u-boot/arch/arm/lib/memset.S
Stefan Agner 75d7a0d7f1 arm: build arch memset/memcpy in Thumb2 mode
Resynchronize memcpy/memset with kernel 3.17 and build them in
Thumb2 mode (unified syntax). Those assembler files can be built
and linked in ARM mode too, however when calling them from Thumb2
built code, the stack got corrupted and the copy did not succeed
(the exact details have not been traced back). However, the Linux
kernel builds those files in Thumb2 mode. Hence U-Boot should
build them in Thumb2 mode too when CONFIG_SYS_THUMB_BUILD is set.

To build the files without warning, some assembler instructions
had to be replaced with their UAL compliant variant (thanks
Jeroen for this input).

To build the file in Thumb2 mode the implicit-it=always option need
to be set to generate Thumb2 compliant IT instructions where needed.
We add this option to the general AFLAGS when building for Thumb2.

Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Stefan Agner <stefan@agner.ch>
2015-01-09 10:20:22 -05:00

128 lines
2.4 KiB
ArmAsm

/*
* linux/arch/arm/lib/memset.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.
*
* ASM optimised string functions
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.text
.align 5
.syntax unified
#ifdef CONFIG_SYS_THUMB_BUILD
.thumb
.thumb_func
#endif
ENTRY(memset)
ands r3, r0, #3 @ 1 unaligned?
mov ip, r0 @ preserve r0 as return value
bne 6f @ 1
/*
* we know that the pointer in ip is aligned to a word boundary.
*/
1: orr r1, r1, r1, lsl #8
orr r1, r1, r1, lsl #16
mov r3, r1
cmp r2, #16
blt 4f
#if ! CALGN(1)+0
/*
* We need 2 extra registers for this loop - use r8 and the LR
*/
stmfd sp!, {r8, lr}
mov r8, r1
mov lr, r1
2: subs r2, r2, #64
stmiage ip!, {r1, r3, r8, lr} @ 64 bytes at a time.
stmiage ip!, {r1, r3, r8, lr}
stmiage ip!, {r1, r3, r8, lr}
stmiage ip!, {r1, r3, r8, lr}
bgt 2b
ldmfdeq sp!, {r8, pc} @ Now <64 bytes to go.
/*
* No need to correct the count; we're only testing bits from now on
*/
tst r2, #32
stmiane ip!, {r1, r3, r8, lr}
stmiane ip!, {r1, r3, r8, lr}
tst r2, #16
stmiane ip!, {r1, r3, r8, lr}
ldmfd sp!, {r8, lr}
#else
/*
* This version aligns the destination pointer in order to write
* whole cache lines at once.
*/
stmfd sp!, {r4-r8, lr}
mov r4, r1
mov r5, r1
mov r6, r1
mov r7, r1
mov r8, r1
mov lr, r1
cmp r2, #96
tstgt ip, #31
ble 3f
and r8, ip, #31
rsb r8, r8, #32
sub r2, r2, r8
movs r8, r8, lsl #(32 - 4)
stmiacs ip!, {r4, r5, r6, r7}
stmiami ip!, {r4, r5}
tst r8, #(1 << 30)
mov r8, r1
strne r1, [ip], #4
3: subs r2, r2, #64
stmiage ip!, {r1, r3-r8, lr}
stmiage ip!, {r1, r3-r8, lr}
bgt 3b
ldmfdeq sp!, {r4-r8, pc}
tst r2, #32
stmiane ip!, {r1, r3-r8, lr}
tst r2, #16
stmiane ip!, {r4-r7}
ldmfd sp!, {r4-r8, lr}
#endif
4: tst r2, #8
stmiane ip!, {r1, r3}
tst r2, #4
strne r1, [ip], #4
/*
* When we get here, we've got less than 4 bytes to zero. We
* may have an unaligned pointer as well.
*/
5: tst r2, #2
strbne r1, [ip], #1
strbne r1, [ip], #1
tst r2, #1
strbne r1, [ip], #1
ret lr
6: subs r2, r2, #4 @ 1 do we have enough
blt 5b @ 1 bytes to align with?
cmp r3, #2 @ 1
strblt r1, [ip], #1 @ 1
strble r1, [ip], #1 @ 1
strb r1, [ip], #1 @ 1
add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
b 1b
ENDPROC(memset)