Commit 438a7616 authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[PATCH] ARM: Fix VFP to use do_div()



VFP used __divdi3 64-bit division needlessly.  Convert it to use
our 64-bit by 32-bit division instead.
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent b3402cf5
......@@ -117,7 +117,13 @@ static inline u64 vfp_estimate_div128to64(u64 nh, u64 nl, u64 m)
if (nh >= m)
return ~0ULL;
mh = m >> 32;
z = (mh << 32 <= nh) ? 0xffffffff00000000ULL : (nh / mh) << 32;
if (mh << 32 <= nh) {
z = 0xffffffff00000000ULL;
} else {
z = nh;
do_div(z, mh);
z <<= 32;
}
mul64to128(&termh, &terml, m, z);
sub128(&remh, &reml, nh, nl, termh, terml);
ml = m << 32;
......@@ -126,7 +132,12 @@ static inline u64 vfp_estimate_div128to64(u64 nh, u64 nl, u64 m)
add128(&remh, &reml, remh, reml, mh, ml);
}
remh = (remh << 32) | (reml >> 32);
z |= (mh << 32 <= remh) ? 0xffffffff : remh / mh;
if (mh << 32 <= remh) {
z |= 0xffffffff;
} else {
do_div(remh, mh);
z |= remh;
}
return z;
}
......
......@@ -32,6 +32,8 @@
*/
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <asm/div64.h>
#include <asm/ptrace.h>
#include <asm/vfp.h>
......
......@@ -32,6 +32,8 @@
*/
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <asm/div64.h>
#include <asm/ptrace.h>
#include <asm/vfp.h>
......@@ -303,7 +305,11 @@ u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand)
if (z <= a)
return (s32)a >> 1;
}
return (u32)(((u64)a << 31) / z) + (z >> 1);
{
u64 v = (u64)a << 31;
do_div(v, z);
return v + (z >> 1);
}
}
static u32 vfp_single_fsqrt(int sd, int unused, s32 m, u32 fpscr)
......@@ -1107,7 +1113,11 @@ static u32 vfp_single_fdiv(int sd, int sn, s32 m, u32 fpscr)
vsn.significand >>= 1;
vsd.exponent++;
}
vsd.significand = ((u64)vsn.significand << 32) / vsm.significand;
{
u64 significand = (u64)vsn.significand << 32;
do_div(significand, vsm.significand);
vsd.significand = significand;
}
if ((vsd.significand & 0x3f) == 0)
vsd.significand |= ((u64)vsm.significand * vsd.significand != (u64)vsn.significand << 32);
......
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