1/*
2 * memscan.S: Optimized memscan for the Sparc.
3 *
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
5 */
6
7/* In essence, this is just a fancy strlen. */
8
9#define LO_MAGIC 0x01010101
10#define HI_MAGIC 0x80808080
11
12	.text
13	.align	4
14	.globl	__memscan_zero, __memscan_generic
15	.globl	memscan
16__memscan_zero:
17	/* %o0 = addr, %o1 = size */
18	cmp	%o1, 0
19	bne,a	1f
20	 andcc	%o0, 3, %g0
21
22	retl
23	 nop
24
251:
26	be	mzero_scan_word
27	 sethi	%hi(HI_MAGIC), %g2
28
29	ldsb	[%o0], %g3
30mzero_still_not_word_aligned:
31	cmp	%g3, 0
32	bne	1f
33	 add	%o0, 1, %o0
34
35	retl
36	 sub	%o0, 1, %o0
37
381:
39	subcc	%o1, 1, %o1
40	bne,a	1f
41	 andcc	%o0, 3, %g0
42
43	retl
44	 nop
45
461:
47	bne,a	mzero_still_not_word_aligned
48	 ldsb	[%o0], %g3
49
50	sethi	%hi(HI_MAGIC), %g2
51mzero_scan_word:
52	or	%g2, %lo(HI_MAGIC), %o3
53	sethi	%hi(LO_MAGIC), %g3
54	or	%g3, %lo(LO_MAGIC), %o2
55mzero_next_word:
56	ld	[%o0], %g2
57mzero_next_word_preloaded:
58	sub	%g2, %o2, %g2
59mzero_next_word_preloaded_next:
60	andcc	%g2, %o3, %g0
61	bne	mzero_byte_zero
62	 add	%o0, 4, %o0
63
64mzero_check_out_of_fuel:
65	subcc	%o1, 4, %o1
66	bg,a	1f
67	 ld	[%o0], %g2
68
69	retl
70	 nop
71
721:
73	b	mzero_next_word_preloaded_next
74	 sub	%g2, %o2, %g2
75
76	/* Check every byte. */
77mzero_byte_zero:
78	ldsb	[%o0 - 4], %g2
79	cmp	%g2, 0
80	bne	mzero_byte_one
81	 sub	%o0, 4, %g3
82
83	retl
84	 mov	%g3, %o0
85
86mzero_byte_one:
87	ldsb	[%o0 - 3], %g2
88	cmp	%g2, 0
89	bne,a	mzero_byte_two_and_three
90	 ldsb	[%o0 - 2], %g2
91
92	retl
93	 sub	%o0, 3, %o0
94
95mzero_byte_two_and_three:
96	cmp	%g2, 0
97	bne,a	1f
98	 ldsb	[%o0 - 1], %g2
99
100	retl
101	 sub	%o0, 2, %o0
102
1031:
104	cmp	%g2, 0
105	bne,a	mzero_next_word_preloaded
106	 ld	[%o0], %g2
107
108	retl
109	 sub	%o0, 1, %o0
110
111mzero_found_it:
112	retl
113	 sub	%o0, 2, %o0
114
115memscan:
116__memscan_generic:
117	/* %o0 = addr, %o1 = c, %o2 = size */
118	cmp	%o2, 0
119	bne,a	0f
120	 ldub	[%o0], %g2
121
122	b,a	2f
1231:
124	ldub	[%o0], %g2
1250:
126	cmp	%g2, %o1
127	be	2f
128	 addcc	%o2, -1, %o2
129	bne	1b
130	 add	%o0, 1, %o0
1312:
132	retl
133	 nop
134