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189 lines
3.8 KiB
189 lines
3.8 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Copyright (C) 2013 ARM Ltd. |
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* Copyright (C) 2013 Linaro. |
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* |
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* This code is based on glibc cortex strings work originally authored by Linaro |
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* be found @ |
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* |
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* http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ |
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* files/head:/src/aarch64/ |
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*/ |
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#include <linux/linkage.h> |
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#include <asm/assembler.h> |
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#include <asm/cache.h> |
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/* |
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* Move a buffer from src to test (alignment handled by the hardware). |
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* If dest <= src, call memcpy, otherwise copy in reverse order. |
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* |
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* Parameters: |
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* x0 - dest |
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* x1 - src |
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* x2 - n |
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* Returns: |
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* x0 - dest |
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*/ |
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dstin .req x0 |
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src .req x1 |
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count .req x2 |
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tmp1 .req x3 |
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tmp1w .req w3 |
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tmp2 .req x4 |
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tmp2w .req w4 |
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tmp3 .req x5 |
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tmp3w .req w5 |
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dst .req x6 |
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A_l .req x7 |
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A_h .req x8 |
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B_l .req x9 |
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B_h .req x10 |
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C_l .req x11 |
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C_h .req x12 |
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D_l .req x13 |
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D_h .req x14 |
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SYM_FUNC_START_ALIAS(__memmove) |
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SYM_FUNC_START_WEAK_PI(memmove) |
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cmp dstin, src |
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b.lo __memcpy |
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add tmp1, src, count |
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cmp dstin, tmp1 |
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b.hs __memcpy /* No overlap. */ |
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add dst, dstin, count |
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add src, src, count |
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cmp count, #16 |
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b.lo .Ltail15 /*probably non-alignment accesses.*/ |
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ands tmp2, src, #15 /* Bytes to reach alignment. */ |
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b.eq .LSrcAligned |
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sub count, count, tmp2 |
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/* |
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* process the aligned offset length to make the src aligned firstly. |
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* those extra instructions' cost is acceptable. It also make the |
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* coming accesses are based on aligned address. |
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*/ |
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tbz tmp2, #0, 1f |
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ldrb tmp1w, [src, #-1]! |
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strb tmp1w, [dst, #-1]! |
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1: |
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tbz tmp2, #1, 2f |
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ldrh tmp1w, [src, #-2]! |
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strh tmp1w, [dst, #-2]! |
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2: |
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tbz tmp2, #2, 3f |
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ldr tmp1w, [src, #-4]! |
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str tmp1w, [dst, #-4]! |
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3: |
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tbz tmp2, #3, .LSrcAligned |
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ldr tmp1, [src, #-8]! |
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str tmp1, [dst, #-8]! |
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.LSrcAligned: |
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cmp count, #64 |
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b.ge .Lcpy_over64 |
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/* |
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* Deal with small copies quickly by dropping straight into the |
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* exit block. |
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*/ |
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.Ltail63: |
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/* |
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* Copy up to 48 bytes of data. At this point we only need the |
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* bottom 6 bits of count to be accurate. |
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*/ |
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ands tmp1, count, #0x30 |
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b.eq .Ltail15 |
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cmp tmp1w, #0x20 |
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b.eq 1f |
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b.lt 2f |
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ldp A_l, A_h, [src, #-16]! |
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stp A_l, A_h, [dst, #-16]! |
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1: |
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ldp A_l, A_h, [src, #-16]! |
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stp A_l, A_h, [dst, #-16]! |
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2: |
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ldp A_l, A_h, [src, #-16]! |
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stp A_l, A_h, [dst, #-16]! |
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.Ltail15: |
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tbz count, #3, 1f |
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ldr tmp1, [src, #-8]! |
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str tmp1, [dst, #-8]! |
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1: |
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tbz count, #2, 2f |
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ldr tmp1w, [src, #-4]! |
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str tmp1w, [dst, #-4]! |
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2: |
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tbz count, #1, 3f |
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ldrh tmp1w, [src, #-2]! |
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strh tmp1w, [dst, #-2]! |
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3: |
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tbz count, #0, .Lexitfunc |
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ldrb tmp1w, [src, #-1] |
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strb tmp1w, [dst, #-1] |
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.Lexitfunc: |
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ret |
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.Lcpy_over64: |
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subs count, count, #128 |
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b.ge .Lcpy_body_large |
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/* |
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* Less than 128 bytes to copy, so handle 64 bytes here and then jump |
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* to the tail. |
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*/ |
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ldp A_l, A_h, [src, #-16] |
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stp A_l, A_h, [dst, #-16] |
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ldp B_l, B_h, [src, #-32] |
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ldp C_l, C_h, [src, #-48] |
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stp B_l, B_h, [dst, #-32] |
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stp C_l, C_h, [dst, #-48] |
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ldp D_l, D_h, [src, #-64]! |
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stp D_l, D_h, [dst, #-64]! |
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tst count, #0x3f |
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b.ne .Ltail63 |
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ret |
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/* |
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* Critical loop. Start at a new cache line boundary. Assuming |
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* 64 bytes per line this ensures the entire loop is in one line. |
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*/ |
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.p2align L1_CACHE_SHIFT |
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.Lcpy_body_large: |
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/* pre-load 64 bytes data. */ |
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ldp A_l, A_h, [src, #-16] |
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ldp B_l, B_h, [src, #-32] |
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ldp C_l, C_h, [src, #-48] |
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ldp D_l, D_h, [src, #-64]! |
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1: |
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/* |
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* interlace the load of next 64 bytes data block with store of the last |
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* loaded 64 bytes data. |
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*/ |
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stp A_l, A_h, [dst, #-16] |
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ldp A_l, A_h, [src, #-16] |
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stp B_l, B_h, [dst, #-32] |
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ldp B_l, B_h, [src, #-32] |
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stp C_l, C_h, [dst, #-48] |
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ldp C_l, C_h, [src, #-48] |
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stp D_l, D_h, [dst, #-64]! |
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ldp D_l, D_h, [src, #-64]! |
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subs count, count, #64 |
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b.ge 1b |
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stp A_l, A_h, [dst, #-16] |
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stp B_l, B_h, [dst, #-32] |
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stp C_l, C_h, [dst, #-48] |
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stp D_l, D_h, [dst, #-64]! |
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tst count, #0x3f |
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b.ne .Ltail63 |
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ret |
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SYM_FUNC_END_PI(memmove) |
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EXPORT_SYMBOL(memmove) |
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SYM_FUNC_END_ALIAS(__memmove) |
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EXPORT_SYMBOL(__memmove)
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