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
|
/* Optimized version of the standard memcpy() function.
This file is part of the GNU C Library.
Copyright (C) 2000, 2001 Free Software Foundation, Inc.
Contributed by Dan Pop <Dan.Pop@cern.ch>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* Return: dest
Inputs:
in0: dest
in1: src
in2: byte count
An assembly implementation of the algorithm used by the generic C
version from glibc. The case when all three arguments are multiples
of 8 is treated separatedly, for extra performance.
In this form, it assumes little endian mode. For big endian mode,
sh1 must be computed using an extra instruction: sub sh1 = 64, sh1
and the order of r[MEMLAT] and r[MEMLAT+1] must be reverted in the
shrp instruction. */
#include <sysdep.h>
#undef ret
#define OP_T_THRES 16
#define OPSIZ 8
#define adest r15
#define saved_pr r17
#define saved_lc r18
#define dest r19
#define src r20
#define len r21
#define asrc r22
#define tmp2 r23
#define tmp3 r24
#define tmp4 r25
#define ptable r26
#define ploop56 r27
#define loopaddr r28
#define sh1 r29
#define loopcnt r30
#define value r31
#define LOOP(shift) \
.align 32 ; \
.loop##shift##: \
(p[0]) ld8 r[0] = [asrc], 8 ; /* w1 */ \
(p[MEMLAT+1]) st8 [dest] = value, 8 ; \
(p[MEMLAT]) shrp value = r[MEMLAT], r[MEMLAT+1], shift ; \
nop.b 0 ; \
nop.b 0 ; \
br.ctop.sptk .loop##shift ; \
br.cond.sptk .cpyfew ; /* deal with the remaining bytes */
#define MEMLAT 21
#define Nrot (((2*MEMLAT+3) + 7) & ~7)
ENTRY(memcpy)
.prologue
alloc r2 = ar.pfs, 3, Nrot - 3, 0, Nrot
.rotr r[MEMLAT + 2], q[MEMLAT + 1]
.rotp p[MEMLAT + 2]
mov ret0 = in0 // return value = dest
.save pr, saved_pr
mov saved_pr = pr // save the predicate registers
.save ar.lc, saved_lc
mov saved_lc = ar.lc // save the loop counter
.body
or tmp3 = in0, in1 ;; // tmp3 = dest | src
or tmp3 = tmp3, in2 // tmp3 = dest | src | len
mov dest = in0 // dest
mov src = in1 // src
mov len = in2 // len
sub tmp2 = r0, in0 // tmp2 = -dest
cmp.eq p6, p0 = in2, r0 // if (len == 0)
(p6) br.cond.spnt .restore_and_exit;;// return dest;
and tmp4 = 7, tmp3 // tmp4 = (dest | src | len) & 7
shr.u loopcnt = len, 4 ;; // loopcnt = len / 16
cmp.ne p6, p0 = tmp4, r0 // if ((dest | src | len) & 7 != 0)
(p6) br.cond.sptk .next // goto next;
// The optimal case, when dest, src and len are all multiples of 8
and tmp3 = 0xf, len // tmp3 = len % 16
mov pr.rot = 1 << 16 // set rotating predicates
mov ar.ec = MEMLAT + 1 ;; // set the epilog counter
cmp.ne p6, p0 = tmp3, r0 // do we have to copy an extra word?
adds loopcnt = -1, loopcnt;; // --loopcnt
(p6) ld8 value = [src], 8;;
(p6) st8 [dest] = value, 8 // copy the "extra" word
mov ar.lc = loopcnt // set the loop counter
cmp.eq p6, p0 = 8, len
(p6) br.cond.spnt .restore_and_exit;;// there was only one word to copy
adds adest = 8, dest
adds asrc = 8, src ;;
.align 32
.l0:
(p[0]) ld8 r[0] = [src], 16
(p[0]) ld8 q[0] = [asrc], 16
(p[MEMLAT]) st8 [dest] = r[MEMLAT], 16
(p[MEMLAT]) st8 [adest] = q[MEMLAT], 16
br.ctop.dptk .l0 ;;
mov pr = saved_pr, -1 // restore the predicate registers
mov ar.lc = saved_lc // restore the loop counter
br.ret.sptk.many b0
.next:
cmp.ge p6, p0 = OP_T_THRES, len // is len <= OP_T_THRES
and loopcnt = 7, tmp2 // loopcnt = -dest % 8
(p6) br.cond.spnt .cpyfew // copy byte by byte
;;
cmp.eq p6, p0 = loopcnt, r0
(p6) br.cond.sptk .dest_aligned
sub len = len, loopcnt // len -= -dest % 8
adds loopcnt = -1, loopcnt // --loopcnt
;;
mov ar.lc = loopcnt
.l1: // copy -dest % 8 bytes
ld1 value = [src], 1 // value = *src++
;;
st1 [dest] = value, 1 // *dest++ = value
br.cloop.dptk .l1 ;;
.dest_aligned:
and sh1 = 7, src // sh1 = src % 8
and tmp2 = -8, len // tmp2 = len & -OPSIZ
and asrc = -8, src // asrc = src & -OPSIZ -- align src
shr.u loopcnt = len, 3 // loopcnt = len / 8
and len = 7, len;; // len = len % 8
adds loopcnt = -1, loopcnt // --loopcnt
addl tmp4 = @ltoff(.table), gp
addl tmp3 = @ltoff(.loop56), gp
mov ar.ec = MEMLAT + 1 // set EC
mov pr.rot = 1 << 16;; // set rotating predicates
mov ar.lc = loopcnt // set LC
cmp.eq p6, p0 = sh1, r0 // is the src aligned?
(p6) br.cond.sptk .src_aligned
add src = src, tmp2 // src += len & -OPSIZ
shl sh1 = sh1, 3 // sh1 = 8 * (src % 8)
ld8 ploop56 = [tmp3] // ploop56 = &loop56
ld8 ptable = [tmp4];; // ptable = &table
add tmp3 = ptable, sh1;; // tmp3 = &table + sh1
mov ar.ec = MEMLAT + 1 + 1 // one more pass needed
ld8 tmp4 = [tmp3];; // tmp4 = loop offset
sub loopaddr = ploop56,tmp4 // loopadd = &loop56 - loop offset
ld8 r[1] = [asrc], 8;; // w0
mov b6 = loopaddr;;
br b6 // jump to the appropriate loop
LOOP(8)
LOOP(16)
LOOP(24)
LOOP(32)
LOOP(40)
LOOP(48)
LOOP(56)
.src_aligned:
.l3:
(p[0]) ld8 r[0] = [src], 8
(p[MEMLAT]) st8 [dest] = r[MEMLAT], 8
br.ctop.dptk .l3 ;;
.cpyfew:
cmp.eq p6, p0 = len, r0 // is len == 0 ?
adds len = -1, len // --len;
(p6) br.cond.spnt .restore_and_exit ;;
mov ar.lc = len
.l4:
ld1 value = [src], 1
;;
st1 [dest] = value, 1
br.cloop.dptk .l4 ;;
.restore_and_exit:
mov pr = saved_pr, -1 // restore the predicate registers
mov ar.lc = saved_lc // restore the loop counter
br.ret.sptk.many b0
.align 8
.table:
data8 0 // dummy entry
data8 .loop56 - .loop8
data8 .loop56 - .loop16
data8 .loop56 - .loop24
data8 .loop56 - .loop32
data8 .loop56 - .loop40
data8 .loop56 - .loop48
data8 .loop56 - .loop56
END(memcpy)
|
