1|
2| skeleton.sa 3.2 4/26/91
3|
4| This file contains code that is system dependent and will
5| need to be modified to install the FPSP.
6|
7| Each entry point for exception 'xxxx' begins with a 'jmp fpsp_xxxx'.
8| Put any target system specific handling that must be done immediately
9| before the jump instruction. If there no handling necessary, then
10| the 'fpsp_xxxx' handler entry point should be placed in the exception
11| table so that the 'jmp' can be eliminated. If the FPSP determines that the
12| exception is one that must be reported then there will be a
13| return from the package by a 'jmp real_xxxx'. At that point
14| the machine state will be identical to the state before
15| the FPSP was entered. In particular, whatever condition
16| that caused the exception will still be pending when the FPSP
17| package returns. Thus, there will be system specific code
18| to handle the exception.
19|
20| If the exception was completely handled by the package, then
21| the return will be via a 'jmp fpsp_done'. Unless there is
22| OS specific work to be done (such as handling a context switch or
23| interrupt) the user program can be resumed via 'rte'.
24|
25| In the following skeleton code, some typical 'real_xxxx' handling
26| code is shown. This code may need to be moved to an appropriate
27| place in the target system, or rewritten.
28|
29
30| Copyright (C) Motorola, Inc. 1990
31| All Rights Reserved
32|
33| For details on the license for this file, please see the
34| file, README, in this same directory.
35
36|
37| Modified for Linux-1.3.x by Jes Sorensen (jds@kom.auc.dk)
38|
39
40#include <linux/linkage.h>
41#include <asm/entry.h>
42#include <asm/asm-offsets.h>
43
44|SKELETON idnt 2,1 | Motorola 040 Floating Point Software Package
45
46 |section 15
47|
48| The following counters are used for standalone testing
49|
50
51 |section 8
52
53#include "fpsp.h"
54
55 |xref b1238_fix
56
57|
58| Divide by Zero exception
59|
60| All dz exceptions are 'real', hence no fpsp_dz entry point.
61|
62 .global dz
63 .global real_dz
64dz:
65real_dz:
66 link %a6,
67 fsave -(%sp)
68 bclrb
69 frestore (%sp)+
70 unlk %a6
71
72 SAVE_ALL_INT
73 GET_CURRENT(%d0)
74 movel %sp,%sp@- | stack frame pointer argument
75 bsrl trap_c
76 addql
77 bral ret_from_exception
78
79|
80| Inexact exception
81|
82| All inexact exceptions are real, but the 'real' handler
83| will probably want to clear the pending exception.
84| The provided code will clear the E3 exception (if pending),
85| otherwise clear the E1 exception. The frestore is not really
86| necessary for E1 exceptions.
87|
88| Code following the 'inex' label is to handle bug
89| bug, if an E1 snan, ovfl, or unfl occurred, and the process was
90| swapped out before taking the exception, the exception taken on
91| return was inex, rather than the correct exception. The snan, ovfl,
92| and unfl exception to be taken must not have been enabled. The
93| fix is to check for E1, and the existence of one of snan, ovfl,
94| or unfl bits set in the fpsr. If any of these are set, branch
95| to the appropriate handler for the exception in the fpsr. Note
96| that this fix is only for d43b parts, and is skipped if the
97| version number is not $40.
98|
99|
100 .global real_inex
101 .global inex
102inex:
103 link %a6,
104 fsave -(%sp)
105 cmpib
106 bnes not_fmt40
107 fmovel %fpsr,-(%sp)
108 btstb
109 beqs not_b1232
110 btstb
111 beq inex_ckofl
112 addl
113 frestore (%sp)+
114 unlk %a6
115 bra snan
116inex_ckofl:
117 btstb
118 beq inex_ckufl
119 addl
120 frestore (%sp)+
121 unlk %a6
122 bra ovfl
123inex_ckufl:
124 btstb
125 beq not_b1232
126 addl
127 frestore (%sp)+
128 unlk %a6
129 bra unfl
130
131|
132| We do not have the bug 1232 case. Clean up the stack and call
133| real_inex.
134|
135not_b1232:
136 addl
137 frestore (%sp)+
138 unlk %a6
139
140real_inex:
141
142 link %a6,
143 fsave -(%sp)
144not_fmt40:
145 bclrb
146 beqs inex_cke1
147|
148| Clear dirty bit on dest resister in the frame before branching
149| to b1238_fix.
150|
151 moveml %d0/%d1,USER_DA(%a6)
152 bfextu CMDREG1B(%a6){
153 bclrb %d0,FPR_DIRTY_BITS(%a6) |clr dest dirty bit
154 bsrl b1238_fix |test for bug1238 case
155 moveml USER_DA(%a6),%d0/%d1
156 bras inex_done
157inex_cke1:
158 bclrb
159inex_done:
160 frestore (%sp)+
161 unlk %a6
162
163 SAVE_ALL_INT
164 GET_CURRENT(%d0)
165 movel %sp,%sp@- | stack frame pointer argument
166 bsrl trap_c
167 addql
168 bral ret_from_exception
169
170|
171| Overflow exception
172|
173 |xref fpsp_ovfl
174 .global real_ovfl
175 .global ovfl
176ovfl:
177 jmp fpsp_ovfl
178real_ovfl:
179
180 link %a6,
181 fsave -(%sp)
182 bclrb
183 bnes ovfl_done
184 bclrb
185ovfl_done:
186 frestore (%sp)+
187 unlk %a6
188
189 SAVE_ALL_INT
190 GET_CURRENT(%d0)
191 movel %sp,%sp@- | stack frame pointer argument
192 bsrl trap_c
193 addql
194 bral ret_from_exception
195
196|
197| Underflow exception
198|
199 |xref fpsp_unfl
200 .global real_unfl
201 .global unfl
202unfl:
203 jmp fpsp_unfl
204real_unfl:
205
206 link %a6,
207 fsave -(%sp)
208 bclrb
209 bnes unfl_done
210 bclrb
211unfl_done:
212 frestore (%sp)+
213 unlk %a6
214
215 SAVE_ALL_INT
216 GET_CURRENT(%d0)
217 movel %sp,%sp@- | stack frame pointer argument
218 bsrl trap_c
219 addql
220 bral ret_from_exception
221
222|
223| Signalling NAN exception
224|
225 |xref fpsp_snan
226 .global real_snan
227 .global snan
228snan:
229 jmp fpsp_snan
230real_snan:
231 link %a6,
232 fsave -(%sp)
233 bclrb
234 frestore (%sp)+
235 unlk %a6
236
237 SAVE_ALL_INT
238 GET_CURRENT(%d0)
239 movel %sp,%sp@- | stack frame pointer argument
240 bsrl trap_c
241 addql
242 bral ret_from_exception
243
244|
245| Operand Error exception
246|
247 |xref fpsp_operr
248 .global real_operr
249 .global operr
250operr:
251 jmp fpsp_operr
252real_operr:
253 link %a6,
254 fsave -(%sp)
255 bclrb
256 frestore (%sp)+
257 unlk %a6
258
259 SAVE_ALL_INT
260 GET_CURRENT(%d0)
261 movel %sp,%sp@- | stack frame pointer argument
262 bsrl trap_c
263 addql
264 bral ret_from_exception
265
266
267|
268| BSUN exception
269|
270| This sample handler simply clears the nan bit in the FPSR.
271|
272 |xref fpsp_bsun
273 .global real_bsun
274 .global bsun
275bsun:
276 jmp fpsp_bsun
277real_bsun:
278 link %a6,
279 fsave -(%sp)
280 bclrb
281 fmovel %FPSR,-(%sp)
282 bclrb
283 fmovel (%sp)+,%FPSR
284 frestore (%sp)+
285 unlk %a6
286
287 SAVE_ALL_INT
288 GET_CURRENT(%d0)
289 movel %sp,%sp@- | stack frame pointer argument
290 bsrl trap_c
291 addql
292 bral ret_from_exception
293
294|
295| F-line exception
296|
297| A 'real' F-line exception is one that the FPSP isn't supposed to
298| handle. E.g. an instruction with a co-processor ID that is not 1.
299|
300|
301 |xref fpsp_fline
302 .global real_fline
303 .global fline
304fline:
305 jmp fpsp_fline
306real_fline:
307
308 SAVE_ALL_INT
309 GET_CURRENT(%d0)
310 movel %sp,%sp@- | stack frame pointer argument
311 bsrl trap_c
312 addql
313 bral ret_from_exception
314
315|
316| Unsupported data type exception
317|
318 |xref fpsp_unsupp
319 .global real_unsupp
320 .global unsupp
321unsupp:
322 jmp fpsp_unsupp
323real_unsupp:
324 link %a6,
325 fsave -(%sp)
326 bclrb
327 frestore (%sp)+
328 unlk %a6
329
330 SAVE_ALL_INT
331 GET_CURRENT(%d0)
332 movel %sp,%sp@- | stack frame pointer argument
333 bsrl trap_c
334 addql
335 bral ret_from_exception
336
337|
338| Trace exception
339|
340 .global real_trace
341real_trace:
342 |
343 bral trap
344
345|
346| fpsp_fmt_error --- exit point for frame format error
347|
348| The fpu stack frame does not match the frames existing
349| or planned at the time of this writing. The fpsp is
350| unable to handle frame sizes not in the following
351| version:size pairs:
352|
353| {4060, 4160} - busy frame
354| {4028, 4130} - unimp frame
355| {4000, 4100} - idle frame
356|
357| This entry point simply holds an f-line illegal value.
358| Replace this with a call to your kernel panic code or
359| code to handle future revisions of the fpu.
360|
361 .global fpsp_fmt_error
362fpsp_fmt_error:
363
364 .long 0xf27f0000 |f-line illegal
365
366|
367| fpsp_done --- FPSP exit point
368|
369| The exception has been handled by the package and we are ready
370| to return to user mode, but there may be OS specific code
371| to execute before we do. If there is, do it now.
372|
373|
374
375 .global fpsp_done
376fpsp_done:
377 btst
378 beq .Lnotkern
379 rte
380.Lnotkern:
381 SAVE_ALL_INT
382 GET_CURRENT(%d0)
383 | deliver signals, reschedule etc..
384 jra ret_from_exception
385
386|
387| mem_write --- write to user or supervisor address space
388|
389| Writes to memory while in supervisor mode. copyout accomplishes
390| this via a 'moves' instruction. copyout is a UNIX SVR3 (and later) function.
391| If you don't have copyout, use the local copy of the function below.
392|
393| a0 - supervisor source address
394| a1 - user destination address
395| d0 - number of bytes to write (maximum count is 12)
396|
397| The supervisor source address is guaranteed to point into the supervisor
398| stack. The result is that a UNIX
399| process is allowed to sleep as a consequence of a page fault during
400| copyout. The probability of a page fault is exceedingly small because
401| the 68040 always reads the destination address and thus the page
402| faults should have already been handled.
403|
404| If the EXC_SR shows that the exception was from supervisor space,
405| then just do a dumb (and slow) memory move. In a UNIX environment
406| there shouldn't be any supervisor mode floating point exceptions.
407|
408 .global mem_write
409mem_write:
410 btstb
411 beqs user_write
412super_write:
413 moveb (%a0)+,(%a1)+
414 subql
415 bnes super_write
416 rts
417user_write:
418 movel %d1,-(%sp) |preserve d1 just in case
419 movel %d0,-(%sp)
420 movel %a1,-(%sp)
421 movel %a0,-(%sp)
422 jsr copyout
423 addw
424 movel (%sp)+,%d1
425 rts
426|
427| mem_read --- read from user or supervisor address space
428|
429| Reads from memory while in supervisor mode. copyin accomplishes
430| this via a 'moves' instruction. copyin is a UNIX SVR3 (and later) function.
431| If you don't have copyin, use the local copy of the function below.
432|
433| The FPSP calls mem_read to read the original F-line instruction in order
434| to extract the data register number when the 'Dn' addressing mode is
435| used.
436|
437|Input:
438| a0 - user source address
439| a1 - supervisor destination address
440| d0 - number of bytes to read (maximum count is 12)
441|
442| Like mem_write, mem_read always reads with a supervisor
443| destination address on the supervisor stack. Also like mem_write,
444| the EXC_SR is checked and a simple memory copy is done if reading
445| from supervisor space is indicated.
446|
447 .global mem_read
448mem_read:
449 btstb
450 beqs user_read
451super_read:
452 moveb (%a0)+,(%a1)+
453 subql
454 bnes super_read
455 rts
456user_read:
457 movel %d1,-(%sp) |preserve d1 just in case
458 movel %d0,-(%sp)
459 movel %a1,-(%sp)
460 movel %a0,-(%sp)
461 jsr copyin
462 addw
463 movel (%sp)+,%d1
464 rts
465
466|
467| Use these routines if your kernel doesn't have copyout/copyin equivalents.
468| Assumes that D0/D1/A0/A1 are scratch registers. copyout overwrites DFC,
469| and copyin overwrites SFC.
470|
471copyout:
472 movel 4(%sp),%a0 | source
473 movel 8(%sp),%a1 | destination
474 movel 12(%sp),%d0 | count
475 subl
476 movel
477
478| DFC is already set
479| movec %d1,%DFC | set dfc for user data space
480moreout:
481 moveb (%a0)+,%d1 | fetch supervisor byte
482out_ea:
483 movesb %d1,(%a1)+ | write user byte
484 dbf %d0,moreout
485 rts
486
487copyin:
488 movel 4(%sp),%a0 | source
489 movel 8(%sp),%a1 | destination
490 movel 12(%sp),%d0 | count
491 subl
492 movel
493| SFC is already set
494| movec %d1,%SFC | set sfc for user space
495morein:
496in_ea:
497 movesb (%a0)+,%d1 | fetch user byte
498 moveb %d1,(%a1)+ | write supervisor byte
499 dbf %d0,morein
500 rts
501
502 .section .fixup,
503 .even
5041:
505 jbra fpsp040_die
506
507 .section __ex_table,
508 .align 4
509
510 .long in_ea,1b
511 .long out_ea,1b
512
513 |end
514
