1 |
2 | get_op.sa 3.6 5/19/92
3 |
4 | get_op.sa 3.5 4/26/91
5 |
6 | Description: This routine is called by the unsupported format/data
7 | type exception handler ('unsupp' - vector 55) and the unimplemented
8 | instruction exception handler ('unimp' - vector 11). 'get_op'
9 | determines the opclass (0, 2, or 3) and branches to the
10 | opclass handler routine. See 68881/2 User's Manual table 4-11
11 | for a description of the opclasses.
12 |
13 | For UNSUPPORTED data/format (exception vector 55) and for
14 | UNIMPLEMENTED instructions (exception vector 11) the following
15 | applies:
16 |
17 | - For unnormalized numbers (opclass 0, 2, or 3) the
18 | number(s) is normalized and the operand type tag is updated.
19 |
20 | - For a packed number (opclass 2) the number is unpacked and the
21 | operand type tag is updated.
22 |
23 | - For denormalized numbers (opclass 0 or 2) the number(s) is not
24 | changed but passed to the next module. The next module for
25 | unimp is do_func, the next module for unsupp is res_func.
26 |
27 | For UNSUPPORTED data/format (exception vector 55) only the
28 | following applies:
29 |
30 | - If there is a move out with a packed number (opclass 3) the
31 | number is packed and written to user memory. For the other
32 | opclasses the number(s) are written back to the fsave stack
33 | and the instruction is then restored back into the '040. The
34 | '040 is then able to complete the instruction.
35 |
36 | For example:
37 | fadd.x fpm,fpn where the fpm contains an unnormalized number.
38 | The '040 takes an unsupported data trap and gets to this
39 | routine. The number is normalized, put back on the stack and
40 | then an frestore is done to restore the instruction back into
41 | the '040. The '040 then re-executes the fadd.x fpm,fpn with
42 | a normalized number in the source and the instruction is
43 | successful.
44 |
45 | Next consider if in the process of normalizing the un-
46 | normalized number it becomes a denormalized number. The
47 | routine which converts the unnorm to a norm (called mk_norm)
48 | detects this and tags the number as a denorm. The routine
49 | res_func sees the denorm tag and converts the denorm to a
50 | norm. The instruction is then restored back into the '040
51 | which re_executes the instruction.
52 |
53 |
54 | Copyright (C) Motorola, Inc. 1990
55 | All Rights Reserved
56 |
57 | For details on the license for this file, please see the
58 | file, README, in this same directory.
59
60 GET_OP: |idnt 2,1 | Motorola 040 Floating Point Software Package
61
62 |section 8
63
64 #include "fpsp.h"
65
66 .global PIRN,PIRZRM,PIRP
67 .global SMALRN,SMALRZRM,SMALRP
68 .global BIGRN,BIGRZRM,BIGRP
69
70 PIRN:
71 .long 0x40000000,0xc90fdaa2,0x2168c235 |pi
72 PIRZRM:
73 .long 0x40000000,0xc90fdaa2,0x2168c234 |pi
74 PIRP:
75 .long 0x40000000,0xc90fdaa2,0x2168c235 |pi
76
77 |round to nearest
78 SMALRN:
79 .long 0x3ffd0000,0x9a209a84,0xfbcff798 |log10(2)
80 .long 0x40000000,0xadf85458,0xa2bb4a9a |e
81 .long 0x3fff0000,0xb8aa3b29,0x5c17f0bc |log2(e)
82 .long 0x3ffd0000,0xde5bd8a9,0x37287195 |log10(e)
83 .long 0x00000000,0x00000000,0x00000000 |0.0
84 | round to zero;round to negative infinity
85 SMALRZRM:
86 .long 0x3ffd0000,0x9a209a84,0xfbcff798 |log10(2)
87 .long 0x40000000,0xadf85458,0xa2bb4a9a |e
88 .long 0x3fff0000,0xb8aa3b29,0x5c17f0bb |log2(e)
89 .long 0x3ffd0000,0xde5bd8a9,0x37287195 |log10(e)
90 .long 0x00000000,0x00000000,0x00000000 |0.0
91 | round to positive infinity
92 SMALRP:
93 .long 0x3ffd0000,0x9a209a84,0xfbcff799 |log10(2)
94 .long 0x40000000,0xadf85458,0xa2bb4a9b |e
95 .long 0x3fff0000,0xb8aa3b29,0x5c17f0bc |log2(e)
96 .long 0x3ffd0000,0xde5bd8a9,0x37287195 |log10(e)
97 .long 0x00000000,0x00000000,0x00000000 |0.0
98
99 |round to nearest
100 BIGRN:
101 .long 0x3ffe0000,0xb17217f7,0xd1cf79ac |ln(2)
102 .long 0x40000000,0x935d8ddd,0xaaa8ac17 |ln(10)
103 .long 0x3fff0000,0x80000000,0x00000000 |10 ^ 0
104
105 .global PTENRN
106 PTENRN:
107 .long 0x40020000,0xA0000000,0x00000000 |10 ^ 1
108 .long 0x40050000,0xC8000000,0x00000000 |10 ^ 2
109 .long 0x400C0000,0x9C400000,0x00000000 |10 ^ 4
110 .long 0x40190000,0xBEBC2000,0x00000000 |10 ^ 8
111 .long 0x40340000,0x8E1BC9BF,0x04000000 |10 ^ 16
112 .long 0x40690000,0x9DC5ADA8,0x2B70B59E |10 ^ 32
113 .long 0x40D30000,0xC2781F49,0xFFCFA6D5 |10 ^ 64
114 .long 0x41A80000,0x93BA47C9,0x80E98CE0 |10 ^ 128
115 .long 0x43510000,0xAA7EEBFB,0x9DF9DE8E |10 ^ 256
116 .long 0x46A30000,0xE319A0AE,0xA60E91C7 |10 ^ 512
117 .long 0x4D480000,0xC9767586,0x81750C17 |10 ^ 1024
118 .long 0x5A920000,0x9E8B3B5D,0xC53D5DE5 |10 ^ 2048
119 .long 0x75250000,0xC4605202,0x8A20979B |10 ^ 4096
120 |round to minus infinity
121 BIGRZRM:
122 .long 0x3ffe0000,0xb17217f7,0xd1cf79ab |ln(2)
123 .long 0x40000000,0x935d8ddd,0xaaa8ac16 |ln(10)
124 .long 0x3fff0000,0x80000000,0x00000000 |10 ^ 0
125
126 .global PTENRM
127 PTENRM:
128 .long 0x40020000,0xA0000000,0x00000000 |10 ^ 1
129 .long 0x40050000,0xC8000000,0x00000000 |10 ^ 2
130 .long 0x400C0000,0x9C400000,0x00000000 |10 ^ 4
131 .long 0x40190000,0xBEBC2000,0x00000000 |10 ^ 8
132 .long 0x40340000,0x8E1BC9BF,0x04000000 |10 ^ 16
133 .long 0x40690000,0x9DC5ADA8,0x2B70B59D |10 ^ 32
134 .long 0x40D30000,0xC2781F49,0xFFCFA6D5 |10 ^ 64
135 .long 0x41A80000,0x93BA47C9,0x80E98CDF |10 ^ 128
136 .long 0x43510000,0xAA7EEBFB,0x9DF9DE8D |10 ^ 256
137 .long 0x46A30000,0xE319A0AE,0xA60E91C6 |10 ^ 512
138 .long 0x4D480000,0xC9767586,0x81750C17 |10 ^ 1024
139 .long 0x5A920000,0x9E8B3B5D,0xC53D5DE5 |10 ^ 2048
140 .long 0x75250000,0xC4605202,0x8A20979A |10 ^ 4096
141 |round to positive infinity
142 BIGRP:
143 .long 0x3ffe0000,0xb17217f7,0xd1cf79ac |ln(2)
144 .long 0x40000000,0x935d8ddd,0xaaa8ac17 |ln(10)
145 .long 0x3fff0000,0x80000000,0x00000000 |10 ^ 0
146
147 .global PTENRP
148 PTENRP:
149 .long 0x40020000,0xA0000000,0x00000000 |10 ^ 1
150 .long 0x40050000,0xC8000000,0x00000000 |10 ^ 2
151 .long 0x400C0000,0x9C400000,0x00000000 |10 ^ 4
152 .long 0x40190000,0xBEBC2000,0x00000000 |10 ^ 8
153 .long 0x40340000,0x8E1BC9BF,0x04000000 |10 ^ 16
154 .long 0x40690000,0x9DC5ADA8,0x2B70B59E |10 ^ 32
155 .long 0x40D30000,0xC2781F49,0xFFCFA6D6 |10 ^ 64
156 .long 0x41A80000,0x93BA47C9,0x80E98CE0 |10 ^ 128
157 .long 0x43510000,0xAA7EEBFB,0x9DF9DE8E |10 ^ 256
158 .long 0x46A30000,0xE319A0AE,0xA60E91C7 |10 ^ 512
159 .long 0x4D480000,0xC9767586,0x81750C18 |10 ^ 1024
160 .long 0x5A920000,0x9E8B3B5D,0xC53D5DE6 |10 ^ 2048
161 .long 0x75250000,0xC4605202,0x8A20979B |10 ^ 4096
162
163 |xref nrm_zero
164 |xref decbin
165 |xref round
166
167 .global get_op
168 .global uns_getop
169 .global uni_getop
170 get_op:
171 clrb DY_MO_FLG(%a6)
172 tstb UFLG_TMP(%a6) |test flag for unsupp/unimp state
173 beq uni_getop
174
175 uns_getop:
176 btstb #direction_bit,CMDREG1B(%a6)
177 bne opclass3 |branch if a fmove out (any kind)
178 btstb #6,CMDREG1B(%a6)
179 beqs uns_notpacked
180
181 bfextu CMDREG1B(%a6){#3:#3},%d0
182 cmpb #3,%d0
183 beq pack_source |check for a packed src op, branch if so
184 uns_notpacked:
185 bsr chk_dy_mo |set the dyadic/monadic flag
186 tstb DY_MO_FLG(%a6)
187 beqs src_op_ck |if monadic, go check src op
188 | ;else, check dst op (fall through)
189
190 btstb #7,DTAG(%a6)
191 beqs src_op_ck |if dst op is norm, check src op
192 bras dst_ex_dnrm |else, handle destination unnorm/dnrm
193
194 uni_getop:
195 bfextu CMDREG1B(%a6){#0:#6},%d0 |get opclass and src fields
196 cmpil #0x17,%d0 |if op class and size fields are $17,
197 | ;it is FMOVECR; if not, continue
198 |
199 | If the instruction is fmovecr, exit get_op. It is handled
200 | in do_func and smovecr.sa.
201 |
202 bne not_fmovecr |handle fmovecr as an unimplemented inst
203 rts
204
205 not_fmovecr:
206 btstb #E1,E_BYTE(%a6) |if set, there is a packed operand
207 bne pack_source |check for packed src op, branch if so
208
209 | The following lines of are coded to optimize on normalized operands
210 moveb STAG(%a6),%d0
211 orb DTAG(%a6),%d0 |check if either of STAG/DTAG msb set
212 bmis dest_op_ck |if so, some op needs to be fixed
213 rts
214
215 dest_op_ck:
216 btstb #7,DTAG(%a6) |check for unsupported data types in
217 beqs src_op_ck |the destination, if not, check src op
218 bsr chk_dy_mo |set dyadic/monadic flag
219 tstb DY_MO_FLG(%a6) |
220 beqs src_op_ck |if monadic, check src op
221 |
222 | At this point, destination has an extended denorm or unnorm.
223 |
224 dst_ex_dnrm:
225 movew FPTEMP_EX(%a6),%d0 |get destination exponent
226 andiw #0x7fff,%d0 |mask sign, check if exp = 0000
227 beqs src_op_ck |if denorm then check source op.
228 | ;denorms are taken care of in res_func
229 | ;(unsupp) or do_func (unimp)
230 | ;else unnorm fall through
231 leal FPTEMP(%a6),%a0 |point a0 to dop - used in mk_norm
232 bsr mk_norm |go normalize - mk_norm returns:
233 | ;L_SCR1{7:5} = operand tag
234 | ; (000 = norm, 100 = denorm)
235 | ;L_SCR1{4} = fpte15 or ete15
236 | ; 0 = exp > $3fff
237 | ; 1 = exp <= $3fff
238 | ;and puts the normalized num back
239 | ;on the fsave stack
240 |
241 moveb L_SCR1(%a6),DTAG(%a6) |write the new tag & fpte15
242 | ;to the fsave stack and fall
243 | ;through to check source operand
244 |
245 src_op_ck:
246 btstb #7,STAG(%a6)
247 beq end_getop |check for unsupported data types on the
248 | ;source operand
249 btstb #5,STAG(%a6)
250 bnes src_sd_dnrm |if bit 5 set, handle sgl/dbl denorms
251 |
252 | At this point only unnorms or extended denorms are possible.
253 |
254 src_ex_dnrm:
255 movew ETEMP_EX(%a6),%d0 |get source exponent
256 andiw #0x7fff,%d0 |mask sign, check if exp = 0000
257 beq end_getop |if denorm then exit, denorms are
258 | ;handled in do_func
259 leal ETEMP(%a6),%a0 |point a0 to sop - used in mk_norm
260 bsr mk_norm |go normalize - mk_norm returns:
261 | ;L_SCR1{7:5} = operand tag
262 | ; (000 = norm, 100 = denorm)
263 | ;L_SCR1{4} = fpte15 or ete15
264 | ; 0 = exp > $3fff
265 | ; 1 = exp <= $3fff
266 | ;and puts the normalized num back
267 | ;on the fsave stack
268 |
269 moveb L_SCR1(%a6),STAG(%a6) |write the new tag & ete15
270 rts |end_getop
271
272 |
273 | At this point, only single or double denorms are possible.
274 | If the inst is not fmove, normalize the source. If it is,
275 | do nothing to the input.
276 |
277 src_sd_dnrm:
278 btstb #4,CMDREG1B(%a6) |differentiate between sgl/dbl denorm
279 bnes is_double
280 is_single:
281 movew #0x3f81,%d1 |write bias for sgl denorm
282 bras common |goto the common code
283 is_double:
284 movew #0x3c01,%d1 |write the bias for a dbl denorm
285 common:
286 btstb #sign_bit,ETEMP_EX(%a6) |grab sign bit of mantissa
287 beqs pos
288 bset #15,%d1 |set sign bit because it is negative
289 pos:
290 movew %d1,ETEMP_EX(%a6)
291 | ;put exponent on stack
292
293 movew CMDREG1B(%a6),%d1
294 andw #0xe3ff,%d1 |clear out source specifier
295 orw #0x0800,%d1 |set source specifier to extended prec
296 movew %d1,CMDREG1B(%a6) |write back to the command word in stack
297 | ;this is needed to fix unsupp data stack
298 leal ETEMP(%a6),%a0 |point a0 to sop
299
300 bsr mk_norm |convert sgl/dbl denorm to norm
301 moveb L_SCR1(%a6),STAG(%a6) |put tag into source tag reg - d0
302 rts |end_getop
303 |
304 | At this point, the source is definitely packed, whether
305 | instruction is dyadic or monadic is still unknown
306 |
307 pack_source:
308 movel FPTEMP_LO(%a6),ETEMP(%a6) |write ms part of packed
309 | ;number to etemp slot
310 bsr chk_dy_mo |set dyadic/monadic flag
311 bsr unpack
312
313 tstb DY_MO_FLG(%a6)
314 beqs end_getop |if monadic, exit
315 | ;else, fix FPTEMP
316 pack_dya:
317 bfextu CMDREG1B(%a6){#6:#3},%d0 |extract dest fp reg
318 movel #7,%d1
319 subl %d0,%d1
320 clrl %d0
321 bsetl %d1,%d0 |set up d0 as a dynamic register mask
322 fmovemx %d0,FPTEMP(%a6) |write to FPTEMP
323
324 btstb #7,DTAG(%a6) |check dest tag for unnorm or denorm
325 bne dst_ex_dnrm |else, handle the unnorm or ext denorm
326 |
327 | Dest is not denormalized. Check for norm, and set fpte15
328 | accordingly.
329 |
330 moveb DTAG(%a6),%d0
331 andib #0xf0,%d0 |strip to only dtag:fpte15
332 tstb %d0 |check for normalized value
333 bnes end_getop |if inf/nan/zero leave get_op
334 movew FPTEMP_EX(%a6),%d0
335 andiw #0x7fff,%d0
336 cmpiw #0x3fff,%d0 |check if fpte15 needs setting
337 bges end_getop |if >= $3fff, leave fpte15=0
338 orb #0x10,DTAG(%a6)
339 bras end_getop
340
341 |
342 | At this point, it is either an fmoveout packed, unnorm or denorm
343 |
344 opclass3:
345 clrb DY_MO_FLG(%a6) |set dyadic/monadic flag to monadic
346 bfextu CMDREG1B(%a6){#4:#2},%d0
347 cmpib #3,%d0
348 bne src_ex_dnrm |if not equal, must be unnorm or denorm
349 | ;else it is a packed move out
350 | ;exit
351 end_getop:
352 rts
353
354 |
355 | Sets the DY_MO_FLG correctly. This is used only on if it is an
356 | unsupported data type exception. Set if dyadic.
357 |
358 chk_dy_mo:
359 movew CMDREG1B(%a6),%d0
360 btstl #5,%d0 |testing extension command word
361 beqs set_mon |if bit 5 = 0 then monadic
362 btstl #4,%d0 |know that bit 5 = 1
363 beqs set_dya |if bit 4 = 0 then dyadic
364 andiw #0x007f,%d0 |get rid of all but extension bits {6:0}
365 cmpiw #0x0038,%d0 |if extension = $38 then fcmp (dyadic)
366 bnes set_mon
367 set_dya:
368 st DY_MO_FLG(%a6) |set the inst flag type to dyadic
369 rts
370 set_mon:
371 clrb DY_MO_FLG(%a6) |set the inst flag type to monadic
372 rts
373 |
374 | MK_NORM
375 |
376 | Normalizes unnormalized numbers, sets tag to norm or denorm, sets unfl
377 | exception if denorm.
378 |
379 | CASE opclass 0x0 unsupp
380 | mk_norm till msb set
381 | set tag = norm
382 |
383 | CASE opclass 0x0 unimp
384 | mk_norm till msb set or exp = 0
385 | if integer bit = 0
386 | tag = denorm
387 | else
388 | tag = norm
389 |
390 | CASE opclass 011 unsupp
391 | mk_norm till msb set or exp = 0
392 | if integer bit = 0
393 | tag = denorm
394 | set unfl_nmcexe = 1
395 | else
396 | tag = norm
397 |
398 | if exp <= $3fff
399 | set ete15 or fpte15 = 1
400 | else set ete15 or fpte15 = 0
401
402 | input:
403 | a0 = points to operand to be normalized
404 | output:
405 | L_SCR1{7:5} = operand tag (000 = norm, 100 = denorm)
406 | L_SCR1{4} = fpte15 or ete15 (0 = exp > $3fff, 1 = exp <=$3fff)
407 | the normalized operand is placed back on the fsave stack
408 mk_norm:
409 clrl L_SCR1(%a6)
410 bclrb #sign_bit,LOCAL_EX(%a0)
411 sne LOCAL_SGN(%a0) |transform into internal extended format
412
413 cmpib #0x2c,1+EXC_VEC(%a6) |check if unimp
414 bnes uns_data |branch if unsupp
415 bsr uni_inst |call if unimp (opclass 0x0)
416 bras reload
417 uns_data:
418 btstb #direction_bit,CMDREG1B(%a6) |check transfer direction
419 bnes bit_set |branch if set (opclass 011)
420 bsr uns_opx |call if opclass 0x0
421 bras reload
422 bit_set:
423 bsr uns_op3 |opclass 011
424 reload:
425 cmpw #0x3fff,LOCAL_EX(%a0) |if exp > $3fff
426 bgts end_mk | fpte15/ete15 already set to 0
427 bsetb #4,L_SCR1(%a6) |else set fpte15/ete15 to 1
428 | ;calling routine actually sets the
429 | ;value on the stack (along with the
430 | ;tag), since this routine doesn't
431 | ;know if it should set ete15 or fpte15
432 | ;ie, it doesn't know if this is the
433 | ;src op or dest op.
434 end_mk:
435 bfclr LOCAL_SGN(%a0){#0:#8}
436 beqs end_mk_pos
437 bsetb #sign_bit,LOCAL_EX(%a0) |convert back to IEEE format
438 end_mk_pos:
439 rts
440 |
441 | CASE opclass 011 unsupp
442 |
443 uns_op3:
444 bsr nrm_zero |normalize till msb = 1 or exp = zero
445 btstb #7,LOCAL_HI(%a0) |if msb = 1
446 bnes no_unfl |then branch
447 set_unfl:
448 orw #dnrm_tag,L_SCR1(%a6) |set denorm tag
449 bsetb #unfl_bit,FPSR_EXCEPT(%a6) |set unfl exception bit
450 no_unfl:
451 rts
452 |
453 | CASE opclass 0x0 unsupp
454 |
455 uns_opx:
456 bsr nrm_zero |normalize the number
457 btstb #7,LOCAL_HI(%a0) |check if integer bit (j-bit) is set
458 beqs uns_den |if clear then now have a denorm
459 uns_nrm:
460 orb #norm_tag,L_SCR1(%a6) |set tag to norm
461 rts
462 uns_den:
463 orb #dnrm_tag,L_SCR1(%a6) |set tag to denorm
464 rts
465 |
466 | CASE opclass 0x0 unimp
467 |
468 uni_inst:
469 bsr nrm_zero
470 btstb #7,LOCAL_HI(%a0) |check if integer bit (j-bit) is set
471 beqs uni_den |if clear then now have a denorm
472 uni_nrm:
473 orb #norm_tag,L_SCR1(%a6) |set tag to norm
474 rts
475 uni_den:
476 orb #dnrm_tag,L_SCR1(%a6) |set tag to denorm
477 rts
478
479 |
480 | Decimal to binary conversion
481 |
482 | Special cases of inf and NaNs are completed outside of decbin.
483 | If the input is an snan, the snan bit is not set.
484 |
485 | input:
486 | ETEMP(a6) - points to packed decimal string in memory
487 | output:
488 | fp0 - contains packed string converted to extended precision
489 | ETEMP - same as fp0
490 unpack:
491 movew CMDREG1B(%a6),%d0 |examine command word, looking for fmove's
492 andw #0x3b,%d0
493 beq move_unpack |special handling for fmove: must set FPSR_CC
494
495 movew ETEMP(%a6),%d0 |get word with inf information
496 bfextu %d0{#20:#12},%d1 |get exponent into d1
497 cmpiw #0x0fff,%d1 |test for inf or NaN
498 bnes try_zero |if not equal, it is not special
499 bfextu %d0{#17:#3},%d1 |get SE and y bits into d1
500 cmpiw #7,%d1 |SE and y bits must be on for special
501 bnes try_zero |if not on, it is not special
502 |input is of the special cases of inf and NaN
503 tstl ETEMP_HI(%a6) |check ms mantissa
504 bnes fix_nan |if non-zero, it is a NaN
505 tstl ETEMP_LO(%a6) |check ls mantissa
506 bnes fix_nan |if non-zero, it is a NaN
507 bra finish |special already on stack
508 fix_nan:
509 btstb #signan_bit,ETEMP_HI(%a6) |test for snan
510 bne finish
511 orl #snaniop_mask,USER_FPSR(%a6) |always set snan if it is so
512 bra finish
513 try_zero:
514 movew ETEMP_EX+2(%a6),%d0 |get word 4
515 andiw #0x000f,%d0 |clear all but last ni(y)bble
516 tstw %d0 |check for zero.
517 bne not_spec
518 tstl ETEMP_HI(%a6) |check words 3 and 2
519 bne not_spec
520 tstl ETEMP_LO(%a6) |check words 1 and 0
521 bne not_spec
522 tstl ETEMP(%a6) |test sign of the zero
523 bges pos_zero
524 movel #0x80000000,ETEMP(%a6) |write neg zero to etemp
525 clrl ETEMP_HI(%a6)
526 clrl ETEMP_LO(%a6)
527 bra finish
528 pos_zero:
529 clrl ETEMP(%a6)
530 clrl ETEMP_HI(%a6)
531 clrl ETEMP_LO(%a6)
532 bra finish
533
534 not_spec:
535 fmovemx %fp0-%fp1,-(%a7) |save fp0 - decbin returns in it
536 bsr decbin
537 fmovex %fp0,ETEMP(%a6) |put the unpacked sop in the fsave stack
538 fmovemx (%a7)+,%fp0-%fp1
539 fmovel #0,%FPSR |clr fpsr from decbin
540 bra finish
541
542 |
543 | Special handling for packed move in: Same results as all other
544 | packed cases, but we must set the FPSR condition codes properly.
545 |
546 move_unpack:
547 movew ETEMP(%a6),%d0 |get word with inf information
548 bfextu %d0{#20:#12},%d1 |get exponent into d1
549 cmpiw #0x0fff,%d1 |test for inf or NaN
550 bnes mtry_zero |if not equal, it is not special
551 bfextu %d0{#17:#3},%d1 |get SE and y bits into d1
552 cmpiw #7,%d1 |SE and y bits must be on for special
553 bnes mtry_zero |if not on, it is not special
554 |input is of the special cases of inf and NaN
555 tstl ETEMP_HI(%a6) |check ms mantissa
556 bnes mfix_nan |if non-zero, it is a NaN
557 tstl ETEMP_LO(%a6) |check ls mantissa
558 bnes mfix_nan |if non-zero, it is a NaN
559 |input is inf
560 orl #inf_mask,USER_FPSR(%a6) |set I bit
561 tstl ETEMP(%a6) |check sign
562 bge finish
563 orl #neg_mask,USER_FPSR(%a6) |set N bit
564 bra finish |special already on stack
565 mfix_nan:
566 orl #nan_mask,USER_FPSR(%a6) |set NaN bit
567 moveb #nan_tag,STAG(%a6) |set stag to NaN
568 btstb #signan_bit,ETEMP_HI(%a6) |test for snan
569 bnes mn_snan
570 orl #snaniop_mask,USER_FPSR(%a6) |set snan bit
571 btstb #snan_bit,FPCR_ENABLE(%a6) |test for snan enabled
572 bnes mn_snan
573 bsetb #signan_bit,ETEMP_HI(%a6) |force snans to qnans
574 mn_snan:
575 tstl ETEMP(%a6) |check for sign
576 bge finish |if clr, go on
577 orl #neg_mask,USER_FPSR(%a6) |set N bit
578 bra finish
579
580 mtry_zero:
581 movew ETEMP_EX+2(%a6),%d0 |get word 4
582 andiw #0x000f,%d0 |clear all but last ni(y)bble
583 tstw %d0 |check for zero.
584 bnes mnot_spec
585 tstl ETEMP_HI(%a6) |check words 3 and 2
586 bnes mnot_spec
587 tstl ETEMP_LO(%a6) |check words 1 and 0
588 bnes mnot_spec
589 tstl ETEMP(%a6) |test sign of the zero
590 bges mpos_zero
591 orl #neg_mask+z_mask,USER_FPSR(%a6) |set N and Z
592 movel #0x80000000,ETEMP(%a6) |write neg zero to etemp
593 clrl ETEMP_HI(%a6)
594 clrl ETEMP_LO(%a6)
595 bras finish
596 mpos_zero:
597 orl #z_mask,USER_FPSR(%a6) |set Z
598 clrl ETEMP(%a6)
599 clrl ETEMP_HI(%a6)
600 clrl ETEMP_LO(%a6)
601 bras finish
602
603 mnot_spec:
604 fmovemx %fp0-%fp1,-(%a7) |save fp0 ,fp1 - decbin returns in fp0
605 bsr decbin
606 fmovex %fp0,ETEMP(%a6)
607 | ;put the unpacked sop in the fsave stack
608 fmovemx (%a7)+,%fp0-%fp1
609
610 finish:
611 movew CMDREG1B(%a6),%d0 |get the command word
612 andw #0xfbff,%d0 |change the source specifier field to
613 | ;extended (was packed).
614 movew %d0,CMDREG1B(%a6) |write command word back to fsave stack
615 | ;we need to do this so the 040 will
616 | ;re-execute the inst. without taking
617 | ;another packed trap.
618
619 fix_stag:
620 |Converted result is now in etemp on fsave stack, now set the source
621 |tag (stag)
622 | if (ete =$7fff) then INF or NAN
623 | if (etemp = $x.0----0) then
624 | stag = INF
625 | else
626 | stag = NAN
627 | else
628 | if (ete = $0000) then
629 | stag = ZERO
630 | else
631 | stag = NORM
632 |
633 | Note also that the etemp_15 bit (just right of the stag) must
634 | be set accordingly.
635 |
636 movew ETEMP_EX(%a6),%d1
637 andiw #0x7fff,%d1 |strip sign
638 cmpw #0x7fff,%d1
639 bnes z_or_nrm
640 movel ETEMP_HI(%a6),%d1
641 bnes is_nan
642 movel ETEMP_LO(%a6),%d1
643 bnes is_nan
644 is_inf:
645 moveb #0x40,STAG(%a6)
646 movel #0x40,%d0
647 rts
648 is_nan:
649 moveb #0x60,STAG(%a6)
650 movel #0x60,%d0
651 rts
652 z_or_nrm:
653 tstw %d1
654 bnes is_nrm
655 is_zro:
656 | For a zero, set etemp_15
657 moveb #0x30,STAG(%a6)
658 movel #0x20,%d0
659 rts
660 is_nrm:
661 | For a norm, check if the exp <= $3fff; if so, set etemp_15
662 cmpiw #0x3fff,%d1
663 bles set_bit15
664 moveb #0,STAG(%a6)
665 bras end_is_nrm
666 set_bit15:
667 moveb #0x10,STAG(%a6)
668 end_is_nrm:
669 movel #0,%d0
670 end_fix:
671 rts
672
673 end_get:
674 rts
675 |end