------- Additional Comments From tkoenig at gcc dot gnu dot org 2005-08-12
20:22 -------
$ gcc -g -ffast-math hello.c
$ gdb ./a.out
GNU gdb 6.3-debian
Copyright 2004 Free Software Foundation, Inc.
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This GDB was configured as "i386-linux"...Using host libthread_db library
"/lib/tls/libthread_db.so.1".
(gdb) r
Starting program: /home/ig25/Krempel/a.out
Program received signal SIGSEGV, Segmentation fault.
0x08048469 in set_fast_math ()
at ../../gcc-4.1/gcc/config/i386/crtfastmath.c:70
70 __builtin_ia32_ldmxcsr (mxcsr);
(gdb) p/x $pc
$1 = 0x8048469
(gdb) info reg
eax 0x681 1665
ecx 0x0 0
edx 0x2000000 33554432
ebx 0x80495b4 134518196
esp 0xbffff570 0xbffff570
ebp 0xbffff578 0xbffff578
esi 0x0 0
edi 0x80483c0 134513600
eip 0x8048469 0x8048469
eflags 0x210206 2163206
cs 0x73 115
ss 0x7b 123
ds 0x7b 123
es 0x7b 123
fs 0x0 0
gs 0x33 51
(gdb) disass
Dump of assembler code for function set_fast_math:
0x08048420 <set_fast_math+0>: push %ebp
0x08048421 <set_fast_math+1>: mov %esp,%ebp
0x08048423 <set_fast_math+3>: push %esi
0x08048424 <set_fast_math+4>: sub $0x4,%esp
0x08048427 <set_fast_math+7>: pushf
0x08048428 <set_fast_math+8>: pushf
0x08048429 <set_fast_math+9>: pop %eax
0x0804842a <set_fast_math+10>: mov %eax,%edx
0x0804842c <set_fast_math+12>: xor $0x200000,%eax
0x08048431 <set_fast_math+17>: push %eax
0x08048432 <set_fast_math+18>: popf
0x08048433 <set_fast_math+19>: pushf
0x08048434 <set_fast_math+20>: pop %eax
0x08048435 <set_fast_math+21>: popf
0x08048436 <set_fast_math+22>: xor %edx,%eax
0x08048438 <set_fast_math+24>: test $0x200000,%eax
0x0804843d <set_fast_math+29>: je 0x8048470 <set_fast_math+80>
0x0804843f <set_fast_math+31>: xor %eax,%eax
0x08048441 <set_fast_math+33>: xchg %ebx,%esi
0x08048443 <set_fast_math+35>: cpuid
0x08048445 <set_fast_math+37>: xchg %ebx,%esi
0x08048447 <set_fast_math+39>: test %eax,%eax
0x08048449 <set_fast_math+41>: je 0x8048470 <set_fast_math+80>
0x0804844b <set_fast_math+43>: mov $0x1,%eax
---Type <return> to continue, or q <return> to quit---
0x08048450 <set_fast_math+48>: xchg %ebx,%esi
0x08048452 <set_fast_math+50>: cpuid
0x08048454 <set_fast_math+52>: xchg %ebx,%esi
0x08048456 <set_fast_math+54>: and $0x2000000,%edx
0x0804845c <set_fast_math+60>: je 0x8048470 <set_fast_math+80>
0x0804845e <set_fast_math+62>: stmxcsr 0xfffffff8(%ebp)
0x08048462 <set_fast_math+66>: orl $0x8040,0xfffffff8(%ebp)
0x08048469 <set_fast_math+73>: ldmxcsr 0xfffffff8(%ebp)
0x0804846d <set_fast_math+77>: lea 0x0(%esi),%esi
0x08048470 <set_fast_math+80>: pop %eax
0x08048471 <set_fast_math+81>: pop %esi
0x08048472 <set_fast_math+82>: pop %ebp
0x08048473 <set_fast_math+83>: ret
End of assembler dump.
(gdb)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23360
