kernel_optimize_test/arch/arm/lib/muldi3.S
Nicolas Pitre f741a1aab5 [ARM] 3049/1: More optimized libgcc functions
Patch from Nicolas Pitre

This patch gets rid of the last C implementations of needed libgcc
functions for the kernel, replacing them with optimized assembly
versions.

Those functions are:

__ashldi3
__ashrdi3
__lshrdi3
__muldi3
__ucmpdi2

The first 3 were lifted from gcc, the other two were written from scratch.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-30 23:08:03 +00:00

45 lines
837 B
ArmAsm

/*
* linux/arch/arm/lib/muldi3.S
*
* Author: Nicolas Pitre
* Created: Oct 19, 2005
* Copyright: Monta Vista Software, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#ifdef __ARMEB__
#define xh r0
#define xl r1
#define yh r2
#define yl r3
#else
#define xl r0
#define xh r1
#define yl r2
#define yh r3
#endif
ENTRY(__muldi3)
mul xh, yl, xh
mla xh, xl, yh, xh
mov ip, xl, asr #16
mov yh, yl, asr #16
bic xl, xl, ip, lsl #16
bic yl, yl, yh, lsl #16
mla xh, yh, ip, xh
mul yh, xl, yh
mul xl, yl, xl
mul ip, yl, ip
adds xl, xl, yh, lsl #16
adc xh, xh, yh, lsr #16
adds xl, xl, ip, lsl #16
adc xh, xh, ip, lsr #16
mov pc, lr