| | |
| | 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 |
| | |
| | THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA |
| | The copyright notice above does not evidence any |
| | actual or intended publication of such source code. |
| |
| |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 upto 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 |