From: dontmailme AT iname DOT com (Steamer)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Help with Inline ASM...
Date: Fri, 14 Apr 2000 11:59:43 GMT
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Thomas J. Hruska wrote:

>Basically, the ASM code does nothing, but I want to be able to self-modify
>the code during run-time and replace the number $32 with the value in y.
>The assembler complains whenever I try replacing the $32 with a variable
>and I think that the only way that I am going to get that number to change
>is to self-modify.  If someone knows of a better solution, let me know.
>Otherwise, how do I self-modify ASM code in 32-bit PM (if such a thing is
>even allowed).

Instead of

    rol $32, %%eax

you can use

    rol %%cl, %%eax

after copying the value of y into ECX.

Unless you have a good reason to do this inline, you're probably
better off writing the assembly code in a separate file and using
NASM, since inline assembler can be difficult to get right. (Also,
the use of CL can cause a partial register stall on current Intel
processors.  This can easily be avoided if the whole procedure is
coded in asm, but might be tricky to avoid with inline asm.)

S.