Messages in this thread | | | Date | Mon, 24 Sep 2012 17:14:00 +0200 | Subject | Re: [PATCH 2/4] lib: vsprintf: Optimize division by 10000 | From | Geert Uytterhoeven <> |
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On Mon, Sep 24, 2012 at 3:56 PM, George Spelvin <linux@horizon.com> wrote: > Michal Nazarewicz <mpn@google.com> wrote: >> Didn't some SPARCs have 32x32->32 multiply? I remember reading some >> rant from a GMP developer about how SPARC is broken that way. > > SPARCv9 only has 64x64->64; there's no 128-bit result version. > That cuts large-integer math speed by a factor of 4 (very > crude approximation), to the same speed as 32x32->64. > > SPARCv8 UMUL puts the high half of the 64-bit result into the Y > register, and SPARCv7 has a multiply-step instruction (MULScc) which > does likewise.
Early SPARCs don't even have a multiply instruction.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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