code / linux / torvalds / linux / 97eeb4d9d755605385fa329da9afa38729f3413c / . / arch / m68k / fpsp040 / bindec.S

| | |

| bindec.sa 3.4 1/3/91 | |

| | |

| bindec | |

| | |

| Description: | |

| Converts an input in extended precision format | |

| to bcd format. | |

| | |

| Input: | |

| a0 points to the input extended precision value | |

| value in memory; d0 contains the k-factor sign-extended | |

| to 32-bits. The input may be either normalized, | |

| unnormalized, or denormalized. | |

| | |

| Output: result in the FP_SCR1 space on the stack. | |

| | |

| Saves and Modifies: D2-D7,A2,FP2 | |

| | |

| Algorithm: | |

| | |

| A1. Set RM and size ext; Set SIGMA = sign of input. | |

| The k-factor is saved for use in d7. Clear the | |

| BINDEC_FLG for separating normalized/denormalized | |

| input. If input is unnormalized or denormalized, | |

| normalize it. | |

| | |

| A2. Set X = abs(input). | |

| | |

| A3. Compute ILOG. | |

| ILOG is the log base 10 of the input value. It is | |

| approximated by adding e + 0.f when the original | |

| value is viewed as 2^^e * 1.f in extended precision. | |

| This value is stored in d6. | |

| | |

| A4. Clr INEX bit. | |

| The operation in A3 above may have set INEX2. | |

| | |

| A5. Set ICTR = 0; | |

| ICTR is a flag used in A13. It must be set before the | |

| loop entry A6. | |

| | |

| A6. Calculate LEN. | |

| LEN is the number of digits to be displayed. The | |

| k-factor can dictate either the total number of digits, | |

| if it is a positive number, or the number of digits | |

| after the decimal point which are to be included as | |

| significant. See the 68882 manual for examples. | |

| If LEN is computed to be greater than 17, set OPERR in | |

| USER_FPSR. LEN is stored in d4. | |

| | |

| A7. Calculate SCALE. | |

| SCALE is equal to 10^ISCALE, where ISCALE is the number | |

| of decimal places needed to insure LEN integer digits | |

| in the output before conversion to bcd. LAMBDA is the | |

| sign of ISCALE, used in A9. Fp1 contains | |

| 10^^(abs(ISCALE)) using a rounding mode which is a | |

| function of the original rounding mode and the signs | |

| of ISCALE and X. A table is given in the code. | |

| | |

| A8. Clr INEX; Force RZ. | |

| The operation in A3 above may have set INEX2. | |

| RZ mode is forced for the scaling operation to insure | |

| only one rounding error. The grs bits are collected in | |

| the INEX flag for use in A10. | |

| | |

| A9. Scale X -> Y. | |

| The mantissa is scaled to the desired number of | |

| significant digits. The excess digits are collected | |

| in INEX2. | |

| | |

| A10. Or in INEX. | |

| If INEX is set, round error occurred. This is | |

| compensated for by 'or-ing' in the INEX2 flag to | |

| the lsb of Y. | |

| | |

| A11. Restore original FPCR; set size ext. | |

| Perform FINT operation in the user's rounding mode. | |

| Keep the size to extended. | |

| | |

| A12. Calculate YINT = FINT(Y) according to user's rounding | |

| mode. The FPSP routine sintd0 is used. The output | |

| is in fp0. | |

| | |

| A13. Check for LEN digits. | |

| If the int operation results in more than LEN digits, | |

| or less than LEN -1 digits, adjust ILOG and repeat from | |

| A6. This test occurs only on the first pass. If the | |

| result is exactly 10^LEN, decrement ILOG and divide | |

| the mantissa by 10. | |

| | |

| A14. Convert the mantissa to bcd. | |

| The binstr routine is used to convert the LEN digit | |

| mantissa to bcd in memory. The input to binstr is | |

| to be a fraction; i.e. (mantissa)/10^LEN and adjusted | |

| such that the decimal point is to the left of bit 63. | |

| The bcd digits are stored in the correct position in | |

| the final string area in memory. | |

| | |

| A15. Convert the exponent to bcd. | |

| As in A14 above, the exp is converted to bcd and the | |

| digits are stored in the final string. | |

| Test the length of the final exponent string. If the | |

| length is 4, set operr. | |

| | |

| A16. Write sign bits to final string. | |

| | |

| Implementation Notes: | |

| | |

| The registers are used as follows: | |

| | |

| d0: scratch; LEN input to binstr | |

| d1: scratch | |

| d2: upper 32-bits of mantissa for binstr | |

| d3: scratch;lower 32-bits of mantissa for binstr | |

| d4: LEN | |

| d5: LAMBDA/ICTR | |

| d6: ILOG | |

| d7: k-factor | |

| a0: ptr for original operand/final result | |

| a1: scratch pointer | |

| a2: pointer to FP_X; abs(original value) in ext | |

| fp0: scratch | |

| fp1: scratch | |

| fp2: scratch | |

| F_SCR1: | |

| F_SCR2: | |

| L_SCR1: | |

| L_SCR2: | |

| Copyright (C) Motorola, Inc. 1990 | |

| All Rights Reserved | |

| | |

| For details on the license for this file, please see the | |

| file, README, in this same directory. | |

|BINDEC idnt 2,1 | Motorola 040 Floating Point Software Package | |

#include "fpsp.h" | |

|section 8 | |

| Constants in extended precision | |

LOG2: .long 0x3FFD0000,0x9A209A84,0xFBCFF798,0x00000000 | |

LOG2UP1: .long 0x3FFD0000,0x9A209A84,0xFBCFF799,0x00000000 | |

| Constants in single precision | |

FONE: .long 0x3F800000,0x00000000,0x00000000,0x00000000 | |

FTWO: .long 0x40000000,0x00000000,0x00000000,0x00000000 | |

FTEN: .long 0x41200000,0x00000000,0x00000000,0x00000000 | |

F4933: .long 0x459A2800,0x00000000,0x00000000,0x00000000 | |

RBDTBL: .byte 0,0,0,0 | |

.byte 3,3,2,2 | |

.byte 3,2,2,3 | |

.byte 2,3,3,2 | |

|xref binstr | |

|xref sintdo | |

|xref ptenrn,ptenrm,ptenrp | |

.global bindec | |

.global sc_mul | |

bindec: | |

moveml %d2-%d7/%a2,-(%a7) | |

fmovemx %fp0-%fp2,-(%a7) | |

| A1. Set RM and size ext. Set SIGMA = sign input; | |

| The k-factor is saved for use in d7. Clear BINDEC_FLG for | |

| separating normalized/denormalized input. If the input | |

| is a denormalized number, set the BINDEC_FLG memory word | |

| to signal denorm. If the input is unnormalized, normalize | |

| the input and test for denormalized result. | |

| | |

fmovel #rm_mode,%FPCR |set RM and ext | |

movel (%a0),L_SCR2(%a6) |save exponent for sign check | |

movel %d0,%d7 |move k-factor to d7 | |

clrb BINDEC_FLG(%a6) |clr norm/denorm flag | |

movew STAG(%a6),%d0 |get stag | |

andiw #0xe000,%d0 |isolate stag bits | |

beq A2_str |if zero, input is norm | |

| | |

| Normalize the denorm | |

| | |

un_de_norm: | |

movew (%a0),%d0 | |

andiw #0x7fff,%d0 |strip sign of normalized exp | |

movel 4(%a0),%d1 | |

movel 8(%a0),%d2 | |

norm_loop: | |

subw #1,%d0 | |

lsll #1,%d2 | |

roxll #1,%d1 | |

tstl %d1 | |

bges norm_loop | |

| | |

| Test if the normalized input is denormalized | |

| | |

tstw %d0 | |

bgts pos_exp |if greater than zero, it is a norm | |

st BINDEC_FLG(%a6) |set flag for denorm | |

pos_exp: | |

andiw #0x7fff,%d0 |strip sign of normalized exp | |

movew %d0,(%a0) | |

movel %d1,4(%a0) | |

movel %d2,8(%a0) | |

| A2. Set X = abs(input). | |

| | |

A2_str: | |

movel (%a0),FP_SCR2(%a6) | move input to work space | |

movel 4(%a0),FP_SCR2+4(%a6) | move input to work space | |

movel 8(%a0),FP_SCR2+8(%a6) | move input to work space | |

andil #0x7fffffff,FP_SCR2(%a6) |create abs(X) | |

| A3. Compute ILOG. | |

| ILOG is the log base 10 of the input value. It is approx- | |

| imated by adding e + 0.f when the original value is viewed | |

| as 2^^e * 1.f in extended precision. This value is stored | |

| in d6. | |

| | |

| Register usage: | |

| Input/Output | |

| d0: k-factor/exponent | |

| d2: x/x | |

| d3: x/x | |

| d4: x/x | |

| d5: x/x | |

| d6: x/ILOG | |

| d7: k-factor/Unchanged | |

| a0: ptr for original operand/final result | |

| a1: x/x | |

| a2: x/x | |

| fp0: x/float(ILOG) | |

| fp1: x/x | |

| fp2: x/x | |

| F_SCR1:x/x | |

| F_SCR2:Abs(X)/Abs(X) with $3fff exponent | |

| L_SCR1:x/x | |

| L_SCR2:first word of X packed/Unchanged | |

tstb BINDEC_FLG(%a6) |check for denorm | |

beqs A3_cont |if clr, continue with norm | |

movel #-4933,%d6 |force ILOG = -4933 | |

bras A4_str | |

A3_cont: | |

movew FP_SCR2(%a6),%d0 |move exp to d0 | |

movew #0x3fff,FP_SCR2(%a6) |replace exponent with 0x3fff | |

fmovex FP_SCR2(%a6),%fp0 |now fp0 has 1.f | |

subw #0x3fff,%d0 |strip off bias | |

faddw %d0,%fp0 |add in exp | |

fsubs FONE,%fp0 |subtract off 1.0 | |

fbge pos_res |if pos, branch | |

fmulx LOG2UP1,%fp0 |if neg, mul by LOG2UP1 | |

fmovel %fp0,%d6 |put ILOG in d6 as a lword | |

bras A4_str |go move out ILOG | |

pos_res: | |

fmulx LOG2,%fp0 |if pos, mul by LOG2 | |

fmovel %fp0,%d6 |put ILOG in d6 as a lword | |

| A4. Clr INEX bit. | |

| The operation in A3 above may have set INEX2. | |

A4_str: | |

fmovel #0,%FPSR |zero all of fpsr - nothing needed | |

| A5. Set ICTR = 0; | |

| ICTR is a flag used in A13. It must be set before the | |

| loop entry A6. The lower word of d5 is used for ICTR. | |

clrw %d5 |clear ICTR | |

| A6. Calculate LEN. | |

| LEN is the number of digits to be displayed. The k-factor | |

| can dictate either the total number of digits, if it is | |

| a positive number, or the number of digits after the | |

| original decimal point which are to be included as | |

| significant. See the 68882 manual for examples. | |

| If LEN is computed to be greater than 17, set OPERR in | |

| USER_FPSR. LEN is stored in d4. | |

| | |

| Register usage: | |

| Input/Output | |

| d0: exponent/Unchanged | |

| d2: x/x/scratch | |

| d3: x/x | |

| d4: exc picture/LEN | |

| d5: ICTR/Unchanged | |

| d6: ILOG/Unchanged | |

| d7: k-factor/Unchanged | |

| a0: ptr for original operand/final result | |

| a1: x/x | |

| a2: x/x | |

| fp0: float(ILOG)/Unchanged | |

| fp1: x/x | |

| fp2: x/x | |

| F_SCR1:x/x | |

| F_SCR2:Abs(X) with $3fff exponent/Unchanged | |

| L_SCR1:x/x | |

| L_SCR2:first word of X packed/Unchanged | |

A6_str: | |

tstl %d7 |branch on sign of k | |

bles k_neg |if k <= 0, LEN = ILOG + 1 - k | |

movel %d7,%d4 |if k > 0, LEN = k | |

bras len_ck |skip to LEN check | |

k_neg: | |

movel %d6,%d4 |first load ILOG to d4 | |

subl %d7,%d4 |subtract off k | |

addql #1,%d4 |add in the 1 | |

len_ck: | |

tstl %d4 |LEN check: branch on sign of LEN | |

bles LEN_ng |if neg, set LEN = 1 | |

cmpl #17,%d4 |test if LEN > 17 | |

bles A7_str |if not, forget it | |

movel #17,%d4 |set max LEN = 17 | |

tstl %d7 |if negative, never set OPERR | |

bles A7_str |if positive, continue | |

orl #opaop_mask,USER_FPSR(%a6) |set OPERR & AIOP in USER_FPSR | |

bras A7_str |finished here | |

LEN_ng: | |

moveql #1,%d4 |min LEN is 1 | |

| A7. Calculate SCALE. | |

| SCALE is equal to 10^ISCALE, where ISCALE is the number | |

| of decimal places needed to insure LEN integer digits | |

| in the output before conversion to bcd. LAMBDA is the sign | |

| of ISCALE, used in A9. Fp1 contains 10^^(abs(ISCALE)) using | |

| the rounding mode as given in the following table (see | |

| Coonen, p. 7.23 as ref.; however, the SCALE variable is | |

| of opposite sign in bindec.sa from Coonen). | |

| | |

| Initial USE | |

| FPCR[6:5] LAMBDA SIGN(X) FPCR[6:5] | |

| ---------------------------------------------- | |

| RN 00 0 0 00/0 RN | |

| RN 00 0 1 00/0 RN | |

| RN 00 1 0 00/0 RN | |

| RN 00 1 1 00/0 RN | |

| RZ 01 0 0 11/3 RP | |

| RZ 01 0 1 11/3 RP | |

| RZ 01 1 0 10/2 RM | |

| RZ 01 1 1 10/2 RM | |

| RM 10 0 0 11/3 RP | |

| RM 10 0 1 10/2 RM | |

| RM 10 1 0 10/2 RM | |

| RM 10 1 1 11/3 RP | |

| RP 11 0 0 10/2 RM | |

| RP 11 0 1 11/3 RP | |

| RP 11 1 0 11/3 RP | |

| RP 11 1 1 10/2 RM | |

| | |

| Register usage: | |

| Input/Output | |

| d0: exponent/scratch - final is 0 | |

| d2: x/0 or 24 for A9 | |

| d3: x/scratch - offset ptr into PTENRM array | |

| d4: LEN/Unchanged | |

| d5: 0/ICTR:LAMBDA | |

| d6: ILOG/ILOG or k if ((k<=0)&(ILOG<k)) | |

| d7: k-factor/Unchanged | |

| a0: ptr for original operand/final result | |

| a1: x/ptr to PTENRM array | |

| a2: x/x | |

| fp0: float(ILOG)/Unchanged | |

| fp1: x/10^ISCALE | |

| fp2: x/x | |

| F_SCR1:x/x | |

| F_SCR2:Abs(X) with $3fff exponent/Unchanged | |

| L_SCR1:x/x | |

| L_SCR2:first word of X packed/Unchanged | |

A7_str: | |

tstl %d7 |test sign of k | |

bgts k_pos |if pos and > 0, skip this | |

cmpl %d6,%d7 |test k - ILOG | |

blts k_pos |if ILOG >= k, skip this | |

movel %d7,%d6 |if ((k<0) & (ILOG < k)) ILOG = k | |

k_pos: | |

movel %d6,%d0 |calc ILOG + 1 - LEN in d0 | |

addql #1,%d0 |add the 1 | |

subl %d4,%d0 |sub off LEN | |

swap %d5 |use upper word of d5 for LAMBDA | |

clrw %d5 |set it zero initially | |

clrw %d2 |set up d2 for very small case | |

tstl %d0 |test sign of ISCALE | |

bges iscale |if pos, skip next inst | |

addqw #1,%d5 |if neg, set LAMBDA true | |

cmpl #0xffffecd4,%d0 |test iscale <= -4908 | |

bgts no_inf |if false, skip rest | |

addil #24,%d0 |add in 24 to iscale | |

movel #24,%d2 |put 24 in d2 for A9 | |

no_inf: | |

negl %d0 |and take abs of ISCALE | |

iscale: | |

fmoves FONE,%fp1 |init fp1 to 1 | |

bfextu USER_FPCR(%a6){#26:#2},%d1 |get initial rmode bits | |

lslw #1,%d1 |put them in bits 2:1 | |

addw %d5,%d1 |add in LAMBDA | |

lslw #1,%d1 |put them in bits 3:1 | |

tstl L_SCR2(%a6) |test sign of original x | |

bges x_pos |if pos, don't set bit 0 | |

addql #1,%d1 |if neg, set bit 0 | |

x_pos: | |

leal RBDTBL,%a2 |load rbdtbl base | |

moveb (%a2,%d1),%d3 |load d3 with new rmode | |

lsll #4,%d3 |put bits in proper position | |

fmovel %d3,%fpcr |load bits into fpu | |

lsrl #4,%d3 |put bits in proper position | |

tstb %d3 |decode new rmode for pten table | |

bnes not_rn |if zero, it is RN | |

leal PTENRN,%a1 |load a1 with RN table base | |

bras rmode |exit decode | |

not_rn: | |

lsrb #1,%d3 |get lsb in carry | |

bccs not_rp |if carry clear, it is RM | |

leal PTENRP,%a1 |load a1 with RP table base | |

bras rmode |exit decode | |

not_rp: | |

leal PTENRM,%a1 |load a1 with RM table base | |

rmode: | |

clrl %d3 |clr table index | |

e_loop: | |

lsrl #1,%d0 |shift next bit into carry | |

bccs e_next |if zero, skip the mul | |

fmulx (%a1,%d3),%fp1 |mul by 10**(d3_bit_no) | |

e_next: | |

addl #12,%d3 |inc d3 to next pwrten table entry | |

tstl %d0 |test if ISCALE is zero | |

bnes e_loop |if not, loop | |

| A8. Clr INEX; Force RZ. | |

| The operation in A3 above may have set INEX2. | |

| RZ mode is forced for the scaling operation to insure | |

| only one rounding error. The grs bits are collected in | |

| the INEX flag for use in A10. | |

| | |

| Register usage: | |

| Input/Output | |

fmovel #0,%FPSR |clr INEX | |

fmovel #rz_mode,%FPCR |set RZ rounding mode | |

| A9. Scale X -> Y. | |

| The mantissa is scaled to the desired number of significant | |

| digits. The excess digits are collected in INEX2. If mul, | |

| Check d2 for excess 10 exponential value. If not zero, | |

| the iscale value would have caused the pwrten calculation | |

| to overflow. Only a negative iscale can cause this, so | |

| multiply by 10^(d2), which is now only allowed to be 24, | |

| with a multiply by 10^8 and 10^16, which is exact since | |

| 10^24 is exact. If the input was denormalized, we must | |

| create a busy stack frame with the mul command and the | |

| two operands, and allow the fpu to complete the multiply. | |

| | |

| Register usage: | |

| Input/Output | |

| d0: FPCR with RZ mode/Unchanged | |

| d2: 0 or 24/unchanged | |

| d3: x/x | |

| d4: LEN/Unchanged | |

| d5: ICTR:LAMBDA | |

| d6: ILOG/Unchanged | |

| d7: k-factor/Unchanged | |

| a0: ptr for original operand/final result | |

| a1: ptr to PTENRM array/Unchanged | |

| a2: x/x | |

| fp0: float(ILOG)/X adjusted for SCALE (Y) | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: x/x | |

| F_SCR1:x/x | |

| F_SCR2:Abs(X) with $3fff exponent/Unchanged | |

| L_SCR1:x/x | |

| L_SCR2:first word of X packed/Unchanged | |

A9_str: | |

fmovex (%a0),%fp0 |load X from memory | |

fabsx %fp0 |use abs(X) | |

tstw %d5 |LAMBDA is in lower word of d5 | |

bne sc_mul |if neg (LAMBDA = 1), scale by mul | |

fdivx %fp1,%fp0 |calculate X / SCALE -> Y to fp0 | |

bras A10_st |branch to A10 | |

sc_mul: | |

tstb BINDEC_FLG(%a6) |check for denorm | |

beqs A9_norm |if norm, continue with mul | |

fmovemx %fp1-%fp1,-(%a7) |load ETEMP with 10^ISCALE | |

movel 8(%a0),-(%a7) |load FPTEMP with input arg | |

movel 4(%a0),-(%a7) | |

movel (%a0),-(%a7) | |

movel #18,%d3 |load count for busy stack | |

A9_loop: | |

clrl -(%a7) |clear lword on stack | |

dbf %d3,A9_loop | |

moveb VER_TMP(%a6),(%a7) |write current version number | |

moveb #BUSY_SIZE-4,1(%a7) |write current busy size | |

moveb #0x10,0x44(%a7) |set fcefpte[15] bit | |

movew #0x0023,0x40(%a7) |load cmdreg1b with mul command | |

moveb #0xfe,0x8(%a7) |load all 1s to cu savepc | |

frestore (%a7)+ |restore frame to fpu for completion | |

fmulx 36(%a1),%fp0 |multiply fp0 by 10^8 | |

fmulx 48(%a1),%fp0 |multiply fp0 by 10^16 | |

bras A10_st | |

A9_norm: | |

tstw %d2 |test for small exp case | |

beqs A9_con |if zero, continue as normal | |

fmulx 36(%a1),%fp0 |multiply fp0 by 10^8 | |

fmulx 48(%a1),%fp0 |multiply fp0 by 10^16 | |

A9_con: | |

fmulx %fp1,%fp0 |calculate X * SCALE -> Y to fp0 | |

| A10. Or in INEX. | |

| If INEX is set, round error occurred. This is compensated | |

| for by 'or-ing' in the INEX2 flag to the lsb of Y. | |

| | |

| Register usage: | |

| Input/Output | |

| d0: FPCR with RZ mode/FPSR with INEX2 isolated | |

| d2: x/x | |

| d3: x/x | |

| d4: LEN/Unchanged | |

| d5: ICTR:LAMBDA | |

| d6: ILOG/Unchanged | |

| d7: k-factor/Unchanged | |

| a0: ptr for original operand/final result | |

| a1: ptr to PTENxx array/Unchanged | |

| a2: x/ptr to FP_SCR2(a6) | |

| fp0: Y/Y with lsb adjusted | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: x/x | |

A10_st: | |

fmovel %FPSR,%d0 |get FPSR | |

fmovex %fp0,FP_SCR2(%a6) |move Y to memory | |

leal FP_SCR2(%a6),%a2 |load a2 with ptr to FP_SCR2 | |

btstl #9,%d0 |check if INEX2 set | |

beqs A11_st |if clear, skip rest | |

oril #1,8(%a2) |or in 1 to lsb of mantissa | |

fmovex FP_SCR2(%a6),%fp0 |write adjusted Y back to fpu | |

| A11. Restore original FPCR; set size ext. | |

| Perform FINT operation in the user's rounding mode. Keep | |

| the size to extended. The sintdo entry point in the sint | |

| routine expects the FPCR value to be in USER_FPCR for | |

| mode and precision. The original FPCR is saved in L_SCR1. | |

A11_st: | |

movel USER_FPCR(%a6),L_SCR1(%a6) |save it for later | |

andil #0x00000030,USER_FPCR(%a6) |set size to ext, | |

| ;block exceptions | |

| A12. Calculate YINT = FINT(Y) according to user's rounding mode. | |

| The FPSP routine sintd0 is used. The output is in fp0. | |

| | |

| Register usage: | |

| Input/Output | |

| d0: FPSR with AINEX cleared/FPCR with size set to ext | |

| d2: x/x/scratch | |

| d3: x/x | |

| d4: LEN/Unchanged | |

| d5: ICTR:LAMBDA/Unchanged | |

| d6: ILOG/Unchanged | |

| d7: k-factor/Unchanged | |

| a0: ptr for original operand/src ptr for sintdo | |

| a1: ptr to PTENxx array/Unchanged | |

| a2: ptr to FP_SCR2(a6)/Unchanged | |

| a6: temp pointer to FP_SCR2(a6) - orig value saved and restored | |

| fp0: Y/YINT | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: x/x | |

| F_SCR1:x/x | |

| F_SCR2:Y adjusted for inex/Y with original exponent | |

| L_SCR1:x/original USER_FPCR | |

| L_SCR2:first word of X packed/Unchanged | |

A12_st: | |

moveml %d0-%d1/%a0-%a1,-(%a7) |save regs used by sintd0 | |

movel L_SCR1(%a6),-(%a7) | |

movel L_SCR2(%a6),-(%a7) | |

leal FP_SCR2(%a6),%a0 |a0 is ptr to F_SCR2(a6) | |

fmovex %fp0,(%a0) |move Y to memory at FP_SCR2(a6) | |

tstl L_SCR2(%a6) |test sign of original operand | |

bges do_fint |if pos, use Y | |

orl #0x80000000,(%a0) |if neg, use -Y | |

do_fint: | |

movel USER_FPSR(%a6),-(%a7) | |

bsr sintdo |sint routine returns int in fp0 | |

moveb (%a7),USER_FPSR(%a6) | |

addl #4,%a7 | |

movel (%a7)+,L_SCR2(%a6) | |

movel (%a7)+,L_SCR1(%a6) | |

moveml (%a7)+,%d0-%d1/%a0-%a1 |restore regs used by sint | |

movel L_SCR2(%a6),FP_SCR2(%a6) |restore original exponent | |

movel L_SCR1(%a6),USER_FPCR(%a6) |restore user's FPCR | |

| A13. Check for LEN digits. | |

| If the int operation results in more than LEN digits, | |

| or less than LEN -1 digits, adjust ILOG and repeat from | |

| A6. This test occurs only on the first pass. If the | |

| result is exactly 10^LEN, decrement ILOG and divide | |

| the mantissa by 10. The calculation of 10^LEN cannot | |

| be inexact, since all powers of ten up to 10^27 are exact | |

| in extended precision, so the use of a previous power-of-ten | |

| table will introduce no error. | |

| | |

| | |

| Register usage: | |

| Input/Output | |

| d0: FPCR with size set to ext/scratch final = 0 | |

| d2: x/x | |

| d3: x/scratch final = x | |

| d4: LEN/LEN adjusted | |

| d5: ICTR:LAMBDA/LAMBDA:ICTR | |

| d6: ILOG/ILOG adjusted | |

| d7: k-factor/Unchanged | |

| a0: pointer into memory for packed bcd string formation | |

| a1: ptr to PTENxx array/Unchanged | |

| a2: ptr to FP_SCR2(a6)/Unchanged | |

| fp0: int portion of Y/abs(YINT) adjusted | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: x/10^LEN | |

| F_SCR1:x/x | |

| F_SCR2:Y with original exponent/Unchanged | |

| L_SCR1:original USER_FPCR/Unchanged | |

| L_SCR2:first word of X packed/Unchanged | |

A13_st: | |

swap %d5 |put ICTR in lower word of d5 | |

tstw %d5 |check if ICTR = 0 | |

bne not_zr |if non-zero, go to second test | |

| | |

| Compute 10^(LEN-1) | |

| | |

fmoves FONE,%fp2 |init fp2 to 1.0 | |

movel %d4,%d0 |put LEN in d0 | |

subql #1,%d0 |d0 = LEN -1 | |

clrl %d3 |clr table index | |

l_loop: | |

lsrl #1,%d0 |shift next bit into carry | |

bccs l_next |if zero, skip the mul | |

fmulx (%a1,%d3),%fp2 |mul by 10**(d3_bit_no) | |

l_next: | |

addl #12,%d3 |inc d3 to next pwrten table entry | |

tstl %d0 |test if LEN is zero | |

bnes l_loop |if not, loop | |

| | |

| 10^LEN-1 is computed for this test and A14. If the input was | |

| denormalized, check only the case in which YINT > 10^LEN. | |

| | |

tstb BINDEC_FLG(%a6) |check if input was norm | |

beqs A13_con |if norm, continue with checking | |

fabsx %fp0 |take abs of YINT | |

bra test_2 | |

| | |

| Compare abs(YINT) to 10^(LEN-1) and 10^LEN | |

| | |

A13_con: | |

fabsx %fp0 |take abs of YINT | |

fcmpx %fp2,%fp0 |compare abs(YINT) with 10^(LEN-1) | |

fbge test_2 |if greater, do next test | |

subql #1,%d6 |subtract 1 from ILOG | |

movew #1,%d5 |set ICTR | |

fmovel #rm_mode,%FPCR |set rmode to RM | |

fmuls FTEN,%fp2 |compute 10^LEN | |

bra A6_str |return to A6 and recompute YINT | |

test_2: | |

fmuls FTEN,%fp2 |compute 10^LEN | |

fcmpx %fp2,%fp0 |compare abs(YINT) with 10^LEN | |

fblt A14_st |if less, all is ok, go to A14 | |

fbgt fix_ex |if greater, fix and redo | |

fdivs FTEN,%fp0 |if equal, divide by 10 | |

addql #1,%d6 | and inc ILOG | |

bras A14_st | and continue elsewhere | |

fix_ex: | |

addql #1,%d6 |increment ILOG by 1 | |

movew #1,%d5 |set ICTR | |

fmovel #rm_mode,%FPCR |set rmode to RM | |

bra A6_str |return to A6 and recompute YINT | |

| | |

| Since ICTR <> 0, we have already been through one adjustment, | |

| and shouldn't have another; this is to check if abs(YINT) = 10^LEN | |

| 10^LEN is again computed using whatever table is in a1 since the | |

| value calculated cannot be inexact. | |

| | |

not_zr: | |

fmoves FONE,%fp2 |init fp2 to 1.0 | |

movel %d4,%d0 |put LEN in d0 | |

clrl %d3 |clr table index | |

z_loop: | |

lsrl #1,%d0 |shift next bit into carry | |

bccs z_next |if zero, skip the mul | |

fmulx (%a1,%d3),%fp2 |mul by 10**(d3_bit_no) | |

z_next: | |

addl #12,%d3 |inc d3 to next pwrten table entry | |

tstl %d0 |test if LEN is zero | |

bnes z_loop |if not, loop | |

fabsx %fp0 |get abs(YINT) | |

fcmpx %fp2,%fp0 |check if abs(YINT) = 10^LEN | |

fbne A14_st |if not, skip this | |

fdivs FTEN,%fp0 |divide abs(YINT) by 10 | |

addql #1,%d6 |and inc ILOG by 1 | |

addql #1,%d4 | and inc LEN | |

fmuls FTEN,%fp2 | if LEN++, the get 10^^LEN | |

| A14. Convert the mantissa to bcd. | |

| The binstr routine is used to convert the LEN digit | |

| mantissa to bcd in memory. The input to binstr is | |

| to be a fraction; i.e. (mantissa)/10^LEN and adjusted | |

| such that the decimal point is to the left of bit 63. | |

| The bcd digits are stored in the correct position in | |

| the final string area in memory. | |

| | |

| | |

| Register usage: | |

| Input/Output | |

| d0: x/LEN call to binstr - final is 0 | |

| d1: x/0 | |

| d2: x/ms 32-bits of mant of abs(YINT) | |

| d3: x/ls 32-bits of mant of abs(YINT) | |

| d4: LEN/Unchanged | |

| d5: ICTR:LAMBDA/LAMBDA:ICTR | |

| d6: ILOG | |

| d7: k-factor/Unchanged | |

| a0: pointer into memory for packed bcd string formation | |

| /ptr to first mantissa byte in result string | |

| a1: ptr to PTENxx array/Unchanged | |

| a2: ptr to FP_SCR2(a6)/Unchanged | |

| fp0: int portion of Y/abs(YINT) adjusted | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: 10^LEN/Unchanged | |

| F_SCR1:x/Work area for final result | |

| F_SCR2:Y with original exponent/Unchanged | |

| L_SCR1:original USER_FPCR/Unchanged | |

| L_SCR2:first word of X packed/Unchanged | |

A14_st: | |

fmovel #rz_mode,%FPCR |force rz for conversion | |

fdivx %fp2,%fp0 |divide abs(YINT) by 10^LEN | |

leal FP_SCR1(%a6),%a0 | |

fmovex %fp0,(%a0) |move abs(YINT)/10^LEN to memory | |

movel 4(%a0),%d2 |move 2nd word of FP_RES to d2 | |

movel 8(%a0),%d3 |move 3rd word of FP_RES to d3 | |

clrl 4(%a0) |zero word 2 of FP_RES | |

clrl 8(%a0) |zero word 3 of FP_RES | |

movel (%a0),%d0 |move exponent to d0 | |

swap %d0 |put exponent in lower word | |

beqs no_sft |if zero, don't shift | |

subil #0x3ffd,%d0 |sub bias less 2 to make fract | |

tstl %d0 |check if > 1 | |

bgts no_sft |if so, don't shift | |

negl %d0 |make exp positive | |

m_loop: | |

lsrl #1,%d2 |shift d2:d3 right, add 0s | |

roxrl #1,%d3 |the number of places | |

dbf %d0,m_loop |given in d0 | |

no_sft: | |

tstl %d2 |check for mantissa of zero | |

bnes no_zr |if not, go on | |

tstl %d3 |continue zero check | |

beqs zer_m |if zero, go directly to binstr | |

no_zr: | |

clrl %d1 |put zero in d1 for addx | |

addil #0x00000080,%d3 |inc at bit 7 | |

addxl %d1,%d2 |continue inc | |

andil #0xffffff80,%d3 |strip off lsb not used by 882 | |

zer_m: | |

movel %d4,%d0 |put LEN in d0 for binstr call | |

addql #3,%a0 |a0 points to M16 byte in result | |

bsr binstr |call binstr to convert mant | |

| A15. Convert the exponent to bcd. | |

| As in A14 above, the exp is converted to bcd and the | |

| digits are stored in the final string. | |

| | |

| Digits are stored in L_SCR1(a6) on return from BINDEC as: | |

| | |

| 32 16 15 0 | |

| ----------------------------------------- | |

| | 0 | e3 | e2 | e1 | e4 | X | X | X | | |

| ----------------------------------------- | |

| | |

| And are moved into their proper places in FP_SCR1. If digit e4 | |

| is non-zero, OPERR is signaled. In all cases, all 4 digits are | |

| written as specified in the 881/882 manual for packed decimal. | |

| | |

| Register usage: | |

| Input/Output | |

| d0: x/LEN call to binstr - final is 0 | |

| d1: x/scratch (0);shift count for final exponent packing | |

| d2: x/ms 32-bits of exp fraction/scratch | |

| d3: x/ls 32-bits of exp fraction | |

| d4: LEN/Unchanged | |

| d5: ICTR:LAMBDA/LAMBDA:ICTR | |

| d6: ILOG | |

| d7: k-factor/Unchanged | |

| a0: ptr to result string/ptr to L_SCR1(a6) | |

| a1: ptr to PTENxx array/Unchanged | |

| a2: ptr to FP_SCR2(a6)/Unchanged | |

| fp0: abs(YINT) adjusted/float(ILOG) | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: 10^LEN/Unchanged | |

| F_SCR1:Work area for final result/BCD result | |

| F_SCR2:Y with original exponent/ILOG/10^4 | |

| L_SCR1:original USER_FPCR/Exponent digits on return from binstr | |

| L_SCR2:first word of X packed/Unchanged | |

A15_st: | |

tstb BINDEC_FLG(%a6) |check for denorm | |

beqs not_denorm | |

ftstx %fp0 |test for zero | |

fbeq den_zero |if zero, use k-factor or 4933 | |

fmovel %d6,%fp0 |float ILOG | |

fabsx %fp0 |get abs of ILOG | |

bras convrt | |

den_zero: | |

tstl %d7 |check sign of the k-factor | |

blts use_ilog |if negative, use ILOG | |

fmoves F4933,%fp0 |force exponent to 4933 | |

bras convrt |do it | |

use_ilog: | |

fmovel %d6,%fp0 |float ILOG | |

fabsx %fp0 |get abs of ILOG | |

bras convrt | |

not_denorm: | |

ftstx %fp0 |test for zero | |

fbne not_zero |if zero, force exponent | |

fmoves FONE,%fp0 |force exponent to 1 | |

bras convrt |do it | |

not_zero: | |

fmovel %d6,%fp0 |float ILOG | |

fabsx %fp0 |get abs of ILOG | |

convrt: | |

fdivx 24(%a1),%fp0 |compute ILOG/10^4 | |

fmovex %fp0,FP_SCR2(%a6) |store fp0 in memory | |

movel 4(%a2),%d2 |move word 2 to d2 | |

movel 8(%a2),%d3 |move word 3 to d3 | |

movew (%a2),%d0 |move exp to d0 | |

beqs x_loop_fin |if zero, skip the shift | |

subiw #0x3ffd,%d0 |subtract off bias | |

negw %d0 |make exp positive | |

x_loop: | |

lsrl #1,%d2 |shift d2:d3 right | |

roxrl #1,%d3 |the number of places | |

dbf %d0,x_loop |given in d0 | |

x_loop_fin: | |

clrl %d1 |put zero in d1 for addx | |

addil #0x00000080,%d3 |inc at bit 6 | |

addxl %d1,%d2 |continue inc | |

andil #0xffffff80,%d3 |strip off lsb not used by 882 | |

movel #4,%d0 |put 4 in d0 for binstr call | |

leal L_SCR1(%a6),%a0 |a0 is ptr to L_SCR1 for exp digits | |

bsr binstr |call binstr to convert exp | |

movel L_SCR1(%a6),%d0 |load L_SCR1 lword to d0 | |

movel #12,%d1 |use d1 for shift count | |

lsrl %d1,%d0 |shift d0 right by 12 | |

bfins %d0,FP_SCR1(%a6){#4:#12} |put e3:e2:e1 in FP_SCR1 | |

lsrl %d1,%d0 |shift d0 right by 12 | |

bfins %d0,FP_SCR1(%a6){#16:#4} |put e4 in FP_SCR1 | |

tstb %d0 |check if e4 is zero | |

beqs A16_st |if zero, skip rest | |

orl #opaop_mask,USER_FPSR(%a6) |set OPERR & AIOP in USER_FPSR | |

| A16. Write sign bits to final string. | |

| Sigma is bit 31 of initial value; RHO is bit 31 of d6 (ILOG). | |

| | |

| Register usage: | |

| Input/Output | |

| d0: x/scratch - final is x | |

| d2: x/x | |

| d3: x/x | |

| d4: LEN/Unchanged | |

| d5: ICTR:LAMBDA/LAMBDA:ICTR | |

| d6: ILOG/ILOG adjusted | |

| d7: k-factor/Unchanged | |

| a0: ptr to L_SCR1(a6)/Unchanged | |

| a1: ptr to PTENxx array/Unchanged | |

| a2: ptr to FP_SCR2(a6)/Unchanged | |

| fp0: float(ILOG)/Unchanged | |

| fp1: 10^ISCALE/Unchanged | |

| fp2: 10^LEN/Unchanged | |

| F_SCR1:BCD result with correct signs | |

| F_SCR2:ILOG/10^4 | |

| L_SCR1:Exponent digits on return from binstr | |

| L_SCR2:first word of X packed/Unchanged | |

A16_st: | |

clrl %d0 |clr d0 for collection of signs | |

andib #0x0f,FP_SCR1(%a6) |clear first nibble of FP_SCR1 | |

tstl L_SCR2(%a6) |check sign of original mantissa | |

bges mant_p |if pos, don't set SM | |

moveql #2,%d0 |move 2 in to d0 for SM | |

mant_p: | |

tstl %d6 |check sign of ILOG | |

bges wr_sgn |if pos, don't set SE | |

addql #1,%d0 |set bit 0 in d0 for SE | |

wr_sgn: | |

bfins %d0,FP_SCR1(%a6){#0:#2} |insert SM and SE into FP_SCR1 | |

| Clean up and restore all registers used. | |

fmovel #0,%FPSR |clear possible inex2/ainex bits | |

fmovemx (%a7)+,%fp0-%fp2 | |

moveml (%a7)+,%d2-%d7/%a2 | |

rts | |

|end |