1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * linux/arch/alpha/lib/memset.S
4 *
5 * This is an efficient (and small) implementation of the C library "memset()"
6 * function for the alpha.
7 *
8 * (C) Copyright 1996 Linus Torvalds
9 *
10 * This routine is "moral-ware": you are free to use it any way you wish, and
11 * the only obligation I put on you is a moral one: if you make any improvements
12 * to the routine, please send me your improvements for me to use similarly.
13 *
14 * The scheduling comments are according to the EV5 documentation (and done by
15 * hand, so they might well be incorrect, please do tell me about it..)
16 */
17#include <linux/export.h>
18 .set noat
19 .set noreorder
20.text
21 .globl memset
22 .globl __memset
23 .globl ___memset
24 .globl __memset16
25 .globl __constant_c_memset
26
27 .ent ___memset
28.align 5
29___memset:
30 .frame $30,0,$26,0
31 .prologue 0
32
33 and $17,255,$1 /* E1 */
34 insbl $17,1,$17 /* .. E0 */
35 bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
36 sll $17,16,$1 /* E1 (p-c latency, next cycle) */
37
38 bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
39 sll $17,32,$1 /* E1 (p-c latency, next cycle) */
40 bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
41 ldq_u $31,0($30) /* .. E1 */
42
43.align 5
44__constant_c_memset:
45 addq $18,$16,$6 /* E0 */
46 bis $16,$16,$0 /* .. E1 */
47 xor $16,$6,$1 /* E0 */
48 ble $18,end /* .. E1 */
49
50 bic $1,7,$1 /* E0 */
51 beq $1,within_one_quad /* .. E1 (note EV5 zero-latency forwarding) */
52 and $16,7,$3 /* E0 */
53 beq $3,aligned /* .. E1 (note EV5 zero-latency forwarding) */
54
55 ldq_u $4,0($16) /* E0 */
56 bis $16,$16,$5 /* .. E1 */
57 insql $17,$16,$2 /* E0 */
58 subq $3,8,$3 /* .. E1 */
59
60 addq $18,$3,$18 /* E0 $18 is new count ($3 is negative) */
61 mskql $4,$16,$4 /* .. E1 (and possible load stall) */
62 subq $16,$3,$16 /* E0 $16 is new aligned destination */
63 bis $2,$4,$1 /* .. E1 */
64
65 bis $31,$31,$31 /* E0 */
66 ldq_u $31,0($30) /* .. E1 */
67 stq_u $1,0($5) /* E0 */
68 bis $31,$31,$31 /* .. E1 */
69
70.align 4
71aligned:
72 sra $18,3,$3 /* E0 */
73 and $18,7,$18 /* .. E1 */
74 bis $16,$16,$5 /* E0 */
75 beq $3,no_quad /* .. E1 */
76
77.align 3
78loop:
79 stq $17,0($5) /* E0 */
80 subq $3,1,$3 /* .. E1 */
81 addq $5,8,$5 /* E0 */
82 bne $3,loop /* .. E1 */
83
84no_quad:
85 bis $31,$31,$31 /* E0 */
86 beq $18,end /* .. E1 */
87 ldq $7,0($5) /* E0 */
88 mskqh $7,$6,$2 /* .. E1 (and load stall) */
89
90 insqh $17,$6,$4 /* E0 */
91 bis $2,$4,$1 /* .. E1 */
92 stq $1,0($5) /* E0 */
93 ret $31,($26),1 /* .. E1 */
94
95.align 3
96within_one_quad:
97 ldq_u $1,0($16) /* E0 */
98 insql $17,$16,$2 /* E1 */
99 mskql $1,$16,$4 /* E0 (after load stall) */
100 bis $2,$4,$2 /* E0 */
101
102 mskql $2,$6,$4 /* E0 */
103 mskqh $1,$6,$2 /* .. E1 */
104 bis $2,$4,$1 /* E0 */
105 stq_u $1,0($16) /* E0 */
106
107end:
108 ret $31,($26),1 /* E1 */
109 .end ___memset
110EXPORT_SYMBOL(___memset)
111EXPORT_SYMBOL(__constant_c_memset)
112
113 .align 5
114 .ent __memset16
115__memset16:
116 .prologue 0
117
118 inswl $17,0,$1 /* E0 */
119 inswl $17,2,$2 /* E0 */
120 inswl $17,4,$3 /* E0 */
121 or $1,$2,$1 /* .. E1 */
122 inswl $17,6,$4 /* E0 */
123 or $1,$3,$1 /* .. E1 */
124 or $1,$4,$17 /* E0 */
125 br __constant_c_memset /* .. E1 */
126
127 .end __memset16
128EXPORT_SYMBOL(__memset16)
129
130memset = ___memset
131__memset = ___memset
132 EXPORT_SYMBOL(memset)
133 EXPORT_SYMBOL(__memset)
134

source code of linux/arch/alpha/lib/memset.S