1 |
2 | bugfix.sa 3.2 1/31/91
3 |
4 |
5 | This file contains workarounds for bugs in the 040
6 | relating to the Floating-Point Software Package (FPSP)
7 |
8 | Fixes for bugs: 1238
9 |
10 | Bug: 1238
11 |
12 |
13 | /* The following dirty_bit clear should be left in
14 | * the handler permanently to improve throughput.
15 | * The dirty_bits are located at bits [23:16] in
16 | * longword $08 in the busy frame $4x60. Bit 16
17 | * corresponds to FP0, bit 17 corresponds to FP1,
18 | * and so on.
19 | */
20 | if (E3_exception_just_serviced) {
21 | dirty_bit[cmdreg3b[9:7]] = 0;
22 | }
23 |
24 | if (fsave_format_version != $40) {goto NOFIX}
25 |
26 | if !(E3_exception_just_serviced) {goto NOFIX}
27 | if (cupc == 0000000) {goto NOFIX}
28 | if ((cmdreg1b[15:13] != 000) &&
29 | (cmdreg1b[15:10] != 010001)) {goto NOFIX}
30 | if (((cmdreg1b[15:13] != 000) || ((cmdreg1b[12:10] != cmdreg2b[9:7]) &&
31 | (cmdreg1b[12:10] != cmdreg3b[9:7])) ) &&
32 | ((cmdreg1b[ 9: 7] != cmdreg2b[9:7]) &&
33 | (cmdreg1b[ 9: 7] != cmdreg3b[9:7])) ) {goto NOFIX}
34 |
35 | /* Note: for 6d43b or 8d43b, you may want to add the following code
36 | * to get better coverage. (If you do not insert this code, the part
37 | * won't lock up; it will simply get the wrong answer.)
38 | * Do NOT insert this code for 10d43b or later parts.
39 | *
40 | * if (fpiarcu == integer stack return address) {
41 | * cupc = 0000000;
42 | * goto NOFIX;
43 | * }
44 | */
45 |
46 | if (cmdreg1b[15:13] != 000) {goto FIX_OPCLASS2}
47 | FIX_OPCLASS0:
48 | if (((cmdreg1b[12:10] == cmdreg2b[9:7]) ||
49 | (cmdreg1b[ 9: 7] == cmdreg2b[9:7])) &&
50 | (cmdreg1b[12:10] != cmdreg3b[9:7]) &&
51 | (cmdreg1b[ 9: 7] != cmdreg3b[9:7])) { /* xu conflict only */
52 | /* We execute the following code if there is an
53 | xu conflict and NOT an nu conflict */
54 |
55 | /* first save some values on the fsave frame */
56 | stag_temp = STAG[fsave_frame];
57 | cmdreg1b_temp = CMDREG1B[fsave_frame];
58 | dtag_temp = DTAG[fsave_frame];
59 | ete15_temp = ETE15[fsave_frame];
60 |
61 | CUPC[fsave_frame] = 0000000;
62 | FRESTORE
63 | FSAVE
64 |
65 | /* If the xu instruction is exceptional, we punt.
66 | * Otherwise, we would have to include OVFL/UNFL handler
67 | * code here to get the correct answer.
68 | */
69 | if (fsave_frame_format == $4060) {goto KILL_PROCESS}
70 |
71 | fsave_frame = /* build a long frame of all zeros */
72 | fsave_frame_format = $4060; /* label it as long frame */
73 |
74 | /* load it with the temps we saved */
75 | STAG[fsave_frame] = stag_temp;
76 | CMDREG1B[fsave_frame] = cmdreg1b_temp;
77 | DTAG[fsave_frame] = dtag_temp;
78 | ETE15[fsave_frame] = ete15_temp;
79 |
80 | /* Make sure that the cmdreg3b dest reg is not going to
81 | * be destroyed by a FMOVEM at the end of all this code.
82 | * If it is, you should move the current value of the reg
83 | * onto the stack so that the reg will loaded with that value.
84 | */
85 |
86 | /* All done. Proceed with the code below */
87 | }
88 |
89 | etemp = FP_reg_[cmdreg1b[12:10]];
90 | ete15 = ~ete14;
91 | cmdreg1b[15:10] = 010010;
92 | clear(bug_flag_procIDxxxx);
93 | FRESTORE and return;
94 |
95 |
96 | FIX_OPCLASS2:
97 | if ((cmdreg1b[9:7] == cmdreg2b[9:7]) &&
98 | (cmdreg1b[9:7] != cmdreg3b[9:7])) { /* xu conflict only */
99 | /* We execute the following code if there is an
100 | xu conflict and NOT an nu conflict */
101 |
102 | /* first save some values on the fsave frame */
103 | stag_temp = STAG[fsave_frame];
104 | cmdreg1b_temp = CMDREG1B[fsave_frame];
105 | dtag_temp = DTAG[fsave_frame];
106 | ete15_temp = ETE15[fsave_frame];
107 | etemp_temp = ETEMP[fsave_frame];
108 |
109 | CUPC[fsave_frame] = 0000000;
110 | FRESTORE
111 | FSAVE
112 |
113 |
114 | /* If the xu instruction is exceptional, we punt.
115 | * Otherwise, we would have to include OVFL/UNFL handler
116 | * code here to get the correct answer.
117 | */
118 | if (fsave_frame_format == $4060) {goto KILL_PROCESS}
119 |
120 | fsave_frame = /* build a long frame of all zeros */
121 | fsave_frame_format = $4060; /* label it as long frame */
122 |
123 | /* load it with the temps we saved */
124 | STAG[fsave_frame] = stag_temp;
125 | CMDREG1B[fsave_frame] = cmdreg1b_temp;
126 | DTAG[fsave_frame] = dtag_temp;
127 | ETE15[fsave_frame] = ete15_temp;
128 | ETEMP[fsave_frame] = etemp_temp;
129 |
130 | /* Make sure that the cmdreg3b dest reg is not going to
131 | * be destroyed by a FMOVEM at the end of all this code.
132 | * If it is, you should move the current value of the reg
133 | * onto the stack so that the reg will loaded with that value.
134 | */
135 |
136 | /* All done. Proceed with the code below */
137 | }
138 |
139 | if (etemp_exponent == min_sgl) etemp_exponent = min_dbl;
140 | if (etemp_exponent == max_sgl) etemp_exponent = max_dbl;
141 | cmdreg1b[15:10] = 010101;
142 | clear(bug_flag_procIDxxxx);
143 | FRESTORE and return;
144 |
145 |
146 | NOFIX:
147 | clear(bug_flag_procIDxxxx);
148 | FRESTORE and return;
149 |
150
151
152 | Copyright (C) Motorola, Inc. 1990
153 | All Rights Reserved
154 |
155 | For details on the license for this file, please see the
156 | file, README, in this same directory.
157
158 |BUGFIX idnt 2,1 | Motorola 040 Floating Point Software Package
159
160 |section 8
161
162 #include "fpsp.h"
163
164 |xref fpsp_fmt_error
165
166 .global b1238_fix
167 b1238_fix:
168 |
169 | This code is entered only on completion of the handling of an
170 | nu-generated ovfl, unfl, or inex exception. If the version
171 | number of the fsave is not $40, this handler is not necessary.
172 | Simply branch to fix_done and exit normally.
173 |
174 cmpib #VER_40,4(%a7)
175 bne fix_done
176 |
177 | Test for cu_savepc equal to zero. If not, this is not a bug
178 | #1238 case.
179 |
180 moveb CU_SAVEPC(%a6),%d0
181 andib #0xFE,%d0
182 beq fix_done |if zero, this is not bug #1238
183
184 |
185 | Test the register conflict aspect. If opclass0, check for
186 | cu src equal to xu dest or equal to nu dest. If so, go to
187 | op0. Else, or if opclass2, check for cu dest equal to
188 | xu dest or equal to nu dest. If so, go to tst_opcl. Else,
189 | exit, it is not the bug case.
190 |
191 | Check for opclass 0. If not, go and check for opclass 2 and sgl.
192 |
193 movew CMDREG1B(%a6),%d0
194 andiw #0xE000,%d0 |strip all but opclass
195 bne op2sgl |not opclass 0, check op2
196 |
197 | Check for cu and nu register conflict. If one exists, this takes
198 | priority over a cu and xu conflict.
199 |
200 bfextu CMDREG1B(%a6){#3:#3},%d0 |get 1st src
201 bfextu CMDREG3B(%a6){#6:#3},%d1 |get 3rd dest
202 cmpb %d0,%d1
203 beqs op0 |if equal, continue bugfix
204 |
205 | Check for cu dest equal to nu dest. If so, go and fix the
206 | bug condition. Otherwise, exit.
207 |
208 bfextu CMDREG1B(%a6){#6:#3},%d0 |get 1st dest
209 cmpb %d0,%d1 |cmp 1st dest with 3rd dest
210 beqs op0 |if equal, continue bugfix
211 |
212 | Check for cu and xu register conflict.
213 |
214 bfextu CMDREG2B(%a6){#6:#3},%d1 |get 2nd dest
215 cmpb %d0,%d1 |cmp 1st dest with 2nd dest
216 beqs op0_xu |if equal, continue bugfix
217 bfextu CMDREG1B(%a6){#3:#3},%d0 |get 1st src
218 cmpb %d0,%d1 |cmp 1st src with 2nd dest
219 beq op0_xu
220 bne fix_done |if the reg checks fail, exit
221 |
222 | We have the opclass 0 situation.
223 |
224 op0:
225 bfextu CMDREG1B(%a6){#3:#3},%d0 |get source register no
226 movel #7,%d1
227 subl %d0,%d1
228 clrl %d0
229 bsetl %d1,%d0
230 fmovemx %d0,ETEMP(%a6) |load source to ETEMP
231
232 moveb #0x12,%d0
233 bfins %d0,CMDREG1B(%a6){#0:#6} |opclass 2, extended
234 |
235 | Set ETEMP exponent bit 15 as the opposite of ete14
236 |
237 btst #6,ETEMP_EX(%a6) |check etemp exponent bit 14
238 beq setete15
239 bclr #etemp15_bit,STAG(%a6)
240 bra finish
241 setete15:
242 bset #etemp15_bit,STAG(%a6)
243 bra finish
244
245 |
246 | We have the case in which a conflict exists between the cu src or
247 | dest and the dest of the xu. We must clear the instruction in
248 | the cu and restore the state, allowing the instruction in the
249 | xu to complete. Remember, the instruction in the nu
250 | was exceptional, and was completed by the appropriate handler.
251 | If the result of the xu instruction is not exceptional, we can
252 | restore the instruction from the cu to the frame and continue
253 | processing the original exception. If the result is also
254 | exceptional, we choose to kill the process.
255 |
256 | Items saved from the stack:
257 |
258 | $3c stag - L_SCR1
259 | $40 cmdreg1b - L_SCR2
260 | $44 dtag - L_SCR3
261 |
262 | The cu savepc is set to zero, and the frame is restored to the
263 | fpu.
264 |
265 op0_xu:
266 movel STAG(%a6),L_SCR1(%a6)
267 movel CMDREG1B(%a6),L_SCR2(%a6)
268 movel DTAG(%a6),L_SCR3(%a6)
269 andil #0xe0000000,L_SCR3(%a6)
270 moveb #0,CU_SAVEPC(%a6)
271 movel (%a7)+,%d1 |save return address from bsr
272 frestore (%a7)+
273 fsave -(%a7)
274 |
275 | Check if the instruction which just completed was exceptional.
276 |
277 cmpw #0x4060,(%a7)
278 beq op0_xb
279 |
280 | It is necessary to isolate the result of the instruction in the
281 | xu if it is to fp0 - fp3 and write that value to the USER_FPn
282 | locations on the stack. The correct destination register is in
283 | cmdreg2b.
284 |
285 bfextu CMDREG2B(%a6){#6:#3},%d0 |get dest register no
286 cmpil #3,%d0
287 bgts op0_xi
288 beqs op0_fp3
289 cmpil #1,%d0
290 blts op0_fp0
291 beqs op0_fp1
292 op0_fp2:
293 fmovemx %fp2-%fp2,USER_FP2(%a6)
294 bras op0_xi
295 op0_fp1:
296 fmovemx %fp1-%fp1,USER_FP1(%a6)
297 bras op0_xi
298 op0_fp0:
299 fmovemx %fp0-%fp0,USER_FP0(%a6)
300 bras op0_xi
301 op0_fp3:
302 fmovemx %fp3-%fp3,USER_FP3(%a6)
303 |
304 | The frame returned is idle. We must build a busy frame to hold
305 | the cu state information and setup etemp.
306 |
307 op0_xi:
308 movel #22,%d0 |clear 23 lwords
309 clrl (%a7)
310 op0_loop:
311 clrl -(%a7)
312 dbf %d0,op0_loop
313 movel #0x40600000,-(%a7)
314 movel L_SCR1(%a6),STAG(%a6)
315 movel L_SCR2(%a6),CMDREG1B(%a6)
316 movel L_SCR3(%a6),DTAG(%a6)
317 moveb #0x6,CU_SAVEPC(%a6)
318 movel %d1,-(%a7) |return bsr return address
319 bfextu CMDREG1B(%a6){#3:#3},%d0 |get source register no
320 movel #7,%d1
321 subl %d0,%d1
322 clrl %d0
323 bsetl %d1,%d0
324 fmovemx %d0,ETEMP(%a6) |load source to ETEMP
325
326 moveb #0x12,%d0
327 bfins %d0,CMDREG1B(%a6){#0:#6} |opclass 2, extended
328 |
329 | Set ETEMP exponent bit 15 as the opposite of ete14
330 |
331 btst #6,ETEMP_EX(%a6) |check etemp exponent bit 14
332 beq op0_sete15
333 bclr #etemp15_bit,STAG(%a6)
334 bra finish
335 op0_sete15:
336 bset #etemp15_bit,STAG(%a6)
337 bra finish
338
339 |
340 | The frame returned is busy. It is not possible to reconstruct
341 | the code sequence to allow completion. We will jump to
342 | fpsp_fmt_error and allow the kernel to kill the process.
343 |
344 op0_xb:
345 jmp fpsp_fmt_error
346
347 |
348 | Check for opclass 2 and single size. If not both, exit.
349 |
350 op2sgl:
351 movew CMDREG1B(%a6),%d0
352 andiw #0xFC00,%d0 |strip all but opclass and size
353 cmpiw #0x4400,%d0 |test for opclass 2 and size=sgl
354 bne fix_done |if not, it is not bug 1238
355 |
356 | Check for cu dest equal to nu dest or equal to xu dest, with
357 | a cu and nu conflict taking priority an nu conflict. If either,
358 | go and fix the bug condition. Otherwise, exit.
359 |
360 bfextu CMDREG1B(%a6){#6:#3},%d0 |get 1st dest
361 bfextu CMDREG3B(%a6){#6:#3},%d1 |get 3rd dest
362 cmpb %d0,%d1 |cmp 1st dest with 3rd dest
363 beq op2_com |if equal, continue bugfix
364 bfextu CMDREG2B(%a6){#6:#3},%d1 |get 2nd dest
365 cmpb %d0,%d1 |cmp 1st dest with 2nd dest
366 bne fix_done |if the reg checks fail, exit
367 |
368 | We have the case in which a conflict exists between the cu src or
369 | dest and the dest of the xu. We must clear the instruction in
370 | the cu and restore the state, allowing the instruction in the
371 | xu to complete. Remember, the instruction in the nu
372 | was exceptional, and was completed by the appropriate handler.
373 | If the result of the xu instruction is not exceptional, we can
374 | restore the instruction from the cu to the frame and continue
375 | processing the original exception. If the result is also
376 | exceptional, we choose to kill the process.
377 |
378 | Items saved from the stack:
379 |
380 | $3c stag - L_SCR1
381 | $40 cmdreg1b - L_SCR2
382 | $44 dtag - L_SCR3
383 | etemp - FP_SCR2
384 |
385 | The cu savepc is set to zero, and the frame is restored to the
386 | fpu.
387 |
388 op2_xu:
389 movel STAG(%a6),L_SCR1(%a6)
390 movel CMDREG1B(%a6),L_SCR2(%a6)
391 movel DTAG(%a6),L_SCR3(%a6)
392 andil #0xe0000000,L_SCR3(%a6)
393 moveb #0,CU_SAVEPC(%a6)
394 movel ETEMP(%a6),FP_SCR2(%a6)
395 movel ETEMP_HI(%a6),FP_SCR2+4(%a6)
396 movel ETEMP_LO(%a6),FP_SCR2+8(%a6)
397 movel (%a7)+,%d1 |save return address from bsr
398 frestore (%a7)+
399 fsave -(%a7)
400 |
401 | Check if the instruction which just completed was exceptional.
402 |
403 cmpw #0x4060,(%a7)
404 beq op2_xb
405 |
406 | It is necessary to isolate the result of the instruction in the
407 | xu if it is to fp0 - fp3 and write that value to the USER_FPn
408 | locations on the stack. The correct destination register is in
409 | cmdreg2b.
410 |
411 bfextu CMDREG2B(%a6){#6:#3},%d0 |get dest register no
412 cmpil #3,%d0
413 bgts op2_xi
414 beqs op2_fp3
415 cmpil #1,%d0
416 blts op2_fp0
417 beqs op2_fp1
418 op2_fp2:
419 fmovemx %fp2-%fp2,USER_FP2(%a6)
420 bras op2_xi
421 op2_fp1:
422 fmovemx %fp1-%fp1,USER_FP1(%a6)
423 bras op2_xi
424 op2_fp0:
425 fmovemx %fp0-%fp0,USER_FP0(%a6)
426 bras op2_xi
427 op2_fp3:
428 fmovemx %fp3-%fp3,USER_FP3(%a6)
429 |
430 | The frame returned is idle. We must build a busy frame to hold
431 | the cu state information and fix up etemp.
432 |
433 op2_xi:
434 movel #22,%d0 |clear 23 lwords
435 clrl (%a7)
436 op2_loop:
437 clrl -(%a7)
438 dbf %d0,op2_loop
439 movel #0x40600000,-(%a7)
440 movel L_SCR1(%a6),STAG(%a6)
441 movel L_SCR2(%a6),CMDREG1B(%a6)
442 movel L_SCR3(%a6),DTAG(%a6)
443 moveb #0x6,CU_SAVEPC(%a6)
444 movel FP_SCR2(%a6),ETEMP(%a6)
445 movel FP_SCR2+4(%a6),ETEMP_HI(%a6)
446 movel FP_SCR2+8(%a6),ETEMP_LO(%a6)
447 movel %d1,-(%a7)
448 bra op2_com
449
450 |
451 | We have the opclass 2 single source situation.
452 |
453 op2_com:
454 moveb #0x15,%d0
455 bfins %d0,CMDREG1B(%a6){#0:#6} |opclass 2, double
456
457 cmpw #0x407F,ETEMP_EX(%a6) |single +max
458 bnes case2
459 movew #0x43FF,ETEMP_EX(%a6) |to double +max
460 bra finish
461 case2:
462 cmpw #0xC07F,ETEMP_EX(%a6) |single -max
463 bnes case3
464 movew #0xC3FF,ETEMP_EX(%a6) |to double -max
465 bra finish
466 case3:
467 cmpw #0x3F80,ETEMP_EX(%a6) |single +min
468 bnes case4
469 movew #0x3C00,ETEMP_EX(%a6) |to double +min
470 bra finish
471 case4:
472 cmpw #0xBF80,ETEMP_EX(%a6) |single -min
473 bne fix_done
474 movew #0xBC00,ETEMP_EX(%a6) |to double -min
475 bra finish
476 |
477 | The frame returned is busy. It is not possible to reconstruct
478 | the code sequence to allow completion. fpsp_fmt_error causes
479 | an fline illegal instruction to be executed.
480 |
481 | You should replace the jump to fpsp_fmt_error with a jump
482 | to the entry point used to kill a process.
483 |
484 op2_xb:
485 jmp fpsp_fmt_error
486
487 |
488 | Enter here if the case is not of the situations affected by
489 | bug #1238, or if the fix is completed, and exit.
490 |
491 finish:
492 fix_done:
493 rts
494
495 |end
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