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__asm behavior, "+" parameters, and c-parse.in
- To: egcs at egcs dot cygnus dot com
- Subject: __asm behavior, "+" parameters, and c-parse.in
- From: Marc Espie <Marc dot Espie at liafa dot jussieu dot fr>
- Date: Fri, 22 Jan 1999 02:37:48 +0100
- Cc: mickey at cvs dot openbsd dot org
Assume a sequence of assembler instructions that has only input/output
operands, plus side-effect on memory.
Unless I'm missing something, the simplest way to write this would be
to specify read/write output parameters ("+regclass"), no input parameters,
and clobbers.
The current C parser can only read asm that look like
asm(instr) or asm(instr : input) or asm(instr : input: output) or
asm(instr : input: output: clobbers), but there is no provision for
asm(instr : input : clobbers).
asm(instr : input : : clobbers) does not work either, results in a syntax
error.
As far as I could tell, there is no possible ambiguity between input/output
and clobbers, so this should be easy to add.
It may be that I'm missing something and there is a good reason to use
the more intricate "=regclass" (par) : "number" (par) input/output match.
--
Marc Espie
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