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From: George van Venrooij <george AT il DOT ft DOT hse DOT nl>
Newsgroups: comp.os.msdos.djgpp
Subject: Optimization and Inline Assembler
Date: 14 Oct 1995 09:49:47 GMT
Organization: Hogeschool Eindhoven
Lines: 16
Nntp-Posting-Host: u86401.hi.ft.hse.nl
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

I have a little question about inline asm-statements:

When I use registers in the input-field, so I could assume a value was in 
a register when my asm code ran, I found that listing registers that were 
only changed by the asm-code as 'changed' worked fine without 
optimization, but gave errors when optimizing.

I managed to correct this by listing the input-registers with the others 
as registers that were changed.

The looked something like this (it doesn't matter really):

asm volatile("cdq; \
              idivl %%ebx"
: "=a" (var1) : "b" (var2)