u-boot-brain/arch/arm/lib/memset.S
Tom Rini 3a649407a4 arm: Migrate SYS_THUMB_BUILD to Kconfig, introduce SPL_SYS_THUMB_BUILD
Today, we have cases where we wish to build all of U-Boot in Thumb2 mode for
various reasons.  We also have cases where we only build SPL in Thumb2 mode due
to size constraints and wish to build the rest of the system in ARM mode.  So
in this migration we introduce a new symbol as well, SPL_SYS_THUMB_BUILD to
control if we build everything or just SPL (or in theory, just U-Boot) in
Thumb2 mode.

Signed-off-by: Tom Rini <trini@konsulko.com>
Acked-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
2017-03-18 20:28:01 -04:00

129 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
#if CONFIG_IS_ENABLED(SYS_THUMB_BUILD) && !defined(MEMSET_NO_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)