Re: [OpenBIOS] [PATCH 9/10] Divide by zero check

[Artyom Tarasenko]

On Tue, Aug 9, 2011 at 11:55 PM, William Hahne  wrote:
> It is possible for BootX to purposefully divide by zero expecting 0 as the
> result.

OBP behaves differently. It puts the result only if there was no
devision by zero:

ok showstack
ok 0 0 /
Trap 3e
ok 1 0 /
Trap 3e
ok 10 8 /
2 ok

Maybe it has to be done platform-dependent.
> Index: kernel/forth.c
>
> --- kernel/forth.c (revision 1041)
> +++ kernel/forth.c (working copy)
> @@ -1157,6 +1157,12 @@
>  {
>   const ucell b = POP();
>   const ducell a = DPOP();
> if (b == 0) { // can't divide by zero
> PUSH(0);
>
> +            DPUSH(0);
> return;
> }
>
> #ifdef NEED_FAKE_INT128_T
>          if (a.hi != 0) {
>              fprintf(stderr, "mudivmod called (0x%016llx %016llx /
> 0x%016llx)\n",
> --
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