Author: Bruce Moreland
Date: 23:18:41 01/26/99
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On January 27, 1999 at 01:32:28, Eugene Nalimov wrote: >On January 26, 1999 at 22:38:37, James Robertson wrote: > >>Once again I show my absolute ignorance of assembly with these two questions: >>I am trying to acces the 3rd [+ 4th] byte of a register. How? E.g., what is next >>after al, ah, ? >>How do I pop something off the stack without moving the stack pointer? >> >>Thanks, >>James > >1. Use shift instruction. E.g. > shr eax, 16 > mov byte ptr [esi], al > You can also use rotate instruction (it'll not destruct > other bytes): > ror eax, 16 > mov byte ptr [esi], al > ror eax, 16 > But if I remember it correctly, rotate is worse than shift > (cannot be executed in parallel) on both Pentium and P6 family. The shift also sucks, AFAIK. >2. mov reg32, dword ptr [esp] esp - 4, right? But can you say [esp - 4]? I seem to remember that you can't. bruce > >Eugene
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