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135 lines
3.4 KiB
ArmAsm
135 lines
3.4 KiB
ArmAsm
/* Optimized strcmp implementation for PowerPC476.
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Copyright (C) 2010-2024 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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/* strcmp
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Register Use
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r0:temp return equality
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r3:source1 address, return equality
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r4:source2 address
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Implementation description
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Check 2 words from src1 and src2. If unequal jump to end and
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return src1 > src2 or src1 < src2.
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If null check bytes before null and then jump to end and
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return src1 > src2, src1 < src2 or src1 = src2.
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If src1 = src2 and no null, repeat. */
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EALIGN (strcmp,5,0)
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neg r7,r3
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clrlwi r7,r7,20
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neg r8,r4
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clrlwi r8,r8,20
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srwi. r7,r7,5
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beq L(byte_loop)
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srwi. r8,r8,5
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beq L(byte_loop)
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cmplw r7,r8
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mtctr r7
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ble L(big_loop)
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mtctr r8
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L(big_loop):
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lwz r5,0(r3)
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lwz r6,4(r3)
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lwz r8,0(r4)
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lwz r9,4(r4)
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dlmzb. r12,r5,r6
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bne L(end_check)
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cmplw r5,r8
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bne L(st1)
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cmplw r6,r9
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bne L(st1)
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lwz r5,8(r3)
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lwz r6,12(r3)
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lwz r8,8(r4)
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lwz r9,12(r4)
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dlmzb. r12,r5,r6
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bne L(end_check)
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cmplw r5,r8
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bne L(st1)
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cmplw r6,r9
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bne L(st1)
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lwz r5,16(r3)
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lwz r6,20(r3)
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lwz r8,16(r4)
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lwz r9,20(r4)
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dlmzb. r12,r5,r6
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bne L(end_check)
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cmplw r5,r8
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bne L(st1)
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cmplw r6,r9
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bne L(st1)
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lwz r5,24(r3)
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lwz r6,28(r3)
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addi r3,r3,0x20
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lwz r8,24(r4)
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lwz r9,28(r4)
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addi r4,r4,0x20
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dlmzb. r12,r5,r6
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bne L(end_check)
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cmplw r5,r8
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bne L(st1)
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cmplw r6,r9
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bne L(st1)
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bdnz L(big_loop)
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b L(byte_loop)
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L(end_check):
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subfic r12,r12,4
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blt L(end_check2)
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rlwinm r12,r12,3,0,31
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srw r5,r5,r12
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srw r8,r8,r12
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cmplw r5,r8
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bne L(st1)
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b L(end_strcmp)
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L(end_check2):
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addi r12,r12,4
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cmplw r5,r8
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rlwinm r12,r12,3,0,31
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bne L(st1)
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srw r6,r6,r12
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srw r9,r9,r12
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cmplw r6,r9
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bne L(st1)
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L(end_strcmp):
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addi r3,r0,0
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blr
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L(st1):
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mfcr r3
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blr
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L(byte_loop):
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lbz r5,0(r3)
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addi r3,r3,1
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lbz r6,0(r4)
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addi r4,r4,1
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cmplw r5,r6
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bne L(st1)
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cmpwi r5,0
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beq L(end_strcmp)
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b L(byte_loop)
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END (strcmp)
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libc_hidden_builtin_def (strcmp)
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