99 lines
2.3 KiB
ArmAsm
99 lines
2.3 KiB
ArmAsm
/* The assembly function for memset. 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 (memset)
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/* Test if len less than 4 bytes. */
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mov r12, r0
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cmplti r2, 8
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bt .L_set_by_byte
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andi r13, r0, 3
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movi r19, 4
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/* Test if dest is not 4 bytes aligned. */
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bnez r13, .L_dest_not_aligned
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/* Hardware can handle unaligned access directly. */
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.L_dest_aligned:
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zextb r1, r1
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mov r3, r1
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lsli r1, 8
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or r1, r3
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lsli r3, r1, 16
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or r3, r1
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/* If dest is aligned, then copy. */
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zext r18, r2, 31, 4
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/* Test if len less than 16 bytes. */
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bez r18, .L_len_less_16bytes
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LABLE_ALIGN
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.L_len_larger_16bytes:
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stw r3, (r0, 0)
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stw r3, (r0, 4)
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stw r3, (r0, 8)
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stw r3, (r0, 12)
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PRE_BNEZAD (r18)
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addi r0, 16
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BNEZAD (r18, .L_len_larger_16bytes)
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.L_len_less_16bytes:
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zext r18, r2, 3, 2
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andi r2, 3
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bez r18, .L_set_by_byte
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.L_len_less_16bytes_loop:
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stw r3, (r0, 0)
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PRE_BNEZAD (r18)
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addi r0, 4
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BNEZAD (r18, .L_len_less_16bytes_loop)
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/* Test if len less than 4 bytes. */
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.L_set_by_byte:
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zext r18, r2, 2, 0
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bez r18, .L_return
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.L_set_by_byte_loop:
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stb r1, (r0, 0)
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PRE_BNEZAD (r18)
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addi r0, 1
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BNEZAD (r18, .L_set_by_byte_loop)
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.L_return:
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mov r0, r12
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rts
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/* If dest is not aligned, just set some bytes makes the dest
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align. */
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.L_dest_not_aligned:
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sub r13, r19, r13
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sub r2, r13
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.L_dest_not_aligned_loop:
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/* Makes the dest align. */
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stb r1, (r0, 0)
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PRE_BNEZAD (r13)
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addi r0, 1
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BNEZAD (r13, .L_dest_not_aligned_loop)
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cmplti r2, 8
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bt .L_set_by_byte
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/* Check whether the src is aligned. */
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br .L_dest_aligned
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END (memset)
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libc_hidden_builtin_def (memset)
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.weak memset
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