| /* |
| * 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 |
| ldmeqfd 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 |
| mov pc, lr |