--- /dev/null
+/* Multiple versions of memchr. AARCH64 version.
+ Copyright (C) 2018 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/>. */
+
+/* Define multiple versions only for the definition in libc. */
+
+#if IS_IN (libc)
+/* Redefine memchr so that the compiler won't complain about the type
+ mismatch with the IFUNC selector in strong_alias, below. */
+# undef memchr
+# define memchr __redirect_memchr
+# include <string.h>
+# include <init-arch.h>
+
+extern __typeof (__redirect_memchr) __memchr;
+
+extern __typeof (__redirect_memchr) __memchr_generic attribute_hidden;
+extern __typeof (__redirect_memchr) __memchr_nosimd attribute_hidden;
+
+libc_ifunc (__memchr,
+ ((IS_EMAG (midr)
+ ? __memchr_nosimd
+ : __memchr_generic)));
+
+# undef memchr
+strong_alias (__memchr, memchr);
+#endif
--- /dev/null
+/* Memchr for aarch64, default version for internal use.
+ Copyright (C) 2018 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/>. */
+
+#if IS_IN (libc)
+# define MEMCHR __memchr_generic
+
+/* Do not hide the generic version of memchr, we use it internally. */
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name)
+
+/* Add a hidden definition for use within libc.so. */
+# ifdef SHARED
+ .globl __GI_memchr; __GI_memchr = __memchr_generic
+# endif
+#endif
+
+# include "../memchr.S"
--- /dev/null
+/* memchr - find a character in a memory zone using base integer registers
+
+ Copyright (C) 2018 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
+ * Use base integer registers.
+ */
+
+#ifndef MEMCHR
+# define MEMCHR __memchr_nosimd
+#endif
+
+/* Arguments and results. */
+#define srcin x0
+#define chrin x1
+#define cntin x2
+
+#define result x0
+
+#define repchr x1
+
+#define tmp1 x2
+#define tmp2 x3
+#define tmp3 x4
+#define tmp4 x5
+
+#define src x6
+#define srcend x7
+#define srcend16 x8
+
+#define anymore x9
+
+#define zeroones x10
+
+#define data1 x11
+#define data2 x12
+
+#define has_chr1 x13
+#define has_chr2 x14
+
+#define REP8_01 0x0101010101010101
+#define REP8_7f 0x7f7f7f7f7f7f7f7f
+
+
+ENTRY_ALIGN (MEMCHR, 6)
+
+ DELOUSE (0)
+ DELOUSE (2)
+
+ /* Do not dereference srcin if no bytes to compare. */
+ cbz cntin, L(none_chr)
+
+ /* Start address is 16-byte aligned or not? */
+ tst srcin, 15
+ bic src, srcin, 15
+
+ mov zeroones, REP8_01
+ and repchr, chrin, 255
+ /* Generate a qword integer as |c|c|c|c|c|c|c|c|. */
+ mul repchr, repchr, zeroones
+
+ add srcend, srcin, cntin
+ /*
+ * srcend16 is address of the block following the last block.
+ *
+ * [A block is 16-byte aligned and sized.]
+ */
+ add srcend16, srcend, 15
+ bic srcend16, srcend16, 15
+
+ b.eq L(loop)
+
+ /* Load the first block containing start address. */
+ ldp data1, data2, [src], 16
+
+ lsl tmp1, srcin, 3
+ mov tmp2, ~0
+#ifdef __AARCH64EB__
+ lsr tmp3, tmp2, tmp1
+#else
+ lsl tmp3, tmp2, tmp1
+#endif
+ /* Start address is in the first or the second qword? */
+ tst srcin, 8
+
+ /*
+ * Transform any byte in the block to zero using XOR operation,
+ * if that byte equals the char to search. In this way, searching
+ * the char becomes detecting zero in the resulting two qwords.
+ */
+ eor data1, data1, repchr
+ eor data2, data2, repchr
+
+ /*
+ * Set those unused bytes(before start address) to 0xff, so
+ * that they will not hit any zero detection.
+ */
+ orn tmp1, data1, tmp3
+ orn tmp2, data2, tmp3
+
+ csinv data1, tmp1, xzr, eq
+ csel data2, data2, tmp2, eq
+
+ /*
+ * When the first and last block are the same, there are two cases:
+ * o. Memory range to search is just in one block.
+ * ( start address - end address) < 0
+ *
+ * o. Memory range is so large that end address wrap-around.
+ * ( start address - end address) > 0
+ */
+ cmp srcin, srcend
+ ccmp src, srcend16, 0, mi
+ csetm anymore, ne
+ b L(find_chr)
+
+ .p2align 4
+L(loop):
+ ldp data1, data2, [src], 16
+
+ subs anymore, src, srcend16
+
+ /*
+ * Transform any byte in the block to zero using XOR operation,
+ * if that byte equals the char to search.
+ */
+ eor data1, data1, repchr
+ eor data2, data2, repchr
+
+L(find_chr):
+ /*
+ * Use the following integer test to find out if any byte in a
+ * qword is zero. If do not contain zero-valued byte, test result
+ * is zero.
+ *
+ * (qword - 0x0101010101010101) & ~(qword) & 0x8080808080808080
+ * =
+ * (qword - 0x0101010101010101) & ~(qword | 0x7f7f7f7f7f7f7f7f)
+ *
+ */
+ sub tmp1, data1, zeroones
+ sub tmp2, data2, zeroones
+
+ orr tmp3, data1, REP8_7f
+ orr tmp4, data2, REP8_7f
+
+ bic has_chr1, tmp1, tmp3
+ bic has_chr2, tmp2, tmp4
+
+ orr tmp1, has_chr1, has_chr2
+ ccmp tmp1, 0, 0, ne
+
+ b.eq L(loop)
+
+ cbz has_chr1, 1f
+ sub result, src, 16
+#ifdef __AARCH64EB__
+ rev data1, data1
+#else
+ rev has_chr1, has_chr1
+#endif
+ b L(done)
+
+1: cbz has_chr2, L(none_chr)
+ sub result, src, 8
+#ifdef __AARCH64EB__
+ rev data1, data2
+#else
+ rev has_chr1, has_chr2
+#endif
+
+L(done):
+#ifdef __AARCH64EB__
+ /*
+ * For big-endian, can not directly use has_chr1/has_chr2 because
+ * two qwords has been reversed after loading from memory.
+ * Thus, have to perform char detection on two qwords again, which
+ * should be byte-swapped this time.
+ */
+ sub tmp1, data1, zeroones
+ orr tmp3, data1, REP8_7f
+ bic has_chr1, tmp1, tmp3
+ rev has_chr1, has_chr1
+#endif
+
+ /*
+ * If the specified char is found in a qword, the corresponding
+ * byte of in has_chr has value of 1, while this is only true for
+ * the first occurrence, not other occurrences.
+ */
+ cmp anymore, 0
+ clz tmp1, has_chr1
+ add result, result, tmp1, lsr 3
+ ccmp result, srcend, 8, eq /* NZCV = 8000 */
+ csel result, result, xzr, mi
+ ret
+
+L(none_chr):
+ mov result, 0
+ ret
+
+END (MEMCHR)
+libc_hidden_builtin_def (MEMCHR)
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