/* The assembly function for memset.  C-SKY ABIV2 version.
   Copyright (C) 2018-2024 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library.  If not, see
   <https://www.gnu.org/licenses/>.  */

#include <sysdep.h>

ENTRY (memset)
	/* Test if len less than 4 bytes.  */
	mov	r12, r0
	cmplti	r2, 8
	bt	.L_set_by_byte

	andi	r13, r0, 3
	movi	r19, 4
	/* Test if dest is not 4 bytes aligned.  */
	bnez	r13, .L_dest_not_aligned
	/* Hardware can handle unaligned access directly.  */
.L_dest_aligned:
	zextb	r1, r1
	mov	r3, r1
	lsli	r1, 8
	or	r1, r3
	lsli	r3, r1, 16
	or	r3, r1

	/* If dest is aligned, then copy.  */
	zext	r18, r2, 31, 4
	/* Test if len less than 16 bytes.  */
	bez	r18, .L_len_less_16bytes

	LABLE_ALIGN
.L_len_larger_16bytes:
	stw	r3, (r0, 0)
	stw	r3, (r0, 4)
	stw	r3, (r0, 8)
	stw	r3, (r0, 12)
	PRE_BNEZAD (r18)
	addi	r0, 16
	BNEZAD (r18, .L_len_larger_16bytes)

.L_len_less_16bytes:
	zext	r18, r2, 3, 2
	andi	r2, 3
	bez	r18, .L_set_by_byte
.L_len_less_16bytes_loop:
	stw	r3, (r0, 0)
	PRE_BNEZAD (r18)
	addi	r0, 4
	BNEZAD (r18, .L_len_less_16bytes_loop)

	/* Test if len less than 4 bytes.  */
.L_set_by_byte:
	zext	r18, r2, 2, 0
	bez	r18, .L_return
.L_set_by_byte_loop:
	stb	r1, (r0, 0)
	PRE_BNEZAD (r18)
	addi	r0, 1
	BNEZAD (r18, .L_set_by_byte_loop)

.L_return:
	mov	r0, r12
	rts

	/* If dest is not aligned, just set some bytes makes the dest
	   align.  */

.L_dest_not_aligned:
	sub	r13, r19, r13
	sub	r2, r13
.L_dest_not_aligned_loop:
	/* Makes the dest align.  */
	stb	r1, (r0, 0)
	PRE_BNEZAD (r13)
	addi	r0, 1
	BNEZAD (r13, .L_dest_not_aligned_loop)
	cmplti	r2, 8
	bt	.L_set_by_byte
	/* Check whether the src is aligned.  */
	br	.L_dest_aligned
END (memset)

libc_hidden_builtin_def (memset)
.weak memset
