1/* SPDX-License-Identifier: GPL-2.0 */
  2// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
  3
  4#include <linux/linkage.h>
  5#include "sysdep.h"
  6
  7ENTRY(memcmp)
  8	/* Test if len less than 4 bytes.  */
  9	mov	r3, r0
 10	movi	r0, 0
 11	mov	r12, r4
 12	cmplti	r2, 4
 13	bt	.L_compare_by_byte
 14
 15	andi	r13, r0, 3
 16	movi	r19, 4
 17
 18	/* Test if s1 is not 4 bytes aligned.  */
 19	bnez	r13, .L_s1_not_aligned
 20
 21	LABLE_ALIGN
 22.L_s1_aligned:
 23	/* If dest is aligned, then copy.  */
 24	zext	r18, r2, 31, 4
 25	/* Test if len less than 16 bytes.  */
 26	bez	r18, .L_compare_by_word
 27
 28.L_compare_by_4word:
 29	/* If aligned, load word each time.  */
 30	ldw	r20, (r3, 0)
 31	ldw	r21, (r1, 0)
 32	/* If s1[i] != s2[i], goto .L_byte_check.  */
 33	cmpne	r20, r21
 34	bt	.L_byte_check
 35
 36	ldw	r20, (r3, 4)
 37	ldw	r21, (r1, 4)
 38	cmpne	r20, r21
 39	bt	.L_byte_check
 40
 41	ldw	r20, (r3, 8)
 42	ldw	r21, (r1, 8)
 43	cmpne	r20, r21
 44	bt	.L_byte_check
 45
 46	ldw	r20, (r3, 12)
 47	ldw	r21, (r1, 12)
 48	cmpne	r20, r21
 49	bt	.L_byte_check
 50
 51	PRE_BNEZAD (r18)
 52	addi	a3, 16
 53	addi	a1, 16
 54
 55	BNEZAD (r18, .L_compare_by_4word)
 56
 57.L_compare_by_word:
 58	zext	r18, r2, 3, 2
 59	bez	r18, .L_compare_by_byte
 60.L_compare_by_word_loop:
 61	ldw	r20, (r3, 0)
 62	ldw	r21, (r1, 0)
 63	addi	r3, 4
 64	PRE_BNEZAD (r18)
 65	cmpne	r20, r21
 66	addi    r1, 4
 67	bt	.L_byte_check
 68	BNEZAD (r18, .L_compare_by_word_loop)
 69
 70.L_compare_by_byte:
 71        zext    r18, r2, 1, 0
 72        bez     r18, .L_return
 73.L_compare_by_byte_loop:
 74        ldb     r0, (r3, 0)
 75        ldb     r4, (r1, 0)
 76        addi    r3, 1
 77        subu    r0, r4
 78        PRE_BNEZAD (r18)
 79        addi    r1, 1
 80        bnez    r0, .L_return
 81        BNEZAD (r18, .L_compare_by_byte_loop)
 82
 83.L_return:
 84        mov     r4, r12
 85        rts
 86
 87# ifdef __CSKYBE__
 88/* d[i] != s[i] in word, so we check byte 0.  */
 89.L_byte_check:
 90        xtrb0   r0, r20
 91        xtrb0   r2, r21
 92        subu    r0, r2
 93        bnez    r0, .L_return
 94
 95        /* check byte 1 */
 96        xtrb1   r0, r20
 97        xtrb1   r2, r21
 98        subu    r0, r2
 99        bnez    r0, .L_return
100
101        /* check byte 2 */
102        xtrb2   r0, r20
103        xtrb2   r2, r21
104        subu    r0, r2
105        bnez    r0, .L_return
106
107        /* check byte 3 */
108        xtrb3   r0, r20
109        xtrb3   r2, r21
110        subu    r0, r2
111# else
112/* s1[i] != s2[i] in word, so we check byte 3.  */
113.L_byte_check:
114	xtrb3	r0, r20
115	xtrb3	r2, r21
116        subu    r0, r2
117        bnez    r0, .L_return
118
119	/* check byte 2 */
120	xtrb2	r0, r20
121	xtrb2	r2, r21
122        subu    r0, r2
123        bnez    r0, .L_return
124
125	/* check byte 1 */
126	xtrb1	r0, r20
127	xtrb1	r2, r21
128	subu	r0, r2
129	bnez    r0, .L_return
130
131	/* check byte 0 */
132	xtrb0	r0, r20
133	xtrb0	r2, r21
134	subu	r0, r2
135	br	.L_return
136# endif /* !__CSKYBE__ */
137
138/* Compare when s1 is not aligned.  */
139.L_s1_not_aligned:
140	sub	r13, r19, r13
141	sub	r2, r13
142.L_s1_not_aligned_loop:
143	ldb	r0, (r3, 0)
144	ldb	r4, (r1, 0)
145	addi	r3, 1
146	subu	r0, r4
147	PRE_BNEZAD (r13)
148	addi	r1, 1
149	bnez	r0, .L_return
150	BNEZAD (r13, .L_s1_not_aligned_loop)
151	br	.L_s1_aligned
152ENDPROC(memcmp)