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authorWaldemar Brodkorb <wbx@uclibc-ng.org>2016-10-04 06:51:35 +0200
committerWaldemar Brodkorb <wbx@openadk.org>2017-02-01 17:48:38 +0100
commitdba942c80dc2cfa5768a856fff98e22a755fdd27 (patch)
tree371e775cb6dfec085945f6834aeb9d3b6de36fbe /libc/string/aarch64/memset.S
parent9b457baf8d46329f7d7ee2aa084022bb0df88551 (diff)
add experimental aarch64 support
Ported over from GNU C Library and runtime tested in Qemu.
Diffstat (limited to 'libc/string/aarch64/memset.S')
-rw-r--r--libc/string/aarch64/memset.S189
1 files changed, 189 insertions, 0 deletions
diff --git a/libc/string/aarch64/memset.S b/libc/string/aarch64/memset.S
new file mode 100644
index 000000000..d6686bedc
--- /dev/null
+++ b/libc/string/aarch64/memset.S
@@ -0,0 +1,189 @@
+/* Copyright (C) 2012-2017 Free Software Foundation, Inc.
+
+ 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
+ *
+ */
+
+#define dstin x0
+#define val x1
+#define valw w1
+#define count x2
+#define dst x3
+#define dstend x4
+#define tmp1 x5
+#define tmp1w w5
+#define tmp2 x6
+#define tmp2w w6
+#define zva_len x7
+#define zva_lenw w7
+
+ENTRY_ALIGN (memset, 6)
+
+ dup v0.16B, valw
+ add dstend, dstin, count
+
+ cmp count, 96
+ b.hi L(set_long)
+ cmp count, 16
+ b.hs L(set_medium)
+ mov val, v0.D[0]
+
+ /* Set 0..15 bytes. */
+ tbz count, 3, 1f
+ str val, [dstin]
+ str val, [dstend, -8]
+ ret
+ nop
+1: tbz count, 2, 2f
+ str valw, [dstin]
+ str valw, [dstend, -4]
+ ret
+2: cbz count, 3f
+ strb valw, [dstin]
+ tbz count, 1, 3f
+ strh valw, [dstend, -2]
+3: ret
+
+ /* Set 17..96 bytes. */
+L(set_medium):
+ str q0, [dstin]
+ tbnz count, 6, L(set96)
+ str q0, [dstend, -16]
+ tbz count, 5, 1f
+ str q0, [dstin, 16]
+ str q0, [dstend, -32]
+1: ret
+
+ .p2align 4
+ /* Set 64..96 bytes. Write 64 bytes from the start and
+ 32 bytes from the end. */
+L(set96):
+ str q0, [dstin, 16]
+ stp q0, q0, [dstin, 32]
+ stp q0, q0, [dstend, -32]
+ ret
+
+ .p2align 3
+ nop
+L(set_long):
+ and valw, valw, 255
+ bic dst, dstin, 15
+ str q0, [dstin]
+ cmp count, 256
+ ccmp valw, 0, 0, cs
+ b.eq L(try_zva)
+L(no_zva):
+ sub count, dstend, dst /* Count is 16 too large. */
+ add dst, dst, 16
+ sub count, count, 64 + 16 /* Adjust count and bias for loop. */
+1: stp q0, q0, [dst], 64
+ stp q0, q0, [dst, -32]
+L(tail64):
+ subs count, count, 64
+ b.hi 1b
+2: stp q0, q0, [dstend, -64]
+ stp q0, q0, [dstend, -32]
+ ret
+
+ .p2align 3
+L(try_zva):
+ mrs tmp1, dczid_el0
+ tbnz tmp1w, 4, L(no_zva)
+ and tmp1w, tmp1w, 15
+ cmp tmp1w, 4 /* ZVA size is 64 bytes. */
+ b.ne L(zva_128)
+
+ /* Write the first and last 64 byte aligned block using stp rather
+ than using DC ZVA. This is faster on some cores.
+ */
+L(zva_64):
+ str q0, [dst, 16]
+ stp q0, q0, [dst, 32]
+ bic dst, dst, 63
+ stp q0, q0, [dst, 64]
+ stp q0, q0, [dst, 96]
+ sub count, dstend, dst /* Count is now 128 too large. */
+ sub count, count, 128+64+64 /* Adjust count and bias for loop. */
+ add dst, dst, 128
+ nop
+1: dc zva, dst
+ add dst, dst, 64
+ subs count, count, 64
+ b.hi 1b
+ stp q0, q0, [dst, 0]
+ stp q0, q0, [dst, 32]
+ stp q0, q0, [dstend, -64]
+ stp q0, q0, [dstend, -32]
+ ret
+
+ .p2align 3
+L(zva_128):
+ cmp tmp1w, 5 /* ZVA size is 128 bytes. */
+ b.ne L(zva_other)
+
+ str q0, [dst, 16]
+ stp q0, q0, [dst, 32]
+ stp q0, q0, [dst, 64]
+ stp q0, q0, [dst, 96]
+ bic dst, dst, 127
+ sub count, dstend, dst /* Count is now 128 too large. */
+ sub count, count, 128+128 /* Adjust count and bias for loop. */
+ add dst, dst, 128
+1: dc zva, dst
+ add dst, dst, 128
+ subs count, count, 128
+ b.hi 1b
+ stp q0, q0, [dstend, -128]
+ stp q0, q0, [dstend, -96]
+ stp q0, q0, [dstend, -64]
+ stp q0, q0, [dstend, -32]
+ ret
+
+L(zva_other):
+ mov tmp2w, 4
+ lsl zva_lenw, tmp2w, tmp1w
+ add tmp1, zva_len, 64 /* Max alignment bytes written. */
+ cmp count, tmp1
+ blo L(no_zva)
+
+ sub tmp2, zva_len, 1
+ add tmp1, dst, zva_len
+ add dst, dst, 16
+ subs count, tmp1, dst /* Actual alignment bytes to write. */
+ bic tmp1, tmp1, tmp2 /* Aligned dc zva start address. */
+ beq 2f
+1: stp q0, q0, [dst], 64
+ stp q0, q0, [dst, -32]
+ subs count, count, 64
+ b.hi 1b
+2: mov dst, tmp1
+ sub count, dstend, tmp1 /* Remaining bytes to write. */
+ subs count, count, zva_len
+ b.lo 4f
+3: dc zva, dst
+ add dst, dst, zva_len
+ subs count, count, zva_len
+ b.hs 3b
+4: add count, count, zva_len
+ b L(tail64)
+
+END (memset)
+libc_hidden_def (memset)