diff options
Diffstat (limited to 'arch/arm/lib/memset.S')
-rw-r--r-- | arch/arm/lib/memset.S | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S new file mode 100644 index 00000000000..a1795f59993 --- /dev/null +++ b/arch/arm/lib/memset.S @@ -0,0 +1,80 @@ +/* + * 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 + .word 0 + +1: subs r2, r2, #4 @ 1 do we have enough + blt 5f @ 1 bytes to align with? + cmp r3, #2 @ 1 + strltb r1, [r0], #1 @ 1 + strleb r1, [r0], #1 @ 1 + strb r1, [r0], #1 @ 1 + add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3)) +/* + * The pointer is now aligned and the length is adjusted. Try doing the + * memzero again. + */ + +ENTRY(memset) + ands r3, r0, #3 @ 1 unaligned? + bne 1b @ 1 +/* + * we know that the pointer in r0 is aligned to a word boundary. + */ + orr r1, r1, r1, lsl #8 + orr r1, r1, r1, lsl #16 + mov r3, r1 + cmp r2, #16 + blt 4f +/* + * We need an extra register for this loop - save the return address and + * use the LR + */ + str lr, [sp, #-4]! + mov ip, r1 + mov lr, r1 + +2: subs r2, r2, #64 + stmgeia r0!, {r1, r3, ip, lr} @ 64 bytes at a time. + stmgeia r0!, {r1, r3, ip, lr} + stmgeia r0!, {r1, r3, ip, lr} + stmgeia r0!, {r1, r3, ip, lr} + bgt 2b + LOADREGS(eqfd, sp!, {pc}) @ Now <64 bytes to go. +/* + * No need to correct the count; we're only testing bits from now on + */ + tst r2, #32 + stmneia r0!, {r1, r3, ip, lr} + stmneia r0!, {r1, r3, ip, lr} + tst r2, #16 + stmneia r0!, {r1, r3, ip, lr} + ldr lr, [sp], #4 + +4: tst r2, #8 + stmneia r0!, {r1, r3} + tst r2, #4 + strne r1, [r0], #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 + strneb r1, [r0], #1 + strneb r1, [r0], #1 + tst r2, #1 + strneb r1, [r0], #1 + RETINSTR(mov,pc,lr) |