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