More careful detection of how well NVs and UVs mix.

Subject: [PATCH] Re: NV preserving UV (wasRe: [ID 20001007.002] Not OK: perl v5.7.0 +DEVEL7158 on armv4l-linux-64int 2.2.17-rmk1 (UNINSTALLED))
Message-ID: <20001108151412.B98736@plum.flirble.org>

Added some SIGFPE paranoia.

p4raw-id: //depot/metaconfig@7605

diff --git a/U/perl/perlxv.U b/U/perl/perlxv.U
index 32e24d9..dd279cc 100644 (file)
--- a/U/perl/perlxv.U
+++ b/U/perl/perlxv.U
@@ -12,7 +12,7 @@
        echo rm use64bitint d_quad quadtype uquadtype \
        d_longdbl uselongdouble longdblsize doublesize \
        charsize shortsize intsize longsize \
-       cat Compile i_inttypes exe_ext test
+       cat Compile i_inttypes exe_ext test d_volatile signal_t
 ?MAKE: -pick add $@ %<
 ?S:ivtype:
 ?S:    This variable contains the C type used for Perl's IV.
@@ -192,6 +192,7 @@
 ?H:#define     NV_PRESERVES_UV_BITS    $d_nv_preserves_uv_bits
 ?H:.
 ?F:!try
+?T:volatile
 
 echo " "
 $echo "Choosing the C types to be used for Perl's internal types..." >&4
@@ -370,64 +371,65 @@ case "$i64type" in
        ;;
 esac
 
-$echo "Checking whether your NVs can preserve your UVs..." >&4
+$echo "Checking how many bits of your UVs your NVs can preserve..." >&4
+: volatile so that the compiler has to store it out to memory.
+if test X"$d_volatile" = X"$define"; then
+       volatile=volatile
+fi
 $cat <<EOP >try.c
 #include <stdio.h>
-int main() {
-    $uvtype k = ($uvtype)~0, l;
-    $nvtype d;
-    l = k;
-    d = ($nvtype)l;
-    l = ($uvtype)d;
-    if (l == k)
-       printf("preserve\n");
-    exit(0);
-}
-EOP
-set try
-if eval $compile; then
-       case "`./try$exe_ext`" in
-       preserve) d_nv_preserves_uv="$define" ;;
-       esac
-fi     
-case "$d_nv_preserves_uv" in
-$define) $echo "Yes, they can."  2>&1 ;;
-*)      $echo "No, they can't." 2>&1
-        d_nv_preserves_uv="$undef"
-        ;;
-esac
-
-$rm -f try.* try
-
-case "$d_nv_preserves_uv" in
-"$define") d_nv_preserves_uv_bits=`expr $uvsize \* 8` ;;
-*)     $echo "Checking how many bits of your UVs your NVs can preserve..." >&4
-       $cat <<EOP >try.c
-#include <stdio.h>
+#include <sys/types.h>
+#include <signal.h>
+#ifdef SIGFPE
+$volatile int bletched = 0;
+$signal_t blech(s) int s; { bletched = 1; }
+#endif
 int main() {
     $uvtype u = 0;
+    $nvtype d;
     int     n = 8 * $uvsize;
     int     i;
+#ifdef SIGFPE
+    signal(SIGFPE, blech);
+#endif
+
     for (i = 0; i < n; i++) {
       u = u << 1 | ($uvtype)1;
-      if (($uvtype)($nvtype)u != u)
+      d = ($nvtype)u;
+      if (($uvtype)d != u)
+        break;
+      if (d <= 0)
+       break;
+      d = ($nvtype)(u - 1);
+      if (($uvtype)d != (u - 1))
         break;
+#ifdef SIGFPE
+      if (bletched) {
+       break;
+#endif
+      }        
     }
-    printf("%d\n", i);
+    printf("%d\n", ((i == n) ? -n : i), u);
     exit(0);
 }
 EOP
-       set try
-       if eval $compile; then
-               d_nv_preserves_uv_bits="`./try$exe_ext`"
-       fi
-       case "$d_nv_preserves_uv_bits" in
-       [1-9]*) $echo "Your NVs can preserve $d_nv_preserves_uv_bits bits of your UVs."  2>&1 ;;
-       *)      $echo "Can't figure out how many bits your NVs preserve." 2>&1
-               d_nv_preserves_uv_bits="$undef"
-               ;;
-       esac
-       $rm -f try.* try
+set try
+
+d_nv_preserves_uv="$undef"
+if eval $compile; then
+       d_nv_preserves_uv_bits="`./try$exe_ext`"
+fi
+case "$d_nv_preserves_uv_bits" in
+\-[1-9]*)      
+       d_nv_preserves_uv_bits=`expr 0 - $d_nv_preserves_uv_bits`
+       $echo "Your NVs can preserve all $d_nv_preserves_uv_bits bits of your UVs."  2>&1
+       d_nv_preserves_uv="$define"
        ;;
+[1-9]*)        $echo "Your NVs can preserve only $d_nv_preserves_uv_bits bits of your UVs."  2>&1
+       d_nv_preserves_uv="$undef" ;;
+*)     $echo "Can't figure out how many bits your NVs preserve." 2>&1
+       d_nv_preserves_uv_bits="$undef" ;;
 esac
 
+$rm -f try.* try
+