1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2013 ARM Ltd. 4 * Copyright (C) 2013 Linaro. 5 * 6 * This code is based on glibc cortex strings work originally authored by Linaro 7 * be found @ 8 * 9 * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ 10 * files/head:/src/aarch64/ 11 */ 12 13 14 /* 15 * Copy a buffer from src to dest (alignment handled by the hardware) 16 * 17 * Parameters: 18 * x0 - dest 19 * x1 - src 20 * x2 - n 21 * Returns: 22 * x0 - dest 23 */ 24 dstin .req x0 25 src .req x1 26 count .req x2 27 tmp1 .req x3 28 tmp1w .req w3 29 tmp2 .req x4 30 tmp2w .req w4 31 dst .req x6 32 33 A_l .req x7 34 A_h .req x8 35 B_l .req x9 36 B_h .req x10 37 C_l .req x11 38 C_h .req x12 39 D_l .req x13 40 D_h .req x14 41 42 mov dst, dstin 43 cmp count, #16 44 /*When memory length is less than 16, the accessed are not aligned.*/ 45 b.lo .Ltiny15 46 47 neg tmp2, src 48 ands tmp2, tmp2, #15/* Bytes to reach alignment. */ 49 b.eq .LSrcAligned 50 sub count, count, tmp2 51 /* 52 * Copy the leading memory data from src to dst in an increasing 53 * address order.By this way,the risk of overwriting the source 54 * memory data is eliminated when the distance between src and 55 * dst is less than 16. The memory accesses here are alignment. 56 */ 57 tbz tmp2, #0, 1f 58 ldrb1 tmp1w, src, #1 59 strb1 tmp1w, dst, #1 60 1: 61 tbz tmp2, #1, 2f 62 ldrh1 tmp1w, src, #2 63 strh1 tmp1w, dst, #2 64 2: 65 tbz tmp2, #2, 3f 66 ldr1 tmp1w, src, #4 67 str1 tmp1w, dst, #4 68 3: 69 tbz tmp2, #3, .LSrcAligned 70 ldr1 tmp1, src, #8 71 str1 tmp1, dst, #8 72 73 .LSrcAligned: 74 cmp count, #64 75 b.ge .Lcpy_over64 76 /* 77 * Deal with small copies quickly by dropping straight into the 78 * exit block. 79 */ 80 .Ltail63: 81 /* 82 * Copy up to 48 bytes of data. At this point we only need the 83 * bottom 6 bits of count to be accurate. 84 */ 85 ands tmp1, count, #0x30 86 b.eq .Ltiny15 87 cmp tmp1w, #0x20 88 b.eq 1f 89 b.lt 2f 90 ldp1 A_l, A_h, src, #16 91 stp1 A_l, A_h, dst, #16 92 1: 93 ldp1 A_l, A_h, src, #16 94 stp1 A_l, A_h, dst, #16 95 2: 96 ldp1 A_l, A_h, src, #16 97 stp1 A_l, A_h, dst, #16 98 .Ltiny15: 99 /* 100 * Prefer to break one ldp/stp into several load/store to access 101 * memory in an increasing address order,rather than to load/store 16 102 * bytes from (src-16) to (dst-16) and to backward the src to aligned 103 * address,which way is used in original cortex memcpy. If keeping 104 * the original memcpy process here, memmove need to satisfy the 105 * precondition that src address is at least 16 bytes bigger than dst 106 * address,otherwise some source data will be overwritten when memove 107 * call memcpy directly. To make memmove simpler and decouple the 108 * memcpy's dependency on memmove, withdrew the original process. 109 */ 110 tbz count, #3, 1f 111 ldr1 tmp1, src, #8 112 str1 tmp1, dst, #8 113 1: 114 tbz count, #2, 2f 115 ldr1 tmp1w, src, #4 116 str1 tmp1w, dst, #4 117 2: 118 tbz count, #1, 3f 119 ldrh1 tmp1w, src, #2 120 strh1 tmp1w, dst, #2 121 3: 122 tbz count, #0, .Lexitfunc 123 ldrb1 tmp1w, src, #1 124 strb1 tmp1w, dst, #1 125 126 b .Lexitfunc 127 128 .Lcpy_over64: 129 subs count, count, #128 130 b.ge .Lcpy_body_large 131 /* 132 * Less than 128 bytes to copy, so handle 64 here and then jump 133 * to the tail. 134 */ 135 ldp1 A_l, A_h, src, #16 136 stp1 A_l, A_h, dst, #16 137 ldp1 B_l, B_h, src, #16 138 ldp1 C_l, C_h, src, #16 139 stp1 B_l, B_h, dst, #16 140 stp1 C_l, C_h, dst, #16 141 ldp1 D_l, D_h, src, #16 142 stp1 D_l, D_h, dst, #16 143 144 tst count, #0x3f 145 b.ne .Ltail63 146 b .Lexitfunc 147 148 /* 149 * Critical loop. Start at a new cache line boundary. Assuming 150 * 64 bytes per line this ensures the entire loop is in one line. 151 */ 152 .p2align L1_CACHE_SHIFT 153 .Lcpy_body_large: 154 /* pre-get 64 bytes data. */ 155 ldp1 A_l, A_h, src, #16 156 ldp1 B_l, B_h, src, #16 157 ldp1 C_l, C_h, src, #16 158 ldp1 D_l, D_h, src, #16 159 1: 160 /* 161 * interlace the load of next 64 bytes data block with store of the last 162 * loaded 64 bytes data. 163 */ 164 stp1 A_l, A_h, dst, #16 165 ldp1 A_l, A_h, src, #16 166 stp1 B_l, B_h, dst, #16 167 ldp1 B_l, B_h, src, #16 168 stp1 C_l, C_h, dst, #16 169 ldp1 C_l, C_h, src, #16 170 stp1 D_l, D_h, dst, #16 171 ldp1 D_l, D_h, src, #16 172 subs count, count, #64 173 b.ge 1b 174 stp1 A_l, A_h, dst, #16 175 stp1 B_l, B_h, dst, #16 176 stp1 C_l, C_h, dst, #16 177 stp1 D_l, D_h, dst, #16 178 179 tst count, #0x3f 180 b.ne .Ltail63 181 .Lexitfunc:
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