157 lines
2.5 KiB
ArmAsm
157 lines
2.5 KiB
ArmAsm
/* The assembly function for string compare. C-SKY ABIV2 version.
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Copyright (C) 2018-2022 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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ENTRY (strcmp)
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mov a3, a0
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/* Check if the s1 addr is aligned. */
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xor a2, a3, a1
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andi a2, 0x3
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bnez a2, 7f
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andi t1, a0, 0x3
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bnez t1, 5f
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1:
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/* If aligned, load word each time. */
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ldw t0, (a3, 0)
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ldw t1, (a1, 0)
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/* If s1[i] != s2[i], goto 2f. */
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cmpne t0, t1
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bt 2f
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/* If s1[i] == s2[i], check if s1 or s2 is at the end. */
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tstnbz t0
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/* If at the end, goto 3f (finish comparing). */
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bf 3f
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ldw t0, (a3, 4)
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ldw t1, (a1, 4)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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ldw t0, (a3, 8)
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ldw t1, (a1, 8)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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ldw t0, (a3, 12)
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ldw t1, (a1, 12)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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ldw t0, (a3, 16)
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ldw t1, (a1, 16)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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ldw t0, (a3, 20)
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ldw t1, (a1, 20)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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ldw t0, (a3, 24)
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ldw t1, (a1, 24)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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ldw t0, (a3, 28)
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ldw t1, (a1, 28)
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cmpne t0, t1
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bt 2f
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tstnbz t0
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bf 3f
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addi a3, 32
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addi a1, 32
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br 1b
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/* s1[i] != s2[i] in word, so we check byte 3. */
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2:
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xtrb3 a0, t0
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xtrb3 a2, t1
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subu a0, a2
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bez a2, 4f
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bnez a0, 4f
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/* Check byte 2. */
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xtrb2 a0, t0
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xtrb2 a2, t1
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subu a0, a2
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bez a2, 4f
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bnez a0, 4f
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/* Check byte 1. */
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xtrb1 a0, t0
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xtrb1 a2, t1
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subu a0, a2
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bez a2, 4f
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bnez a0, 4f
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/* Check byte 0. */
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xtrb0 a0, t0
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xtrb0 a2, t1
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subu a0, a2
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jmp lr
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3:
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movi a0, 0
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4:
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jmp lr
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/* Compare when s1 or s2 is not aligned. */
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5:
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subi t1, 4
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6:
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ldb a0, (a3, 0)
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ldb a2, (a1, 0)
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subu a0, a2
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bnez a0, 4b
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addi t1, 1
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bez a2, 4b
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addi a1, 1
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addi a3, 1
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bez t1, 1b
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br 6b
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7:
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ldb a0, (a3, 0)
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addi a3, 1
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ldb a2, (a1, 0)
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addi a1, 1
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subu a0, a2
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bnez a0, 4b
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bnez a2, 7b
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jmp r15
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END (strcmp)
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libc_hidden_def (strcmp)
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.weak strcmp
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