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wdenk4a551702003-10-08 23:26:14 +00001/*
2 * (C) Copyright 2003, Psyent Corporation <www.psyent.com>
3 * Scott McNutt <smcnutt@psyent.com>
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
23
24#include <config.h>
25
26/*************************************************************************
27 * Register window underflow
28 *
29 * The register window underflow exception occurs whenever the lowest
30 * valid register window is in use (CWP=LO_LIMIT) and a save instruction
31 * is issued. The save moves CWP below LO_LIMIT, %sp is set as normal,
32 * then the exception is generated prior to executing the instruction
33 * after the save.
34 ************************************************************************/
35 .text
36 .global _cwp_lolimit
37 .align 4
38
39_cwp_lolimit:
40
41 /* Sixteen words are always allocated by the compiler in every
42 * procedure's stack frame, always starting at %sp, for saving
43 * 'in' and 'local' registers on a window overflow.
44 *
45 * Save the 'global' and 'in' regs on stack. They are restored
46 * at cwp = HI_LIMIT. The 'local' regs aren't in-use at this point.
47 */
48 sts [%sp,0], %g0 /* Save 'global' regs*/
49 sts [%sp,1], %g1
50 sts [%sp,2], %g2
51 sts [%sp,3], %g3
52 sts [%sp,4], %g4
53 sts [%sp,5], %g5
54 sts [%sp,6], %g6
55 sts [%sp,7], %g7
56
57 sts [%sp,8], %i0 /* Save 'in' regs */
58 sts [%sp,9], %i1
59 sts [%sp,10], %i2
60 sts [%sp,11], %i3
61 sts [%sp,12], %i4
62 sts [%sp,13], %i5
63 sts [%sp,14], %i6
64 sts [%sp,15], %i7
65
66 /* Save current %sp and return address in a global so they are
67 * available at cwp = HI_LIMIT ... where the 'global'/'in' regs
68 * are restored. NOTE: %sp changes with cwp.
69 */
70 mov %g7, %o7
71 mov %g6, %sp
72
73 /* Get LO_LIMIT/HI_LIMIT to know where to start & stop. Note: in
74 * the underflow exception, cwp is __NOT__ guaranteed to be zero.
75 * If the OCI debug module is enabled the reset value for LO_LIMIT
76 * is 2, not 1 -- so cwp can be 1 or 0.
77 */
78 pfx 2 /* WVALID */
79 rdctl %g1
80 mov %g2, %g1
81 pfx 0
82 and %g1, 0x1f /* g1 <- LO_LIMIT */
83 lsri %g2, 5
84 pfx 0
85 and %g2,0x1f /* g2 <- HI_LIMIT */
86
87 /* Set istatus so cwp = HI_LIMIT after tret
88 */
89 movi %g5, 0x1f
90 lsli %g5, 4
91 not %g5 /* mask to clr cwp */
92 pfx 1 /* istatus */
93 rdctl %g0
94 and %g0, %g5 /* clear cwp field */
95
96 mov %g4, %g2
97 lsli %g4, 4
98 or %g0, %g4 /* cwp = HI_LIMIT */
99 pfx 1
100 wrctl %g0 /* update istatus */
101
102 /* Now move up the register file, saving as we go. When loop
103 * is first entered, %g1 is at LO_LIMIT.
104 */
1050:
106 restore /* cwp++ */
107 sts [%sp,0], %l0 /* Save "local" regs*/
108 sts [%sp,1], %l1
109 sts [%sp,2], %l2
110 sts [%sp,3], %l3
111 sts [%sp,4], %l4
112 sts [%sp,5], %l5
113 sts [%sp,6], %l6
114 sts [%sp,7], %l7
115
116 sts [%sp,8], %i0 /* Save 'in' regs */
117 sts [%sp,9], %i1
118 sts [%sp,10], %i2
119 sts [%sp,11], %i3
120 sts [%sp,12], %i4
121 sts [%sp,13], %i5
122 sts [%sp,14], %i6
123 sts [%sp,15], %i7
124
125 cmp %g1, %g2 /* cwp == HI_LIMIT ? */
126 skps cc_ne /* if so, we're done */
127 br 1f
128 nop /* delay slot */
129
130 inc %g1 /* g1 <- cwp++ */
131 br 0b
132 nop /* delay slot */
133
134 /* At this point cwp = HI_LIMIT, so the global/in regs that were
135 * in place when the underflow occurred must be restored using
136 * the original stack pointer (saved in g6).
137 */
1381:
139 mov %o7, %g7 /* restore return addr */
140 mov %sp, %g6 /* Restore original sp */
141
142 lds %g0, [%sp,0] /* Restore 'global' regs*/
143 lds %g1, [%sp,1]
144 lds %g2, [%sp,2]
145 lds %g3, [%sp,3]
146 lds %g4, [%sp,4]
147 lds %g5, [%sp,5]
148 lds %g6, [%sp,6]
149 lds %g7, [%sp,7]
150
151 lds %i0, [%sp,8] /* Restore 'in' regs*/
152 lds %i1, [%sp,9]
153 lds %i2, [%sp,10]
154 lds %i3, [%sp,11]
155 lds %i4, [%sp,12]
156 lds %i5, [%sp,13]
157 lds %i6, [%sp,14]
158 lds %i7, [%sp,15]
159
160 tret %o7 /* All done */
161
162/*************************************************************************
163 * Register window overflow
164 *
165 * The register window overflow exception occurs whenever the highest
166 * valid register window is in use (cwp = HI_LIMIT) and a restore
167 * instruction is issued. Control is transferred to the overflow handler
168 * before the instruction following restore is executed.
169 *
170 * When a register window overflow exception is taken, the exception
171 * handler sees cwp at HI_LIMIT.
172 ************************************************************************/
173 .text
174 .global _cwp_hilimit
175 .align 4
176
177_cwp_hilimit:
178
179 /* Save 'global'/'in' regs on the stack -- will restore when cwp
180 * is at LO_LIMIT. Locals don't need saving as they are going away.
181 */
182 sts [%sp,0], %g0 /* Save "global" regs*/
183 sts [%sp,1], %g1
184 sts [%sp,2], %g2
185 sts [%sp,3], %g3
186 sts [%sp,4], %g4
187 sts [%sp,5], %g5
188 sts [%sp,6], %g6
189 sts [%sp,7], %g7
190
191 sts [%sp,8], %i0 /* Save 'in' regs */
192 sts [%sp,9], %i1
193 sts [%sp,10], %i2
194 sts [%sp,11], %i3
195 sts [%sp,12], %i4
196 sts [%sp,13], %i5
197 sts [%sp,14], %i6
198 sts [%sp,15], %i7
199
200 /* The current %sp must be available in global to restore regs
201 * saved on stack. Need return addr as well ;-)
202 */
203 mov %g7, %o7
204 mov %g6, %sp
205
206 /* Get HI_LIMIT & LO_LIMIT
207 */
208 pfx 2 /* WVALID */
209 rdctl %g1
210 mov %g2, %g1
211 pfx 0
212 and %g1, 0x1f /* g1 <- LO_LIMIT */
213 lsri %g2, 5
214 pfx 0
215 and %g2,0x1f /* g2 <- HI_LIMIT */
216
217 /* Set istatus so cwp = LO_LIMIT after tret
218 */
219 movi %g5, 0x1f
220 lsli %g5, 4
221 not %g5 /* mask to clr cwp */
222 pfx 1 /* istatus */
223 rdctl %g0
224 and %g0, %g5 /* clear cwp field */
225
226 mov %g4, %g1 /* g4 <- LO_LIMIT */
227 lsli %g4, 4
228 or %g0, %g4 /* cwp = LO_LIMIT */
229 pfx 1
230 wrctl %g0 /* update istatus */
231
232 /* Move to cwp = LO_LIMIT-1 and restore 'in' regs.
233 */
234 subi %g4,(1 << 4) /* g4 <- LO_LIMIT - 1 */
235 rdctl %g0
236 and %g0, %g5 /* clear cwp field */
237 or %g0, %g4 /* cwp = LO_LIMIT - 1 */
238 wrctl %g0 /* update status */
239 nop
240
241 mov %sp, %g6 /* Restore sp */
242 lds %i0, [%sp,8] /* Restore 'in' regs */
243 lds %i1, [%sp,9]
244 lds %i2, [%sp,10]
245 lds %i3, [%sp,11]
246 lds %i4, [%sp,12]
247 lds %i5, [%sp,13]
248 lds %i6, [%sp,14] /* sp in next window */
249 lds %i7, [%sp,15]
250
251 /* Starting at LO_LIMIT-1, move up the register file, restoring
252 * along the way.
253 */
2540:
255 restore /* cwp++ */
256 lds %l0, [%sp,0] /* Restore 'local' regs*/
257 lds %l1, [%sp,1]
258 lds %l2, [%sp,2]
259 lds %l3, [%sp,3]
260 lds %l4, [%sp,4]
261 lds %l5, [%sp,5]
262 lds %l6, [%sp,6]
263 lds %l7, [%sp,7]
264
265 lds %i0, [%sp,8] /* Restore 'in' regs */
266 lds %i1, [%sp,9]
267 lds %i2, [%sp,10]
268 lds %i3, [%sp,11]
269 lds %i4, [%sp,12]
270 lds %i5, [%sp,13]
271 lds %i6, [%sp,14] /* sp in next window */
272 lds %i7, [%sp,15]
273
274 cmp %g1, %g2 /* cwp == HI_LIMIT ? */
275 skps cc_ne /* if so, we're done */
276 br 1f
277 nop /* delay slot */
278
279 inc %g1 /* cwp++ */
280 br 0b
281 nop /* delay slot */
282
283 /* All windows have been updated at this point, but the globals
284 * still need to be restored. Go to cwp = LO_LIMIT-1 to get
285 * some registers to use.
286 */
2871:
288 rdctl %g0
289 and %g0, %g5 /* clear cwp field */
290 or %g0, %g4 /* cwp = LO_LIMIT - 1 */
291 wrctl %g0 /* update status */
292 nop
293
294 /* Now there are some registers available to use in restoring
295 * the globals.
296 */
297 mov %sp, %g6
298 mov %o7, %g7
299
300 lds %g0, [%sp,0] /* Restore "global" regs*/
301 lds %g1, [%sp,1]
302 lds %g2, [%sp,2]
303 lds %g3, [%sp,3]
304 lds %g4, [%sp,4]
305 lds %g5, [%sp,5]
306 lds %g6, [%sp,6]
307 lds %g7, [%sp,7]
308
309 /* The tret moves istatus -> status. istatus was already set for
310 * cwp = LO_LIMIT.
311 */
312
313 tret %o7 /* done */
314
315/*************************************************************************
316 * Default exception handler
317 *
318 * The default handler passes control to external_interrupt(). So trap
319 * or hardware interrupt hanlders can be installed using the familiar
320 * irq_install_handler().
321 *
322 * Here, the stack is fixed-up and cwp is incremented prior to calling
323 * external_interrupt(). This lets the underflow and overflow handlers
324 * operate normally during the exception.
325 ************************************************************************/
326 .text
327 .global _def_xhandler
328 .align 4
329
330_def_xhandler:
331
332 /* Allocate some stack space: 16 words at %sp to accomodate
333 * a reg window underflow, 8 words to save interrupted task's
334 * 'out' regs (which are now the 'in' regs), 8 words to preserve
335 * the 'global' regs and 3 words to save the return address,
336 * status and istatus. istatus must be saved in the event an
337 * underflow occurs in a dispatched handler. status is saved so
338 * a handler can access it on stack.
339 */
340 pfx %hi((16+16+3) * 4)
341 subi %fp, %lo((16+16+3) * 4)
342 mov %sp, %fp
343
344 /* Save the 'global' regs and the interrupted task's 'out' regs
345 * (our 'in' regs) along with the return addr, status & istatus.
346 * First 16 words are for underflow exception.
347 */
348 rdctl %l0 /* status */
349 pfx 1 /* istatus */
350 rdctl %l1
351
352 sts [%sp,16+0], %g0 /* Save 'global' regs*/
353 sts [%sp,16+1], %g1
354 sts [%sp,16+2], %g2
355 sts [%sp,16+3], %g3
356 sts [%sp,16+4], %g4
357 sts [%sp,16+5], %g5
358 sts [%sp,16+6], %g6
359 sts [%sp,16+7], %g7
360
361 sts [%sp,16+8], %i0 /* Save 'in' regs */
362 sts [%sp,16+9], %i1
363 sts [%sp,16+10], %i2
364 sts [%sp,16+11], %i3
365 sts [%sp,16+12], %i4
366 sts [%sp,16+13], %i5
367 sts [%sp,16+14], %i6
368 sts [%sp,16+15], %i7
369
370 sts [%sp,16+16], %l0 /* status */
371 sts [%sp,16+17], %l1 /* istatus */
372 sts [%sp,16+18], %o7 /* return addr */
373
374 /* Move to cwp+1 ... this guarantees cwp is at or above LO_LIMIT.
375 * Need to set IPRI=3 and IE=1 to enable underflow exceptions.
376 * NOTE: only the 'out' regs have been saved ... can't touch
377 * the 'in' or 'local' here.
378 */
379 restore /* cwp++ */
380 rdctl %o0 /* o0 <- status */
381
382 pfx %hi(0x7e00)
383 movi %o1, %lo(0x7e00)
384 not %o1
385 and %o0, %o1 /* clear IPRI */
386
387 pfx %hi(0x8600)
388 movi %o1, %lo(0x8600)
389 or %o0, %o1 /* IPRI=3, IE=1 */
390
391 wrctl %o0 /* o0 -> status */
392 nop
393
394 /* It's ok to call a C routine now since cwp >= LO_LIMIT,
395 * interrupt task's registers are/will be preserved, and
396 * underflow exceptions can be handled.
397 */
398 pfx %hi(external_interrupt@h)
399 movi %o1, %lo(external_interrupt@h)
400 pfx %xhi(external_interrupt@h)
401 movhi %o1, %xlo(external_interrupt@h)
402 bgen %o0, 4+2 /* 16 * 4 */
403 add %o0, %sp /* Ptr to regs */
404 call %o1
405 nop
406
407 /* Move back to the exception register window, restore the 'out'
408 * registers, then return from exception.
409 */
410 rdctl %o0 /* o0 <- status */
411 subi %o0, 16
412 wrctl %o0 /* cwp-- */
413 nop
414
415 mov %sp, %fp
416 lds %g0, [%sp,16+0] /* Restore 'global' regs*/
417 lds %g1, [%sp,16+1]
418 lds %g2, [%sp,16+2]
419 lds %g3, [%sp,16+3]
420 lds %g4, [%sp,16+4]
421 lds %g5, [%sp,16+5]
422 lds %g6, [%sp,16+6]
423 lds %g7, [%sp,16+7]
424
425 lds %i0, [%sp,16+8] /* Restore 'in' regs*/
426 lds %i1, [%sp,16+9]
427 lds %i2, [%sp,16+10]
428 lds %i3, [%sp,16+11]
429 lds %i4, [%sp,16+12]
430 lds %i5, [%sp,16+13]
431 lds %i6, [%sp,16+14]
432 lds %i7, [%sp,16+15]
433
434 lds %l0, [%sp,16+16] /* status */
435 lds %l1, [%sp,16+17] /* istatus */
436 lds %o7, [%sp,16+18] /* return addr */
437
438 pfx 1
439 wrctl %l1 /* restore istatus */
440
441 pfx %hi((16+16+3) * 4)
442 addi %sp, %lo((16+16+3) * 4)
443 mov %fp, %sp
444
445 tret %o7 /* Done */
446
447
448/*************************************************************************
449 * Timebase Timer Interrupt -- This has identical structure to above,
450 * but calls timer_interrupt(). Doing it this way keeps things similar
451 * to other architectures (e.g. ppc).
452 ************************************************************************/
453 .text
454 .global _timebase_int
455 .align 4
456
457_timebase_int:
458
459 /* Allocate stack space.
460 */
461 pfx %hi((16+16+3) * 4)
462 subi %fp, %lo((16+16+3) * 4)
463 mov %sp, %fp
464
465 /* Save the 'global' regs & 'out' regs (our 'in' regs)
466 */
467 rdctl %l0 /* status */
468 pfx 1 /* istatus */
469 rdctl %l1
470
471 sts [%sp,16+0], %g0 /* Save 'global' regs*/
472 sts [%sp,16+1], %g1
473 sts [%sp,16+2], %g2
474 sts [%sp,16+3], %g3
475 sts [%sp,16+4], %g4
476 sts [%sp,16+5], %g5
477 sts [%sp,16+6], %g6
478 sts [%sp,16+7], %g7
479
480 sts [%sp,16+8], %i0 /* Save 'in' regs */
481 sts [%sp,16+9], %i1
482 sts [%sp,16+10], %i2
483 sts [%sp,16+11], %i3
484 sts [%sp,16+12], %i4
485 sts [%sp,16+13], %i5
486 sts [%sp,16+14], %i6
487 sts [%sp,16+15], %i7
488
489 sts [%sp,16+16], %l0 /* status */
490 sts [%sp,16+17], %l1 /* istatus */
491 sts [%sp,16+18], %o7 /* return addr */
492
493 /* Move to cwp+1.
494 */
495 restore /* cwp++ */
496 rdctl %o0 /* o0 <- status */
497
498 pfx %hi(0x7e00)
499 movi %o1, %lo(0x7e00)
500 not %o1
501 and %o0, %o1 /* clear IPRI */
502
503 pfx %hi(0x8600)
504 movi %o1, %lo(0x8600)
505 or %o0, %o1 /* IPRI=3, IE=1 */
506
507 wrctl %o0 /* o0 -> status */
508 nop
509
510 /* Call timer_interrupt()
511 */
512 pfx %hi(timer_interrupt@h)
513 movi %o1, %lo(timer_interrupt@h)
514 pfx %xhi(timer_interrupt@h)
515 movhi %o1, %xlo(timer_interrupt@h)
516 bgen %o0, 4+2 /* 16 * 4 */
517 add %o0, %sp /* Ptr to regs */
518 call %o1
519 nop
520
521 /* Move back to the exception register window, restore the 'out'
522 * registers, then return from exception.
523 */
524 rdctl %o0 /* o0 <- status */
525 subi %o0, 16
526 wrctl %o0 /* cwp-- */
527 nop
528
529 mov %sp, %fp
530 lds %g0, [%sp,16+0] /* Restore 'global' regs*/
531 lds %g1, [%sp,16+1]
532 lds %g2, [%sp,16+2]
533 lds %g3, [%sp,16+3]
534 lds %g4, [%sp,16+4]
535 lds %g5, [%sp,16+5]
536 lds %g6, [%sp,16+6]
537 lds %g7, [%sp,16+7]
538
539 lds %i0, [%sp,16+8] /* Restore 'in' regs*/
540 lds %i1, [%sp,16+9]
541 lds %i2, [%sp,16+10]
542 lds %i3, [%sp,16+11]
543 lds %i4, [%sp,16+12]
544 lds %i5, [%sp,16+13]
545 lds %i6, [%sp,16+14]
546 lds %i7, [%sp,16+15]
547
548 lds %l0, [%sp,16+16] /* status */
549 lds %l1, [%sp,16+17] /* istatus */
550 lds %o7, [%sp,16+18] /* return addr */
551
552 pfx 1
553 wrctl %l1 /* restore istatus */
554
555 pfx %hi((16+16+3) * 4)
556 addi %sp, %lo((16+16+3) * 4)
557 mov %fp, %sp
558
559 tret %o7 /* Done */
wdenke4cc71a2004-05-19 21:33:14 +0000560
561/*************************************************************************
562 * GDB stubs
563 ************************************************************************/
564 .text
565 .global _brkpt_hw_int, _brkpt_sw_int
566 .align 4
567
568_brkpt_hw_int:
569 movi %l1, 9
570 pfx 3
571 wrctl %l1
572 pfx 4
573 wrctl %l1
574
575_brkpt_sw_int:
576 movi %l1, 9
577 pfx 3
578 wrctl %l1
579 pfx 4
580 wrctl %l1
581
582 tret %o7