[FFmpeg-devel] [PATCH]Drop local label from ppc asm timer

[Carl Eugen Hoyos]

Michael Niedermayer <michaelni <at> gmx.at> writes:

> > > > Attached patch allows compilation of ppc asm 
> > > > timer on aix, the aix assembler does not 
> > > > support local labels.
> > > 
> > > how does the compiler do if() if it has no 
> > > (local) labels ?
> > 
> > Hm, isn't PPC a fixed-size instruction architecture?
> > Then it can calculate the offset based on the number 
> > of instructions.
> 
> > But yes, seeing an if() compiled with -S to 
> > assembler code would be interesting.
> 
> does make ffmpeg.s or (some smalelr source file) not work ?
> It would show the used syntax for branches and labels

Labels are no problem for the assembler, but I 
don't think it supports local labels (that may 
be used multiple times).

f(int x)
{
    if (x > 0)
        return 0;
    else
        return 1;
}

        .file   "test.c"
        .csect .text[PR]
        .toc
        .csect .text[PR]
        .align 2
        .globl f
        .globl .f
        .csect f[DS]
f:
        .long .f, TOC[tc0], 0
        .csect .text[PR]
.f:
        stw 31,-4(1)
        stwu 1,-32(1)
        mr 31,1
        stw 3,56(31)
        lwz 9,56(31)
        cmpwi 7,9,0
        ble 7,L..2
        li 9,0
        b L..3
L..2:
        li 9,1
L..3:
        mr 3,9
        addi 1,31,32
        lwz 31,-4(1)
        blr
LT..f:
        .long 0
        .byte 0,0,32,96,128,1,1,1
        .long 0
        .long LT..f-.f
        .short 1
        .byte "f"
        .byte 31
        .align 2
_section_.text:
        .csect .data[RW],4
        .long _section_.text