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6eaf95cbfa
This patch add a optimized strcspn for POWER7 by using a different algorithm than default implementation: it constructs a table based on the 'accept' argument and use this table to check for any occurance on the input string. The idea is similar as x86_64 uses. For PowerPC some tunings were added, such as unroll loops and align stack memory to table to 16 bytes (so VSX clean can ran without alignment issues).
140 lines
3.1 KiB
ArmAsm
140 lines
3.1 KiB
ArmAsm
/* Optimized strcspn implementation for PowerPC64.
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Copyright (C) 2014 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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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* size_t [r3] strcspn (const char [r4] *s, const char [r5] *reject) */
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.machine power7
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EALIGN (strcspn, 4, 0)
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CALL_MCOUNT 3
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/* The idea to speed up the algorithm is to create a lookup table
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for fast check if input character should be considered. For ASCII
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or ISO-8859-X character sets it has 256 positions. */
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lbz r10,0(r4)
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/* First the table should be cleared and to avoid unaligned accesses
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when using the VSX stores the table address is aligned to 16
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bytes. */
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xxlxor v0,v0,v0
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/* PPC64 ELF ABI stack is aligned to 16 bytes. */
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addi r9,r1,-256
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li r8,48
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li r5,16
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li r6,32
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cmpdi cr7,r10,0 /* reject[0] == '\0' ? */
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addi r12,r9,64
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/* Clear the table with 0 values */
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stxvw4x v0,r0,r9
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addi r11,r9,128
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addi r7,r9,192
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stxvw4x v0,r9,r5
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stxvw4x v0,r9,r6
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stxvw4x v0,r9,r8
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stxvw4x v0,r0,r12
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stxvw4x v0,r12,r5
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stxvw4x v0,r12,r6
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stxvw4x v0,r12,r8
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stxvw4x v0,r0,r11
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stxvw4x v0,r11,r5
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stxvw4x v0,r11,r6
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stxvw4x v0,r11,r8
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stxvw4x v0,r0,r7
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stxvw4x v0,r7,r5
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stxvw4x v0,r7,r6
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stxvw4x v0,r7,r8
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li r8,1
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beq cr7,L(finish_table) /* If reject[0] == '\0' skip */
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/* Initialize the table as:
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for (i=0; reject[i]; i++
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table[reject[i]]] = 1 */
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.p2align 4,,15
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L(init_table):
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stbx r8,r9,r10
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lbzu r10,1(r4)
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cmpdi cr7,r10,0 /* If reject[0] == '\0' finish */
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bne cr7,L(init_table)
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L(finish_table):
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/* set table[0] = 1 */
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li r10,1
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stb r10,0(r9)
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li r10,0
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b L(mainloop)
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/* Unrool the loop 4 times and check using the table as:
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i = 0;
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while (1)
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{
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if (table[input[i++]] == 1)
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return i - 1;
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if (table[input[i++]] == 1)
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return i - 1;
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if (table[input[i++]] == 1)
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return i - 1;
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if (table[input[i++]] == 1)
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return i - 1;
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} */
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.p2align 4,,15
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L(unroll):
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lbz r8,1(r3)
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addi r10,r10,4
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lbzx r8,r9,r8
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cmpwi r7,r8,1
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beq cr7,L(end)
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lbz r8,2(r3)
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addi r3,r3,4
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lbzx r8,r9,r8
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cmpwi cr7,r8,1
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beq cr7,L(end2)
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lbz r8,3(r7)
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lbzx r8,r9,r8
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cmpwi cr7,r8,1
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beq cr7,L(end3)
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L(mainloop):
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lbz r8,0(r3)
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mr r7,r3
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addi r6,r10,1
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addi r4,r10,2
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addi r5,r10,3
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lbzx r8,r9,8
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cmpwi cr7,r8,1
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bne cr7,L(unroll)
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mr r3,r10
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blr
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.p2align 4,,15
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L(end):
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mr r3,r6
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blr
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.p2align 4,,15
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L(end2):
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mr r3,r4
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blr
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.p2align 4,,15
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L(end3):
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mr r3,r5
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blr
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END (strcspn)
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libc_hidden_builtin_def (strcspn)
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