Re: [linuxsh-dev] Other changes

[Mitch D. <md...@po...>]

NIIBE Yutaka wrote:
> 
> Support "syscall" syscall and assembler change.  The register name
> in the input/output/clobber list, no "$" would be correct.

Hi Niibe-san,

A couple of months ago, registers did not have dollar signs on the
front.
But then the decision was made to add dollars (which I think is a good
idea).
For a while we had code with both styles, but we got that sorted out. 
Now
I see code without dollars again - sometimes.

Looking at your mail, this code keeps its dollar:

>                 "mov    $r0, $r4\n\t"   /* return value to arg of exit */
> -               "mov    %2, $r3\n\t"    /* exit */
> +               "mov    %1, $r3\n\t"    /* exit */
>                 "trapa  #0x11\n"

This code does not:

>  {
> -    register long r0 __asm__("$r0") = func;
> -    register long r4 __asm__("$r4") = arg0;
> -    register long r5 __asm__("$r5") = arg1;
> -    register long r6 __asm__("$r6") = arg2;
> -    register long r7 __asm__("$r7") = arg3;
> +    register long r0 __asm__("r0") = func;
> +    register long r4 __asm__("r4") = arg0;
> +    register long r5 __asm__("r5") = arg1;
> +    register long r6 __asm__("r6") = arg2;
> +    register long r7 __asm__("r7") = arg3;
>      __asm__ __volatile__("trapa        #0x3f"

I am very confused.  I am not questioning your wisdom, but I do wish I
knew
what the rationale is - when should one use a dollar, when should one
not,
and what should we do in the future.

Regards,

Mitch.