| David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 1 | /* Optimised simple memory fill |
| 2 | * |
| 3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public Licence |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the Licence, or (at your option) any later version. |
| 10 | */ |
| 11 | #include <asm/cache.h> |
| 12 | |
| 13 | .section .text |
| 14 | .balign L1_CACHE_BYTES |
| 15 | |
| 16 | ############################################################################### |
| 17 | # |
| 18 | # void *memset(void *dst, int c, size_t n) |
| 19 | # |
| 20 | ############################################################################### |
| 21 | .globl memset |
| 22 | .type memset,@function |
| 23 | memset: |
| 24 | movm [d2,d3],(sp) |
| 25 | mov d0,(12,sp) |
| 26 | mov d1,(16,sp) |
| 27 | mov (20,sp),d2 # count |
| 28 | mov d0,a0 # dst |
| 29 | mov d0,e3 # the return value |
| 30 | |
| 31 | cmp +0,d2 |
| 32 | beq memset_done # return if zero-length fill |
| 33 | |
| 34 | # see if the region parameters are four-byte aligned |
| 35 | or d0,d2,d3 |
| 36 | and +3,d3 |
| 37 | bne memset_1 # jump if not |
| 38 | |
| 39 | extbu d1 |
| 40 | mov_asl d1,d3,8,d1 |
| 41 | or_asl d1,d3,8,d1 |
| 42 | or_asl d1,d3,8,d1 |
| 43 | or d3,d1 |
| 44 | |
| 45 | # we want to transfer as much as we can in chunks of 32 bytes |
| 46 | cmp +31,d2 |
| 47 | bls memset_4_remainder # 4-byte aligned remainder |
| 48 | |
| 49 | add -32,d2 |
| 50 | mov +32,d3 |
| 51 | |
| 52 | memset_4_loop: |
| 53 | mov d1,(a0+) |
| 54 | mov d1,(a0+) |
| 55 | mov d1,(a0+) |
| 56 | mov d1,(a0+) |
| 57 | mov d1,(a0+) |
| 58 | mov d1,(a0+) |
| 59 | mov d1,(a0+) |
| 60 | mov d1,(a0+) |
| 61 | |
| 62 | sub d3,d2 |
| 63 | bcc memset_4_loop |
| 64 | |
| 65 | add d3,d2 |
| 66 | beq memset_4_no_remainder |
| 67 | |
| 68 | memset_4_remainder: |
| 69 | # cut 4-7 words down to 0-3 |
| 70 | cmp +16,d2 |
| 71 | bcs memset_4_three_or_fewer_words |
| 72 | mov d1,(a0+) |
| 73 | mov d1,(a0+) |
| 74 | mov d1,(a0+) |
| 75 | mov d1,(a0+) |
| 76 | add -16,d2 |
| 77 | beq memset_4_no_remainder |
| 78 | |
| 79 | # copy the remaining 1, 2 or 3 words |
| 80 | memset_4_three_or_fewer_words: |
| 81 | cmp +8,d2 |
| 82 | bcs memset_4_one_word |
| 83 | beq memset_4_two_words |
| 84 | mov d1,(a0+) |
| 85 | memset_4_two_words: |
| 86 | mov d1,(a0+) |
| 87 | memset_4_one_word: |
| 88 | mov d1,(a0+) |
| 89 | |
| 90 | memset_4_no_remainder: |
| 91 | # check we set the correct amount |
| 92 | # TODO: REMOVE CHECK |
| 93 | sub e3,a0,d2 |
| 94 | mov (20,sp),d1 |
| 95 | cmp d2,d1 |
| 96 | beq memset_done |
| 97 | break |
| 98 | break |
| 99 | break |
| 100 | |
| 101 | memset_done: |
| 102 | mov e3,a0 |
| 103 | ret [d2,d3],8 |
| 104 | |
| 105 | # handle misaligned copying |
| 106 | memset_1: |
| 107 | add -1,d2 |
| 108 | mov +1,d3 |
| 109 | setlb # setlb requires the next insns |
| 110 | # to occupy exactly 4 bytes |
| 111 | |
| 112 | sub d3,d2 |
| 113 | movbu d1,(a0) |
| 114 | inc a0 |
| 115 | lcc |
| 116 | |
| 117 | mov e3,a0 |
| 118 | ret [d2,d3],8 |
| 119 | |
| 120 | memset_end: |
| 121 | .size memset, memset_end-memset |