| /* |
| * 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, [ip], #1 @ 1 |
| strleb r1, [ip], #1 @ 1 |
| strb r1, [ip], #1 @ 1 |
| add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3)) |
| /* |
| * The pointer is now aligned and the length is adjusted. Try doing the |
| * memset again. |
| */ |
| |
| ENTRY(memset) |
| /* |
| * Preserve the contents of r0 for the return value. |
| */ |
| mov ip, r0 |
| ands r3, ip, #3 @ 1 unaligned? |
| bne 1b @ 1 |
| /* |
| * we know that the pointer in ip 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 |
| |
| #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 |
| stmgeia ip!, {r1, r3, r8, lr} @ 64 bytes at a time. |
| stmgeia ip!, {r1, r3, r8, lr} |
| stmgeia ip!, {r1, r3, r8, lr} |
| stmgeia ip!, {r1, r3, r8, lr} |
| bgt 2b |
| ldmeqfd 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 |
| stmneia ip!, {r1, r3, r8, lr} |
| stmneia ip!, {r1, r3, r8, lr} |
| tst r2, #16 |
| stmneia 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) |
| stmcsia ip!, {r4, r5, r6, r7} |
| stmmiia ip!, {r4, r5} |
| tst r8, #(1 << 30) |
| mov r8, r1 |
| strne r1, [ip], #4 |
| |
| 3: subs r2, r2, #64 |
| stmgeia ip!, {r1, r3-r8, lr} |
| stmgeia ip!, {r1, r3-r8, lr} |
| bgt 3b |
| ldmeqfd sp!, {r4-r8, pc} |
| |
| tst r2, #32 |
| stmneia ip!, {r1, r3-r8, lr} |
| tst r2, #16 |
| stmneia ip!, {r4-r7} |
| ldmfd sp!, {r4-r8, lr} |
| |
| #endif |
| |
| 4: tst r2, #8 |
| stmneia 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 |
| strneb r1, [ip], #1 |
| strneb r1, [ip], #1 |
| tst r2, #1 |
| strneb r1, [ip], #1 |
| mov pc, lr |
| ENDPROC(memset) |