456 lines
11 KiB
ArmAsm
456 lines
11 KiB
ArmAsm
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/* Optimized strrchr implementation for PowerPC64/POWER7 using cmpb insn.
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Copyright (C) 2017-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* char *[r3] strrchr (char *s [r3], int c [r4]) */
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#ifdef __LITTLE_ENDIAN__
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/* Find the match position from v6 and place result in r6. */
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# define CALCULATE_MATCH() \
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vbpermq v6, v6, v10; \
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vsldoi v6, v6, v6, 6; \
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mfvrd r7, v6; \
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cntlzd r6, r7; \
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subfic r6, r6, 15;
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/*
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* Find the first null position to mask bytes after null.
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* (reg): vcmpequb result: v2 for 1st qw v3 for 2nd qw.
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* Result placed at v2.
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*/
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# define FIND_NULL_POS(reg) \
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vspltisb v11, -1; \
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vadduqm v11, reg, v11; \
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vandc v11, v11, reg; \
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vpopcntd v2, v11; \
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vspltb v11, v2, 15; \
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vcmpequb. v11, v11, v9; \
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blt cr6, 1f; \
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vsldoi v9, v0, v9, 1; \
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vslo v2, v2, v9; \
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1: \
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vsumsws v2, v2, v0;
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#else
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# define CALCULATE_MATCH() \
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vbpermq v6, v6, v10; \
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mfvrd r7, v6; \
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addi r6, r7, -1; \
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andc r6, r6, r7; \
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popcntd r6, r6; \
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subfic r6, r6, 15;
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# define FIND_NULL_POS(reg) \
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vclzd v2, reg; \
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vspltb v11, v2, 7; \
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vcmpequb. v11, v11, v9; \
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blt cr6, 1f; \
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vsldoi v9, v0, v9, 1; \
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vsro v2, v2, v9; \
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1: \
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vsumsws v2, v2, v0;
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#endif /* !__LITTLE_ENDIAN__ */
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#ifndef STRRCHR
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# define STRRCHR strrchr
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#endif
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.machine power8
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ENTRY_TOCLESS (STRRCHR)
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CALL_MCOUNT 2
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dcbt 0,r3
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clrrdi r8,r3,3 /* Align the address to doubleword boundary. */
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cmpdi cr7,r4,0
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ld r12,0(r8) /* Load doubleword from memory. */
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li r9,0 /* Used to store last occurence. */
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li r0,0 /* Doubleword with null chars to use
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with cmpb. */
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rlwinm r6,r3,3,26,28 /* Calculate padding. */
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beq cr7,L(null_match)
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/* Replicate byte to doubleword. */
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insrdi r4,r4,8,48
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insrdi r4,r4,16,32
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insrdi r4,r4,32,0
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/* r4 is changed now. If it's passed more chars, then
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check for null again. */
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cmpdi cr7,r4,0
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beq cr7,L(null_match)
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/* Now r4 has a doubleword of c bytes and r0 has
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a doubleword of null bytes. */
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cmpb r10,r12,r4 /* Compare each byte against c byte. */
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cmpb r11,r12,r0 /* Compare each byte against null byte. */
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/* Move the doublewords left and right to discard the bits that are
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not part of the string and bring them back as zeros. */
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#ifdef __LITTLE_ENDIAN__
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srd r10,r10,r6
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srd r11,r11,r6
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sld r10,r10,r6
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sld r11,r11,r6
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#else
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sld r10,r10,r6
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sld r11,r11,r6
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srd r10,r10,r6
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srd r11,r11,r6
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#endif
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or r5,r10,r11 /* OR the results to speed things up. */
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cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
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have been found. */
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bne cr7,L(done)
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L(align):
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andi. r12, r8, 15
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/* Are we now aligned to a doubleword boundary? If so, skip to
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the main loop. Otherwise, go through the alignment code. */
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bne cr0, L(loop)
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/* Handle WORD2 of pair. */
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ldu r12,8(r8)
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cmpb r10,r12,r4
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cmpb r11,r12,r0
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or r5,r10,r11
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cmpdi cr7,r5,0
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bne cr7,L(done)
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b L(loop) /* We branch here (rather than falling through)
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to skip the nops due to heavy alignment
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of the loop below. */
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.p2align 5
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L(loop):
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/* Load two doublewords, compare and merge in a
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single register for speed. This is an attempt
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to speed up the null-checking process for bigger strings. */
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ld r12,8(r8)
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ldu r7,16(r8)
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cmpb r10,r12,r4
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cmpb r11,r12,r0
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cmpb r6,r7,r4
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cmpb r7,r7,r0
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or r12,r10,r11
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or r5,r6,r7
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or r5,r12,r5
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cmpdi cr7,r5,0
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beq cr7,L(vector)
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/* OK, one (or both) of the doublewords contains a c/null byte. Check
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the first doubleword and decrement the address in case the first
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doubleword really contains a c/null byte. */
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cmpdi cr6,r12,0
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addi r8,r8,-8
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bne cr6,L(done)
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/* The c/null byte must be in the second doubleword. Adjust the
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address again and move the result of cmpb to r10 so we can calculate
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the pointer. */
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mr r10,r6
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mr r11,r7
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addi r8,r8,8
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/* r10/r11 have the output of the cmpb instructions, that is,
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0xff in the same position as the c/null byte in the original
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doubleword from the string. Use that to calculate the pointer. */
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L(done):
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/* If there are more than one 0xff in r11, find the first position of
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0xff in r11 and fill r10 with 0 from that position. */
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cmpdi cr7,r11,0
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beq cr7,L(no_null)
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#ifdef __LITTLE_ENDIAN__
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addi r3,r11,-1
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andc r3,r3,r11
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popcntd r0,r3
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#else
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cntlzd r0,r11
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#endif
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subfic r0,r0,63
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li r6,-1
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#ifdef __LITTLE_ENDIAN__
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srd r0,r6,r0
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#else
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sld r0,r6,r0
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#endif
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and r10,r0,r10
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L(no_null):
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#ifdef __LITTLE_ENDIAN__
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cntlzd r0,r10 /* Count leading zeros before c matches. */
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addi r3,r10,-1
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andc r3,r3,r10
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addi r10,r11,-1
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andc r10,r10,r11
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cmpld cr7,r3,r10
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bgt cr7,L(no_match)
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#else
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addi r3,r10,-1 /* Count trailing zeros before c matches. */
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andc r3,r3,r10
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popcntd r0,r3
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cmpld cr7,r11,r10
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bgt cr7,L(no_match)
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#endif
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srdi r0,r0,3 /* Convert trailing zeros to bytes. */
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subfic r0,r0,7
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add r9,r8,r0 /* Return address of the matching c byte
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or null in case c was not found. */
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li r0,0
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cmpdi cr7,r11,0 /* If r11 == 0, no null's have been found. */
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beq cr7,L(align)
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.align 4
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L(no_match):
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mr r3,r9
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blr
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/* Check the first 32B in GPR's and move to vectorized loop. */
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.p2align 5
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L(vector):
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addi r3, r8, 8
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/* Make sure 32B aligned. */
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andi. r10, r3, 31
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bne cr0, L(loop)
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vspltisb v0, 0
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/* Precompute vbpermq constant. */
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vspltisb v10, 3
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lvsl v11, r0, r0
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vslb v10, v11, v10
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mtvrd v1, r4
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li r5, 16
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vspltb v1, v1, 7
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/* Compare 32 bytes in each loop. */
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L(continue):
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lvx v4, 0, r3
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lvx v5, r3, r5
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vcmpequb v2, v0, v4
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vcmpequb v3, v0, v5
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vcmpequb v6, v1, v4
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vcmpequb v7, v1, v5
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vor v8, v2, v3
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vor v9, v6, v7
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vor v11, v8, v9
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vcmpequb. v11, v0, v11
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addi r3, r3, 32
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blt cr6, L(continue)
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vcmpequb. v8, v0, v8
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blt cr6, L(match)
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/* One (or both) of the quadwords contains c/null. */
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vspltisb v8, 2
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vspltisb v9, 5
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/* Precompute values used for comparison. */
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vsl v9, v8, v9 /* v9 = 0x4040404040404040. */
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vaddubm v8, v9, v9
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vsldoi v8, v0, v8, 1 /* v8 = 0x80. */
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/* Check if null is in second qw. */
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vcmpequb. v11, v0, v2
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blt cr6, L(secondqw)
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/* Null found in first qw. */
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addi r8, r3, -32
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/* Calculate the null position. */
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FIND_NULL_POS(v2)
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/* Check if null is in the first byte. */
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vcmpequb. v11, v0, v2
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blt cr6, L(no_match)
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vsububm v2, v8, v2
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/* Mask unwanted bytes after null. */
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#ifdef __LITTLE_ENDIAN__
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vslo v6, v6, v2
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vsro v6, v6, v2
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#else
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vsro v6, v6, v2
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vslo v6, v6, v2
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#endif
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vcmpequb. v11, v0, v6
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blt cr6, L(no_match)
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/* Found a match before null. */
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CALCULATE_MATCH()
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add r3, r8, r6
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blr
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L(secondqw):
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addi r8, r3, -16
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FIND_NULL_POS(v3)
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vcmpequb. v11, v0, v2
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blt cr6, L(no_match1)
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vsububm v2, v8, v2
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/* Mask unwanted bytes after null. */
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#ifdef __LITTLE_ENDIAN__
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vslo v7, v7, v2
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vsro v7, v7, v2
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#else
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vsro v7, v7, v2
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vslo v7, v7, v2
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#endif
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vcmpequb. v11, v0, v7
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blt cr6, L(no_match1)
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addi r8, r8, 16
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vor v6, v0, v7
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L(no_match1):
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addi r8, r8, -16
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vcmpequb. v11, v0, v6
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blt cr6, L(no_match)
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/* Found a match before null. */
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CALCULATE_MATCH()
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add r3, r8, r6
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blr
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L(match):
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/* One (or both) of the quadwords contains a match. */
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mr r8, r3
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vcmpequb. v8, v0, v7
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blt cr6, L(firstqw)
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/* Match found in second qw. */
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addi r8, r8, 16
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vor v6, v0, v7
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L(firstqw):
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addi r8, r8, -32
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CALCULATE_MATCH()
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add r9, r8, r6 /* Compute final length. */
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b L(continue)
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/* We are here because strrchr was called with a null byte. */
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.align 4
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L(null_match):
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/* r0 has a doubleword of null bytes. */
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cmpb r5,r12,r0 /* Compare each byte against null bytes. */
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/* Move the doublewords left and right to discard the bits that are
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not part of the string and bring them back as zeros. */
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#ifdef __LITTLE_ENDIAN__
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srd r5,r5,r6
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sld r5,r5,r6
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#else
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sld r5,r5,r6
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srd r5,r5,r6
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#endif
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cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
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have been found. */
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bne cr7,L(done_null)
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andi. r12, r8, 15
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/* Are we now aligned to a quadword boundary? If so, skip to
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the main loop. Otherwise, go through the alignment code. */
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bne cr0, L(loop_null)
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||
|
|
/* 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 trailing zeros to bytes. */
|
||
|
|
add r3,r8,r0 /* Return address of the matching null byte. */
|
||
|
|
blr
|
||
|
|
/* Check the first 32B in GPR's and move to vectorized loop. */
|
||
|
|
.p2align 5
|
||
|
|
L(vector1):
|
||
|
|
addi r3, r8, 8
|
||
|
|
/* Make sure 32B aligned. */
|
||
|
|
andi. r10, r3, 31
|
||
|
|
bne cr0, L(loop_null)
|
||
|
|
vspltisb v0, 0
|
||
|
|
/* Precompute vbpermq constant. */
|
||
|
|
vspltisb v10, 3
|
||
|
|
lvsl v11, r0, r0
|
||
|
|
vslb v10, v11, v10
|
||
|
|
li r5, 16
|
||
|
|
/* Compare 32 bytes in each loop. */
|
||
|
|
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
|
||
|
|
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_GEN_TB (STRRCHR, TB_TOCLESS)
|
||
|
|
weak_alias (strrchr, rindex)
|
||
|
|
libc_hidden_builtin_def (strrchr)
|