--- /dev/null
+/* Optimized strchr implementation for PowerPC64/POWER8.
+ Copyright (C) 2016 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>
+
+#ifdef USE_AS_STRCHRNUL
+# define FUNC_NAME __strchrnul
+#else
+# define FUNC_NAME strchr
+#endif
+/* int [r3] strchr (char *s [r3], int c [r4]) */
+/* TODO: change these to the actual instructions when the minimum required
+ binutils allows it. */
+#define MTVRD(v,r) .long (0x7c000167 | ((v)<<(32-11)) | ((r)<<(32-16)))
+#define MFVRD(r,v) .long (0x7c000067 | ((v)<<(32-11)) | ((r)<<(32-16)))
+#define VBPERMQ(t,a,b) .long (0x1000054c \
+ | ((t)<<(32-11)) \
+ | ((a)<<(32-16)) \
+ | ((b)<<(32-21)) )
+/* TODO: change this to .machine power8 when the minimum required binutils
+ allows it. */
+ .machine power7
+ENTRY (FUNC_NAME)
+ CALL_MCOUNT 2
+ dcbt 0,r3
+ clrrdi r8,r3,3 /* Align the address to doubleword boundary. */
+ cmpdi cr7,r4,0
+ ld r12,0(r8) /* Load doubleword from memory. */
+ li r0,0 /* Doubleword with null chars to use
+ with cmpb. */
+
+ rlwinm r6,r3,3,26,28 /* Calculate padding. */
+
+ beq cr7,L(null_match)
+
+ /* Replicate byte to doubleword. */
+ insrdi r4,r4,8,48
+ insrdi r4,r4,16,32
+ insrdi r4,r4,32,0
+
+ /* Now r4 has a doubleword of c bytes and r0 has
+ a doubleword of null bytes. */
+
+ cmpb r10,r12,r4 /* Compare each byte against c byte. */
+ cmpb r11,r12,r0 /* Compare each byte against null byte. */
+
+ /* Move the doublewords left and right to discard the bits that are
+ not part of the string and bring them back as zeros. */
+#ifdef __LITTLE_ENDIAN__
+ srd r10,r10,r6
+ srd r11,r11,r6
+ sld r10,r10,r6
+ sld r11,r11,r6
+#else
+ sld r10,r10,r6
+ sld r11,r11,r6
+ srd r10,r10,r6
+ srd r11,r11,r6
+#endif
+ or r5,r10,r11 /* OR the results to speed things up. */
+ cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
+ have been found. */
+ bne cr7,L(done)
+
+ mtcrf 0x01,r8
+
+ /* Are we now aligned to a doubleword boundary? If so, skip to
+ the main loop. Otherwise, go through the alignment code. */
+
+ bt 28,L(loop)
+
+ /* Handle WORD2 of pair. */
+ ldu r12,8(r8)
+ cmpb r10,r12,r4
+ cmpb r11,r12,r0
+ or r5,r10,r11
+ cmpdi cr7,r5,0
+ bne cr7,L(done)
+ b L(loop) /* We branch here (rather than falling through)
+ to skip the nops due to heavy alignment
+ of the loop below. */
+
+ .p2align 5
+L(loop):
+ /* Load two doublewords, compare and merge in a
+ single register for speed. This is an attempt
+ to speed up the null-checking process for bigger strings. */
+ ld r12,8(r8)
+ ldu r9,16(r8)
+ cmpb r10,r12,r4
+ cmpb r11,r12,r0
+ cmpb r6,r9,r4
+ cmpb r7,r9,r0
+ or r5,r10,r11
+ or r9,r6,r7
+ or r12,r5,r9
+ cmpdi cr7,r12,0
+ beq cr7,L(vector)
+ /* OK, one (or both) of the doublewords contains a c/null byte. Check
+ the first doubleword and decrement the address in case the first
+ doubleword really contains a c/null byte. */
+
+ cmpdi cr6,r5,0
+ addi r8,r8,-8
+ bne cr6,L(done)
+
+ /* The c/null byte must be in the second doubleword. Adjust the
+ address again and move the result of cmpb to r10 so we can calculate
+ the pointer. */
+
+ mr r10,r6
+ mr r11,r7
+ addi r8,r8,8
+#ifdef USE_AS_STRCHRNUL
+ mr r5, r9
+#endif
+ /* r10/r11 have the output of the cmpb instructions, that is,
+ 0xff in the same position as the c/null byte in the original
+ doubleword from the string. Use that to calculate the pointer. */
+L(done):
+#ifdef USE_AS_STRCHRNUL
+ mr r10, r5
+#endif
+#ifdef __LITTLE_ENDIAN__
+ addi r3,r10,-1
+ andc r3,r3,r10
+ popcntd r0,r3
+# ifndef USE_AS_STRCHRNUL
+ addi r4,r11,-1
+ andc r4,r4,r11
+ cmpld cr7,r3,r4
+ bgt cr7,L(no_match)
+# endif
+#else
+ cntlzd r0,r10 /* Count leading zeros before c matches. */
+# ifndef USE_AS_STRCHRNUL
+ cmpld cr7,r11,r10
+ bgt cr7,L(no_match)
+# endif
+#endif
+ srdi r0,r0,3 /* Convert leading zeros to bytes. */
+ add r3,r8,r0 /* Return address of the matching c byte
+ or null in case c was not found. */
+ blr
+
+ /* Check the first 32B in GPR's and move to vectorized loop. */
+ .p2align 5
+L(vector):
+ addi r3, r8, 8
+ andi. r10, r3, 31
+ bne cr0, L(loop)
+ vspltisb v0, 0
+ /* Precompute vbpermq constant. */
+ vspltisb v10, 3
+ lvsl v11, r0, r0
+ vslb v10, v11, v10
+ MTVRD(v1,r4)
+ li r5, 16
+ vspltb v1, v1, 7
+ /* Compare 32 bytes in each loop. */
+L(continue):
+ lvx v4, 0, r3
+ lvx v5, r3, r5
+ vcmpequb v2, v0, v4
+ vcmpequb v3, v0, v5
+ vcmpequb v6, v1, v4
+ vcmpequb v7, v1, v5
+ vor v8, v2, v3
+ vor v9, v6, v7
+ vor v11, v8, v9
+ vcmpequb. v11, v0, v11
+ addi r3, r3, 32
+ blt cr6, L(continue)
+ /* One (or both) of the quadwords contains a c/null byte. */
+ addi r3, r3, -32
+#ifndef USE_AS_STRCHRNUL
+ vcmpequb. v11, v0, v9
+ blt cr6, L(no_match)
+#endif
+ /* Permute the first bit of each byte into bits 48-63. */
+ VBPERMQ(v2, v2, v10)
+ VBPERMQ(v3, v3, v10)
+ VBPERMQ(v6, v6, v10)
+ VBPERMQ(v7, v7, v10)
+ /* Shift each component into its correct position for merging. */
+#ifdef __LITTLE_ENDIAN__
+ vsldoi v3, v3, v3, 2
+ vsldoi v7, v7, v7, 2
+#else
+ vsldoi v2, v2, v2, 6
+ vsldoi v3, v3, v3, 4
+ vsldoi v6, v6, v6, 6
+ vsldoi v7, v7, v7, 4
+#endif
+
+ /* Merge the results and move to a GPR. */
+ vor v1, v3, v2
+ vor v2, v6, v7
+ vor v4, v1, v2
+ MFVRD(r5, v4)
+#ifdef __LITTLE_ENDIAN__
+ addi r6, r5, -1
+ andc r6, r6, r5
+ popcntd r6, r6
+#else
+ cntlzd r6, r5 /* Count leading zeros before the match. */
+#endif
+ add r3, r3, r6 /* Compute final length. */
+ /* Return NULL if null found before c. */
+#ifndef USE_AS_STRCHRNUL
+ lbz r4, 0(r3)
+ cmpdi cr7, r4, 0
+ beq cr7, L(no_match)
+#endif
+ blr
+
+#ifndef USE_AS_STRCHRNUL
+ .align 4
+L(no_match):
+ li r3,0
+ blr
+#endif
+
+/* We are here because strchr was called with a null byte. */
+ .align 4
+L(null_match):
+ /* r0 has a doubleword of null bytes. */
+
+ cmpb r5,r12,r0 /* Compare each byte against null bytes. */
+
+ /* Move the doublewords left and right to discard the bits that are
+ not part of the string and bring them back as zeros. */
+#ifdef __LITTLE_ENDIAN__
+ srd r5,r5,r6
+ sld r5,r5,r6
+#else
+ sld r5,r5,r6
+ srd r5,r5,r6
+#endif
+ cmpdi cr7,r5,0 /* If r10 == 0, no c or null bytes
+ have been found. */
+ bne cr7,L(done_null)
+
+ mtcrf 0x01,r8
+
+ /* Are we now aligned to a quadword boundary? If so, skip to
+ the main loop. Otherwise, go through the alignment code. */
+
+ bt 28,L(loop_null)
+
+ /* Handle WORD2 of pair. */
+ ldu r12,8(r8)
+ cmpb r5,r12,r0
+ cmpdi cr7,r5,0
+ bne cr7,L(done_null)
+ b L(loop_null) /* We branch here (rather than falling through)
+ to skip the nops due to heavy alignment
+ of the loop below. */
+
+ /* Main loop to look for the end of the string. Since it's a
+ small loop (< 8 instructions), align it to 32-bytes. */
+ .p2align 5
+L(loop_null):
+ /* Load two doublewords, compare and merge in a
+ single register for speed. This is an attempt
+ to speed up the null-checking process for bigger strings. */
+ ld r12,8(r8)
+ ldu r11,16(r8)
+ cmpb r5,r12,r0
+ cmpb r10,r11,r0
+ or r6,r5,r10
+ cmpdi cr7,r6,0
+ beq cr7,L(vector1)
+
+ /* OK, one (or both) of the doublewords contains a null byte. Check
+ the first doubleword and decrement the address in case the first
+ doubleword really contains a null byte. */
+
+ cmpdi cr6,r5,0
+ addi r8,r8,-8
+ bne cr6,L(done_null)
+
+ /* The null byte must be in the second doubleword. Adjust the address
+ again and move the result of cmpb to r10 so we can calculate the
+ pointer. */
+
+ mr r5,r10
+ addi r8,r8,8
+
+ /* r5 has the output of the cmpb instruction, that is, it contains
+ 0xff in the same position as the null byte in the original
+ doubleword from the string. Use that to calculate the pointer. */
+L(done_null):
+#ifdef __LITTLE_ENDIAN__
+ addi r0,r5,-1
+ andc r0,r0,r5
+ popcntd r0,r0
+#else
+ cntlzd r0,r5 /* Count leading zeros before the match. */
+#endif
+ srdi r0,r0,3 /* Convert leading zeros to bytes. */
+ add r3,r8,r0 /* Return address of the matching null byte. */
+ blr
+ .p2align 5
+L(vector1):
+ addi r3, r8, 8
+ andi. r10, r3, 31
+ bne cr0, L(loop_null)
+ vspltisb v8, -1
+ vspltisb v0, 0
+ vspltisb v10, 3
+ lvsl v11, r0, r0
+ vslb v10, v11, v10
+ li r5, 16
+L(continue1):
+ lvx v4, 0, r3
+ lvx v5, r3, r5
+ vcmpequb v2, v0, v4
+ vcmpequb v3, v0, v5
+ vor v8, v2, v3
+ vcmpequb. v11, v0, v8
+ addi r3, r3, 32
+ blt cr6, L(continue1)
+ addi r3, r3, -32
+L(end1):
+ VBPERMQ(v2, v2, v10)
+ VBPERMQ(v3, v3, v10)
+ /* Shift each component into its correct position for merging. */
+#ifdef __LITTLE_ENDIAN__
+ vsldoi v3, v3, v3, 2
+#else
+ vsldoi v2, v2, v2, 6
+ vsldoi v3, v3, v3, 4
+#endif
+
+ /* Merge the results and move to a GPR. */
+ vor v4, v3, v2
+ MFVRD(r5, v4)
+#ifdef __LITTLE_ENDIAN__
+ addi r6, r5, -1
+ andc r6, r6, r5
+ popcntd r6, r6
+#else
+ cntlzd r6, r5 /* Count leading zeros before the match. */
+#endif
+ add r3, r3, r6 /* Compute final length. */
+ blr
+END (FUNC_NAME)
+
+#ifndef USE_AS_STRCHRNUL
+weak_alias (strchr, index)
+libc_hidden_builtin_def (strchr)
+#endif
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