xref: /openbmc/linux/arch/hexagon/lib/memcpy.S (revision 4f6cce39)
1/*
2 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
3 *
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 and
7 * only version 2 as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 */
19
20/*
21 * Description
22 *
23 *   library function for memcpy where length bytes are copied from
24 *   ptr_in to ptr_out. ptr_out is returned unchanged.
25 *   Allows any combination of alignment on input and output pointers
26 *   and length from 0 to 2^32-1
27 *
28 * Restrictions
29 *   The arrays should not overlap, the program will produce undefined output
30 *   if they do.
31 *   For blocks less than 16 bytes a byte by byte copy is performed. For
32 *   8byte alignments, and length multiples, a dword copy is performed up to
33 *   96bytes
34 * History
35 *
36 *   DJH  5/15/09 Initial version 1.0
37 *   DJH  6/ 1/09 Version 1.1 modified ABI to inlcude R16-R19
38 *   DJH  7/12/09 Version 1.2 optimized codesize down to 760 was 840
39 *   DJH 10/14/09 Version 1.3 added special loop for aligned case, was
40 *                            overreading bloated codesize back up to 892
41 *   DJH  4/20/10 Version 1.4 fixed Ldword_loop_epilog loop to prevent loads
42 *                            occurring if only 1 left outstanding, fixes bug
43 *                            # 3888, corrected for all alignments. Peeled off
44 *                            1 32byte chunk from kernel loop and extended 8byte
45 *                            loop at end to solve all combinations and prevent
46 *                            over read.  Fixed Ldword_loop_prolog to prevent
47 *                            overread for blocks less than 48bytes. Reduced
48 *                            codesize to 752 bytes
49 *   DJH  4/21/10 version 1.5 1.4 fix broke code for input block ends not
50 *                            aligned to dword boundaries,underwriting by 1
51 *                            byte, added detection for this and fixed. A
52 *                            little bloat.
53 *   DJH  4/23/10 version 1.6 corrected stack error, R20 was not being restored
54 *                            always, fixed the error of R20 being modified
55 *                            before it was being saved
56 * Natural c model
57 * ===============
58 * void * memcpy(char * ptr_out, char * ptr_in, int length) {
59 *   int i;
60 *   if(length) for(i=0; i < length; i++) { ptr_out[i] = ptr_in[i]; }
61 *   return(ptr_out);
62 * }
63 *
64 * Optimized memcpy function
65 * =========================
66 * void * memcpy(char * ptr_out, char * ptr_in, int len) {
67 *   int i, prolog, kernel, epilog, mask;
68 *   u8 offset;
69 *   s64 data0, dataF8, data70;
70 *
71 *   s64 * ptr8_in;
72 *   s64 * ptr8_out;
73 *   s32 * ptr4;
74 *   s16 * ptr2;
75 *
76 *   offset = ((int) ptr_in) & 7;
77 *   ptr8_in = (s64 *) &ptr_in[-offset];   //read in the aligned pointers
78 *
79 *   data70 = *ptr8_in++;
80 *   dataF8 = *ptr8_in++;
81 *
82 *   data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
83 *
84 *   prolog = 32 - ((int) ptr_out);
85 *   mask  = 0x7fffffff >> HEXAGON_R_cl0_R(len);
86 *   prolog = prolog & mask;
87 *   kernel = len - prolog;
88 *   epilog = kernel & 0x1F;
89 *   kernel = kernel>>5;
90 *
91 *   if (prolog & 1) { ptr_out[0] = (u8) data0; data0 >>= 8; ptr_out += 1;}
92 *   ptr2 = (s16 *) &ptr_out[0];
93 *   if (prolog & 2) { ptr2[0] = (u16) data0;  data0 >>= 16; ptr_out += 2;}
94 *   ptr4 = (s32 *) &ptr_out[0];
95 *   if (prolog & 4) { ptr4[0] = (u32) data0;  data0 >>= 32; ptr_out += 4;}
96 *
97 *   offset = offset + (prolog & 7);
98 *   if (offset >= 8) {
99 *     data70 = dataF8;
100 *     dataF8 = *ptr8_in++;
101 *   }
102 *   offset = offset & 0x7;
103 *
104 *   prolog = prolog >> 3;
105 *   if (prolog) for (i=0; i < prolog; i++) {
106 *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
107 *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
108 *       data70 = dataF8;
109 *       dataF8 = *ptr8_in++;
110 *   }
111 *   if(kernel) { kernel -= 1; epilog += 32; }
112 *   if(kernel) for(i=0; i < kernel; i++) {
113 *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
114 *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
115 *       data70 = *ptr8_in++;
116 *
117 *       data0 = HEXAGON_P_valignb_PPp(data70, dataF8, offset);
118 *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
119 *       dataF8 = *ptr8_in++;
120 *
121 *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
122 *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
123 *       data70 = *ptr8_in++;
124 *
125 *       data0 = HEXAGON_P_valignb_PPp(data70, dataF8, offset);
126 *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
127 *       dataF8 = *ptr8_in++;
128 *   }
129 *   epilogdws = epilog >> 3;
130 *   if (epilogdws) for (i=0; i < epilogdws; i++) {
131 *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
132 *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
133 *       data70 = dataF8;
134 *       dataF8 = *ptr8_in++;
135 *   }
136 *   data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
137 *
138 *   ptr4 = (s32 *) &ptr_out[0];
139 *   if (epilog & 4) { ptr4[0] = (u32) data0; data0 >>= 32; ptr_out += 4;}
140 *   ptr2 = (s16 *) &ptr_out[0];
141 *   if (epilog & 2) { ptr2[0] = (u16) data0; data0 >>= 16; ptr_out += 2;}
142 *   if (epilog & 1) { *ptr_out++ = (u8) data0; }
143 *
144 *   return(ptr_out - length);
145 * }
146 *
147 * Codesize : 784 bytes
148 */
149
150
151#define ptr_out		R0	/*  destination  pounter  */
152#define ptr_in		R1	/*  source pointer  */
153#define len		R2	/*  length of copy in bytes  */
154
155#define data70		R13:12	/*  lo 8 bytes of non-aligned transfer  */
156#define dataF8		R11:10	/*  hi 8 bytes of non-aligned transfer  */
157#define ldata0		R7:6	/*  even 8 bytes chunks  */
158#define ldata1		R25:24	/*  odd 8 bytes chunks  */
159#define data1		R7	/*  lower 8 bytes of ldata1  */
160#define data0		R6	/*  lower 8 bytes of ldata0  */
161
162#define ifbyte		p0	/*  if transfer has bytes in epilog/prolog  */
163#define ifhword		p0	/*  if transfer has shorts in epilog/prolog  */
164#define ifword		p0	/*  if transfer has words in epilog/prolog  */
165#define noprolog	p0	/*  no prolog, xfer starts at 32byte  */
166#define nokernel	p1	/*  no 32byte multiple block in the transfer  */
167#define noepilog	p0	/*  no epilog, xfer ends on 32byte boundary  */
168#define align		p2	/*  alignment of input rel to 8byte boundary  */
169#define kernel1		p0	/*  kernel count == 1  */
170
171#define dalign		R25	/*  rel alignment of input to output data  */
172#define star3		R16	/*  number bytes in prolog - dwords  */
173#define rest		R8	/*  length - prolog bytes  */
174#define back		R7	/*  nr bytes > dword boundary in src block  */
175#define epilog		R3	/*  bytes in epilog  */
176#define inc		R15:14	/*  inc kernel by -1 and defetch ptr by 32  */
177#define kernel		R4	/*  number of 32byte chunks in kernel  */
178#define ptr_in_p_128	R5	/*  pointer for prefetch of input data  */
179#define mask		R8	/*  mask used to determine prolog size  */
180#define shift		R8	/*  used to work a shifter to extract bytes  */
181#define shift2		R5	/*  in epilog to workshifter to extract bytes */
182#define prolog		R15	/*  bytes in  prolog  */
183#define epilogdws	R15	/*  number dwords in epilog  */
184#define shiftb		R14	/*  used to extract bytes  */
185#define offset		R9	/*  same as align in reg  */
186#define ptr_out_p_32	R17	/*  pointer to output dczero  */
187#define align888	R14	/*  if simple dword loop can be used  */
188#define len8		R9	/*  number of dwords in length  */
189#define over		R20	/*  nr of bytes > last inp buf dword boundary */
190
191#define ptr_in_p_128kernel	R5:4	/*  packed fetch pointer & kernel cnt */
192
193	.section .text
194	.p2align 4
195        .global memcpy
196        .type memcpy, @function
197memcpy:
198{
199	p2 = cmp.eq(len, #0);		/*  =0 */
200	align888 = or(ptr_in, ptr_out);	/*  %8 < 97 */
201	p0 = cmp.gtu(len, #23);		/*  %1, <24 */
202	p1 = cmp.eq(ptr_in, ptr_out);	/*  attempt to overwrite self */
203}
204{
205	p1 = or(p2, p1);
206	p3 = cmp.gtu(len, #95);		/*  %8 < 97 */
207	align888 = or(align888, len);	/*  %8 < 97 */
208	len8 = lsr(len, #3);		/*  %8 < 97 */
209}
210{
211	dcfetch(ptr_in);		/*  zero/ptrin=ptrout causes fetch */
212	p2 = bitsclr(align888, #7);	/*  %8 < 97  */
213	if(p1) jumpr r31;		/*  =0  */
214}
215{
216	p2 = and(p2,!p3);			/*  %8 < 97  */
217	if (p2.new) len = add(len, #-8);	/*  %8 < 97  */
218	if (p2.new) jump:NT .Ldwordaligned; 	/*  %8 < 97  */
219}
220{
221	if(!p0) jump .Lbytes23orless;	/*  %1, <24  */
222	mask.l = #LO(0x7fffffff);
223	/*  all bytes before line multiples of data  */
224	prolog = sub(#0, ptr_out);
225}
226{
227	/*  save r31 on stack, decrement sp by 16  */
228	allocframe(#24);
229	mask.h = #HI(0x7fffffff);
230	ptr_in_p_128 = add(ptr_in, #32);
231	back = cl0(len);
232}
233{
234	memd(sp+#0) = R17:16;		/*  save r16,r17 on stack6  */
235	r31.l = #LO(.Lmemcpy_return);	/*  set up final return pointer  */
236	prolog &= lsr(mask, back);
237	offset = and(ptr_in, #7);
238}
239{
240	memd(sp+#8) = R25:24;		/*  save r25,r24 on stack  */
241	dalign = sub(ptr_out, ptr_in);
242	r31.h = #HI(.Lmemcpy_return);	/*  set up final return pointer  */
243}
244{
245	/*  see if there if input buffer end if aligned  */
246	over = add(len, ptr_in);
247	back = add(len, offset);
248	memd(sp+#16) = R21:20;		/*  save r20,r21 on stack  */
249}
250{
251	noprolog = bitsclr(prolog, #7);
252	prolog = and(prolog, #31);
253	dcfetch(ptr_in_p_128);
254	ptr_in_p_128 = add(ptr_in_p_128, #32);
255}
256{
257	kernel = sub(len, prolog);
258	shift = asl(prolog, #3);
259	star3 = and(prolog, #7);
260	ptr_in = and(ptr_in, #-8);
261}
262{
263	prolog = lsr(prolog, #3);
264	epilog = and(kernel, #31);
265	ptr_out_p_32 = add(ptr_out, prolog);
266	over = and(over, #7);
267}
268{
269	p3 = cmp.gtu(back, #8);
270	kernel = lsr(kernel, #5);
271	dcfetch(ptr_in_p_128);
272	ptr_in_p_128 = add(ptr_in_p_128, #32);
273}
274{
275	p1 = cmp.eq(prolog, #0);
276	if(!p1.new) prolog = add(prolog, #1);
277	dcfetch(ptr_in_p_128);	/*  reserve the line 64bytes on  */
278	ptr_in_p_128 = add(ptr_in_p_128, #32);
279}
280{
281	nokernel = cmp.eq(kernel,#0);
282	dcfetch(ptr_in_p_128);	/* reserve the line 64bytes on  */
283	ptr_in_p_128 = add(ptr_in_p_128, #32);
284	shiftb = and(shift, #8);
285}
286{
287	dcfetch(ptr_in_p_128);		/*  reserve the line 64bytes on  */
288	ptr_in_p_128 = add(ptr_in_p_128, #32);
289	if(nokernel) jump .Lskip64;
290	p2 = cmp.eq(kernel, #1);	/*  skip ovr if kernel == 0  */
291}
292{
293	dczeroa(ptr_out_p_32);
294	/*  don't advance pointer  */
295	if(!p2) ptr_out_p_32 = add(ptr_out_p_32, #32);
296}
297{
298	dalign = and(dalign, #31);
299	dczeroa(ptr_out_p_32);
300}
301.Lskip64:
302{
303	data70 = memd(ptr_in++#16);
304	if(p3) dataF8 = memd(ptr_in+#8);
305	if(noprolog) jump .Lnoprolog32;
306	align = offset;
307}
308/*  upto initial 7 bytes  */
309{
310	ldata0 = valignb(dataF8, data70, align);
311	ifbyte = tstbit(shift,#3);
312	offset = add(offset, star3);
313}
314{
315	if(ifbyte) memb(ptr_out++#1) = data0;
316	ldata0 = lsr(ldata0, shiftb);
317	shiftb = and(shift, #16);
318	ifhword = tstbit(shift,#4);
319}
320{
321	if(ifhword) memh(ptr_out++#2) = data0;
322	ldata0 = lsr(ldata0, shiftb);
323	ifword = tstbit(shift,#5);
324	p2 = cmp.gtu(offset, #7);
325}
326{
327	if(ifword) memw(ptr_out++#4) = data0;
328	if(p2) data70 = dataF8;
329	if(p2) dataF8 = memd(ptr_in++#8);	/*  another 8 bytes  */
330	align = offset;
331}
332.Lnoprolog32:
333{
334	p3 = sp1loop0(.Ldword_loop_prolog, prolog)
335	rest = sub(len, star3);	/*  whats left after the loop  */
336	p0 = cmp.gt(over, #0);
337}
338	if(p0) rest = add(rest, #16);
339.Ldword_loop_prolog:
340{
341	if(p3) memd(ptr_out++#8) = ldata0;
342	ldata0 = valignb(dataF8, data70, align);
343	p0 = cmp.gt(rest, #16);
344}
345{
346	data70 = dataF8;
347	if(p0) dataF8 = memd(ptr_in++#8);
348	rest = add(rest, #-8);
349}:endloop0
350.Lkernel:
351{
352	/*  kernel is at least 32bytes  */
353	p3 = cmp.gtu(kernel, #0);
354	/*  last itn. remove edge effects  */
355	if(p3.new) kernel = add(kernel, #-1);
356	/*  dealt with in last dword loop  */
357	if(p3.new) epilog = add(epilog, #32);
358}
359{
360	nokernel = cmp.eq(kernel, #0);		/*  after adjustment, recheck */
361	if(nokernel.new) jump:NT .Lepilog;	/*  likely not taken  */
362	inc = combine(#32, #-1);
363	p3 = cmp.gtu(dalign, #24);
364}
365{
366	if(p3) jump .Lodd_alignment;
367}
368{
369	loop0(.Loword_loop_25to31, kernel);
370	kernel1 = cmp.gtu(kernel, #1);
371	rest = kernel;
372}
373	.falign
374.Loword_loop_25to31:
375{
376	dcfetch(ptr_in_p_128);	/*  prefetch 4 lines ahead  */
377	if(kernel1) ptr_out_p_32 = add(ptr_out_p_32, #32);
378}
379{
380	dczeroa(ptr_out_p_32);	/*  reserve the next 32bytes in cache  */
381	p3 = cmp.eq(kernel, rest);
382}
383{
384	/*  kernel -= 1  */
385	ptr_in_p_128kernel = vaddw(ptr_in_p_128kernel, inc);
386	/*  kill write on first iteration  */
387	if(!p3) memd(ptr_out++#8) = ldata1;
388	ldata1 = valignb(dataF8, data70, align);
389	data70 = memd(ptr_in++#8);
390}
391{
392	memd(ptr_out++#8) = ldata0;
393	ldata0 = valignb(data70, dataF8, align);
394	dataF8 = memd(ptr_in++#8);
395}
396{
397	memd(ptr_out++#8) = ldata1;
398	ldata1 = valignb(dataF8, data70, align);
399	data70 = memd(ptr_in++#8);
400}
401{
402	memd(ptr_out++#8) = ldata0;
403	ldata0 = valignb(data70, dataF8, align);
404	dataF8 = memd(ptr_in++#8);
405	kernel1 = cmp.gtu(kernel, #1);
406}:endloop0
407{
408	memd(ptr_out++#8) = ldata1;
409	jump .Lepilog;
410}
411.Lodd_alignment:
412{
413	loop0(.Loword_loop_00to24, kernel);
414	kernel1 = cmp.gtu(kernel, #1);
415	rest = add(kernel, #-1);
416}
417	.falign
418.Loword_loop_00to24:
419{
420	dcfetch(ptr_in_p_128);	/*  prefetch 4 lines ahead  */
421	ptr_in_p_128kernel = vaddw(ptr_in_p_128kernel, inc);
422	if(kernel1) ptr_out_p_32 = add(ptr_out_p_32, #32);
423}
424{
425	dczeroa(ptr_out_p_32);	/*  reserve the next 32bytes in cache  */
426}
427{
428	memd(ptr_out++#8) = ldata0;
429	ldata0 = valignb(dataF8, data70, align);
430	data70 = memd(ptr_in++#8);
431}
432{
433	memd(ptr_out++#8) = ldata0;
434	ldata0 = valignb(data70, dataF8, align);
435	dataF8 = memd(ptr_in++#8);
436}
437{
438	memd(ptr_out++#8) = ldata0;
439	ldata0 = valignb(dataF8, data70, align);
440	data70 = memd(ptr_in++#8);
441}
442{
443	memd(ptr_out++#8) = ldata0;
444	ldata0 = valignb(data70, dataF8, align);
445	dataF8 = memd(ptr_in++#8);
446	kernel1 = cmp.gtu(kernel, #1);
447}:endloop0
448.Lepilog:
449{
450	noepilog = cmp.eq(epilog,#0);
451	epilogdws = lsr(epilog, #3);
452	kernel = and(epilog, #7);
453}
454{
455	if(noepilog) jumpr r31;
456	if(noepilog) ptr_out = sub(ptr_out, len);
457	p3 = cmp.eq(epilogdws, #0);
458	shift2 = asl(epilog, #3);
459}
460{
461	shiftb = and(shift2, #32);
462	ifword = tstbit(epilog,#2);
463	if(p3) jump .Lepilog60;
464	if(!p3) epilog = add(epilog, #-16);
465}
466{
467	loop0(.Ldword_loop_epilog, epilogdws);
468	/*  stop criteria is lsbs unless = 0 then its 8  */
469	p3 = cmp.eq(kernel, #0);
470	if(p3.new) kernel= #8;
471	p1 = cmp.gt(over, #0);
472}
473	/*  if not aligned to end of buffer execute 1 more iteration  */
474	if(p1) kernel= #0;
475.Ldword_loop_epilog:
476{
477	memd(ptr_out++#8) = ldata0;
478	ldata0 = valignb(dataF8, data70, align);
479	p3 = cmp.gt(epilog, kernel);
480}
481{
482	data70 = dataF8;
483	if(p3) dataF8 = memd(ptr_in++#8);
484	epilog = add(epilog, #-8);
485}:endloop0
486/* copy last 7 bytes */
487.Lepilog60:
488{
489	if(ifword) memw(ptr_out++#4) = data0;
490	ldata0 = lsr(ldata0, shiftb);
491	ifhword = tstbit(epilog,#1);
492	shiftb = and(shift2, #16);
493}
494{
495	if(ifhword) memh(ptr_out++#2) = data0;
496	ldata0 = lsr(ldata0, shiftb);
497	ifbyte = tstbit(epilog,#0);
498	if(ifbyte.new) len = add(len, #-1);
499}
500{
501	if(ifbyte) memb(ptr_out) = data0;
502	ptr_out = sub(ptr_out, len);	/*  return dest pointer  */
503        jumpr r31;
504}
505/*  do byte copy for small n  */
506.Lbytes23orless:
507{
508	p3 = sp1loop0(.Lbyte_copy, len);
509	len = add(len, #-1);
510}
511.Lbyte_copy:
512{
513	data0 = memb(ptr_in++#1);
514	if(p3) memb(ptr_out++#1) = data0;
515}:endloop0
516{
517	memb(ptr_out) = data0;
518	ptr_out = sub(ptr_out, len);
519	jumpr r31;
520}
521/*  do dword copies for aligned in, out and length  */
522.Ldwordaligned:
523{
524	p3 = sp1loop0(.Ldword_copy, len8);
525}
526.Ldword_copy:
527{
528	if(p3) memd(ptr_out++#8) = ldata0;
529	ldata0 = memd(ptr_in++#8);
530}:endloop0
531{
532	memd(ptr_out) = ldata0;
533	ptr_out = sub(ptr_out, len);
534	jumpr r31;	/*  return to function caller  */
535}
536.Lmemcpy_return:
537	r21:20 = memd(sp+#16);	/*  restore r20+r21  */
538{
539	r25:24 = memd(sp+#8);	/*  restore r24+r25  */
540	r17:16 = memd(sp+#0);	/*  restore r16+r17  */
541}
542	deallocframe;	/*  restore r31 and incrment stack by 16  */
543	jumpr r31
544