Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | ! |
2 | ! Fast SH memcpy | |
3 | ! | |
4 | ! by Toshiyasu Morita (tm@netcom.com) | |
5 | ! hacked by J"orn Rernnecke (joern.rennecke@superh.com) ("o for o-umlaut) | |
6 | ! SH5 code Copyright 2002 SuperH Ltd. | |
7 | ! | |
8 | ! Entry: ARG0: destination pointer | |
9 | ! ARG1: source pointer | |
10 | ! ARG2: byte count | |
11 | ! | |
12 | ! Exit: RESULT: destination pointer | |
13 | ! any other registers in the range r0-r7: trashed | |
14 | ! | |
15 | ! Notes: Usually one wants to do small reads and write a longword, but | |
16 | ! unfortunately it is difficult in some cases to concatanate bytes | |
17 | ! into a longword on the SH, so this does a longword read and small | |
18 | ! writes. | |
19 | ! | |
20 | ! This implementation makes two assumptions about how it is called: | |
21 | ! | |
22 | ! 1.: If the byte count is nonzero, the address of the last byte to be | |
23 | ! copied is unsigned greater than the address of the first byte to | |
24 | ! be copied. This could be easily swapped for a signed comparison, | |
25 | ! but the algorithm used needs some comparison. | |
26 | ! | |
27 | ! 2.: When there are two or three bytes in the last word of an 11-or-more | |
28 | ! bytes memory chunk to b copied, the rest of the word can be read | |
29 | ! without side effects. | |
25985edc | 30 | ! This could be easily changed by increasing the minimum size of |
1da177e4 LT |
31 | ! a fast memcpy and the amount subtracted from r7 before L_2l_loop be 2, |
32 | ! however, this would cost a few extra cyles on average. | |
33 | ! For SHmedia, the assumption is that any quadword can be read in its | |
34 | ! enirety if at least one byte is included in the copy. | |
35 | ||
36 | /* Imported into Linux kernel by Richard Curnow. This is used to implement the | |
37 | __copy_user function in the general case, so it has to be a distinct | |
38 | function from intra-kernel memcpy to allow for exception fix-ups in the | |
39 | event that the user pointer is bad somewhere in the copy (e.g. due to | |
40 | running off the end of the vma). | |
41 | ||
42 | Note, this algorithm will be slightly wasteful in the case where the source | |
43 | and destination pointers are equally aligned, because the stlo/sthi pairs | |
44 | could then be merged back into single stores. If there are a lot of cache | |
45 | misses, this is probably offset by the stall lengths on the preloads. | |
46 | ||
47 | */ | |
48 | ||
49 | /* NOTE : Prefetches removed and allocos guarded by synco to avoid TAKum03020 | |
50 | * erratum. The first two prefetches are nop-ed out to avoid upsetting the | |
51 | * instruction counts used in the jump address calculation. | |
52 | * */ | |
53 | ||
54 | .section .text..SHmedia32,"ax" | |
55 | .little | |
56 | .balign 32 | |
57 | .global copy_user_memcpy | |
58 | .global copy_user_memcpy_end | |
59 | copy_user_memcpy: | |
60 | ||
61 | #define LDUAQ(P,O,D0,D1) ldlo.q P,O,D0; ldhi.q P,O+7,D1 | |
62 | #define STUAQ(P,O,D0,D1) stlo.q P,O,D0; sthi.q P,O+7,D1 | |
63 | #define LDUAL(P,O,D0,D1) ldlo.l P,O,D0; ldhi.l P,O+3,D1 | |
64 | #define STUAL(P,O,D0,D1) stlo.l P,O,D0; sthi.l P,O+3,D1 | |
65 | ||
66 | nop ! ld.b r3,0,r63 ! TAKum03020 | |
67 | pta/l Large,tr0 | |
68 | movi 25,r0 | |
69 | bgeu/u r4,r0,tr0 | |
70 | nsb r4,r0 | |
71 | shlli r0,5,r0 | |
72 | movi (L1-L0+63*32 + 1) & 0xffff,r1 | |
73 | sub r1, r0, r0 | |
74 | L0: ptrel r0,tr0 | |
75 | add r2,r4,r5 | |
76 | ptabs r18,tr1 | |
77 | add r3,r4,r6 | |
78 | blink tr0,r63 | |
79 | ||
80 | /* Rearranged to make cut2 safe */ | |
81 | .balign 8 | |
82 | L4_7: /* 4..7 byte memcpy cntd. */ | |
83 | stlo.l r2, 0, r0 | |
84 | or r6, r7, r6 | |
85 | sthi.l r5, -1, r6 | |
86 | stlo.l r5, -4, r6 | |
87 | blink tr1,r63 | |
88 | ||
89 | .balign 8 | |
90 | L1: /* 0 byte memcpy */ | |
91 | nop | |
92 | blink tr1,r63 | |
93 | nop | |
94 | nop | |
95 | nop | |
96 | nop | |
97 | ||
98 | L2_3: /* 2 or 3 byte memcpy cntd. */ | |
99 | st.b r5,-1,r6 | |
100 | blink tr1,r63 | |
101 | ||
102 | /* 1 byte memcpy */ | |
103 | ld.b r3,0,r0 | |
104 | st.b r2,0,r0 | |
105 | blink tr1,r63 | |
106 | ||
107 | L8_15: /* 8..15 byte memcpy cntd. */ | |
108 | stlo.q r2, 0, r0 | |
109 | or r6, r7, r6 | |
110 | sthi.q r5, -1, r6 | |
111 | stlo.q r5, -8, r6 | |
112 | blink tr1,r63 | |
113 | ||
114 | /* 2 or 3 byte memcpy */ | |
115 | ld.b r3,0,r0 | |
116 | nop ! ld.b r2,0,r63 ! TAKum03020 | |
117 | ld.b r3,1,r1 | |
118 | st.b r2,0,r0 | |
119 | pta/l L2_3,tr0 | |
120 | ld.b r6,-1,r6 | |
121 | st.b r2,1,r1 | |
122 | blink tr0, r63 | |
123 | ||
124 | /* 4 .. 7 byte memcpy */ | |
125 | LDUAL (r3, 0, r0, r1) | |
126 | pta L4_7, tr0 | |
127 | ldlo.l r6, -4, r7 | |
128 | or r0, r1, r0 | |
129 | sthi.l r2, 3, r0 | |
130 | ldhi.l r6, -1, r6 | |
131 | blink tr0, r63 | |
132 | ||
133 | /* 8 .. 15 byte memcpy */ | |
134 | LDUAQ (r3, 0, r0, r1) | |
135 | pta L8_15, tr0 | |
136 | ldlo.q r6, -8, r7 | |
137 | or r0, r1, r0 | |
138 | sthi.q r2, 7, r0 | |
139 | ldhi.q r6, -1, r6 | |
140 | blink tr0, r63 | |
141 | ||
142 | /* 16 .. 24 byte memcpy */ | |
143 | LDUAQ (r3, 0, r0, r1) | |
144 | LDUAQ (r3, 8, r8, r9) | |
145 | or r0, r1, r0 | |
146 | sthi.q r2, 7, r0 | |
147 | or r8, r9, r8 | |
148 | sthi.q r2, 15, r8 | |
149 | ldlo.q r6, -8, r7 | |
150 | ldhi.q r6, -1, r6 | |
151 | stlo.q r2, 8, r8 | |
152 | stlo.q r2, 0, r0 | |
153 | or r6, r7, r6 | |
154 | sthi.q r5, -1, r6 | |
155 | stlo.q r5, -8, r6 | |
156 | blink tr1,r63 | |
157 | ||
158 | Large: | |
159 | ! ld.b r2, 0, r63 ! TAKum03020 | |
160 | pta/l Loop_ua, tr1 | |
161 | ori r3, -8, r7 | |
162 | sub r2, r7, r22 | |
163 | sub r3, r2, r6 | |
164 | add r2, r4, r5 | |
165 | ldlo.q r3, 0, r0 | |
166 | addi r5, -16, r5 | |
167 | movi 64+8, r27 ! could subtract r7 from that. | |
168 | stlo.q r2, 0, r0 | |
169 | sthi.q r2, 7, r0 | |
170 | ldx.q r22, r6, r0 | |
171 | bgtu/l r27, r4, tr1 | |
172 | ||
173 | addi r5, -48, r27 | |
174 | pta/l Loop_line, tr0 | |
175 | addi r6, 64, r36 | |
176 | addi r6, -24, r19 | |
177 | addi r6, -16, r20 | |
178 | addi r6, -8, r21 | |
179 | ||
180 | Loop_line: | |
181 | ! ldx.q r22, r36, r63 ! TAKum03020 | |
182 | alloco r22, 32 | |
183 | synco | |
184 | addi r22, 32, r22 | |
185 | ldx.q r22, r19, r23 | |
186 | sthi.q r22, -25, r0 | |
187 | ldx.q r22, r20, r24 | |
188 | ldx.q r22, r21, r25 | |
189 | stlo.q r22, -32, r0 | |
190 | ldx.q r22, r6, r0 | |
191 | sthi.q r22, -17, r23 | |
192 | sthi.q r22, -9, r24 | |
193 | sthi.q r22, -1, r25 | |
194 | stlo.q r22, -24, r23 | |
195 | stlo.q r22, -16, r24 | |
196 | stlo.q r22, -8, r25 | |
197 | bgeu r27, r22, tr0 | |
198 | ||
199 | Loop_ua: | |
200 | addi r22, 8, r22 | |
201 | sthi.q r22, -1, r0 | |
202 | stlo.q r22, -8, r0 | |
203 | ldx.q r22, r6, r0 | |
204 | bgtu/l r5, r22, tr1 | |
205 | ||
206 | add r3, r4, r7 | |
207 | ldlo.q r7, -8, r1 | |
208 | sthi.q r22, 7, r0 | |
209 | ldhi.q r7, -1, r7 | |
210 | ptabs r18,tr1 | |
211 | stlo.q r22, 0, r0 | |
212 | or r1, r7, r1 | |
213 | sthi.q r5, 15, r1 | |
214 | stlo.q r5, 8, r1 | |
215 | blink tr1, r63 | |
216 | copy_user_memcpy_end: | |
217 | nop |