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b168057a | 1 | /* Copyright (C) 2000-2015 Free Software Foundation, Inc. |
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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 | |
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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. | |
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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 | |
3214b89b | 13 | Lesser General Public License for more details. |
ba26d033 | 14 | |
3214b89b | 15 | You should have received a copy of the GNU Lesser General Public |
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16 | License along with the GNU C Library. If not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
1c7f9c93 | 18 | |
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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 | ||
40 | ENTRY(memcpy) | |
def004d7 | 41 | .prologue 0 |
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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 | |
1c7f9c93 | 89 | cmple $18, 127, $1 # E : Can we go through the unrolled loop? |
ba26d033 | 90 | bne $1, $tail_quads # U : Nope |
1c7f9c93 | 91 | nop # E : |
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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 | ||
254 | END(memcpy) | |
79b7c863 | 255 | libc_hidden_builtin_def (memcpy) |