1 |
2 | gen_except.sa 3.7 1/16/92
3 |
4 | gen_except --- FPSP routine to detect reportable exceptions
5 |
6 | This routine compares the exception enable byte of the
7 | user_fpcr on the stack with the exception status byte
8 | of the user_fpsr.
9 |
10 | Any routine which may report an exceptions must load
11 | the stack frame in memory with the exceptional operand(s).
12 |
13 | Priority for exceptions is:
14 |
15 | Highest: bsun
16 | snan
17 | operr
18 | ovfl
19 | unfl
20 | dz
21 | inex2
22 | Lowest: inex1
23 |
24 | Note: The IEEE standard specifies that inex2 is to be
25 | reported if ovfl occurs and the ovfl enable bit is not
26 | set but the inex2 enable bit is.
27 |
28 |
29 | Copyright (C) Motorola, Inc. 1990
30 | All Rights Reserved
31 |
32 | THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
33 | The copyright notice above does not evidence any
34 | actual or intended publication of such source code.
35
36 GEN_EXCEPT: |idnt 2,1 | Motorola 040 Floating Point Software Package
37
38 |section 8
39
40 .include "fpsp.h"
41
42 |xref real_trace
43 |xref fpsp_done
44 |xref fpsp_fmt_error
45
46 exc_tbl:
47 .long bsun_exc
48 .long commonE1
49 .long commonE1
50 .long ovfl_unfl
51 .long ovfl_unfl
52 .long commonE1
53 .long commonE3
54 .long commonE3
55 .long no_match
56
57 .global gen_except
58 gen_except:
59 cmpib #IDLE_SIZE-4,1(%a7) |test for idle frame
60 beq do_check |go handle idle frame
61 cmpib #UNIMP_40_SIZE-4,1(%a7) |test for orig unimp frame
62 beqs unimp_x |go handle unimp frame
63 cmpib #UNIMP_41_SIZE-4,1(%a7) |test for rev unimp frame
64 beqs unimp_x |go handle unimp frame
65 cmpib #BUSY_SIZE-4,1(%a7) |if size <> $60, fmt error
66 bnel fpsp_fmt_error
67 leal BUSY_SIZE+LOCAL_SIZE(%a7),%a1 |init a1 so fpsp.h
68 | ;equates will work
69 | Fix up the new busy frame with entries from the unimp frame
70 |
71 movel ETEMP_EX(%a6),ETEMP_EX(%a1) |copy etemp from unimp
72 movel ETEMP_HI(%a6),ETEMP_HI(%a1) |frame to busy frame
73 movel ETEMP_LO(%a6),ETEMP_LO(%a1)
74 movel CMDREG1B(%a6),CMDREG1B(%a1) |set inst in frame to unimp
75 movel CMDREG1B(%a6),%d0 |fix cmd1b to make it
76 andl #0x03c30000,%d0 |work for cmd3b
77 bfextu CMDREG1B(%a6){#13:#1},%d1 |extract bit 2
78 lsll #5,%d1
79 swap %d1
80 orl %d1,%d0 |put it in the right place
81 bfextu CMDREG1B(%a6){#10:#3},%d1 |extract bit 3,4,5
82 lsll #2,%d1
83 swap %d1
84 orl %d1,%d0 |put them in the right place
85 movel %d0,CMDREG3B(%a1) |in the busy frame
86 |
87 | Or in the FPSR from the emulation with the USER_FPSR on the stack.
88 |
89 fmovel %FPSR,%d0
90 orl %d0,USER_FPSR(%a6)
91 movel USER_FPSR(%a6),FPSR_SHADOW(%a1) |set exc bits
92 orl #sx_mask,E_BYTE(%a1)
93 bra do_clean
94
95 |
96 | Frame is an unimp frame possible resulting from an fmove <ea>,fp0
97 | that caused an exception
98 |
99 | a1 is modified to point into the new frame allowing fpsp equates
100 | to be valid.
101 |
102 unimp_x:
103 cmpib #UNIMP_40_SIZE-4,1(%a7) |test for orig unimp frame
104 bnes test_rev
105 leal UNIMP_40_SIZE+LOCAL_SIZE(%a7),%a1
106 bras unimp_con
107 test_rev:
108 cmpib #UNIMP_41_SIZE-4,1(%a7) |test for rev unimp frame
109 bnel fpsp_fmt_error |if not $28 or $30
110 leal UNIMP_41_SIZE+LOCAL_SIZE(%a7),%a1
111
112 unimp_con:
113 |
114 | Fix up the new unimp frame with entries from the old unimp frame
115 |
116 movel CMDREG1B(%a6),CMDREG1B(%a1) |set inst in frame to unimp
117 |
118 | Or in the FPSR from the emulation with the USER_FPSR on the stack.
119 |
120 fmovel %FPSR,%d0
121 orl %d0,USER_FPSR(%a6)
122 bra do_clean
123
124 |
125 | Frame is idle, so check for exceptions reported through
126 | USER_FPSR and set the unimp frame accordingly.
127 | A7 must be incremented to the point before the
128 | idle fsave vector to the unimp vector.
129 |
130
131 do_check:
132 addl #4,%a7 |point A7 back to unimp frame
133 |
134 | Or in the FPSR from the emulation with the USER_FPSR on the stack.
135 |
136 fmovel %FPSR,%d0
137 orl %d0,USER_FPSR(%a6)
138 |
139 | On a busy frame, we must clear the nmnexc bits.
140 |
141 cmpib #BUSY_SIZE-4,1(%a7) |check frame type
142 bnes check_fr |if busy, clr nmnexc
143 clrw NMNEXC(%a6) |clr nmnexc & nmcexc
144 btstb #5,CMDREG1B(%a6) |test for fmove out
145 bnes frame_com
146 movel USER_FPSR(%a6),FPSR_SHADOW(%a6) |set exc bits
147 orl #sx_mask,E_BYTE(%a6)
148 bras frame_com
149 check_fr:
150 cmpb #UNIMP_40_SIZE-4,1(%a7)
151 beqs frame_com
152 clrw NMNEXC(%a6)
153 frame_com:
154 moveb FPCR_ENABLE(%a6),%d0 |get fpcr enable byte
155 andb FPSR_EXCEPT(%a6),%d0 |and in the fpsr exc byte
156 bfffo %d0{#24:#8},%d1 |test for first set bit
157 leal exc_tbl,%a0 |load jmp table address
158 subib #24,%d1 |normalize bit offset to 0-8
159 movel (%a0,%d1.w*4),%a0 |load routine address based
160 | ;based on first enabled exc
161 jmp (%a0) |jump to routine
162 |
163 | Bsun is not possible in unimp or unsupp
164 |
165 bsun_exc:
166 bra do_clean
167 |
168 | The typical work to be done to the unimp frame to report an
169 | exception is to set the E1/E3 byte and clr the U flag.
170 | commonE1 does this for E1 exceptions, which are snan,
171 | operr, and dz. commonE3 does this for E3 exceptions, which
172 | are inex2 and inex1, and also clears the E1 exception bit
173 | left over from the unimp exception.
174 |
175 commonE1:
176 bsetb #E1,E_BYTE(%a6) |set E1 flag
177 bra commonE |go clean and exit
178
179 commonE3:
180 tstb UFLG_TMP(%a6) |test flag for unsup/unimp state
181 bnes unsE3
182 uniE3:
183 bsetb #E3,E_BYTE(%a6) |set E3 flag
184 bclrb #E1,E_BYTE(%a6) |clr E1 from unimp
185 bra commonE
186
187 unsE3:
188 tstb RES_FLG(%a6)
189 bnes unsE3_0
190 unsE3_1:
191 bsetb #E3,E_BYTE(%a6) |set E3 flag
192 unsE3_0:
193 bclrb #E1,E_BYTE(%a6) |clr E1 flag
194 movel CMDREG1B(%a6),%d0
195 andl #0x03c30000,%d0 |work for cmd3b
196 bfextu CMDREG1B(%a6){#13:#1},%d1 |extract bit 2
197 lsll #5,%d1
198 swap %d1
199 orl %d1,%d0 |put it in the right place
200 bfextu CMDREG1B(%a6){#10:#3},%d1 |extract bit 3,4,5
201 lsll #2,%d1
202 swap %d1
203 orl %d1,%d0 |put them in the right place
204 movel %d0,CMDREG3B(%a6) |in the busy frame
205
206 commonE:
207 bclrb #UFLAG,T_BYTE(%a6) |clr U flag from unimp
208 bra do_clean |go clean and exit
209 |
210 | No bits in the enable byte match existing exceptions. Check for
211 | the case of the ovfl exc without the ovfl enabled, but with
212 | inex2 enabled.
213 |
214 no_match:
215 btstb #inex2_bit,FPCR_ENABLE(%a6) |check for ovfl/inex2 case
216 beqs no_exc |if clear, exit
217 btstb #ovfl_bit,FPSR_EXCEPT(%a6) |now check ovfl
218 beqs no_exc |if clear, exit
219 bras ovfl_unfl |go to unfl_ovfl to determine if
220 | ;it is an unsupp or unimp exc
221
222 | No exceptions are to be reported. If the instruction was
223 | unimplemented, no FPU restore is necessary. If it was
224 | unsupported, we must perform the restore.
225 no_exc:
226 tstb UFLG_TMP(%a6) |test flag for unsupp/unimp state
227 beqs uni_no_exc
228 uns_no_exc:
229 tstb RES_FLG(%a6) |check if frestore is needed
230 bne do_clean |if clear, no frestore needed
231 uni_no_exc:
232 moveml USER_DA(%a6),%d0-%d1/%a0-%a1
233 fmovemx USER_FP0(%a6),%fp0-%fp3
234 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
235 unlk %a6
236 bra finish_up
237 |
238 | Unsupported Data Type Handler:
239 | Ovfl:
240 | An fmoveout that results in an overflow is reported this way.
241 | Unfl:
242 | An fmoveout that results in an underflow is reported this way.
243 |
244 | Unimplemented Instruction Handler:
245 | Ovfl:
246 | Only scosh, setox, ssinh, stwotox, and scale can set overflow in
247 | this manner.
248 | Unfl:
249 | Stwotox, setox, and scale can set underflow in this manner.
250 | Any of the other Library Routines such that f(x)=x in which
251 | x is an extended denorm can report an underflow exception.
252 | It is the responsibility of the exception-causing exception
253 | to make sure that WBTEMP is correct.
254 |
255 | The exceptional operand is in FP_SCR1.
256 |
257 ovfl_unfl:
258 tstb UFLG_TMP(%a6) |test flag for unsupp/unimp state
259 beqs ofuf_con
260 |
261 | The caller was from an unsupported data type trap. Test if the
262 | caller set CU_ONLY. If so, the exceptional operand is expected in
263 | FPTEMP, rather than WBTEMP.
264 |
265 tstb CU_ONLY(%a6) |test if inst is cu-only
266 beq unsE3
267 | move.w #$fe,CU_SAVEPC(%a6)
268 clrb CU_SAVEPC(%a6)
269 bsetb #E1,E_BYTE(%a6) |set E1 exception flag
270 movew ETEMP_EX(%a6),FPTEMP_EX(%a6)
271 movel ETEMP_HI(%a6),FPTEMP_HI(%a6)
272 movel ETEMP_LO(%a6),FPTEMP_LO(%a6)
273 bsetb #fptemp15_bit,DTAG(%a6) |set fpte15
274 bclrb #UFLAG,T_BYTE(%a6) |clr U flag from unimp
275 bra do_clean |go clean and exit
276
277 ofuf_con:
278 moveb (%a7),VER_TMP(%a6) |save version number
279 cmpib #BUSY_SIZE-4,1(%a7) |check for busy frame
280 beqs busy_fr |if unimp, grow to busy
281 cmpib #VER_40,(%a7) |test for orig unimp frame
282 bnes try_41 |if not, test for rev frame
283 moveql #13,%d0 |need to zero 14 lwords
284 bras ofuf_fin
285 try_41:
286 cmpib #VER_41,(%a7) |test for rev unimp frame
287 bnel fpsp_fmt_error |if neither, exit with error
288 moveql #11,%d0 |need to zero 12 lwords
289
290 ofuf_fin:
291 clrl (%a7)
292 loop1:
293 clrl -(%a7) |clear and dec a7
294 dbra %d0,loop1
295 moveb VER_TMP(%a6),(%a7)
296 moveb #BUSY_SIZE-4,1(%a7) |write busy fmt word.
297 busy_fr:
298 movel FP_SCR1(%a6),WBTEMP_EX(%a6) |write
299 movel FP_SCR1+4(%a6),WBTEMP_HI(%a6) |exceptional op to
300 movel FP_SCR1+8(%a6),WBTEMP_LO(%a6) |wbtemp
301 bsetb #E3,E_BYTE(%a6) |set E3 flag
302 bclrb #E1,E_BYTE(%a6) |make sure E1 is clear
303 bclrb #UFLAG,T_BYTE(%a6) |clr U flag
304 movel USER_FPSR(%a6),FPSR_SHADOW(%a6)
305 orl #sx_mask,E_BYTE(%a6)
306 movel CMDREG1B(%a6),%d0 |fix cmd1b to make it
307 andl #0x03c30000,%d0 |work for cmd3b
308 bfextu CMDREG1B(%a6){#13:#1},%d1 |extract bit 2
309 lsll #5,%d1
310 swap %d1
311 orl %d1,%d0 |put it in the right place
312 bfextu CMDREG1B(%a6){#10:#3},%d1 |extract bit 3,4,5
313 lsll #2,%d1
314 swap %d1
315 orl %d1,%d0 |put them in the right place
316 movel %d0,CMDREG3B(%a6) |in the busy frame
317
318 |
319 | Check if the frame to be restored is busy or unimp.
320 |** NOTE *** Bug fix for errata (0d43b #3)
321 | If the frame is unimp, we must create a busy frame to
322 | fix the bug with the nmnexc bits in cases in which they
323 | are set by a previous instruction and not cleared by
324 | the save. The frame will be unimp only if the final
325 | instruction in an emulation routine caused the exception
326 | by doing an fmove <ea>,fp0. The exception operand, in
327 | internal format, is in fptemp.
328 |
329 do_clean:
330 cmpib #UNIMP_40_SIZE-4,1(%a7)
331 bnes do_con
332 moveql #13,%d0 |in orig, need to zero 14 lwords
333 bras do_build
334 do_con:
335 cmpib #UNIMP_41_SIZE-4,1(%a7)
336 bnes do_restore |frame must be busy
337 moveql #11,%d0 |in rev, need to zero 12 lwords
338
339 do_build:
340 moveb (%a7),VER_TMP(%a6)
341 clrl (%a7)
342 loop2:
343 clrl -(%a7) |clear and dec a7
344 dbra %d0,loop2
345 |
346 | Use a1 as pointer into new frame. a6 is not correct if an unimp or
347 | busy frame was created as the result of an exception on the final
348 | instruction of an emulation routine.
349 |
350 | We need to set the nmcexc bits if the exception is E1. Otherwise,
351 | the exc taken will be inex2.
352 |
353 leal BUSY_SIZE+LOCAL_SIZE(%a7),%a1 |init a1 for new frame
354 moveb VER_TMP(%a6),(%a7) |write busy fmt word
355 moveb #BUSY_SIZE-4,1(%a7)
356 movel FP_SCR1(%a6),WBTEMP_EX(%a1) |write
357 movel FP_SCR1+4(%a6),WBTEMP_HI(%a1) |exceptional op to
358 movel FP_SCR1+8(%a6),WBTEMP_LO(%a1) |wbtemp
359 | btst.b #E1,E_BYTE(%a1)
360 | beq.b do_restore
361 bfextu USER_FPSR(%a6){#17:#4},%d0 |get snan/operr/ovfl/unfl bits
362 bfins %d0,NMCEXC(%a1){#4:#4} |and insert them in nmcexc
363 movel USER_FPSR(%a6),FPSR_SHADOW(%a1) |set exc bits
364 orl #sx_mask,E_BYTE(%a1)
365
366 do_restore:
367 moveml USER_DA(%a6),%d0-%d1/%a0-%a1
368 fmovemx USER_FP0(%a6),%fp0-%fp3
369 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar
370 frestore (%a7)+
371 tstb RES_FLG(%a6) |RES_FLG indicates a "continuation" frame
372 beq cont
373 bsr bug1384
374 cont:
375 unlk %a6
376 |
377 | If trace mode enabled, then go to trace handler. This handler
378 | cannot have any fp instructions. If there are fp inst's and an
379 | exception has been restored into the machine then the exception
380 | will occur upon execution of the fp inst. This is not desirable
381 | in the kernel (supervisor mode). See MC68040 manual Section 9.3.8.
382 |
383 finish_up:
384 btstb #7,(%a7) |test T1 in SR
385 bnes g_trace
386 btstb #6,(%a7) |test T0 in SR
387 bnes g_trace
388 bral fpsp_done
389 |
390 | Change integer stack to look like trace stack
391 | The address of the instruction that caused the
392 | exception is already in the integer stack (is
393 | the same as the saved friar)
394 |
395 | If the current frame is already a 6-word stack then all
396 | that needs to be done is to change the vector# to TRACE.
397 | If the frame is only a 4-word stack (meaning we got here
398 | on an Unsupported data type exception), then we need to grow
399 | the stack an extra 2 words and get the FPIAR from the FPU.
400 |
401 g_trace:
402 bftst EXC_VEC-4(%sp){#0:#4} 403 bne g_easy
404
405 subw #4,%sp | make room
406 movel 4(%sp),(%sp)
407 movel 8(%sp),4(%sp)
408 subw #BUSY_SIZE,%sp
409 fsave (%sp)
410 fmovel %fpiar,BUSY_SIZE+EXC_EA-4(%sp)
411 frestore (%sp)
412 addw #BUSY_SIZE,%sp
413
414 g_easy:
415 movew #TRACE_VEC,EXC_VEC-4(%a7)
416 bral real_trace
417 |
418 | This is a work-around for hardware bug 1384.
419 |
420 bug1384:
421 link %a5,#0
422 fsave -(%sp)
423 cmpib #0x41,(%sp) | check for correct frame
424 beq frame_41
425 bgt nofix | if more advanced mask, do nada
426
427 frame_40:
428 tstb 1(%sp) | check to see if idle
429 bne notidle
430 idle40:
431 clrl (%sp) | get rid of old fsave frame
432 movel %d1,USER_D1(%a6) | save d1
433 movew #8,%d1 | place unimp frame instead
434 loop40: clrl -(%sp)
435 dbra %d1,loop40
436 movel USER_D1(%a6),%d1 | restore d1
437 movel #0x40280000,-(%sp)
438 frestore (%sp)+
439 unlk %a5
440 rts
441
442 frame_41:
443 tstb 1(%sp) | check to see if idle
444 bne notidle
445 idle41:
446 clrl (%sp) | get rid of old fsave frame
447 movel %d1,USER_D1(%a6) | save d1
448 movew #10,%d1 | place unimp frame instead
449 loop41: clrl -(%sp)
450 dbra %d1,loop41
451 movel USER_D1(%a6),%d1 | restore d1
452 movel #0x41300000,-(%sp)
453 frestore (%sp)+
454 unlk %a5
455 rts
456
457 notidle:
458 bclrb #etemp15_bit,-40(%a5)
459 frestore (%sp)+
460 unlk %a5
461 rts
462
463 nofix:
464 frestore (%sp)+
465 unlk %a5
466 rts
467
468 |end
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