True or False:
test al,al sets ZF only if al = 0
On Tue, 29 Dec 2020 02:26:42 -0800
bilsch01 <fy247@nospicedham.always.com> wrote:
True or False:
test al,al sets ZF only if al = 0
Look up TEST instruction here:
http://qcd.phys.cmu.edu/QCDcluster/intel/vtune/reference/About_IA-32_In structions.htm
That's a browse-able HTML version of an IA-32 manual.
True or False:
test al,al sets ZF only if al = 0
TIA. Bill S.
On Tue, 29 Dec 2020 02:26:42 -0800
bilsch01 <fy247@nospicedham.always.com> wrote:
True or False:
test al,al sets ZF only if al = 0
Look up TEST instruction here:
http://qcd.phys.cmu.edu/QCDcluster/intel/vtune/reference/About_IA-32_Instructions.htm
That's a browse-able HTML version of an IA-32 manual.
On Wed, 30 Dec 2020 10:18:28 GMT, Rod Pemberton <nomailings@nospicedham.trgzxcqvbe.cpm> wrote:
On Tue, 29 Dec 2020 02:26:42 -0800or elsewhere https://reverseengineering.stackexchange.com/questions/25188/what-does- test-al-al-mean
bilsch01 <fy247@nospicedham.always.com> wrote:
True or False:
test al,al sets ZF only if al = 0
Look up TEST instruction here:
http://qcd.phys.cmu.edu/QCDcluster/intel/vtune/reference/About_IA-32_In
structions.htm
That's a browse-able HTML version of an IA-32 manual.
Yes. But why do that if you want to test if al=0? far clearer to code
"cmp al,0"
but is cy set identically? back at the OP!
Kerr-Mudd,John wrote:_In
On Wed, 30 Dec 2020 10:18:28 GMT, Rod Pemberton
<nomailings@nospicedham.trgzxcqvbe.cpm> wrote:
On Tue, 29 Dec 2020 02:26:42 -0800
bilsch01 <fy247@nospicedham.always.com> wrote:
True or False:
test al,al sets ZF only if al = 0
Look up TEST instruction here:
http://qcd.phys.cmu.edu/QCDcluster/intel/vtune/reference/About_IA-32
does-structions.htmor elsewhere
That's a browse-able HTML version of an IA-32 manual.
https://reverseengineering.stackexchange.com/questions/25188/what-
test-al-al-meanCMP AX,0 is longer than TEST AX,AX but I'm not sure if the same is true
Yes. But why do that if you want to test if al=0? far clearer to code
"cmp al,0"
but is cy set identically? back at the OP!
for CMP AL,0? I.e. is there a one-byte form of CMP AL with a one-byte immediate?
Terje
On 12/30/20 2:18 AM, Rod Pemberton wrote:
On Tue, 29 Dec 2020 02:26:42 -0800
bilsch01 <fy247@nospicedham.always.com> wrote:
True or False:
test al,al sets ZF only if al = 0
Look up TEST instruction here:
http://qcd.phys.cmu.edu/QCDcluster/intel/vtune/reference/About_IA-32_Instructions.htm
That's a browse-able HTML version of an IA-32 manual.
I've been using this one.
http://www.felixcloutier.com/x86/
I couldn't believe what I read.
The ref you provide is no more help to me.
I found the following, which I recognize - answered my question.
00000102Â BEC87DÂ Â Â Â Â Â Â Â Â Â Â mov si,0x7dc8Â ;msg: Error. 00000105Â ACÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â lodsb
00000106Â 84C0Â Â Â Â Â Â Â Â Â Â Â Â Â test al,al
00000108Â 74FCÂ Â Â Â Â Â Â Â Â Â Â Â Â jz 0x106
0000010AÂ B40EÂ Â Â Â Â Â Â Â Â Â Â Â Â mov ah,0xe
0000010CÂ B307Â Â Â Â Â Â Â Â Â Â Â Â Â mov bl,0x7
0000010EÂ CD10Â Â Â Â Â Â Â Â Â Â Â Â Â int 0x10
00000110Â EBF3Â Â Â Â Â Â Â Â Â Â Â Â Â jmp short 0x105
Consider this: Why not just answer the question that was asked?
Thanks for your post.  Bill S.
The ref you provide is no more help to me.
Consider this: Why not just answer the question that was asked?
On Wed, 30 Dec 2020 18:12:37 GMT, Terje Mathisen <terje.mathisen@nospicedham.tmsw.no> wrote:
for CMP AL,0? I.e. is there a one-byte form of CMP AL with a one-byte
immediate?
Terje
Hugi tips & tricks snippet:
1. Test the value in AL
To test whether AL is 0 or 1, one single-byte instruction is enough:
aaa
jz @zero
I'm not claiming it's faster than "test".
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