Warning: That file was not part of the compilation database. It may have many parsing errors.

1/* Copyright (C) 2000-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 EV6 optimized by Rick Gorton <rick.gorton@alpha-processor.com>.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <http://www.gnu.org/licenses/>. */
18
19/*
20 * Much of the information about 21264 scheduling/coding comes from:
21 * Compiler Writer's Guide for the Alpha 21264
22 * abbreviated as 'CWG' in other comments here
23 * ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
24 * Scheduling notation:
25 * E - either cluster
26 * U - upper subcluster; U0 - subcluster U0; U1 - subcluster U1
27 * L - lower subcluster; L0 - subcluster L0; L1 - subcluster L1
28 *
29 * Temp usage notes:
30 * $0 - destination address
31 * $1,$2, - scratch
32 */
33
34#include <sysdep.h>
35
36 .arch ev6
37 .set noreorder
38 .set noat
39
40ENTRY(memcpy)
41 .prologue 0
42
43 mov $16, $0 # E : copy dest to return
44 ble $18, $nomoredata # U : done with the copy?
45 xor $16, $17, $1 # E : are source and dest alignments the same?
46 and $1, 7, $1 # E : are they the same mod 8?
47
48 bne $1, $misaligned # U : Nope - gotta do this the slow way
49 /* source and dest are same mod 8 address */
50 and $16, 7, $1 # E : Are both 0mod8?
51 beq $1, $both_0mod8 # U : Yes
52 nop # E :
53
54 /*
55 * source and dest are same misalignment. move a byte at a time
56 * until a 0mod8 alignment for both is reached.
57 * At least one byte more to move
58 */
59
60$head_align:
61 ldbu $1, 0($17) # L : grab a byte
62 subq $18, 1, $18 # E : count--
63 addq $17, 1, $17 # E : src++
64 stb $1, 0($16) # L :
65 addq $16, 1, $16 # E : dest++
66 and $16, 7, $1 # E : Are we at 0mod8 yet?
67 ble $18, $nomoredata # U : done with the copy?
68 bne $1, $head_align # U :
69
70$both_0mod8:
71 cmple $18, 127, $1 # E : Can we unroll the loop?
72 bne $1, $no_unroll # U :
73 and $16, 63, $1 # E : get mod64 alignment
74 beq $1, $do_unroll # U : no single quads to fiddle
75
76$single_head_quad:
77 ldq $1, 0($17) # L : get 8 bytes
78 subq $18, 8, $18 # E : count -= 8
79 addq $17, 8, $17 # E : src += 8
80 nop # E :
81
82 stq $1, 0($16) # L : store
83 addq $16, 8, $16 # E : dest += 8
84 and $16, 63, $1 # E : get mod64 alignment
85 bne $1, $single_head_quad # U : still not fully aligned
86
87$do_unroll:
88 addq $16, 64, $7 # E : Initial (+1 trip) wh64 address
89 cmple $18, 127, $1 # E : Can we go through the unrolled loop?
90 bne $1, $tail_quads # U : Nope
91 nop # E :
92
93$unroll_body:
94 wh64 ($7) # L1 : memory subsystem hint: 64 bytes at
95 # ($7) are about to be over-written
96 ldq $6, 0($17) # L0 : bytes 0..7
97 nop # E :
98 nop # E :
99
100 ldq $4, 8($17) # L : bytes 8..15
101 ldq $5, 16($17) # L : bytes 16..23
102 addq $7, 64, $7 # E : Update next wh64 address
103 nop # E :
104
105 ldq $3, 24($17) # L : bytes 24..31
106 addq $16, 64, $1 # E : fallback value for wh64
107 nop # E :
108 nop # E :
109
110 addq $17, 32, $17 # E : src += 32 bytes
111 stq $6, 0($16) # L : bytes 0..7
112 nop # E :
113 nop # E :
114
115 stq $4, 8($16) # L : bytes 8..15
116 stq $5, 16($16) # L : bytes 16..23
117 subq $18, 192, $2 # E : At least two more trips to go?
118 nop # E :
119
120 stq $3, 24($16) # L : bytes 24..31
121 addq $16, 32, $16 # E : dest += 32 bytes
122 nop # E :
123 nop # E :
124
125 ldq $6, 0($17) # L : bytes 0..7
126 ldq $4, 8($17) # L : bytes 8..15
127 cmovlt $2, $1, $7 # E : Latency 2, extra map slot - Use
128 # fallback wh64 address if < 2 more trips
129 nop # E :
130
131 ldq $5, 16($17) # L : bytes 16..23
132 ldq $3, 24($17) # L : bytes 24..31
133 addq $16, 32, $16 # E : dest += 32
134 subq $18, 64, $18 # E : count -= 64
135
136 addq $17, 32, $17 # E : src += 32
137 stq $6, -32($16) # L : bytes 0..7
138 stq $4, -24($16) # L : bytes 8..15
139 cmple $18, 63, $1 # E : At least one more trip?
140
141 stq $5, -16($16) # L : bytes 16..23
142 stq $3, -8($16) # L : bytes 24..31
143 nop # E :
144 beq $1, $unroll_body
145
146$tail_quads:
147$no_unroll:
148 .align 4
149 subq $18, 8, $18 # E : At least a quad left?
150 blt $18, $less_than_8 # U : Nope
151 nop # E :
152 nop # E :
153
154$move_a_quad:
155 ldq $1, 0($17) # L : fetch 8
156 subq $18, 8, $18 # E : count -= 8
157 addq $17, 8, $17 # E : src += 8
158 nop # E :
159
160 stq $1, 0($16) # L : store 8
161 addq $16, 8, $16 # E : dest += 8
162 bge $18, $move_a_quad # U :
163 nop # E :
164
165$less_than_8:
166 .align 4
167 addq $18, 8, $18 # E : add back for trailing bytes
168 ble $18, $nomoredata # U : All-done
169 nop # E :
170 nop # E :
171
172 /* Trailing bytes */
173$tail_bytes:
174 subq $18, 1, $18 # E : count--
175 ldbu $1, 0($17) # L : fetch a byte
176 addq $17, 1, $17 # E : src++
177 nop # E :
178
179 stb $1, 0($16) # L : store a byte
180 addq $16, 1, $16 # E : dest++
181 bgt $18, $tail_bytes # U : more to be done?
182 nop # E :
183
184 /* branching to exit takes 3 extra cycles, so replicate exit here */
185 ret $31, ($26), 1 # L0 :
186 nop # E :
187 nop # E :
188 nop # E :
189
190$misaligned:
191 mov $0, $4 # E : dest temp
192 and $0, 7, $1 # E : dest alignment mod8
193 beq $1, $dest_0mod8 # U : life doesnt totally suck
194 nop
195
196$aligndest:
197 ble $18, $nomoredata # U :
198 ldbu $1, 0($17) # L : fetch a byte
199 subq $18, 1, $18 # E : count--
200 addq $17, 1, $17 # E : src++
201
202 stb $1, 0($4) # L : store it
203 addq $4, 1, $4 # E : dest++
204 and $4, 7, $1 # E : dest 0mod8 yet?
205 bne $1, $aligndest # U : go until we are aligned.
206
207 /* Source has unknown alignment, but dest is known to be 0mod8 */
208$dest_0mod8:
209 subq $18, 8, $18 # E : At least a quad left?
210 blt $18, $misalign_tail # U : Nope
211 ldq_u $3, 0($17) # L : seed (rotating load) of 8 bytes
212 nop # E :
213
214$mis_quad:
215 ldq_u $16, 8($17) # L : Fetch next 8
216 extql $3, $17, $3 # U : masking
217 extqh $16, $17, $1 # U : masking
218 bis $3, $1, $1 # E : merged bytes to store
219
220 subq $18, 8, $18 # E : count -= 8
221 addq $17, 8, $17 # E : src += 8
222 stq $1, 0($4) # L : store 8 (aligned)
223 mov $16, $3 # E : "rotate" source data
224
225 addq $4, 8, $4 # E : dest += 8
226 bge $18, $mis_quad # U : More quads to move
227 nop
228 nop
229
230$misalign_tail:
231 addq $18, 8, $18 # E : account for tail stuff
232 ble $18, $nomoredata # U :
233 nop
234 nop
235
236$misalign_byte:
237 ldbu $1, 0($17) # L : fetch 1
238 subq $18, 1, $18 # E : count--
239 addq $17, 1, $17 # E : src++
240 nop # E :
241
242 stb $1, 0($4) # L : store
243 addq $4, 1, $4 # E : dest++
244 bgt $18, $misalign_byte # U : more to go?
245 nop
246
247
248$nomoredata:
249 ret $31, ($26), 1 # L0 :
250 nop # E :
251 nop # E :
252 nop # E :
253
254END(memcpy)
255libc_hidden_builtin_def (memcpy)
256

Warning: That file was not part of the compilation database. It may have many parsing errors.