--- /dev/null
+/* Copyright (C) 2012-2013 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+/* Assumptions:
+ *
+ * ARMv8-a, AArch64
+ * Unaligned accesses
+ */
+
+/* Parameters and result. */
+#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
+
+ENTRY_ALIGN (memmove, 6)
+
+ cmp dstin, src
+ b.lo L(downwards)
+ 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 L(mov_not_short_up)
+
+ /* Deal with small moves quickly by dropping straight into the
+ * exit block. */
+L(tail63up):
+ /* 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 L(tail15up)
+ 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]
+L(tail15up):
+ /* 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
+
+L(mov_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 L(tail63up)
+2:
+ subs count, count, #128
+ b.ge L(mov_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 L(tail63up)
+ 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
+L(mov_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 L(tail63up)
+ RET
+
+L(downwards):
+ /* 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 L(mov_not_short_down)
+
+ /* Deal with small moves quickly by dropping straight into the
+ * exit block. */
+L(tail63down):
+ /* 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 L(tail15down)
+ 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]
+L(tail15down):
+ /* 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
+
+L(mov_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 L(tail63down)
+2:
+ subs count, count, #128
+ b.ge L(mov_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 L(tail63down)
+ 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
+L(mov_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 L(tail63down)
+ RET
+END (memmove)
+
+libc_hidden_builtin_def (memmove)
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