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

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VFP used __divdi3 64-bit division needlessly.  Convert it to use
our 64-bit by 32-bit division instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2005-06-29 23:01:02 +01:00 committed by Russell King
parent b3402cf50e
commit 438a761679
3 changed files with 27 additions and 4 deletions
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15
arch/arm/vfp/vfp.h
View File

@ -117,7 +117,13 @@ static inline u64 vfp_estimate_div128to64(u64 nh, u64 nl, u64 m)
if (nh >= m) if (nh >= m)
return ~0ULL; return ~0ULL;
mh = m >> 32; 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); mul64to128(&termh, &terml, m, z);
sub128(&remh, &reml, nh, nl, termh, terml); sub128(&remh, &reml, nh, nl, termh, terml);
ml = m << 32; 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); add128(&remh, &reml, remh, reml, mh, ml);
} }
remh = (remh << 32) | (reml >> 32); 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; return z;
} }

2
arch/arm/vfp/vfpdouble.c
View File

@ -32,6 +32,8 @@
*/ */
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/bitops.h> #include <linux/bitops.h>
#include <asm/div64.h>
#include <asm/ptrace.h> #include <asm/ptrace.h>
#include <asm/vfp.h> #include <asm/vfp.h>

14
arch/arm/vfp/vfpsingle.c
View File

@ -32,6 +32,8 @@
*/ */
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/bitops.h> #include <linux/bitops.h>
#include <asm/div64.h>
#include <asm/ptrace.h> #include <asm/ptrace.h>
#include <asm/vfp.h> #include <asm/vfp.h>
@ -303,7 +305,11 @@ u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand)
if (z <= a) if (z <= a)
return (s32)a >> 1; 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) 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; vsn.significand >>= 1;
vsd.exponent++; 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) if ((vsd.significand & 0x3f) == 0)
vsd.significand |= ((u64)vsm.significand * vsd.significand != (u64)vsn.significand << 32); vsd.significand |= ((u64)vsm.significand * vsd.significand != (u64)vsn.significand << 32);