Re: [PATCH 2/4] lib: vsprintf: Optimize division by 10000

[George Spelvin]

Michal Nazarewicz <mpn@xxxxxxxxxx> 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.
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