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d5efd131 MF |
1 | /* Optimized version of the standard memmove() function. |
2 | This file is part of the GNU C Library. | |
688903eb | 3 | Copyright (C) 2000-2018 Free Software Foundation, Inc. |
d5efd131 MF |
4 | Contributed by Dan Pop <Dan.Pop@cern.ch>. |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
75efb018 MF |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
d5efd131 MF |
19 | |
20 | /* Return: dest | |
21 | ||
22 | Inputs: | |
23 | in0: dest | |
24 | in1: src | |
25 | in2: byte count | |
26 | ||
27 | The core of the function is the memcpy implementation used in memcpy.S. | |
28 | When bytes have to be copied backwards, only the easy case, when | |
29 | all arguments are multiples of 8, is optimised. | |
30 | ||
31 | In this form, it assumes little endian mode. For big endian mode, | |
32 | sh1 must be computed using an extra instruction: sub sh1 = 64, sh1 | |
33 | or the UM.be bit should be cleared at the beginning and set at the end. */ | |
34 | ||
35 | #include <sysdep.h> | |
36 | #undef ret | |
37 | ||
38 | #define OP_T_THRES 16 | |
39 | #define OPSIZ 8 | |
40 | ||
41 | #define adest r15 | |
42 | #define saved_pr r17 | |
43 | #define saved_lc r18 | |
44 | #define dest r19 | |
45 | #define src r20 | |
46 | #define len r21 | |
47 | #define asrc r22 | |
48 | #define tmp2 r23 | |
49 | #define tmp3 r24 | |
50 | #define tmp4 r25 | |
51 | #define ptable r26 | |
52 | #define ploop56 r27 | |
53 | #define loopaddr r28 | |
54 | #define sh1 r29 | |
55 | #define loopcnt r30 | |
56 | #define value r31 | |
57 | ||
58 | #ifdef GAS_ALIGN_BREAKS_UNWIND_INFO | |
59 | # define ALIGN(n) { nop 0 } | |
60 | #else | |
61 | # define ALIGN(n) .align n | |
62 | #endif | |
63 | ||
64 | #define LOOP(shift) \ | |
65 | ALIGN(32); \ | |
66 | .loop##shift##: \ | |
67 | (p[0]) ld8 r[0] = [asrc], 8 ; /* w1 */ \ | |
68 | (p[MEMLAT+1]) st8 [dest] = value, 8 ; \ | |
69 | (p[MEMLAT]) shrp value = r[MEMLAT], r[MEMLAT+1], shift ; \ | |
70 | nop.b 0 ; \ | |
71 | nop.b 0 ; \ | |
72 | br.ctop.sptk .loop##shift ; \ | |
73 | br.cond.sptk .cpyfew ; /* deal with the remaining bytes */ | |
74 | ||
75 | #define MEMLAT 21 | |
76 | #define Nrot (((2*MEMLAT+3) + 7) & ~7) | |
77 | ||
78 | ENTRY(memmove) | |
79 | .prologue | |
80 | alloc r2 = ar.pfs, 3, Nrot - 3, 0, Nrot | |
81 | .rotr r[MEMLAT + 2], q[MEMLAT + 1] | |
82 | .rotp p[MEMLAT + 2] | |
83 | mov ret0 = in0 // return value = dest | |
84 | .save pr, saved_pr | |
85 | mov saved_pr = pr // save the predicate registers | |
86 | .save ar.lc, saved_lc | |
87 | mov saved_lc = ar.lc // save the loop counter | |
88 | .body | |
89 | or tmp3 = in0, in1 ;; // tmp3 = dest | src | |
90 | or tmp3 = tmp3, in2 // tmp3 = dest | src | len | |
91 | mov dest = in0 // dest | |
92 | mov src = in1 // src | |
93 | mov len = in2 // len | |
94 | sub tmp2 = r0, in0 // tmp2 = -dest | |
95 | cmp.eq p6, p0 = in2, r0 // if (len == 0) | |
96 | (p6) br.cond.spnt .restore_and_exit;;// return dest; | |
97 | and tmp4 = 7, tmp3 // tmp4 = (dest | src | len) & 7 | |
98 | cmp.le p6, p0 = dest, src // if dest <= src it's always safe | |
99 | (p6) br.cond.spnt .forward // to copy forward | |
100 | add tmp3 = src, len;; | |
101 | cmp.lt p6, p0 = dest, tmp3 // if dest > src && dest < src + len | |
102 | (p6) br.cond.spnt .backward // we have to copy backward | |
103 | ||
104 | .forward: | |
105 | shr.u loopcnt = len, 4 ;; // loopcnt = len / 16 | |
106 | cmp.ne p6, p0 = tmp4, r0 // if ((dest | src | len) & 7 != 0) | |
107 | (p6) br.cond.sptk .next // goto next; | |
108 | ||
109 | // The optimal case, when dest, src and len are all multiples of 8 | |
110 | ||
111 | and tmp3 = 0xf, len | |
112 | mov pr.rot = 1 << 16 // set rotating predicates | |
113 | mov ar.ec = MEMLAT + 1 ;; // set the epilog counter | |
114 | cmp.ne p6, p0 = tmp3, r0 // do we have to copy an extra word? | |
115 | adds loopcnt = -1, loopcnt;; // --loopcnt | |
116 | (p6) ld8 value = [src], 8;; | |
117 | (p6) st8 [dest] = value, 8 // copy the "odd" word | |
118 | mov ar.lc = loopcnt // set the loop counter | |
119 | cmp.eq p6, p0 = 8, len | |
120 | (p6) br.cond.spnt .restore_and_exit;;// the one-word special case | |
121 | adds adest = 8, dest // set adest one word ahead of dest | |
122 | adds asrc = 8, src ;; // set asrc one word ahead of src | |
123 | nop.b 0 // get the "golden" alignment for | |
124 | nop.b 0 // the next loop | |
125 | .l0: | |
126 | (p[0]) ld8 r[0] = [src], 16 | |
127 | (p[0]) ld8 q[0] = [asrc], 16 | |
128 | (p[MEMLAT]) st8 [dest] = r[MEMLAT], 16 | |
129 | (p[MEMLAT]) st8 [adest] = q[MEMLAT], 16 | |
130 | br.ctop.dptk .l0 ;; | |
131 | ||
132 | mov pr = saved_pr, -1 // restore the predicate registers | |
133 | mov ar.lc = saved_lc // restore the loop counter | |
134 | br.ret.sptk.many b0 | |
135 | .next: | |
136 | cmp.ge p6, p0 = OP_T_THRES, len // is len <= OP_T_THRES | |
137 | and loopcnt = 7, tmp2 // loopcnt = -dest % 8 | |
138 | (p6) br.cond.spnt .cpyfew // copy byte by byte | |
139 | ;; | |
140 | cmp.eq p6, p0 = loopcnt, r0 | |
141 | (p6) br.cond.sptk .dest_aligned | |
142 | sub len = len, loopcnt // len -= -dest % 8 | |
143 | adds loopcnt = -1, loopcnt // --loopcnt | |
144 | ;; | |
145 | mov ar.lc = loopcnt | |
146 | .l1: // copy -dest % 8 bytes | |
147 | ld1 value = [src], 1 // value = *src++ | |
148 | ;; | |
149 | st1 [dest] = value, 1 // *dest++ = value | |
150 | br.cloop.dptk .l1 | |
151 | .dest_aligned: | |
152 | and sh1 = 7, src // sh1 = src % 8 | |
153 | and tmp2 = -8, len // tmp2 = len & -OPSIZ | |
154 | and asrc = -8, src // asrc = src & -OPSIZ -- align src | |
155 | shr.u loopcnt = len, 3 // loopcnt = len / 8 | |
156 | and len = 7, len;; // len = len % 8 | |
157 | adds loopcnt = -1, loopcnt // --loopcnt | |
158 | addl tmp4 = @ltoff(.table), gp | |
159 | addl tmp3 = @ltoff(.loop56), gp | |
160 | mov ar.ec = MEMLAT + 1 // set EC | |
161 | mov pr.rot = 1 << 16;; // set rotating predicates | |
162 | mov ar.lc = loopcnt // set LC | |
163 | cmp.eq p6, p0 = sh1, r0 // is the src aligned? | |
164 | (p6) br.cond.sptk .src_aligned | |
165 | add src = src, tmp2 // src += len & -OPSIZ | |
166 | shl sh1 = sh1, 3 // sh1 = 8 * (src % 8) | |
167 | ld8 ploop56 = [tmp3] // ploop56 = &loop56 | |
168 | ld8 ptable = [tmp4];; // ptable = &table | |
169 | add tmp3 = ptable, sh1;; // tmp3 = &table + sh1 | |
170 | mov ar.ec = MEMLAT + 1 + 1 // one more pass needed | |
171 | ld8 tmp4 = [tmp3];; // tmp4 = loop offset | |
172 | sub loopaddr = ploop56,tmp4 // loopadd = &loop56 - loop offset | |
173 | ld8 r[1] = [asrc], 8;; // w0 | |
174 | mov b6 = loopaddr;; | |
175 | br b6 // jump to the appropriate loop | |
176 | ||
177 | LOOP(8) | |
178 | LOOP(16) | |
179 | LOOP(24) | |
180 | LOOP(32) | |
181 | LOOP(40) | |
182 | LOOP(48) | |
183 | LOOP(56) | |
184 | ||
185 | .src_aligned: | |
186 | .l3: | |
187 | (p[0]) ld8 r[0] = [src], 8 | |
188 | (p[MEMLAT]) st8 [dest] = r[MEMLAT], 8 | |
189 | br.ctop.dptk .l3 | |
190 | .cpyfew: | |
191 | cmp.eq p6, p0 = len, r0 // is len == 0 ? | |
192 | adds len = -1, len // --len; | |
193 | (p6) br.cond.spnt .restore_and_exit ;; | |
194 | mov ar.lc = len | |
195 | .l4: | |
196 | ld1 value = [src], 1 | |
197 | ;; | |
198 | st1 [dest] = value, 1 | |
199 | br.cloop.dptk .l4 ;; | |
200 | .restore_and_exit: | |
201 | mov pr = saved_pr, -1 // restore the predicate registers | |
202 | mov ar.lc = saved_lc // restore the loop counter | |
203 | br.ret.sptk.many b0 | |
204 | ||
205 | // In the case of a backward copy, optimise only the case when everything | |
206 | // is a multiple of 8, otherwise copy byte by byte. The backward copy is | |
207 | // used only when the blocks are overlapping and dest > src. | |
208 | ||
209 | .backward: | |
210 | shr.u loopcnt = len, 3 // loopcnt = len / 8 | |
211 | add src = src, len // src points one byte past the end | |
212 | add dest = dest, len ;; // dest points one byte past the end | |
213 | mov ar.ec = MEMLAT + 1 // set the epilog counter | |
214 | mov pr.rot = 1 << 16 // set rotating predicates | |
215 | adds loopcnt = -1, loopcnt // --loopcnt | |
216 | cmp.ne p6, p0 = tmp4, r0 // if ((dest | src | len) & 7 != 0) | |
217 | (p6) br.cond.sptk .bytecopy ;; // copy byte by byte backward | |
218 | adds src = -8, src // src points to the last word | |
219 | adds dest = -8, dest // dest points to the last word | |
220 | mov ar.lc = loopcnt;; // set the loop counter | |
221 | .l5: | |
222 | (p[0]) ld8 r[0] = [src], -8 | |
223 | (p[MEMLAT]) st8 [dest] = r[MEMLAT], -8 | |
224 | br.ctop.dptk .l5 | |
225 | br.cond.sptk .restore_and_exit | |
226 | .bytecopy: | |
227 | adds src = -1, src // src points to the last byte | |
228 | adds dest = -1, dest // dest points to the last byte | |
229 | adds loopcnt = -1, len;; // loopcnt = len - 1 | |
230 | mov ar.lc = loopcnt;; // set the loop counter | |
231 | .l6: | |
232 | (p[0]) ld1 r[0] = [src], -1 | |
233 | (p[MEMLAT]) st1 [dest] = r[MEMLAT], -1 | |
234 | br.ctop.dptk .l6 | |
235 | br.cond.sptk .restore_and_exit | |
236 | END(memmove) | |
237 | ||
238 | .rodata | |
239 | .align 8 | |
240 | .table: | |
241 | data8 0 // dummy entry | |
242 | data8 .loop56 - .loop8 | |
243 | data8 .loop56 - .loop16 | |
244 | data8 .loop56 - .loop24 | |
245 | data8 .loop56 - .loop32 | |
246 | data8 .loop56 - .loop40 | |
247 | data8 .loop56 - .loop48 | |
248 | data8 .loop56 - .loop56 | |
249 | ||
250 | libc_hidden_builtin_def (memmove) |