98 строки
1.4 KiB
ArmAsm
98 строки
1.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/linkage.h>
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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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# ifdef __CSKYBE__
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xtrb0 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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xtrb2 r3, r1
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bez r3, .L_return
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addi r0, 1
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# else
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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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# endif /* !__CSKYBE__ */
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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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ENDPROC(strlen)
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