xref: /freebsd/lib/libc/amd64/string/memset.S (revision b0d29bc47dba79f6f38e67eabadfb4b32ffd9390)
1/*-
2 * Copyright (c) 2018 The FreeBSD Foundation
3 *
4 * This software was developed by Mateusz Guzik <mjg@FreeBSD.org>
5 * under sponsorship from the FreeBSD Foundation.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#include <machine/asm.h>
32__FBSDID("$FreeBSD$");
33
34#define ALIGN_TEXT      .p2align 4,0x90 /* 16-byte alignment, nop filled */
35
36.macro MEMSET erms
37	movq	%rdi,%rax
38	movq	%rdx,%rcx
39	movzbq	%sil,%r8
40	movabs	$0x0101010101010101,%r10
41	imulq	%r8,%r10
42
43	cmpq	$32,%rcx
44	jbe	101632f
45
46	cmpq	$256,%rcx
47	ja	1256f
48
49103200:
50	movq	%r10,(%rdi)
51	movq	%r10,8(%rdi)
52	movq	%r10,16(%rdi)
53	movq	%r10,24(%rdi)
54	leaq	32(%rdi),%rdi
55	subq	$32,%rcx
56	cmpq	$32,%rcx
57	ja	103200b
58	cmpb	$16,%cl
59	ja	201632f
60	movq	%r10,-16(%rdi,%rcx)
61	movq	%r10,-8(%rdi,%rcx)
62	ret
63	ALIGN_TEXT
64101632:
65	cmpb	$16,%cl
66	jl	100816f
67201632:
68	movq	%r10,(%rdi)
69	movq	%r10,8(%rdi)
70	movq	%r10,-16(%rdi,%rcx)
71	movq	%r10,-8(%rdi,%rcx)
72	ret
73	ALIGN_TEXT
74100816:
75	cmpb	$8,%cl
76	jl	100408f
77	movq	%r10,(%rdi)
78	movq	%r10,-8(%rdi,%rcx)
79	ret
80	ALIGN_TEXT
81100408:
82	cmpb	$4,%cl
83	jl	100204f
84	movl	%r10d,(%rdi)
85	movl	%r10d,-4(%rdi,%rcx)
86	ret
87	ALIGN_TEXT
88100204:
89	cmpb	$2,%cl
90	jl	100001f
91	movw	%r10w,(%rdi)
92	movw	%r10w,-2(%rdi,%rcx)
93	ret
94	ALIGN_TEXT
95100001:
96	cmpb	$0,%cl
97	je	100000f
98	movb	%r10b,(%rdi)
99100000:
100	ret
101	ALIGN_TEXT
1021256:
103	movq	%rdi,%r9
104	movq	%r10,%rax
105	testl	$15,%edi
106	jnz	3f
1071:
108.if \erms == 1
109	rep
110	stosb
111	movq	%r9,%rax
112.else
113	movq	%rcx,%rdx
114	shrq	$3,%rcx
115	rep
116	stosq
117	movq	%r9,%rax
118	andl	$7,%edx
119	jnz	2f
120	ret
1212:
122	movq	%r10,-8(%rdi,%rdx)
123.endif
124	ret
125	ALIGN_TEXT
1263:
127	movq	%r10,(%rdi)
128	movq	%r10,8(%rdi)
129	movq	%rdi,%r8
130	andq	$15,%r8
131	leaq	-16(%rcx,%r8),%rcx
132	neg	%r8
133	leaq	16(%rdi,%r8),%rdi
134	jmp	1b
135.endm
136
137
138ENTRY(memset)
139	MEMSET erms=0
140END(memset)
141
142	.section .note.GNU-stack,"",%progbits
143