linux/arch/arm/lib/io-writesb.S

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/*
* linux/arch/arm/lib/io-writesb.S
*
* Copyright (C) 1995-2000 Russell King
*
* 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>
#include <asm/assembler.h>
.macro outword, rd
#ifndef __ARMEB__
strb \rd, [r0]
mov \rd, \rd, lsr #8
strb \rd, [r0]
mov \rd, \rd, lsr #8
strb \rd, [r0]
mov \rd, \rd, lsr #8
strb \rd, [r0]
#else
mov lr, \rd, lsr #24
strb lr, [r0]
mov lr, \rd, lsr #16
strb lr, [r0]
mov lr, \rd, lsr #8
strb lr, [r0]
strb \rd, [r0]
#endif
.endm
.Loutsb_align: rsb ip, ip, #4
cmp ip, r2
movgt ip, r2
cmp ip, #2
ldrb r3, [r1], #1
strb r3, [r0]
ldrgeb r3, [r1], #1
strgeb r3, [r0]
ldrgtb r3, [r1], #1
strgtb r3, [r0]
subs r2, r2, ip
bne .Loutsb_aligned
ENTRY(__raw_writesb)
teq r2, #0 @ do we have to check for the zero len?
moveq pc, lr
ands ip, r1, #3
bne .Loutsb_align
.Loutsb_aligned:
stmfd sp!, {r4, r5, lr}
subs r2, r2, #16
bmi .Loutsb_no_16
.Loutsb_16_lp: ldmia r1!, {r3, r4, r5, ip}
outword r3
outword r4
outword r5
outword ip
subs r2, r2, #16
bpl .Loutsb_16_lp
tst r2, #15
ldmeqfd sp!, {r4, r5, pc}
.Loutsb_no_16: tst r2, #8
beq .Loutsb_no_8
ldmia r1!, {r3, r4}
outword r3
outword r4
.Loutsb_no_8: tst r2, #4
beq .Loutsb_no_4
ldr r3, [r1], #4
outword r3
.Loutsb_no_4: ands r2, r2, #3
ldmeqfd sp!, {r4, r5, pc}
cmp r2, #2
ldrb r3, [r1], #1
strb r3, [r0]
ldrgeb r3, [r1], #1
strgeb r3, [r0]
ldrgtb r3, [r1]
strgtb r3, [r0]
ldmfd sp!, {r4, r5, pc}