Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm/lib/memset.S |
| 3 | * |
| 4 | * Copyright (C) 1995-2000 Russell King |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * ASM optimised string functions |
| 11 | */ |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 12 | |
| 13 | #include <arch/asm.h> |
| 14 | #include "asmlib.h" |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 15 | |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 16 | ENTRY(memset) |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 17 | ands r3, r0, #3 @ 1 unaligned? |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 18 | mov ip, r0 @ preserve r0 as return value |
| 19 | bne 6f @ 1 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 20 | /* |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 21 | * we know that the pointer in ip is aligned to a word boundary. |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 22 | */ |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 23 | 1: orr r1, r1, r1, lsl #8 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 24 | orr r1, r1, r1, lsl #16 |
| 25 | mov r3, r1 |
| 26 | cmp r2, #16 |
| 27 | blt 4f |
| 28 | |
| 29 | #if ! CALGN(1)+0 |
| 30 | |
| 31 | /* |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 32 | * We need 2 extra registers for this loop - use r8 and the LR |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 33 | */ |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 34 | stmfd sp!, {r8, lr} |
| 35 | mov r8, r1 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 36 | mov lr, r1 |
| 37 | |
| 38 | 2: subs r2, r2, #64 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 39 | stmgeia ip!, {r1, r3, r8, lr} @ 64 bytes at a time. |
| 40 | stmgeia ip!, {r1, r3, r8, lr} |
| 41 | stmgeia ip!, {r1, r3, r8, lr} |
| 42 | stmgeia ip!, {r1, r3, r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 43 | bgt 2b |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 44 | ldmeqfd sp!, {r8, pc} @ Now <64 bytes to go. |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 45 | /* |
| 46 | * No need to correct the count; we're only testing bits from now on |
| 47 | */ |
| 48 | tst r2, #32 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 49 | stmneia ip!, {r1, r3, r8, lr} |
| 50 | stmneia ip!, {r1, r3, r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 51 | tst r2, #16 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 52 | stmneia ip!, {r1, r3, r8, lr} |
| 53 | ldmfd sp!, {r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 54 | |
| 55 | #else |
| 56 | |
| 57 | /* |
| 58 | * This version aligns the destination pointer in order to write |
| 59 | * whole cache lines at once. |
| 60 | */ |
| 61 | |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 62 | stmfd sp!, {r4-r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 63 | mov r4, r1 |
| 64 | mov r5, r1 |
| 65 | mov r6, r1 |
| 66 | mov r7, r1 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 67 | mov r8, r1 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 68 | mov lr, r1 |
| 69 | |
| 70 | cmp r2, #96 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 71 | tstgt ip, #31 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 72 | ble 3f |
| 73 | |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 74 | and r8, ip, #31 |
| 75 | rsb r8, r8, #32 |
| 76 | sub r2, r2, r8 |
| 77 | movs r8, r8, lsl #(32 - 4) |
| 78 | stmcsia ip!, {r4, r5, r6, r7} |
| 79 | stmmiia ip!, {r4, r5} |
| 80 | tst r8, #(1 << 30) |
| 81 | mov r8, r1 |
| 82 | strne r1, [ip], #4 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 83 | |
| 84 | 3: subs r2, r2, #64 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 85 | stmgeia ip!, {r1, r3-r8, lr} |
| 86 | stmgeia ip!, {r1, r3-r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 87 | bgt 3b |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 88 | ldmeqfd sp!, {r4-r8, pc} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 89 | |
| 90 | tst r2, #32 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 91 | stmneia ip!, {r1, r3-r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 92 | tst r2, #16 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 93 | stmneia ip!, {r4-r7} |
| 94 | ldmfd sp!, {r4-r8, lr} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 95 | |
| 96 | #endif |
| 97 | |
| 98 | 4: tst r2, #8 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 99 | stmneia ip!, {r1, r3} |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 100 | tst r2, #4 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 101 | strne r1, [ip], #4 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 102 | /* |
| 103 | * When we get here, we've got less than 4 bytes to zero. We |
| 104 | * may have an unaligned pointer as well. |
| 105 | */ |
| 106 | 5: tst r2, #2 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 107 | strneb r1, [ip], #1 |
| 108 | strneb r1, [ip], #1 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 109 | tst r2, #1 |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 110 | strneb r1, [ip], #1 |
Stefan Reinauer | 52db0b9 | 2012-12-07 17:15:04 -0800 | [diff] [blame] | 111 | mov pc, lr |
Julius Werner | d65e214 | 2013-12-13 12:59:57 -0800 | [diff] [blame] | 112 | |
| 113 | 6: subs r2, r2, #4 @ 1 do we have enough |
| 114 | blt 5b @ 1 bytes to align with? |
| 115 | cmp r3, #2 @ 1 |
| 116 | strltb r1, [ip], #1 @ 1 |
| 117 | strleb r1, [ip], #1 @ 1 |
| 118 | strb r1, [ip], #1 @ 1 |
| 119 | add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3)) |
| 120 | b 1b |
| 121 | ENDPROC(memset) |