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| comp.lang.asm.x86 | Ahh, the lost art of x86 assembly | 4,675 messages |
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| Message 4,261 of 4,675 |
| Bernhard Schornak to All |
| Re: test al,al setting of ZF |
| 30 Dec 20 14:45:22 |
From: schornak@nospicedham.web.de bilsch01 wrote: > True or False: > test al,al sets ZF only if al = 0 > > TIA. Bill S. testb %al, %al internally performs andb %al, %al without writing the result to the destination. Hence, andb %al, %al sets ZF if %al is zero. in all other cases, ZF is cleared. PF and SF are set according to %al's content. CF and OF are set to zero, no matter, what %al currently holds. "AMD64 Architecture Programmer’s Manual Volume 3: General-Purpose and System Instructions" [PDF 24594, page 342] Greetings from Augburg Bernhard Schornak --- SoupGate-Win32 v1.05 * Origin: you cannot sedate... all the things you hate (1:229/2) |
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