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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/arm64/lib/memchr.S
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm64/lib/memchr.S')
-rw-r--r--arch/arm64/lib/memchr.S76
1 files changed, 76 insertions, 0 deletions
diff --git a/arch/arm64/lib/memchr.S b/arch/arm64/lib/memchr.S
new file mode 100644
index 000000000..37a9f2a4f
--- /dev/null
+++ b/arch/arm64/lib/memchr.S
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 Arm Ltd.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Find a character in an area of memory.
+ *
+ * Parameters:
+ * x0 - buf
+ * x1 - c
+ * x2 - n
+ * Returns:
+ * x0 - address of first occurrence of 'c' or 0
+ */
+
+#define L(label) .L ## label
+
+#define REP8_01 0x0101010101010101
+#define REP8_7f 0x7f7f7f7f7f7f7f7f
+
+#define srcin x0
+#define chrin w1
+#define cntin x2
+
+#define result x0
+
+#define wordcnt x3
+#define rep01 x4
+#define repchr x5
+#define cur_word x6
+#define cur_byte w6
+#define tmp x7
+#define tmp2 x8
+
+ .p2align 4
+ nop
+SYM_FUNC_START(__pi_memchr)
+ and chrin, chrin, #0xff
+ lsr wordcnt, cntin, #3
+ cbz wordcnt, L(byte_loop)
+ mov rep01, #REP8_01
+ mul repchr, x1, rep01
+ and cntin, cntin, #7
+L(word_loop):
+ ldr cur_word, [srcin], #8
+ sub wordcnt, wordcnt, #1
+ eor cur_word, cur_word, repchr
+ sub tmp, cur_word, rep01
+ orr tmp2, cur_word, #REP8_7f
+ bics tmp, tmp, tmp2
+ b.ne L(found_word)
+ cbnz wordcnt, L(word_loop)
+L(byte_loop):
+ cbz cntin, L(not_found)
+ ldrb cur_byte, [srcin], #1
+ sub cntin, cntin, #1
+ cmp cur_byte, chrin
+ b.ne L(byte_loop)
+ sub srcin, srcin, #1
+ ret
+L(found_word):
+CPU_LE( rev tmp, tmp)
+ clz tmp, tmp
+ sub tmp, tmp, #64
+ add result, srcin, tmp, asr #3
+ ret
+L(not_found):
+ mov result, #0
+ ret
+SYM_FUNC_END(__pi_memchr)
+SYM_FUNC_ALIAS_WEAK(memchr, __pi_memchr)
+EXPORT_SYMBOL_NOKASAN(memchr)