At Wed, 23 Aug 2006 11:02:24 +0100,
Andrew Haley wrote:
>
> Weird. There's not really enough information here. Can you provide
> the .s file from the compiler? That would give us more of a clue.
I've attached it below.
At Wed, 23 Aug 2006 11:14:45 +0100,
Andrew Haley wrote:
>
> Simon Kagstrom writes:
> >
> > #define _syscall1(type,name,atype,a) \
> > type name(atype a) { \
> > register unsigned long __v0 asm("$2"); \
> > __asm__ volatile (".set push\n.set noreorder\n"); \
> > __emit_parameter(a); \
> > __asm__ volatile ( \
> > ".short 0xffff\t#" #name "\n\t" \
> > ".short %1\n" \
> > : "=&r" (__v0) \
> > : "i" (__NR_##name) ); \
> > __asm__ volatile(".set\tpop\n"); \
> > return (type) __v0; \
> > }
>
> I'm still trying to get my head around what the assembler will do when
> gcc moves these asms around.
>
> Put the ".set push\n.set noreorder\n" stuff *inside* the asms. Please. :-)
I tried placing the .set push / .set noreorder stuff in the
__emit_parameter and the main asm statement, and the generated code
looks better:
1002314: addiu sp,sp,72
1002318: 0xfffe0009
100231c: j 100229c <test_malloc+0x144>
1002320: nop
01002324 <main>:
1002324: addiu sp,sp,-24
But I cannot quite understand where the difference comes from. What I
would like the original macro to generate is:
.set push
.set noreorder
.long 0xfffe0009
.short 0xffff
.short 9
.set pop
Is the problem perhaps that GCC outputs assembly directives "between"
the __emit_parameter and the main asm statement without pushing the
current settings?
// Simon
Attachment:
main.s
Description: Binary data
