https://bugs.kde.org/show_bug.cgi?id=366237
Bug ID: 366237
Summary: pextrw - Unrecoginzed instruction
Product: valgrind
Version: 3.12 SVN
Platform: Other
OS: Linux
Status: UNCONFIRMED
Severity: normal
Priority: NOR
Component: vex
Assignee: jsew...@acm.org
Reporter: olek...@gmail.com
Created attachment 100373
--> https://bugs.kde.org/attachment.cgi?id=100373&action=edit
sample project
valgrind complains about unrecognized instruction, generated by NASM assembler.
A sample project is attached.
YASM and NASM generate different instructions:
Yasm listing:
1 %line 1+1 test_pextrw.nas
2 [bits 64]
3 [default rel]
4
5 [section .text align=16]
6
7 [global test_pextrw]
8 test_pextrw:
9 00000000 0F1007 movups xmm0, [rdi]
10 00000003 66480FC5C000 pextrw rax, xmm0, 0
11 00000009 C3 ret
12
nasm listing:
1 [bits 64]
2 [default rel]
3
4 [section .text align=16]
5
6 [global test_pextrw]
7 test_pextrw:
8 00000000 0F1007 movups xmm0, [rdi]
9 00000003 66480F3A15C000 pextrw rax, xmm0, 0
10 0000000A C3 ret
11
NASM 2.12.02rc7 (latest rc)
yasm 1.3.0.28.g51af (current git)
valgrind-3.12.0.SVN (current svn)
yasm generates instruction that executes on Intel Celeron E3400
nasm's instruction causes "illegal hardware instruction" exception on Celeron
E3400
both versions work on Core i7-4770S
This might be a bug in nasm.
I'll report to the nasm team too.
valgrind error messages on nasm version:
vex amd64->IR: unhandled instruction bytes: 0x66 0x48 0xF 0x3A 0x15 0xC0 0x0
0xC3 0x90 0x90
vex amd64->IR: REX=1 REX.W=1 REX.R=0 REX.X=0 REX.B=0
vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=0F3A
vex amd64->IR: PFX.66=1 PFX.F2=0 PFX.F3=0
==6168== valgrind: Unrecognised instruction at address 0x400583.
==6168== at 0x400583: ??? (test_pextrw.nas:9)
==6168== by 0x4E4FCDC: (below main) (in /lib64/libc-2.12.so)
==6168== 1. Your program has a bug and erroneously jumped to a non-code
==6168== location. If you are running Memcheck and you just saw a
==6168== warning about a bad jump, it's probably your program's fault.
==6168== 2. The instruction is legitimate but Valgrind doesn't handle it,
==6168== i.e. it's Valgrind's fault. If you think this is the case or
==6168== you are not sure, please let us know and we'll try to fix it.
==6168== Either way, Valgrind will now raise a SIGILL signal which will
==6168== probably kill your program.
==6168==
==6168== Process terminating with default action of signal 4 (SIGILL)
==6168== Illegal opcode at address 0x400583
==6168== at 0x400583: ??? (test_pextrw.nas:9)
==6168== by 0x4E4FCDC: (below main) (in /lib64/libc-2.12.so)
code produced by yasm works under valgrind without errors.
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