1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/* Optimized strcmp implementation for PowerPC64/POWER10.
Copyright (C) 2021-2023 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>
#ifndef STRCMP
# define STRCMP strcmp
#endif
/* Implements the function
int [r3] strcmp (const char *s1 [r3], const char *s2 [r4]). */
/* TODO: Change this to actual instructions when minimum binutils is upgraded
to 2.27. Macros are defined below for these newer instructions in order
to maintain compatibility. */
#define LXVP(xtp,dq,ra) \
.long(((6)<<(32-6)) \
| ((((xtp)-32)>>1)<<(32-10)) \
| ((1)<<(32-11)) \
| ((ra)<<(32-16)) \
| dq)
#define COMPARE_16(vreg1,vreg2,offset) \
lxv vreg1+32,offset(r3); \
lxv vreg2+32,offset(r4); \
vcmpnezb. v7,vreg1,vreg2; \
bne cr6,L(different); \
#define COMPARE_32(vreg1,vreg2,offset,label1,label2) \
LXVP(vreg1+32,offset,r3); \
LXVP(vreg2+32,offset,r4); \
vcmpnezb. v7,vreg1+1,vreg2+1; \
bne cr6,L(label1); \
vcmpnezb. v7,vreg1,vreg2; \
bne cr6,L(label2); \
#define TAIL(vreg1,vreg2) \
vctzlsbb r6,v7; \
vextubrx r5,r6,vreg1; \
vextubrx r4,r6,vreg2; \
subf r3,r4,r5; \
blr; \
#define CHECK_N_BYTES(reg1,reg2,len_reg) \
sldi r0,len_reg,56; \
lxvl 32+v4,reg1,r0; \
lxvl 32+v5,reg2,r0; \
add reg1,reg1,len_reg; \
add reg2,reg2,len_reg; \
vcmpnezb. v7,v4,v5; \
vctzlsbb r6,v7; \
cmpld cr7,r6,len_reg; \
blt cr7,L(different); \
/* TODO: change this to .machine power10 when the minimum required
binutils allows it. */
.machine power9
ENTRY_TOCLESS (STRCMP, 4)
li r11,16
/* eq bit of cr1 used as swap status flag to indicate if
source pointers were swapped. */
crclr 4*cr1+eq
vspltisb v19,-1
andi. r7,r3,15
sub r7,r11,r7 /* r7(nalign1) = 16 - (str1 & 15). */
andi. r9,r4,15
sub r5,r11,r9 /* r5(nalign2) = 16 - (str2 & 15). */
cmpld cr7,r7,r5
beq cr7,L(same_aligned)
blt cr7,L(nalign1_min)
/* Swap r3 and r4, and r7 and r5 such that r3 and r7 hold the
pointer which is closer to the next 16B boundary so that only
one CHECK_N_BYTES is needed before entering the loop below. */
mr r8,r4
mr r4,r3
mr r3,r8
mr r12,r7
mr r7,r5
mr r5,r12
crset 4*cr1+eq /* Set bit on swapping source pointers. */
.p2align 5
L(nalign1_min):
CHECK_N_BYTES(r3,r4,r7)
.p2align 5
L(s1_aligned):
/* r9 and r5 is number of bytes to be read after and before
page boundary correspondingly. */
sub r5,r5,r7
subfic r9,r5,16
/* Now let r7 hold the count of quadwords which can be
checked without crossing a page boundary. quadword offset is
(str2>>4)&0xFF. */
rlwinm r7,r4,28,0xFF
/* Below check is required only for first iteration. For second
iteration and beyond, the new loop counter is always 255. */
cmpldi r7,255
beq L(L3)
/* Get the initial loop count by 255-((str2>>4)&0xFF). */
subfic r11,r7,255
.p2align 5
L(L1):
mtctr r11
.p2align 5
L(L2):
COMPARE_16(v4,v5,0) /* Load 16B blocks using lxv. */
addi r3,r3,16
addi r4,r4,16
bdnz L(L2)
/* Cross the page boundary of s2, carefully. */
.p2align 5
L(L3):
CHECK_N_BYTES(r3,r4,r5)
CHECK_N_BYTES(r3,r4,r9)
li r11,255 /* Load the new loop counter. */
b L(L1)
.p2align 5
L(same_aligned):
CHECK_N_BYTES(r3,r4,r7)
/* Align s1 to 32B and adjust s2 address.
Use lxvp only if both s1 and s2 are 32B aligned. */
COMPARE_16(v4,v5,0)
COMPARE_16(v4,v5,16)
COMPARE_16(v4,v5,32)
COMPARE_16(v4,v5,48)
addi r3,r3,64
addi r4,r4,64
COMPARE_16(v4,v5,0)
COMPARE_16(v4,v5,16)
clrldi r6,r3,59
subfic r5,r6,32
add r3,r3,r5
add r4,r4,r5
andi. r5,r4,0x1F
beq cr0,L(32B_aligned_loop)
.p2align 5
L(16B_aligned_loop):
COMPARE_16(v4,v5,0)
COMPARE_16(v4,v5,16)
COMPARE_16(v4,v5,32)
COMPARE_16(v4,v5,48)
addi r3,r3,64
addi r4,r4,64
b L(16B_aligned_loop)
/* Calculate and return the difference. */
L(different):
vctzlsbb r6,v7
vextubrx r5,r6,v4
vextubrx r4,r6,v5
bt 4*cr1+eq,L(swapped)
subf r3,r4,r5
blr
/* If src pointers were swapped, then swap the
indices and calculate the return value. */
L(swapped):
subf r3,r5,r4
blr
.p2align 5
L(32B_aligned_loop):
COMPARE_32(v14,v16,0,tail1,tail2)
COMPARE_32(v18,v20,32,tail3,tail4)
COMPARE_32(v22,v24,64,tail5,tail6)
COMPARE_32(v26,v28,96,tail7,tail8)
addi r3,r3,128
addi r4,r4,128
b L(32B_aligned_loop)
L(tail1): TAIL(v15,v17)
L(tail2): TAIL(v14,v16)
L(tail3): TAIL(v19,v21)
L(tail4): TAIL(v18,v20)
L(tail5): TAIL(v23,v25)
L(tail6): TAIL(v22,v24)
L(tail7): TAIL(v27,v29)
L(tail8): TAIL(v26,v28)
END (STRCMP)
libc_hidden_builtin_def (strcmp)
|