License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* The actual code in this memcpy and memmove is in memcpy_thunderx.S.
- The only real differences are with the prefetching instructions. */
+#include <sysdep.h>
+/* Assumptions:
+ *
+ * ARMv8-a, AArch64, unaligned accesses.
+ *
+ */
+
+#define dstin x0
+#define src x1
+#define count x2
+#define dst x3
+#define srcend x4
+#define dstend x5
+#define tmp2 x6
+#define tmp3 x7
+#define tmp3w w7
+#define A_l x6
+#define A_lw w6
+#define A_h x7
+#define A_hw w7
+#define B_l x8
+#define B_lw w8
+#define B_h x9
+#define C_l x10
+#define C_h x11
+#define D_l x12
+#define D_h x13
+#define E_l src
+#define E_h count
+#define F_l srcend
+#define F_h dst
+#define G_l count
+#define G_h dst
+#define tmp1 x14
+
+#define A_q q0
+#define B_q q1
+#define C_q q2
+#define D_q q3
+#define E_q q4
+#define F_q q5
+#define G_q q6
+#define H_q q7
+#define I_q q16
+#define J_q q17
+
+#define A_v v0
+#define B_v v1
+#define C_v v2
+#define D_v v3
+#define E_v v4
+#define F_v v5
+#define G_v v6
+#define H_v v7
+#define I_v v16
+#define J_v v17
+
+#ifndef MEMMOVE
+# define MEMMOVE memmove
+#endif
+#ifndef MEMCPY
+# define MEMCPY memcpy
+#endif
+
+#if IS_IN (libc)
+
+#undef MEMCPY
+#undef MEMMOVE
#define MEMCPY __memcpy_thunderx2
#define MEMMOVE __memmove_thunderx2
-#define USE_THUNDERX2
-#include "memcpy_thunderx.S"
+
+/* Moves are split into 3 main cases: small copies of up to 16 bytes,
+ medium copies of 17..96 bytes which are fully unrolled. Large copies
+ of more than 96 bytes align the destination and use an unrolled loop
+ processing 64 bytes per iteration.
+ Overlapping large forward memmoves use a loop that copies backwards.
+*/
+
+ENTRY_ALIGN (MEMMOVE, 6)
+
+ DELOUSE (0)
+ DELOUSE (1)
+ DELOUSE (2)
+
+ sub tmp1, dstin, src
+ cmp count, 96
+ ccmp tmp1, count, 2, hi
+ b.lo L(move_long)
+
+ prfm PLDL1KEEP, [src]
+ add srcend, src, count
+ add dstend, dstin, count
+ cmp count, 16
+ b.ls L(copy16)
+ cmp count, 96
+ b.hi L(copy_long)
+
+ /* Medium copies: 17..96 bytes. */
+ sub tmp1, count, 1
+ ldp A_l, A_h, [src]
+ tbnz tmp1, 6, L(copy96)
+ ldp D_l, D_h, [srcend, -16]
+ tbz tmp1, 5, 1f
+ ldp B_l, B_h, [src, 16]
+ ldp C_l, C_h, [srcend, -32]
+ stp B_l, B_h, [dstin, 16]
+ stp C_l, C_h, [dstend, -32]
+1:
+ stp A_l, A_h, [dstin]
+ stp D_l, D_h, [dstend, -16]
+ ret
+
+ .p2align 4
+ /* Small copies: 0..16 bytes. */
+L(copy16):
+ cmp count, 8
+ b.lo 1f
+ ldr A_l, [src]
+ ldr A_h, [srcend, -8]
+ str A_l, [dstin]
+ str A_h, [dstend, -8]
+ ret
+ .p2align 4
+1:
+ tbz count, 2, 1f
+ ldr A_lw, [src]
+ ldr A_hw, [srcend, -4]
+ str A_lw, [dstin]
+ str A_hw, [dstend, -4]
+ ret
+
+ /* Copy 0..3 bytes. Use a branchless sequence that copies the same
+ byte 3 times if count==1, or the 2nd byte twice if count==2. */
+1:
+ cbz count, 2f
+ lsr tmp1, count, 1
+ ldrb A_lw, [src]
+ ldrb A_hw, [srcend, -1]
+ ldrb B_lw, [src, tmp1]
+ strb A_lw, [dstin]
+ strb B_lw, [dstin, tmp1]
+ strb A_hw, [dstend, -1]
+2: ret
+
+ .p2align 4
+ /* Copy 64..96 bytes. Copy 64 bytes from the start and
+ 32 bytes from the end. */
+L(copy96):
+ ldp B_l, B_h, [src, 16]
+ ldp C_l, C_h, [src, 32]
+ ldp D_l, D_h, [src, 48]
+ ldp E_l, E_h, [srcend, -32]
+ ldp F_l, F_h, [srcend, -16]
+ stp A_l, A_h, [dstin]
+ stp B_l, B_h, [dstin, 16]
+ stp C_l, C_h, [dstin, 32]
+ stp D_l, D_h, [dstin, 48]
+ stp E_l, E_h, [dstend, -32]
+ stp F_l, F_h, [dstend, -16]
+ ret
+
+ /* Align DST 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. */
+
+ .p2align 4
+L(copy_long):
+ and tmp1, dstin, 15
+ bic dst, dstin, 15
+ ldp D_l, D_h, [src]
+ sub src, src, tmp1
+ add count, count, tmp1 /* Count is now 16 too large. */
+ ldp A_l, A_h, [src, 16]
+ stp D_l, D_h, [dstin]
+ ldp B_l, B_h, [src, 32]
+ ldp C_l, C_h, [src, 48]
+ ldp D_l, D_h, [src, 64]!
+ subs count, count, 128 + 16 /* Test and readjust count. */
+ b.ls L(last64)
+L(loop64):
+ 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.hi L(loop64)
+
+ /* 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 end even if
+ there is just 1 byte left. */
+L(last64):
+ ldp E_l, E_h, [srcend, -64]
+ stp A_l, A_h, [dst, 16]
+ ldp A_l, A_h, [srcend, -48]
+ stp B_l, B_h, [dst, 32]
+ ldp B_l, B_h, [srcend, -32]
+ stp C_l, C_h, [dst, 48]
+ ldp C_l, C_h, [srcend, -16]
+ stp D_l, D_h, [dst, 64]
+ stp E_l, E_h, [dstend, -64]
+ stp A_l, A_h, [dstend, -48]
+ stp B_l, B_h, [dstend, -32]
+ stp C_l, C_h, [dstend, -16]
+ ret
+
+ .p2align 4
+L(move_long):
+ cbz tmp1, 3f
+
+ add srcend, src, count
+ add dstend, dstin, 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:
+ ldp G_l, G_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 G_l, G_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
+
+END (MEMMOVE)
+libc_hidden_builtin_def (MEMMOVE)
+
+
+/* Copies are split into 3 main cases: small copies of up to 16 bytes,
+ medium copies of 17..96 bytes which are fully unrolled. Large copies
+ of more than 96 bytes align the destination and use load-and-merge
+ approach in the case src and dst addresses are unaligned not evenly,
+ so that, loads and stores are always aligned.
+ Large copies use an unrolled loop processing 64 bytes per iteration.
+ The current optimized memcpy implementation is not compatible with
+ memmove and is separated from it completely.
+
+ memcpy implementation below is not compatible with memmove
+ because of pipelined loads/stores, which are faster, but they
+ can't be used in the case of overlapping memmove arrays */
+
+#define MEMCPY_PREFETCH_LDR 640
+
+ENTRY (MEMCPY)
+ DELOUSE (0)
+ DELOUSE (1)
+ DELOUSE (2)
+
+ add srcend, src, count
+ cmp count, 16
+ b.ls L(memcopy16)
+ ldr A_q, [src], #16
+ add dstend, dstin, count
+ and tmp1, src, 15
+ cmp count, 96
+ b.hi L(memcopy_long)
+
+ /* Medium copies: 17..96 bytes. */
+ ldr E_q, [srcend, -16]
+ cmp count, 64
+ b.gt L(memcpy_copy96)
+ cmp count, 48
+ b.le L(bytes_17_to_48)
+ /* 49..64 bytes */
+ ldp B_q, C_q, [src]
+ str E_q, [dstend, -16]
+ stp A_q, B_q, [dstin]
+ str C_q, [dstin, 32]
+ ret
+
+L(bytes_17_to_48):
+ /* 17..48 bytes*/
+ cmp count, 32
+ b.gt L(bytes_32_to_48)
+ /* 17..32 bytes*/
+ str A_q, [dstin]
+ str E_q, [dstend, -16]
+ ret
+
+L(bytes_32_to_48):
+ /* 32..48 */
+ ldr B_q, [src]
+ str A_q, [dstin]
+ str E_q, [dstend, -16]
+ str B_q, [dstin, 16]
+ ret
+
+ .p2align 4
+ /* Small copies: 0..16 bytes. */
+L(memcopy16):
+ cmp count, 8
+ b.lo L(bytes_0_to_8)
+ ldr A_l, [src]
+ ldr A_h, [srcend, -8]
+ add dstend, dstin, count
+ str A_l, [dstin]
+ str A_h, [dstend, -8]
+ ret
+ .p2align 4
+
+L(bytes_0_to_8):
+ tbz count, 2, L(bytes_0_to_3)
+ ldr A_lw, [src]
+ ldr A_hw, [srcend, -4]
+ add dstend, dstin, count
+ str A_lw, [dstin]
+ str A_hw, [dstend, -4]
+ ret
+
+ /* Copy 0..3 bytes. Use a branchless sequence that copies the same
+ byte 3 times if count==1, or the 2nd byte twice if count==2. */
+L(bytes_0_to_3):
+ cbz count, L(end)
+ lsr tmp1, count, 1
+ ldrb A_lw, [src]
+ ldrb A_hw, [srcend, -1]
+ add dstend, dstin, count
+ ldrb B_lw, [src, tmp1]
+ strb A_lw, [dstin]
+ strb B_lw, [dstin, tmp1]
+ strb A_hw, [dstend, -1]
+L(end): ret
+
+ .p2align 4
+
+L(memcpy_copy96):
+ /* Copying 65..96 bytes. A_q (first 16 bytes) and
+ E_q(last 16 bytes) are already loaded.
+
+ The size is large enough to benefit from aligned
+ loads */
+ bic src, src, 15
+ ldp B_q, C_q, [src]
+ str A_q, [dstin]
+ /* Loaded 64 bytes, second 16-bytes chunk can be
+ overlapping with the first chunk by tmp1 bytes.
+ Stored 16 bytes. */
+ sub dst, dstin, tmp1
+ add count, count, tmp1
+ /* The range of count being [65..96] becomes [65..111]
+ after tmp [0..15] gets added to it,
+ count now is <bytes-left-to-load>+48 */
+ cmp count, 80
+ b.gt L(copy96_medium)
+ ldr D_q, [src, 32]
+ stp B_q, C_q, [dst, 16]
+ str E_q, [dstend, -16]
+ str D_q, [dst, 48]
+ ret
+
+ .p2align 4
+L(copy96_medium):
+ ldp D_q, A_q, [src, 32]
+ str B_q, [dst, 16]
+ cmp count, 96
+ b.gt L(copy96_large)
+ str E_q, [dstend, -16]
+ stp C_q, D_q, [dst, 32]
+ str A_q, [dst, 64]
+ ret
+
+L(copy96_large):
+ ldr F_q, [src, 64]
+ stp C_q, D_q, [dst, 32]
+ str E_q, [dstend, -16]
+ stp A_q, F_q, [dst, 64]
+ ret
+
+ .p2align 4
+L(memcopy_long):
+ bic src, src, 15
+ ldp B_q, C_q, [src], #32
+ str A_q, [dstin]
+ sub dst, dstin, tmp1
+ add count, count, tmp1
+ add dst, dst, 16
+ and tmp1, dst, 15
+ ldp D_q, E_q, [src], #32
+ str B_q, [dst], #16
+
+ /* Already loaded 64+16 bytes. Check if at
+ least 64 more bytes left */
+ subs count, count, 64+64+16
+ b.lt L(loop128_exit2)
+ cmp count, MEMCPY_PREFETCH_LDR + 64 + 32
+ b.lt L(loop128)
+ cbnz tmp1, L(dst_unaligned)
+ sub count, count, MEMCPY_PREFETCH_LDR + 64 + 32
+
+ .p2align 4
+
+L(loop128_prefetch):
+ str C_q, [dst], #16
+ prfm pldl1strm, [src, MEMCPY_PREFETCH_LDR]
+ str D_q, [dst], #16
+ ldp F_q, G_q, [src], #32
+ str E_q, [dst], #16
+ ldp H_q, A_q, [src], #32
+ str F_q, [dst], #16
+ prfm pldl1strm, [src, MEMCPY_PREFETCH_LDR]
+ str G_q, [dst], #16
+ ldp B_q, C_q, [src], #32
+ str H_q, [dst], #16
+ ldp D_q, E_q, [src], #32
+ stp A_q, B_q, [dst], #32
+ subs count, count, 128
+ b.ge L(loop128_prefetch)
+
+L(preloop128):
+ add count, count, MEMCPY_PREFETCH_LDR + 64 + 32
+ .p2align 4
+L(loop128):
+ ldp F_q, G_q, [src], #32
+ str C_q, [dst], #16
+ ldp B_q, A_q, [src], #32
+ str D_q, [dst], #16
+ stp E_q, F_q, [dst], #32
+ stp G_q, B_q, [dst], #32
+ subs count, count, 64
+ b.lt L(loop128_exit1)
+L(loop128_proceed):
+ ldp B_q, C_q, [src], #32
+ str A_q, [dst], #16
+ ldp D_q, E_q, [src], #32
+ str B_q, [dst], #16
+ subs count, count, 64
+ b.ge L(loop128)
+
+ .p2align 4
+L(loop128_exit2):
+ stp C_q, D_q, [dst], #32
+ str E_q, [dst], #16
+ b L(copy_long_check32);
+
+L(loop128_exit1):
+ /* A_q is still not stored and 0..63 bytes left,
+ so, count is -64..-1.
+ Check if less than 32 bytes left (count < -32) */
+ str A_q, [dst], #16
+L(copy_long_check32):
+ cmn count, 64
+ b.eq L(copy_long_done)
+ cmn count, 32
+ b.le L(copy_long_last32)
+ ldp B_q, C_q, [src]
+ stp B_q, C_q, [dst]
+
+L(copy_long_last32):
+ ldp F_q, G_q, [srcend, -32]
+ stp F_q, G_q, [dstend, -32]
+
+L(copy_long_done):
+ ret
+
+L(dst_unaligned):
+ /* For the unaligned store case the code loads two
+ aligned chunks and then merges them using ext
+ instruction. This can be up to 30% faster than
+ the the simple unaligned store access.
+
+ Current state: tmp1 = dst % 16; C_q, D_q, E_q
+ contains data yet to be stored. src and dst points
+ to next-to-be-processed data. A_q, B_q contains
+ data already stored before, count = bytes left to
+ be load decremented by 64.
+
+ The control is passed here if at least 64 bytes left
+ to be loaded. The code does two aligned loads and then
+ extracts (16-tmp1) bytes from the first register and
+ tmp1 bytes from the next register forming the value
+ for the aligned store.
+
+ As ext instruction can only have it's index encoded
+ as immediate. 15 code chunks process each possible
+ index value. Computed goto is used to reach the
+ required code. */
+
+ /* Store the 16 bytes to dst and align dst for further
+ operations, several bytes will be stored at this
+ address once more */
+ str C_q, [dst], #16
+ ldp F_q, G_q, [src], #32
+ bic dst, dst, 15
+ adrp tmp2, L(ext_table)
+ add tmp2, tmp2, :lo12:L(ext_table)
+ add tmp2, tmp2, tmp1, LSL #2
+ ldr tmp3w, [tmp2]
+ add tmp2, tmp2, tmp3w, SXTW
+ br tmp2
+
+#define EXT_CHUNK(shft) \
+.p2align 4 ;\
+L(ext_size_ ## shft):;\
+ ext A_v.16b, C_v.16b, D_v.16b, 16-shft;\
+ ext B_v.16b, D_v.16b, E_v.16b, 16-shft;\
+ subs count, count, 32;\
+ b.ge 2f;\
+1:;\
+ stp A_q, B_q, [dst], #32;\
+ ext H_v.16b, E_v.16b, F_v.16b, 16-shft;\
+ ext I_v.16b, F_v.16b, G_v.16b, 16-shft;\
+ stp H_q, I_q, [dst], #16;\
+ add dst, dst, tmp1;\
+ str G_q, [dst], #16;\
+ b L(copy_long_check32);\
+2:;\
+ stp A_q, B_q, [dst], #32;\
+ prfm pldl1strm, [src, MEMCPY_PREFETCH_LDR];\
+ ldp D_q, J_q, [src], #32;\
+ ext H_v.16b, E_v.16b, F_v.16b, 16-shft;\
+ ext I_v.16b, F_v.16b, G_v.16b, 16-shft;\
+ mov C_v.16b, G_v.16b;\
+ stp H_q, I_q, [dst], #32;\
+ ldp F_q, G_q, [src], #32;\
+ ext A_v.16b, C_v.16b, D_v.16b, 16-shft;\
+ ext B_v.16b, D_v.16b, J_v.16b, 16-shft;\
+ mov E_v.16b, J_v.16b;\
+ subs count, count, 64;\
+ b.ge 2b;\
+ b 1b;\
+
+EXT_CHUNK(1)
+EXT_CHUNK(2)
+EXT_CHUNK(3)
+EXT_CHUNK(4)
+EXT_CHUNK(5)
+EXT_CHUNK(6)
+EXT_CHUNK(7)
+EXT_CHUNK(8)
+EXT_CHUNK(9)
+EXT_CHUNK(10)
+EXT_CHUNK(11)
+EXT_CHUNK(12)
+EXT_CHUNK(13)
+EXT_CHUNK(14)
+EXT_CHUNK(15)
+
+END (MEMCPY)
+ .section .rodata
+ .p2align 4
+
+L(ext_table):
+ /* The first entry is for the alignment of 0 and is never
+ actually used (could be any value). */
+ .word 0
+ .word L(ext_size_1) -.
+ .word L(ext_size_2) -.
+ .word L(ext_size_3) -.
+ .word L(ext_size_4) -.
+ .word L(ext_size_5) -.
+ .word L(ext_size_6) -.
+ .word L(ext_size_7) -.
+ .word L(ext_size_8) -.
+ .word L(ext_size_9) -.
+ .word L(ext_size_10) -.
+ .word L(ext_size_11) -.
+ .word L(ext_size_12) -.
+ .word L(ext_size_13) -.
+ .word L(ext_size_14) -.
+ .word L(ext_size_15) -.
+
+libc_hidden_builtin_def (MEMCPY)
+#endif
git://sourceware.org / glibc.git / commitdiff