /* This should be threadsafe because in ithreads there is only
       * one thread per interpreter.  If this would not be true,
       * we would need a mutex to protect this malloc. */
        PL_reentrant_buffer->_crypt_struct_buffer =
	  (struct crypt_data *)safemalloc(sizeof(struct crypt_data));
#if defined(__GLIBC__) || defined(__EMX__)
	if (PL_reentrant_buffer->_crypt_struct_buffer) {
	    PL_reentrant_buffer->_crypt_struct_buffer->initialized = 0;
	    /* work around glibc-2.2.5 bug */
	    PL_reentrant_buffer->_crypt_struct_buffer->current_saltbits = 0;
	}
#endif
    }
#     endif /* HAS_CRYPT_R */
#   endif /* USE_ITHREADS */
#   ifdef FCRYPT
    sv_setpv(TARG, fcrypt(tmps, SvPV_nolen_const(right)));
#   else
    sv_setpv(TARG, PerlProc_crypt(tmps, SvPV_nolen_const(right)));
#   endif
    SETTARG;
    RETURN;
#else
    DIE(aTHX_
      "The crypt() function is unimplemented due to excessive paranoia.");
#endif
}

/* Generally UTF-8 and UTF-EBCDIC are indistinguishable at this level.  So 
 * most comments below say UTF-8, when in fact they mean UTF-EBCDIC as well */

/* Generates code to store a unicode codepoint c that is known to occupy
 * exactly two UTF-8 and UTF-EBCDIC bytes; it is stored into p and p+1,
 * and p is advanced to point to the next available byte after the two bytes */
#define CAT_UNI_TO_UTF8_TWO_BYTE(p, c)					    \
    STMT_START {							    \
	*(p)++ = UTF8_TWO_BYTE_HI(c);					    \
	*((p)++) = UTF8_TWO_BYTE_LO(c);					    \
    } STMT_END

PP(pp_ucfirst)
{
    /* Actually is both lcfirst() and ucfirst().  Only the first character
     * changes.  This means that possibly we can change in-place, ie., just
     * take the source and change that one character and store it back, but not
     * if read-only etc, or if the length changes */

    dVAR;
    dSP;
    SV *source = TOPs;
    STRLEN slen; /* slen is the byte length of the whole SV. */
    STRLEN need;
    SV *dest;
    bool inplace;   /* ? Convert first char only, in-place */
    bool doing_utf8 = FALSE;		   /* ? using utf8 */
    bool convert_source_to_utf8 = FALSE;   /* ? need to convert */
    const int op_type = PL_op->op_type;
    const U8 *s;
    U8 *d;
    U8 tmpbuf[UTF8_MAXBYTES_CASE+1];
    STRLEN ulen;    /* ulen is the byte length of the original Unicode character
		     * stored as UTF-8 at s. */
    STRLEN tculen;  /* tculen is the byte length of the freshly titlecased (or
		     * lowercased) character stored in tmpbuf.  May be either
		     * UTF-8 or not, but in either case is the number of bytes */
    bool tainted = FALSE;

    SvGETMAGIC(source);
    if (SvOK(source)) {
	s = (const U8*)SvPV_nomg_const(source, slen);
    } else {
	if (ckWARN(WARN_UNINITIALIZED))
	    report_uninit(source);
	s = (const U8*)"";
	slen = 0;
    }

    /* We may be able to get away with changing only the first character, in
     * place, but not if read-only, etc.  Later we may discover more reasons to
     * not convert in-place. */
    inplace = SvPADTMP(source) && !SvREADONLY(source) && SvTEMP(source);

    /* First calculate what the changed first character should be.  This affects
     * whether we can just swap it out, leaving the rest of the string unchanged,
     * or even if have to convert the dest to UTF-8 when the source isn't */

    if (! slen) {   /* If empty */
	need = 1; /* still need a trailing NUL */
	ulen = 0;
    }
    else if (DO_UTF8(source)) {	/* Is the source utf8? */
	doing_utf8 = TRUE;
        ulen = UTF8SKIP(s);
        if (op_type == OP_UCFIRST) {
	    _to_utf8_title_flags(s, tmpbuf, &tculen,
				 cBOOL(IN_LOCALE_RUNTIME), &tainted);
	}
        else {
	    _to_utf8_lower_flags(s, tmpbuf, &tculen,
				 cBOOL(IN_LOCALE_RUNTIME), &tainted);
	}

        /* we can't do in-place if the length changes.  */
        if (ulen != tculen) inplace = FALSE;
        need = slen + 1 - ulen + tculen;
    }
    else { /* Non-zero length, non-UTF-8,  Need to consider locale and if
	    * latin1 is treated as caseless.  Note that a locale takes
	    * precedence */ 
	ulen = 1;	/* Original character is 1 byte */
	tculen = 1;	/* Most characters will require one byte, but this will
			 * need to be overridden for the tricky ones */
	need = slen + 1;

	if (op_type == OP_LCFIRST) {

	    /* lower case the first letter: no trickiness for any character */
	    *tmpbuf = (IN_LOCALE_RUNTIME) ? toLOWER_LC(*s) :
			((IN_UNI_8_BIT) ? toLOWER_LATIN1(*s) : toLOWER(*s));
	}
	/* is ucfirst() */
	else if (IN_LOCALE_RUNTIME) {
	    *tmpbuf = toUPPER_LC(*s);	/* This would be a bug if any locales
					 * have upper and title case different
					 */
	}
	else if (! IN_UNI_8_BIT) {
	    *tmpbuf = toUPPER(*s);	/* Returns caseless for non-ascii, or
					 * on EBCDIC machines whatever the
					 * native function does */
	}
	else { /* is ucfirst non-UTF-8, not in locale, and cased latin1 */
	    UV title_ord = _to_upper_title_latin1(*s, tmpbuf, &tculen, 's');
	    if (tculen > 1) {
		assert(tculen == 2);

                /* If the result is an upper Latin1-range character, it can
                 * still be represented in one byte, which is its ordinal */
		if (UTF8_IS_DOWNGRADEABLE_START(*tmpbuf)) {
		    *tmpbuf = (U8) title_ord;
		    tculen = 1;
		}
		else {
                    /* Otherwise it became more than one ASCII character (in
                     * the case of LATIN_SMALL_LETTER_SHARP_S) or changed to
                     * beyond Latin1, so the number of bytes changed, so can't
                     * replace just the first character in place. */
		    inplace = FALSE;

		    /* If the result won't fit in a byte, the entire result will
		     * have to be in UTF-8.  Assume worst case sizing in
		     * conversion. (all latin1 characters occupy at most two bytes
		     * in utf8) */
		    if (title_ord > 255) {
			doing_utf8 = TRUE;
			convert_source_to_utf8 = TRUE;
			need = slen * 2 + 1;

                        /* The (converted) UTF-8 and UTF-EBCDIC lengths of all
                         * (both) characters whose title case is above 255 is
                         * 2. */
			ulen = 2;
		    }
                    else { /* LATIN_SMALL_LETTER_SHARP_S expands by 1 byte */
			need = slen + 1 + 1;
		    }
		}
	    }
	} /* End of use Unicode (Latin1) semantics */
    } /* End of changing the case of the first character */

    /* Here, have the first character's changed case stored in tmpbuf.  Ready to
     * generate the result */
    if (inplace) {

	/* We can convert in place.  This means we change just the first
	 * character without disturbing the rest; no need to grow */
	dest = source;
	s = d = (U8*)SvPV_force_nomg(source, slen);
    } else {
	dTARGET;

	dest = TARG;

	/* Here, we can't convert in place; we earlier calculated how much
	 * space we will need, so grow to accommodate that */
	SvUPGRADE(dest, SVt_PV);
	d = (U8*)SvGROW(dest, need);
	(void)SvPOK_only(dest);

	SETs(dest);
    }

    if (doing_utf8) {
	if (! inplace) {
	    if (! convert_source_to_utf8) {

		/* Here  both source and dest are in UTF-8, but have to create
		 * the entire output.  We initialize the result to be the
		 * title/lower cased first character, and then append the rest
		 * of the string. */
		sv_setpvn(dest, (char*)tmpbuf, tculen);
		if (slen > ulen) {
		    sv_catpvn(dest, (char*)(s + ulen), slen - ulen);
		}
	    }
	    else {
		const U8 *const send = s + slen;

		/* Here the dest needs to be in UTF-8, but the source isn't,
		 * except we earlier UTF-8'd the first character of the source
		 * into tmpbuf.  First put that into dest, and then append the
		 * rest of the source, converting it to UTF-8 as we go. */

		/* Assert tculen is 2 here because the only two characters that
		 * get to this part of the code have 2-byte UTF-8 equivalents */
		*d++ = *tmpbuf;
		*d++ = *(tmpbuf + 1);
		s++;	/* We have just processed the 1st char */

		for (; s < send; s++) {
		    d = uvchr_to_utf8(d, *s);
		}
		*d = '\0';
		SvCUR_set(dest, d - (U8*)SvPVX_const(dest));
	    }
	    SvUTF8_on(dest);
	}
	else {   /* in-place UTF-8.  Just overwrite the first character */
	    Copy(tmpbuf, d, tculen, U8);
	    SvCUR_set(dest, need - 1);
	}

	if (tainted) {
	    TAINT;
	    SvTAINTED_on(dest);
	}
    }
    else {  /* Neither source nor dest are in or need to be UTF-8 */
	if (slen) {
	    if (IN_LOCALE_RUNTIME) {
		TAINT;
		SvTAINTED_on(dest);
	    }
	    if (inplace) {  /* in-place, only need to change the 1st char */
		*d = *tmpbuf;
	    }
	    else {	/* Not in-place */

		/* Copy the case-changed character(s) from tmpbuf */
		Copy(tmpbuf, d, tculen, U8);
		d += tculen - 1; /* Code below expects d to point to final
				  * character stored */
	    }
	}
	else {	/* empty source */
	    /* See bug #39028: Don't taint if empty  */
	    *d = *s;
	}

	/* In a "use bytes" we don't treat the source as UTF-8, but, still want
	 * the destination to retain that flag */
	if (SvUTF8(source))
	    SvUTF8_on(dest);

	if (!inplace) {	/* Finish the rest of the string, unchanged */
	    /* This will copy the trailing NUL  */
	    Copy(s + 1, d + 1, slen, U8);
	    SvCUR_set(dest, need - 1);
	}
    }
    if (dest != source && SvTAINTED(source))
	SvTAINT(dest);
    SvSETMAGIC(dest);
    RETURN;
}

/* There's so much setup/teardown code common between uc and lc, I wonder if
   it would be worth merging the two, and just having a switch outside each
   of the three tight loops.  There is less and less commonality though */
PP(pp_uc)
{
    dVAR;
    dSP;
    SV *source = TOPs;
    STRLEN len;
    STRLEN min;
    SV *dest;
    const U8 *s;
    U8 *d;

    SvGETMAGIC(source);

    if (SvPADTMP(source) && !SvREADONLY(source) && !SvAMAGIC(source)
	&& SvTEMP(source) && !DO_UTF8(source)
	&& (IN_LOCALE_RUNTIME || ! IN_UNI_8_BIT)) {