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Diffstat (limited to 'kernel/arch/m68k/fpsp040/bindec.S')
| -rw-r--r-- | kernel/arch/m68k/fpsp040/bindec.S | 919 |
1 files changed, 919 insertions, 0 deletions
diff --git a/kernel/arch/m68k/fpsp040/bindec.S b/kernel/arch/m68k/fpsp040/bindec.S new file mode 100644 index 000000000..f2e795231 --- /dev/null +++ b/kernel/arch/m68k/fpsp040/bindec.S @@ -0,0 +1,919 @@ +| +| 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 |