lkml.org 
[lkml]   [2012]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/4] lib: vsprintf: Optimize division by 10000
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.


\
 
 \ /
  Last update: 2012-09-24 16:41    [W:0.507 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site