1 | 2 | bindec.sa 3.4 1/3/91 3 | 4 | bindec 5 | 6 | Description: 7 | Converts an input in extended precision format 8 | to bcd format. 9 | 10 | Input: 11 | a0 points to the input extended precision value 12 | value in memory; d0 contains the k-factor sign-extended 13 | to 32-bits. The input may be either normalized, 14 | unnormalized, or denormalized. 15 | 16 | Output: result in the FP_SCR1 space on the stack. 17 | 18 | Saves and Modifies: D2-D7,A2,FP2 19 | 20 | Algorithm: 21 | 22 | A1. Set RM and size ext; Set SIGMA = sign of input. 23 | The k-factor is saved for use in d7. Clear the 24 | BINDEC_FLG for separating normalized/denormalized 25 | input. If input is unnormalized or denormalized, 26 | normalize it. 27 | 28 | A2. Set X = abs(input). 29 | 30 | A3. Compute ILOG. 31 | ILOG is the log base 10 of the input value. It is 32 | approximated by adding e + 0.f when the original 33 | value is viewed as 2^^e * 1.f in extended precision. 34 | This value is stored in d6. 35 | 36 | A4. Clr INEX bit. 37 | The operation in A3 above may have set INEX2. 38 | 39 | A5. Set ICTR = 0; 40 | ICTR is a flag used in A13. It must be set before the 41 | loop entry A6. 42 | 43 | A6. Calculate LEN. 44 | LEN is the number of digits to be displayed. The 45 | k-factor can dictate either the total number of digits, 46 | if it is a positive number, or the number of digits 47 | after the decimal point which are to be included as 48 | significant. See the 68882 manual for examples. 49 | If LEN is computed to be greater than 17, set OPERR in 50 | USER_FPSR. LEN is stored in d4. 51 | 52 | A7. Calculate SCALE. 53 | SCALE is equal to 10^ISCALE, where ISCALE is the number 54 | of decimal places needed to insure LEN integer digits 55 | in the output before conversion to bcd. LAMBDA is the 56 | sign of ISCALE, used in A9. Fp1 contains 57 | 10^^(abs(ISCALE)) using a rounding mode which is a 58 | function of the original rounding mode and the signs 59 | of ISCALE and X. A table is given in the code. 60 | 61 | A8. Clr INEX; Force RZ. 62 | The operation in A3 above may have set INEX2. 63 | RZ mode is forced for the scaling operation to insure 64 | only one rounding error. The grs bits are collected in 65 | the INEX flag for use in A10. 66 | 67 | A9. Scale X -> Y. 68 | The mantissa is scaled to the desired number of 69 | significant digits. The excess digits are collected 70 | in INEX2. 71 | 72 | A10. Or in INEX. 73 | If INEX is set, round error occurred. This is 74 | compensated for by 'or-ing' in the INEX2 flag to 75 | the lsb of Y. 76 | 77 | A11. Restore original FPCR; set size ext. 78 | Perform FINT operation in the user's rounding mode. 79 | Keep the size to extended. 80 | 81 | A12. Calculate YINT = FINT(Y) according to user's rounding 82 | mode. The FPSP routine sintd0 is used. The output 83 | is in fp0. 84 | 85 | A13. Check for LEN digits. 86 | If the int operation results in more than LEN digits, 87 | or less than LEN -1 digits, adjust ILOG and repeat from 88 | A6. This test occurs only on the first pass. If the 89 | result is exactly 10^LEN, decrement ILOG and divide 90 | the mantissa by 10. 91 | 92 | A14. Convert the mantissa to bcd. 93 | The binstr routine is used to convert the LEN digit 94 | mantissa to bcd in memory. The input to binstr is 95 | to be a fraction; i.e. (mantissa)/10^LEN and adjusted 96 | such that the decimal point is to the left of bit 63. 97 | The bcd digits are stored in the correct position in 98 | the final string area in memory. 99 | 100 | A15. Convert the exponent to bcd. 101 | As in A14 above, the exp is converted to bcd and the 102 | digits are stored in the final string. 103 | Test the length of the final exponent string. If the 104 | length is 4, set operr. 105 | 106 | A16. Write sign bits to final string. 107 | 108 | Implementation Notes: 109 | 110 | The registers are used as follows: 111 | 112 | d0: scratch; LEN input to binstr 113 | d1: scratch 114 | d2: upper 32-bits of mantissa for binstr 115 | d3: scratch;lower 32-bits of mantissa for binstr 116 | d4: LEN 117 | d5: LAMBDA/ICTR 118 | d6: ILOG 119 | d7: k-factor 120 | a0: ptr for original operand/final result 121 | a1: scratch pointer 122 | a2: pointer to FP_X; abs(original value) in ext 123 | fp0: scratch 124 | fp1: scratch 125 | fp2: scratch 126 | F_SCR1: 127 | F_SCR2: 128 | L_SCR1: 129 | L_SCR2: 130 131 | Copyright (C) Motorola, Inc. 1990 132 | All Rights Reserved 133 | 134 | For details on the license for this file, please see the 135 | file, README, in this same directory. 136 137 |BINDEC idnt 2,1 | Motorola 040 Floating Point Software Package 138 139 #include "fpsp.h" 140 141 |section 8 142 143 | Constants in extended precision 144 LOG2: .long 0x3FFD0000,0x9A209A84,0xFBCFF798,0x00000000 145 LOG2UP1: .long 0x3FFD0000,0x9A209A84,0xFBCFF799,0x00000000 146 147 | Constants in single precision 148 FONE: .long 0x3F800000,0x00000000,0x00000000,0x00000000 149 FTWO: .long 0x40000000,0x00000000,0x00000000,0x00000000 150 FTEN: .long 0x41200000,0x00000000,0x00000000,0x00000000 151 F4933: .long 0x459A2800,0x00000000,0x00000000,0x00000000 152 153 RBDTBL: .byte 0,0,0,0 154 .byte 3,3,2,2 155 .byte 3,2,2,3 156 .byte 2,3,3,2 157 158 |xref binstr 159 |xref sintdo 160 |xref ptenrn,ptenrm,ptenrp 161 162 .global bindec 163 .global sc_mul 164 bindec: 165 moveml %d2-%d7/%a2,-(%a7) 166 fmovemx %fp0-%fp2,-(%a7) 167 168 | A1. Set RM and size ext. Set SIGMA = sign input; 169 | The k-factor is saved for use in d7. Clear BINDEC_FLG for 170 | separating normalized/denormalized input. If the input 171 | is a denormalized number, set the BINDEC_FLG memory word 172 | to signal denorm. If the input is unnormalized, normalize 173 | the input and test for denormalized result. 174 | 175 fmovel #rm_mode,%FPCR |set RM and ext 176 movel (%a0),L_SCR2(%a6) |save exponent for sign check 177 movel %d0,%d7 |move k-factor to d7 178 clrb BINDEC_FLG(%a6) |clr norm/denorm flag 179 movew STAG(%a6),%d0 |get stag 180 andiw #0xe000,%d0 |isolate stag bits 181 beq A2_str |if zero, input is norm 182 | 183 | Normalize the denorm 184 | 185 un_de_norm: 186 movew (%a0),%d0 187 andiw #0x7fff,%d0 |strip sign of normalized exp 188 movel 4(%a0),%d1 189 movel 8(%a0),%d2 190 norm_loop: 191 subw #1,%d0 192 lsll #1,%d2 193 roxll #1,%d1 194 tstl %d1 195 bges norm_loop 196 | 197 | Test if the normalized input is denormalized 198 | 199 tstw %d0 200 bgts pos_exp |if greater than zero, it is a norm 201 st BINDEC_FLG(%a6) |set flag for denorm 202 pos_exp: 203 andiw #0x7fff,%d0 |strip sign of normalized exp 204 movew %d0,(%a0) 205 movel %d1,4(%a0) 206 movel %d2,8(%a0) 207 208 | A2. Set X = abs(input). 209 | 210 A2_str: 211 movel (%a0),FP_SCR2(%a6) | move input to work space 212 movel 4(%a0),FP_SCR2+4(%a6) | move input to work space 213 movel 8(%a0),FP_SCR2+8(%a6) | move input to work space 214 andil #0x7fffffff,FP_SCR2(%a6) |create abs(X) 215 216 | A3. Compute ILOG. 217 | ILOG is the log base 10 of the input value. It is approx- 218 | imated by adding e + 0.f when the original value is viewed 219 | as 2^^e * 1.f in extended precision. This value is stored 220 | in d6. 221 | 222 | Register usage: 223 | Input/Output 224 | d0: k-factor/exponent 225 | d2: x/x 226 | d3: x/x 227 | d4: x/x 228 | d5: x/x 229 | d6: x/ILOG 230 | d7: k-factor/Unchanged 231 | a0: ptr for original operand/final result 232 | a1: x/x 233 | a2: x/x 234 | fp0: x/float(ILOG) 235 | fp1: x/x 236 | fp2: x/x 237 | F_SCR1:x/x 238 | F_SCR2:Abs(X)/Abs(X) with $3fff exponent 239 | L_SCR1:x/x 240 | L_SCR2:first word of X packed/Unchanged 241 242 tstb BINDEC_FLG(%a6) |check for denorm 243 beqs A3_cont |if clr, continue with norm 244 movel #-4933,%d6 |force ILOG = -4933 245 bras A4_str 246 A3_cont: 247 movew FP_SCR2(%a6),%d0 |move exp to d0 248 movew #0x3fff,FP_SCR2(%a6) |replace exponent with 0x3fff 249 fmovex FP_SCR2(%a6),%fp0 |now fp0 has 1.f 250 subw #0x3fff,%d0 |strip off bias 251 faddw %d0,%fp0 |add in exp 252 fsubs FONE,%fp0 |subtract off 1.0 253 fbge pos_res |if pos, branch 254 fmulx LOG2UP1,%fp0 |if neg, mul by LOG2UP1 255 fmovel %fp0,%d6 |put ILOG in d6 as a lword 256 bras A4_str |go move out ILOG 257 pos_res: 258 fmulx LOG2,%fp0 |if pos, mul by LOG2 259 fmovel %fp0,%d6 |put ILOG in d6 as a lword 260 261 262 | A4. Clr INEX bit. 263 | The operation in A3 above may have set INEX2. 264 265 A4_str: 266 fmovel #0,%FPSR |zero all of fpsr - nothing needed 267 268 269 | A5. Set ICTR = 0; 270 | ICTR is a flag used in A13. It must be set before the 271 | loop entry A6. The lower word of d5 is used for ICTR. 272 273 clrw %d5 |clear ICTR 274 275 276 | A6. Calculate LEN. 277 | LEN is the number of digits to be displayed. The k-factor 278 | can dictate either the total number of digits, if it is 279 | a positive number, or the number of digits after the 280 | original decimal point which are to be included as 281 | significant. See the 68882 manual for examples. 282 | If LEN is computed to be greater than 17, set OPERR in 283 | USER_FPSR. LEN is stored in d4. 284 | 285 | Register usage: 286 | Input/Output 287 | d0: exponent/Unchanged 288 | d2: x/x/scratch 289 | d3: x/x 290 | d4: exc picture/LEN 291 | d5: ICTR/Unchanged 292 | d6: ILOG/Unchanged 293 | d7: k-factor/Unchanged 294 | a0: ptr for original operand/final result 295 | a1: x/x 296 | a2: x/x 297 | fp0: float(ILOG)/Unchanged 298 | fp1: x/x 299 | fp2: x/x 300 | F_SCR1:x/x 301 | F_SCR2:Abs(X) with $3fff exponent/Unchanged 302 | L_SCR1:x/x 303 | L_SCR2:first word of X packed/Unchanged 304 305 A6_str: 306 tstl %d7 |branch on sign of k 307 bles k_neg |if k <= 0, LEN = ILOG + 1 - k 308 movel %d7,%d4 |if k > 0, LEN = k 309 bras len_ck |skip to LEN check 310 k_neg: 311 movel %d6,%d4 |first load ILOG to d4 312 subl %d7,%d4 |subtract off k 313 addql #1,%d4 |add in the 1 314 len_ck: 315 tstl %d4 |LEN check: branch on sign of LEN 316 bles LEN_ng |if neg, set LEN = 1 317 cmpl #17,%d4 |test if LEN > 17 318 bles A7_str |if not, forget it 319 movel #17,%d4 |set max LEN = 17 320 tstl %d7 |if negative, never set OPERR 321 bles A7_str |if positive, continue 322 orl #opaop_mask,USER_FPSR(%a6) |set OPERR & AIOP in USER_FPSR 323 bras A7_str |finished here 324 LEN_ng: 325 moveql #1,%d4 |min LEN is 1 326 327 328 | A7. Calculate SCALE. 329 | SCALE is equal to 10^ISCALE, where ISCALE is the number 330 | of decimal places needed to insure LEN integer digits 331 | in the output before conversion to bcd. LAMBDA is the sign 332 | of ISCALE, used in A9. Fp1 contains 10^^(abs(ISCALE)) using 333 | the rounding mode as given in the following table (see 334 | Coonen, p. 7.23 as ref.; however, the SCALE variable is 335 | of opposite sign in bindec.sa from Coonen). 336 | 337 | Initial USE 338 | FPCR[6:5] LAMBDA SIGN(X) FPCR[6:5] 339 | ---------------------------------------------- 340 | RN 00 0 0 00/0 RN 341 | RN 00 0 1 00/0 RN 342 | RN 00 1 0 00/0 RN 343 | RN 00 1 1 00/0 RN 344 | RZ 01 0 0 11/3 RP 345 | RZ 01 0 1 11/3 RP 346 | RZ 01 1 0 10/2 RM 347 | RZ 01 1 1 10/2 RM 348 | RM 10 0 0 11/3 RP 349 | RM 10 0 1 10/2 RM 350 | RM 10 1 0 10/2 RM 351 | RM 10 1 1 11/3 RP 352 | RP 11 0 0 10/2 RM 353 | RP 11 0 1 11/3 RP 354 | RP 11 1 0 11/3 RP 355 | RP 11 1 1 10/2 RM 356 | 357 | Register usage: 358 | Input/Output 359 | d0: exponent/scratch - final is 0 360 | d2: x/0 or 24 for A9 361 | d3: x/scratch - offset ptr into PTENRM array 362 | d4: LEN/Unchanged 363 | d5: 0/ICTR:LAMBDA 364 | d6: ILOG/ILOG or k if ((k<=0)&(ILOG<k)) 365 | d7: k-factor/Unchanged 366 | a0: ptr for original operand/final result 367 | a1: x/ptr to PTENRM array 368 | a2: x/x 369 | fp0: float(ILOG)/Unchanged 370 | fp1: x/10^ISCALE 371 | fp2: x/x 372 | F_SCR1:x/x 373 | F_SCR2:Abs(X) with $3fff exponent/Unchanged 374 | L_SCR1:x/x 375 | L_SCR2:first word of X packed/Unchanged 376 377 A7_str: 378 tstl %d7 |test sign of k 379 bgts k_pos |if pos and > 0, skip this 380 cmpl %d6,%d7 |test k - ILOG 381 blts k_pos |if ILOG >= k, skip this 382 movel %d7,%d6 |if ((k<0) & (ILOG < k)) ILOG = k 383 k_pos: 384 movel %d6,%d0 |calc ILOG + 1 - LEN in d0 385 addql #1,%d0 |add the 1 386 subl %d4,%d0 |sub off LEN 387 swap %d5 |use upper word of d5 for LAMBDA 388 clrw %d5 |set it zero initially 389 clrw %d2 |set up d2 for very small case 390 tstl %d0 |test sign of ISCALE 391 bges iscale |if pos, skip next inst 392 addqw #1,%d5 |if neg, set LAMBDA true 393 cmpl #0xffffecd4,%d0 |test iscale <= -4908 394 bgts no_inf |if false, skip rest 395 addil #24,%d0 |add in 24 to iscale 396 movel #24,%d2 |put 24 in d2 for A9 397 no_inf: 398 negl %d0 |and take abs of ISCALE 399 iscale: 400 fmoves FONE,%fp1 |init fp1 to 1 401 bfextu USER_FPCR(%a6){#26:#2},%d1 |get initial rmode bits 402 lslw #1,%d1 |put them in bits 2:1 403 addw %d5,%d1 |add in LAMBDA 404 lslw #1,%d1 |put them in bits 3:1 405 tstl L_SCR2(%a6) |test sign of original x 406 bges x_pos |if pos, don't set bit 0 407 addql #1,%d1 |if neg, set bit 0 408 x_pos: 409 leal RBDTBL,%a2 |load rbdtbl base 410 moveb (%a2,%d1),%d3 |load d3 with new rmode 411 lsll #4,%d3 |put bits in proper position 412 fmovel %d3,%fpcr |load bits into fpu 413 lsrl #4,%d3 |put bits in proper position 414 tstb %d3 |decode new rmode for pten table 415 bnes not_rn |if zero, it is RN 416 leal PTENRN,%a1 |load a1 with RN table base 417 bras rmode |exit decode 418 not_rn: 419 lsrb #1,%d3 |get lsb in carry 420 bccs not_rp |if carry clear, it is RM 421 leal PTENRP,%a1 |load a1 with RP table base 422 bras rmode |exit decode 423 not_rp: 424 leal PTENRM,%a1 |load a1 with RM table base 425 rmode: 426 clrl %d3 |clr table index 427 e_loop: 428 lsrl #1,%d0 |shift next bit into carry 429 bccs e_next |if zero, skip the mul 430 fmulx (%a1,%d3),%fp1 |mul by 10**(d3_bit_no) 431 e_next: 432 addl #12,%d3 |inc d3 to next pwrten table entry 433 tstl %d0 |test if ISCALE is zero 434 bnes e_loop |if not, loop 435 436 437 | A8. Clr INEX; Force RZ. 438 | The operation in A3 above may have set INEX2. 439 | RZ mode is forced for the scaling operation to insure 440 | only one rounding error. The grs bits are collected in 441 | the INEX flag for use in A10. 442 | 443 | Register usage: 444 | Input/Output 445 446 fmovel #0,%FPSR |clr INEX 447 fmovel #rz_mode,%FPCR |set RZ rounding mode 448 449 450 | A9. Scale X -> Y. 451 | The mantissa is scaled to the desired number of significant 452 | digits. The excess digits are collected in INEX2. If mul, 453 | Check d2 for excess 10 exponential value. If not zero, 454 | the iscale value would have caused the pwrten calculation 455 | to overflow. Only a negative iscale can cause this, so 456 | multiply by 10^(d2), which is now only allowed to be 24, 457 | with a multiply by 10^8 and 10^16, which is exact since 458 | 10^24 is exact. If the input was denormalized, we must 459 | create a busy stack frame with the mul command and the 460 | two operands, and allow the fpu to complete the multiply. 461 | 462 | Register usage: 463 | Input/Output 464 | d0: FPCR with RZ mode/Unchanged 465 | d2: 0 or 24/unchanged 466 | d3: x/x 467 | d4: LEN/Unchanged 468 | d5: ICTR:LAMBDA 469 | d6: ILOG/Unchanged 470 | d7: k-factor/Unchanged 471 | a0: ptr for original operand/final result 472 | a1: ptr to PTENRM array/Unchanged 473 | a2: x/x 474 | fp0: float(ILOG)/X adjusted for SCALE (Y) 475 | fp1: 10^ISCALE/Unchanged 476 | fp2: x/x 477 | F_SCR1:x/x 478 | F_SCR2:Abs(X) with $3fff exponent/Unchanged 479 | L_SCR1:x/x 480 | L_SCR2:first word of X packed/Unchanged 481 482 A9_str: 483 fmovex (%a0),%fp0 |load X from memory 484 fabsx %fp0 |use abs(X) 485 tstw %d5 |LAMBDA is in lower word of d5 486 bne sc_mul |if neg (LAMBDA = 1), scale by mul 487 fdivx %fp1,%fp0 |calculate X / SCALE -> Y to fp0 488 bras A10_st |branch to A10 489 490 sc_mul: 491 tstb BINDEC_FLG(%a6) |check for denorm 492 beqs A9_norm |if norm, continue with mul 493 fmovemx %fp1-%fp1,-(%a7) |load ETEMP with 10^ISCALE 494 movel 8(%a0),-(%a7) |load FPTEMP with input arg 495 movel 4(%a0),-(%a7) 496 movel (%a0),-(%a7) 497 movel #18,%d3 |load count for busy stack 498 A9_loop: 499 clrl -(%a7) |clear lword on stack 500 dbf %d3,A9_loop 501 moveb VER_TMP(%a6),(%a7) |write current version number 502 moveb #BUSY_SIZE-4,1(%a7) |write current busy size 503 moveb #0x10,0x44(%a7) |set fcefpte[15] bit 504 movew #0x0023,0x40(%a7) |load cmdreg1b with mul command 505 moveb #0xfe,0x8(%a7) |load all 1s to cu savepc 506 frestore (%a7)+ |restore frame to fpu for completion 507 fmulx 36(%a1),%fp0 |multiply fp0 by 10^8 508 fmulx 48(%a1),%fp0 |multiply fp0 by 10^16 509 bras A10_st 510 A9_norm: 511 tstw %d2 |test for small exp case 512 beqs A9_con |if zero, continue as normal 513 fmulx 36(%a1),%fp0 |multiply fp0 by 10^8 514 fmulx 48(%a1),%fp0 |multiply fp0 by 10^16 515 A9_con: 516 fmulx %fp1,%fp0 |calculate X * SCALE -> Y to fp0 517 518 519 | A10. Or in INEX. 520 | If INEX is set, round error occurred. This is compensated 521 | for by 'or-ing' in the INEX2 flag to the lsb of Y. 522 | 523 | Register usage: 524 | Input/Output 525 | d0: FPCR with RZ mode/FPSR with INEX2 isolated 526 | d2: x/x 527 | d3: x/x 528 | d4: LEN/Unchanged 529 | d5: ICTR:LAMBDA 530 | d6: ILOG/Unchanged 531 | d7: k-factor/Unchanged 532 | a0: ptr for original operand/final result 533 | a1: ptr to PTENxx array/Unchanged 534 | a2: x/ptr to FP_SCR2(a6) 535 | fp0: Y/Y with lsb adjusted 536 | fp1: 10^ISCALE/Unchanged 537 | fp2: x/x 538 539 A10_st: 540 fmovel %FPSR,%d0 |get FPSR 541 fmovex %fp0,FP_SCR2(%a6) |move Y to memory 542 leal FP_SCR2(%a6),%a2 |load a2 with ptr to FP_SCR2 543 btstl #9,%d0 |check if INEX2 set 544 beqs A11_st |if clear, skip rest 545 oril #1,8(%a2) |or in 1 to lsb of mantissa 546 fmovex FP_SCR2(%a6),%fp0 |write adjusted Y back to fpu 547 548 549 | A11. Restore original FPCR; set size ext. 550 | Perform FINT operation in the user's rounding mode. Keep 551 | the size to extended. The sintdo entry point in the sint 552 | routine expects the FPCR value to be in USER_FPCR for 553 | mode and precision. The original FPCR is saved in L_SCR1. 554 555 A11_st: 556 movel USER_FPCR(%a6),L_SCR1(%a6) |save it for later 557 andil #0x00000030,USER_FPCR(%a6) |set size to ext, 558 | ;block exceptions 559 560 561 | A12. Calculate YINT = FINT(Y) according to user's rounding mode. 562 | The FPSP routine sintd0 is used. The output is in fp0. 563 | 564 | Register usage: 565 | Input/Output 566 | d0: FPSR with AINEX cleared/FPCR with size set to ext 567 | d2: x/x/scratch 568 | d3: x/x 569 | d4: LEN/Unchanged 570 | d5: ICTR:LAMBDA/Unchanged 571 | d6: ILOG/Unchanged 572 | d7: k-factor/Unchanged 573 | a0: ptr for original operand/src ptr for sintdo 574 | a1: ptr to PTENxx array/Unchanged 575 | a2: ptr to FP_SCR2(a6)/Unchanged 576 | a6: temp pointer to FP_SCR2(a6) - orig value saved and restored 577 | fp0: Y/YINT 578 | fp1: 10^ISCALE/Unchanged 579 | fp2: x/x 580 | F_SCR1:x/x 581 | F_SCR2:Y adjusted for inex/Y with original exponent 582 | L_SCR1:x/original USER_FPCR 583 | L_SCR2:first word of X packed/Unchanged 584 585 A12_st: 586 moveml %d0-%d1/%a0-%a1,-(%a7) |save regs used by sintd0 587 movel L_SCR1(%a6),-(%a7) 588 movel L_SCR2(%a6),-(%a7) 589 leal FP_SCR2(%a6),%a0 |a0 is ptr to F_SCR2(a6) 590 fmovex %fp0,(%a0) |move Y to memory at FP_SCR2(a6) 591 tstl L_SCR2(%a6) |test sign of original operand 592 bges do_fint |if pos, use Y 593 orl #0x80000000,(%a0) |if neg, use -Y 594 do_fint: 595 movel USER_FPSR(%a6),-(%a7) 596 bsr sintdo |sint routine returns int in fp0 597 moveb (%a7),USER_FPSR(%a6) 598 addl #4,%a7 599 movel (%a7)+,L_SCR2(%a6) 600 movel (%a7)+,L_SCR1(%a6) 601 moveml (%a7)+,%d0-%d1/%a0-%a1 |restore regs used by sint 602 movel L_SCR2(%a6),FP_SCR2(%a6) |restore original exponent 603 movel L_SCR1(%a6),USER_FPCR(%a6) |restore user's FPCR 604 605 606 | A13. Check for LEN digits. 607 | If the int operation results in more than LEN digits, 608 | or less than LEN -1 digits, adjust ILOG and repeat from 609 | A6. This test occurs only on the first pass. If the 610 | result is exactly 10^LEN, decrement ILOG and divide 611 | the mantissa by 10. The calculation of 10^LEN cannot 612 | be inexact, since all powers of ten up to 10^27 are exact 613 | in extended precision, so the use of a previous power-of-ten 614 | table will introduce no error. 615 | 616 | 617 | Register usage: 618 | Input/Output 619 | d0: FPCR with size set to ext/scratch final = 0 620 | d2: x/x 621 | d3: x/scratch final = x 622 | d4: LEN/LEN adjusted 623 | d5: ICTR:LAMBDA/LAMBDA:ICTR 624 | d6: ILOG/ILOG adjusted 625 | d7: k-factor/Unchanged 626 | a0: pointer into memory for packed bcd string formation 627 | a1: ptr to PTENxx array/Unchanged 628 | a2: ptr to FP_SCR2(a6)/Unchanged 629 | fp0: int portion of Y/abs(YINT) adjusted 630 | fp1: 10^ISCALE/Unchanged 631 | fp2: x/10^LEN 632 | F_SCR1:x/x 633 | F_SCR2:Y with original exponent/Unchanged 634 | L_SCR1:original USER_FPCR/Unchanged 635 | L_SCR2:first word of X packed/Unchanged 636 637 A13_st: 638 swap %d5 |put ICTR in lower word of d5 639 tstw %d5 |check if ICTR = 0 640 bne not_zr |if non-zero, go to second test 641 | 642 | Compute 10^(LEN-1) 643 | 644 fmoves FONE,%fp2 |init fp2 to 1.0 645 movel %d4,%d0 |put LEN in d0 646 subql #1,%d0 |d0 = LEN -1 647 clrl %d3 |clr table index 648 l_loop: 649 lsrl #1,%d0 |shift next bit into carry 650 bccs l_next |if zero, skip the mul 651 fmulx (%a1,%d3),%fp2 |mul by 10**(d3_bit_no) 652 l_next: 653 addl #12,%d3 |inc d3 to next pwrten table entry 654 tstl %d0 |test if LEN is zero 655 bnes l_loop |if not, loop 656 | 657 | 10^LEN-1 is computed for this test and A14. If the input was 658 | denormalized, check only the case in which YINT > 10^LEN. 659 | 660 tstb BINDEC_FLG(%a6) |check if input was norm 661 beqs A13_con |if norm, continue with checking 662 fabsx %fp0 |take abs of YINT 663 bra test_2 664 | 665 | Compare abs(YINT) to 10^(LEN-1) and 10^LEN 666 | 667 A13_con: 668 fabsx %fp0 |take abs of YINT 669 fcmpx %fp2,%fp0 |compare abs(YINT) with 10^(LEN-1) 670 fbge test_2 |if greater, do next test 671 subql #1,%d6 |subtract 1 from ILOG 672 movew #1,%d5 |set ICTR 673 fmovel #rm_mode,%FPCR |set rmode to RM 674 fmuls FTEN,%fp2 |compute 10^LEN 675 bra A6_str |return to A6 and recompute YINT 676 test_2: 677 fmuls FTEN,%fp2 |compute 10^LEN 678 fcmpx %fp2,%fp0 |compare abs(YINT) with 10^LEN 679 fblt A14_st |if less, all is ok, go to A14 680 fbgt fix_ex |if greater, fix and redo 681 fdivs FTEN,%fp0 |if equal, divide by 10 682 addql #1,%d6 | and inc ILOG 683 bras A14_st | and continue elsewhere 684 fix_ex: 685 addql #1,%d6 |increment ILOG by 1 686 movew #1,%d5 |set ICTR 687 fmovel #rm_mode,%FPCR |set rmode to RM 688 bra A6_str |return to A6 and recompute YINT 689 | 690 | Since ICTR <> 0, we have already been through one adjustment, 691 | and shouldn't have another; this is to check if abs(YINT) = 10^LEN 692 | 10^LEN is again computed using whatever table is in a1 since the 693 | value calculated cannot be inexact. 694 | 695 not_zr: 696 fmoves FONE,%fp2 |init fp2 to 1.0 697 movel %d4,%d0 |put LEN in d0 698 clrl %d3 |clr table index 699 z_loop: 700 lsrl #1,%d0 |shift next bit into carry 701 bccs z_next |if zero, skip the mul 702 fmulx (%a1,%d3),%fp2 |mul by 10**(d3_bit_no) 703 z_next: 704 addl #12,%d3 |inc d3 to next pwrten table entry 705 tstl %d0 |test if LEN is zero 706 bnes z_loop |if not, loop 707 fabsx %fp0 |get abs(YINT) 708 fcmpx %fp2,%fp0 |check if abs(YINT) = 10^LEN 709 fbne A14_st |if not, skip this 710 fdivs FTEN,%fp0 |divide abs(YINT) by 10 711 addql #1,%d6 |and inc ILOG by 1 712 addql #1,%d4 | and inc LEN 713 fmuls FTEN,%fp2 | if LEN++, the get 10^^LEN 714 715 716 | A14. Convert the mantissa to bcd. 717 | The binstr routine is used to convert the LEN digit 718 | mantissa to bcd in memory. The input to binstr is 719 | to be a fraction; i.e. (mantissa)/10^LEN and adjusted 720 | such that the decimal point is to the left of bit 63. 721 | The bcd digits are stored in the correct position in 722 | the final string area in memory. 723 | 724 | 725 | Register usage: 726 | Input/Output 727 | d0: x/LEN call to binstr - final is 0 728 | d1: x/0 729 | d2: x/ms 32-bits of mant of abs(YINT) 730 | d3: x/ls 32-bits of mant of abs(YINT) 731 | d4: LEN/Unchanged 732 | d5: ICTR:LAMBDA/LAMBDA:ICTR 733 | d6: ILOG 734 | d7: k-factor/Unchanged 735 | a0: pointer into memory for packed bcd string formation 736 | /ptr to first mantissa byte in result string 737 | a1: ptr to PTENxx array/Unchanged 738 | a2: ptr to FP_SCR2(a6)/Unchanged 739 | fp0: int portion of Y/abs(YINT) adjusted 740 | fp1: 10^ISCALE/Unchanged 741 | fp2: 10^LEN/Unchanged 742 | F_SCR1:x/Work area for final result 743 | F_SCR2:Y with original exponent/Unchanged 744 | L_SCR1:original USER_FPCR/Unchanged 745 | L_SCR2:first word of X packed/Unchanged 746 747 A14_st: 748 fmovel #rz_mode,%FPCR |force rz for conversion 749 fdivx %fp2,%fp0 |divide abs(YINT) by 10^LEN 750 leal FP_SCR1(%a6),%a0 751 fmovex %fp0,(%a0) |move abs(YINT)/10^LEN to memory 752 movel 4(%a0),%d2 |move 2nd word of FP_RES to d2 753 movel 8(%a0),%d3 |move 3rd word of FP_RES to d3 754 clrl 4(%a0) |zero word 2 of FP_RES 755 clrl 8(%a0) |zero word 3 of FP_RES 756 movel (%a0),%d0 |move exponent to d0 757 swap %d0 |put exponent in lower word 758 beqs no_sft |if zero, don't shift 759 subil #0x3ffd,%d0 |sub bias less 2 to make fract 760 tstl %d0 |check if > 1 761 bgts no_sft |if so, don't shift 762 negl %d0 |make exp positive 763 m_loop: 764 lsrl #1,%d2 |shift d2:d3 right, add 0s 765 roxrl #1,%d3 |the number of places 766 dbf %d0,m_loop |given in d0 767 no_sft: 768 tstl %d2 |check for mantissa of zero 769 bnes no_zr |if not, go on 770 tstl %d3 |continue zero check 771 beqs zer_m |if zero, go directly to binstr 772 no_zr: 773 clrl %d1 |put zero in d1 for addx 774 addil #0x00000080,%d3 |inc at bit 7 775 addxl %d1,%d2 |continue inc 776 andil #0xffffff80,%d3 |strip off lsb not used by 882 777 zer_m: 778 movel %d4,%d0 |put LEN in d0 for binstr call 779 addql #3,%a0 |a0 points to M16 byte in result 780 bsr binstr |call binstr to convert mant 781 782 783 | A15. Convert the exponent to bcd. 784 | As in A14 above, the exp is converted to bcd and the 785 | digits are stored in the final string. 786 | 787 | Digits are stored in L_SCR1(a6) on return from BINDEC as: 788 | 789 | 32 16 15 0 790 | ----------------------------------------- 791 | | 0 | e3 | e2 | e1 | e4 | X | X | X | 792 | ----------------------------------------- 793 | 794 | And are moved into their proper places in FP_SCR1. If digit e4 795 | is non-zero, OPERR is signaled. In all cases, all 4 digits are 796 | written as specified in the 881/882 manual for packed decimal. 797 | 798 | Register usage: 799 | Input/Output 800 | d0: x/LEN call to binstr - final is 0 801 | d1: x/scratch (0);shift count for final exponent packing 802 | d2: x/ms 32-bits of exp fraction/scratch 803 | d3: x/ls 32-bits of exp fraction 804 | d4: LEN/Unchanged 805 | d5: ICTR:LAMBDA/LAMBDA:ICTR 806 | d6: ILOG 807 | d7: k-factor/Unchanged 808 | a0: ptr to result string/ptr to L_SCR1(a6) 809 | a1: ptr to PTENxx array/Unchanged 810 | a2: ptr to FP_SCR2(a6)/Unchanged 811 | fp0: abs(YINT) adjusted/float(ILOG) 812 | fp1: 10^ISCALE/Unchanged 813 | fp2: 10^LEN/Unchanged 814 | F_SCR1:Work area for final result/BCD result 815 | F_SCR2:Y with original exponent/ILOG/10^4 816 | L_SCR1:original USER_FPCR/Exponent digits on return from binstr 817 | L_SCR2:first word of X packed/Unchanged 818 819 A15_st: 820 tstb BINDEC_FLG(%a6) |check for denorm 821 beqs not_denorm 822 ftstx %fp0 |test for zero 823 fbeq den_zero |if zero, use k-factor or 4933 824 fmovel %d6,%fp0 |float ILOG 825 fabsx %fp0 |get abs of ILOG 826 bras convrt 827 den_zero: 828 tstl %d7 |check sign of the k-factor 829 blts use_ilog |if negative, use ILOG 830 fmoves F4933,%fp0 |force exponent to 4933 831 bras convrt |do it 832 use_ilog: 833 fmovel %d6,%fp0 |float ILOG 834 fabsx %fp0 |get abs of ILOG 835 bras convrt 836 not_denorm: 837 ftstx %fp0 |test for zero 838 fbne not_zero |if zero, force exponent 839 fmoves FONE,%fp0 |force exponent to 1 840 bras convrt |do it 841 not_zero: 842 fmovel %d6,%fp0 |float ILOG 843 fabsx %fp0 |get abs of ILOG 844 convrt: 845 fdivx 24(%a1),%fp0 |compute ILOG/10^4 846 fmovex %fp0,FP_SCR2(%a6) |store fp0 in memory 847 movel 4(%a2),%d2 |move word 2 to d2 848 movel 8(%a2),%d3 |move word 3 to d3 849 movew (%a2),%d0 |move exp to d0 850 beqs x_loop_fin |if zero, skip the shift 851 subiw #0x3ffd,%d0 |subtract off bias 852 negw %d0 |make exp positive 853 x_loop: 854 lsrl #1,%d2 |shift d2:d3 right 855 roxrl #1,%d3 |the number of places 856 dbf %d0,x_loop |given in d0 857 x_loop_fin: 858 clrl %d1 |put zero in d1 for addx 859 addil #0x00000080,%d3 |inc at bit 6 860 addxl %d1,%d2 |continue inc 861 andil #0xffffff80,%d3 |strip off lsb not used by 882 862 movel #4,%d0 |put 4 in d0 for binstr call 863 leal L_SCR1(%a6),%a0 |a0 is ptr to L_SCR1 for exp digits 864 bsr binstr |call binstr to convert exp 865 movel L_SCR1(%a6),%d0 |load L_SCR1 lword to d0 866 movel #12,%d1 |use d1 for shift count 867 lsrl %d1,%d0 |shift d0 right by 12 868 bfins %d0,FP_SCR1(%a6){#4:#12} |put e3:e2:e1 in FP_SCR1 869 lsrl %d1,%d0 |shift d0 right by 12 870 bfins %d0,FP_SCR1(%a6){#16:#4} |put e4 in FP_SCR1 871 tstb %d0 |check if e4 is zero 872 beqs A16_st |if zero, skip rest 873 orl #opaop_mask,USER_FPSR(%a6) |set OPERR & AIOP in USER_FPSR 874 875 876 | A16. Write sign bits to final string. 877 | Sigma is bit 31 of initial value; RHO is bit 31 of d6 (ILOG). 878 | 879 | Register usage: 880 | Input/Output 881 | d0: x/scratch - final is x 882 | d2: x/x 883 | d3: x/x 884 | d4: LEN/Unchanged 885 | d5: ICTR:LAMBDA/LAMBDA:ICTR 886 | d6: ILOG/ILOG adjusted 887 | d7: k-factor/Unchanged 888 | a0: ptr to L_SCR1(a6)/Unchanged 889 | a1: ptr to PTENxx array/Unchanged 890 | a2: ptr to FP_SCR2(a6)/Unchanged 891 | fp0: float(ILOG)/Unchanged 892 | fp1: 10^ISCALE/Unchanged 893 | fp2: 10^LEN/Unchanged 894 | F_SCR1:BCD result with correct signs 895 | F_SCR2:ILOG/10^4 896 | L_SCR1:Exponent digits on return from binstr 897 | L_SCR2:first word of X packed/Unchanged 898 899 A16_st: 900 clrl %d0 |clr d0 for collection of signs 901 andib #0x0f,FP_SCR1(%a6) |clear first nibble of FP_SCR1 902 tstl L_SCR2(%a6) |check sign of original mantissa 903 bges mant_p |if pos, don't set SM 904 moveql #2,%d0 |move 2 in to d0 for SM 905 mant_p: 906 tstl %d6 |check sign of ILOG 907 bges wr_sgn |if pos, don't set SE 908 addql #1,%d0 |set bit 0 in d0 for SE 909 wr_sgn: 910 bfins %d0,FP_SCR1(%a6){#0:#2} |insert SM and SE into FP_SCR1 911 912 | Clean up and restore all registers used. 913 914 fmovel #0,%FPSR |clear possible inex2/ainex bits 915 fmovemx (%a7)+,%fp0-%fp2 916 moveml (%a7)+,%d2-%d7/%a2 917 rts 918 919 |end 920
