From: shaunspiller at gmail dot com
Operating system: Win32
PHP version: 5.2.6
PHP Bug Type: Reproducible crash
Bug description: php_gmp.dll uses exotic instructions
Description:
------------
I'm using the latest precompiled Win32 binaries of PHP-5.2.6 (and have
also tried PHP-5.1.6) and get a program crash with an #Undefined Opcode
exception when loading php_gmp.dll.
I know what the problem is and I'm not sure if one would consider it a bug
or not since it will only happen on very old machines, but I can't believe
I'm the first person to have ever encountered this.
The instruction in php_gmp.dll which causes the crash is CMOVZ EDX, EAX.
The conditional move instructions were only added with the Pentium Pro.
Tough luck for me -- my computer literally blew up last week and I'm stuck
temporarally with a Pentium MMX and a K6 laptop, neither of which support
CMOVcc.
It's understandable that compiling for P6+ instructions might be a good
tradeoff between performance and compatibility, but current versions of PHP
are *stated* to work with even Windows 98 and up, and so are the
precompiled binaries (other extensions seem to work just fine). I don't
know how much CMOVcc is relied on in php_gmp.dll, and changing the build
options to use generic I386+ might be undesirable, but the P6 instruction
set requirement should at least be *mentioned* somewhere, and it isn't (not
that I found).
Disappointing for me in either case, because recompiling the DLL is a
little beyond what I can do on this old system right now. I would normally
have just used BCMath instead, but I need the base-conversion stuff, which
that doesn't have.
Reproduce code:
---------------
<?php
dl('php_gmp.dll');
echo 'hi!';
?>
Expected result:
----------------
hi!
Actual result:
--------------
Instant program crash. Windows provides the following info:
PHP executed an invalid instruction in
module PHP_GMP.DLL at 0187:01a760f4.
Registers:
EAX=01a7ced0 CS=0187 EIP=01a760f4 EFLGS=00010202
EBX=01a710e0 SS=018f ESP=00d3f904 EBP=01989c20
ECX=01a710c0 DS=018f ESI=0000001a FS=12c7
EDX=01a710b0 ES=018f EDI=01370ae0 GS=0000
Bytes at CS:EIP:
0f 44 d0 b8 60 cf a7 01 85 c9 0f 44 c8 85 db b8
Stack dump:
1001a380 01a710a4 01a710b0 01a710c0 01a710e0 01a8c2f0 0000000c 01a76120
00000003 0000001a 01370ae0 01a8c2fc 00000013 00000002 00000003 0000001a
--
Edit bug report at http://bugs.php.net/?id=45215&edit=1
--
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=45215&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=45215&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=45215&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=45215&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=45215&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=45215&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=45215&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=45215&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=45215&r=support
Expected behavior: http://bugs.php.net/fix.php?id=45215&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=45215&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=45215&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=45215&r=globals
PHP 4 support discontinued: http://bugs.php.net/fix.php?id=45215&r=php4
Daylight Savings: http://bugs.php.net/fix.php?id=45215&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=45215&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=45215&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=45215&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=45215&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=45215&r=mysqlcfg
