diff options
Diffstat (limited to 'libc/arch-arm64/generic/bionic/memmove.S')
| -rw-r--r-- | libc/arch-arm64/generic/bionic/memmove.S | 386 |
1 files changed, 105 insertions, 281 deletions
diff --git a/libc/arch-arm64/generic/bionic/memmove.S b/libc/arch-arm64/generic/bionic/memmove.S index 739ce4982..c50112d94 100644 --- a/libc/arch-arm64/generic/bionic/memmove.S +++ b/libc/arch-arm64/generic/bionic/memmove.S @@ -1,4 +1,4 @@ -/* Copyright (c) 2014, Linaro Limited +/* Copyright (c) 2013, Linaro Limited All rights reserved. Redistribution and use in source and binary forms, with or without @@ -22,14 +22,39 @@ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -*/ + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ + +/* + * Copyright (c) 2015 ARM Ltd + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the company may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ /* Assumptions: * - * ARMv8-a, AArch64 - * Unaligned accesses - * wchar_t is 4 bytes + * ARMv8-a, AArch64, unaligned accesses, wchar_t is 4 bytes */ #include <private/bionic_asm.h> @@ -38,22 +63,25 @@ #define dstin x0 #define src x1 #define count x2 -#define tmp1 x3 -#define tmp1w w3 -#define tmp2 x4 -#define tmp2w w4 -#define tmp3 x5 -#define tmp3w w5 -#define dst x6 - -#define A_l x7 -#define A_h x8 -#define B_l x9 -#define B_h x10 -#define C_l x11 -#define C_h x12 -#define D_l x13 -#define D_h x14 +#define srcend x3 +#define dstend x4 +#define tmp1 x5 +#define A_l x6 +#define A_h x7 +#define B_l x8 +#define B_h x9 +#define C_l x10 +#define C_h x11 +#define D_l x12 +#define D_h x13 +#define E_l count +#define E_h tmp1 + +/* All memmoves up to 96 bytes are done by memcpy as it supports overlaps. + Larger backwards copies are also handled by memcpy. The only remaining + case is forward large copies. The destination is aligned, and an + unrolled loop processes 64 bytes per iteration. +*/ #if defined(WMEMMOVE) ENTRY(wmemmove) @@ -61,267 +89,63 @@ ENTRY(wmemmove) #else ENTRY(memmove) #endif - cmp dstin, src - b.lo .Ldownwards - add tmp1, src, count - cmp dstin, tmp1 - b.hs memcpy /* No overlap. */ - - /* Upwards move with potential overlap. - * Need to move from the tail backwards. SRC and DST point one - * byte beyond the remaining data to move. */ - add dst, dstin, count - add src, src, count - cmp count, #64 - b.ge .Lmov_not_short_up - - /* Deal with small moves quickly by dropping straight into the - * exit block. */ -.Ltail63up: - /* Move up to 48 bytes of data. At this point we only need the - * bottom 6 bits of count to be accurate. */ - ands tmp1, count, #0x30 - b.eq .Ltail15up - sub dst, dst, tmp1 - sub src, src, tmp1 - cmp tmp1w, #0x20 - b.eq 1f - b.lt 2f - ldp A_l, A_h, [src, #32] - stp A_l, A_h, [dst, #32] -1: - ldp A_l, A_h, [src, #16] - stp A_l, A_h, [dst, #16] -2: - ldp A_l, A_h, [src] - stp A_l, A_h, [dst] -.Ltail15up: - /* Move up to 15 bytes of data. Does not assume additional data - * being moved. */ - tbz count, #3, 1f - ldr tmp1, [src, #-8]! - str tmp1, [dst, #-8]! -1: - tbz count, #2, 1f - ldr tmp1w, [src, #-4]! - str tmp1w, [dst, #-4]! -1: - tbz count, #1, 1f - ldrh tmp1w, [src, #-2]! - strh tmp1w, [dst, #-2]! -1: - tbz count, #0, 1f - ldrb tmp1w, [src, #-1] - strb tmp1w, [dst, #-1] -1: - ret - -.Lmov_not_short_up: - /* We don't much care about the alignment of DST, but we want SRC - * to be 128-bit (16 byte) aligned so that we don't cross cache line - * boundaries on both loads and stores. */ - ands tmp2, src, #15 /* Bytes to reach alignment. */ - b.eq 2f - sub count, count, tmp2 - /* Move enough data to reach alignment; unlike memcpy, we have to - * be aware of the overlap, which means we can't move data twice. */ - tbz tmp2, #3, 1f - ldr tmp1, [src, #-8]! - str tmp1, [dst, #-8]! -1: - tbz tmp2, #2, 1f - ldr tmp1w, [src, #-4]! - str tmp1w, [dst, #-4]! -1: - tbz tmp2, #1, 1f - ldrh tmp1w, [src, #-2]! - strh tmp1w, [dst, #-2]! -1: - tbz tmp2, #0, 1f - ldrb tmp1w, [src, #-1]! - strb tmp1w, [dst, #-1]! -1: - - /* There may be less than 63 bytes to go now. */ - cmp count, #63 - b.le .Ltail63up + sub tmp1, dstin, src + cmp count, 96 + ccmp tmp1, count, 2, hi + b.hs memcpy + + cbz tmp1, 3f + add dstend, dstin, count + add srcend, src, count + + /* Align dstend to 16 byte alignment so that we don't cross cache line + boundaries on both loads and stores. There are at least 96 bytes + to copy, so copy 16 bytes unaligned and then align. The loop + copies 64 bytes per iteration and prefetches one iteration ahead. */ + + and tmp1, dstend, 15 + ldp D_l, D_h, [srcend, -16] + sub srcend, srcend, tmp1 + sub count, count, tmp1 + ldp A_l, A_h, [srcend, -16] + stp D_l, D_h, [dstend, -16] + ldp B_l, B_h, [srcend, -32] + ldp C_l, C_h, [srcend, -48] + ldp D_l, D_h, [srcend, -64]! + sub dstend, dstend, tmp1 + subs count, count, 128 + b.ls 2f + nop +1: + stp A_l, A_h, [dstend, -16] + ldp A_l, A_h, [srcend, -16] + stp B_l, B_h, [dstend, -32] + ldp B_l, B_h, [srcend, -32] + stp C_l, C_h, [dstend, -48] + ldp C_l, C_h, [srcend, -48] + stp D_l, D_h, [dstend, -64]! + ldp D_l, D_h, [srcend, -64]! + subs count, count, 64 + b.hi 1b + + /* Write the last full set of 64 bytes. The remainder is at most 64 + bytes, so it is safe to always copy 64 bytes from the start even if + there is just 1 byte left. */ 2: - subs count, count, #128 - b.ge .Lmov_body_large_up - /* Less than 128 bytes to move, so handle 64 here and then jump - * to the tail. */ - ldp A_l, A_h, [src, #-64]! - ldp B_l, B_h, [src, #16] - ldp C_l, C_h, [src, #32] - ldp D_l, D_h, [src, #48] - stp A_l, A_h, [dst, #-64]! - stp B_l, B_h, [dst, #16] - stp C_l, C_h, [dst, #32] - stp D_l, D_h, [dst, #48] - tst count, #0x3f - b.ne .Ltail63up - ret + ldp E_l, E_h, [src, 48] + stp A_l, A_h, [dstend, -16] + ldp A_l, A_h, [src, 32] + stp B_l, B_h, [dstend, -32] + ldp B_l, B_h, [src, 16] + stp C_l, C_h, [dstend, -48] + ldp C_l, C_h, [src] + stp D_l, D_h, [dstend, -64] + stp E_l, E_h, [dstin, 48] + stp A_l, A_h, [dstin, 32] + stp B_l, B_h, [dstin, 16] + stp C_l, C_h, [dstin] +3: ret - /* Critical loop. Start at a new Icache line boundary. Assuming - * 64 bytes per line this ensures the entire loop is in one line. */ - .p2align 6 -.Lmov_body_large_up: - /* There are at least 128 bytes to move. */ - ldp A_l, A_h, [src, #-16] - ldp B_l, B_h, [src, #-32] - ldp C_l, C_h, [src, #-48] - ldp D_l, D_h, [src, #-64]! -1: - stp A_l, A_h, [dst, #-16] - ldp A_l, A_h, [src, #-16] - stp B_l, B_h, [dst, #-32] - ldp B_l, B_h, [src, #-32] - stp C_l, C_h, [dst, #-48] - ldp C_l, C_h, [src, #-48] - stp D_l, D_h, [dst, #-64]! - ldp D_l, D_h, [src, #-64]! - subs count, count, #64 - b.ge 1b - stp A_l, A_h, [dst, #-16] - stp B_l, B_h, [dst, #-32] - stp C_l, C_h, [dst, #-48] - stp D_l, D_h, [dst, #-64]! - tst count, #0x3f - b.ne .Ltail63up - ret - - -.Ldownwards: - /* For a downwards move we can safely use memcpy provided that - * DST is more than 16 bytes away from SRC. */ - sub tmp1, src, #16 - cmp dstin, tmp1 - b.ls memcpy /* May overlap, but not critically. */ - - mov dst, dstin /* Preserve DSTIN for return value. */ - cmp count, #64 - b.ge .Lmov_not_short_down - - /* Deal with small moves quickly by dropping straight into the - * exit block. */ -.Ltail63down: - /* Move up to 48 bytes of data. At this point we only need the - * bottom 6 bits of count to be accurate. */ - ands tmp1, count, #0x30 - b.eq .Ltail15down - add dst, dst, tmp1 - add src, src, tmp1 - cmp tmp1w, #0x20 - b.eq 1f - b.lt 2f - ldp A_l, A_h, [src, #-48] - stp A_l, A_h, [dst, #-48] -1: - ldp A_l, A_h, [src, #-32] - stp A_l, A_h, [dst, #-32] -2: - ldp A_l, A_h, [src, #-16] - stp A_l, A_h, [dst, #-16] -.Ltail15down: - /* Move up to 15 bytes of data. Does not assume additional data - being moved. */ - tbz count, #3, 1f - ldr tmp1, [src], #8 - str tmp1, [dst], #8 -1: - tbz count, #2, 1f - ldr tmp1w, [src], #4 - str tmp1w, [dst], #4 -1: - tbz count, #1, 1f - ldrh tmp1w, [src], #2 - strh tmp1w, [dst], #2 -1: - tbz count, #0, 1f - ldrb tmp1w, [src] - strb tmp1w, [dst] -1: - ret - -.Lmov_not_short_down: - /* We don't much care about the alignment of DST, but we want SRC - * to be 128-bit (16 byte) aligned so that we don't cross cache line - * boundaries on both loads and stores. */ - neg tmp2, src - ands tmp2, tmp2, #15 /* Bytes to reach alignment. */ - b.eq 2f - sub count, count, tmp2 - /* Move enough data to reach alignment; unlike memcpy, we have to - * be aware of the overlap, which means we can't move data twice. */ - tbz tmp2, #3, 1f - ldr tmp1, [src], #8 - str tmp1, [dst], #8 -1: - tbz tmp2, #2, 1f - ldr tmp1w, [src], #4 - str tmp1w, [dst], #4 -1: - tbz tmp2, #1, 1f - ldrh tmp1w, [src], #2 - strh tmp1w, [dst], #2 -1: - tbz tmp2, #0, 1f - ldrb tmp1w, [src], #1 - strb tmp1w, [dst], #1 -1: - - /* There may be less than 63 bytes to go now. */ - cmp count, #63 - b.le .Ltail63down -2: - subs count, count, #128 - b.ge .Lmov_body_large_down - /* Less than 128 bytes to move, so handle 64 here and then jump - * to the tail. */ - ldp A_l, A_h, [src] - ldp B_l, B_h, [src, #16] - ldp C_l, C_h, [src, #32] - ldp D_l, D_h, [src, #48] - stp A_l, A_h, [dst] - stp B_l, B_h, [dst, #16] - stp C_l, C_h, [dst, #32] - stp D_l, D_h, [dst, #48] - tst count, #0x3f - add src, src, #64 - add dst, dst, #64 - b.ne .Ltail63down - ret - - /* Critical loop. Start at a new cache line boundary. Assuming - * 64 bytes per line this ensures the entire loop is in one line. */ - .p2align 6 -.Lmov_body_large_down: - /* There are at least 128 bytes to move. */ - ldp A_l, A_h, [src, #0] - sub dst, dst, #16 /* Pre-bias. */ - ldp B_l, B_h, [src, #16] - ldp C_l, C_h, [src, #32] - ldp D_l, D_h, [src, #48]! /* src += 64 - Pre-bias. */ -1: - stp A_l, A_h, [dst, #16] - ldp A_l, A_h, [src, #16] - stp B_l, B_h, [dst, #32] - ldp B_l, B_h, [src, #32] - stp C_l, C_h, [dst, #48] - ldp C_l, C_h, [src, #48] - stp D_l, D_h, [dst, #64]! - ldp D_l, D_h, [src, #64]! - subs count, count, #64 - b.ge 1b - stp A_l, A_h, [dst, #16] - stp B_l, B_h, [dst, #32] - stp C_l, C_h, [dst, #48] - stp D_l, D_h, [dst, #64] - add src, src, #16 - add dst, dst, #64 + 16 - tst count, #0x3f - b.ne .Ltail63down - ret #if defined(WMEMMOVE) END(wmemmove) #else |