103 lines
2.0 KiB
ArmAsm
103 lines
2.0 KiB
ArmAsm
/* The assembly function for string length. C-SKY ABIV2 version.
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Copyright (C) 2018 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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ENTRY (strlen)
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/* Check if the start addr is aligned. */
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mov r3, r0
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andi r1, r0, 3
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movi r2, 4
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movi r0, 0
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bnez r1, .L_start_not_aligned
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LABLE_ALIGN
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.L_start_addr_aligned:
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/* Check if all the bytes in the word are not zero. */
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ldw r1, (r3)
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 4)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 8)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 12)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 16)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 20)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 24)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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ldw r1, (r3, 28)
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addi r0, 4
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tstnbz r1
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bf .L_string_tail
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addi r0, 4
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addi r3, 32
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br .L_start_addr_aligned
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.L_string_tail:
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xtrb3 r3, r1
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bez r3, .L_return
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addi r0, 1
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xtrb2 r3, r1
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bez r3, .L_return
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addi r0, 1
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xtrb1 r3, r1
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bez r3, .L_return
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addi r0, 1
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.L_return:
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rts
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.L_start_not_aligned:
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sub r2, r2, r1
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.L_start_not_aligned_loop:
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ldb r1, (r3)
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PRE_BNEZAD (r2)
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addi r3, 1
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bez r1, .L_return
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addi r0, 1
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BNEZAD (r2, .L_start_not_aligned_loop)
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br .L_start_addr_aligned
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END (strlen)
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libc_hidden_def (strlen)
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.weak strlen
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