mirror of
https://github.com/elliotnunn/supermario.git
synced 2024-11-29 20:49:19 +00:00
531 lines
16 KiB
Plaintext
531 lines
16 KiB
Plaintext
;
|
|
; File: DecBin.a
|
|
;
|
|
; Contains: Packed Decimal to Binary conversion code
|
|
;
|
|
; Originally Written by: Motorola Inc.
|
|
; Adapted to Apple/MPW: Jon Okada
|
|
;
|
|
; Copyright: © 1990, 1991 by Apple Computer, Inc., all rights reserved.
|
|
;
|
|
; This file is used in these builds: Mac32
|
|
;
|
|
; Change History (most recent first):
|
|
;
|
|
; <2> 3/30/91 BG Rolling in Jon Okada's latest changes.
|
|
; <1> 12/14/90 BG First checked into TERROR/BBS.
|
|
|
|
; decbin.a
|
|
|
|
; Based upon Motorola file 'decbin.sa'
|
|
|
|
; CHANGE LOG:
|
|
; 02 Jan 91 JPO Removed constants FZERO, FONE, and FTEN; embedded
|
|
; constant values in instructions.
|
|
;
|
|
|
|
*
|
|
* decbin.sa 3.1 12/10/90
|
|
*
|
|
* Description: Converts normalized packed bcd value pointed to by
|
|
* register A6 to extended-precision value in FP0.
|
|
*
|
|
* Input: Normalized packed bcd value in ETEMP(a6).
|
|
*
|
|
* Output: Exact floating-point representation of the packed bcd value.
|
|
*
|
|
* Saves and Modifies: D2-D5
|
|
*
|
|
* Speed: The program decbin takes ??? cycles to execute.
|
|
*
|
|
* Object Size:
|
|
*
|
|
* External Reference(s): None.
|
|
*
|
|
* Algorithm:
|
|
* Expected is a normal bcd (i.e. non-exceptional; all inf, zero,
|
|
* and NaN operands are dispatched without entering this routine)
|
|
* value in 68881/882 format at location ETEMP(A6).
|
|
*
|
|
* A1. Convert the bcd exponent to binary by successive adds and muls.
|
|
* Set the sign according to SE. Subtract 16 to compensate
|
|
* for the mantissa which is to be interpreted as 17 integer
|
|
* digits, rather than 1 integer and 16 fraction digits.
|
|
* Note: this operation can never overflow.
|
|
*
|
|
* A2. Convert the bcd mantissa to binary by successive
|
|
* adds and muls in FP0. Set the sign according to SM.
|
|
* The mantissa digits will be converted with the decimal point
|
|
* assumed following the least-significant digit.
|
|
* Note: this operation can never overflow.
|
|
*
|
|
* A3. Count the number of leading/trailing zeros in the
|
|
* bcd string. If SE is positive, count the leading zeros;
|
|
* if negative, count the trailing zeros. Set the adjusted
|
|
* exponent equal to the exponent from A1 and the zero count
|
|
* added if SM = 1 and subtracted if SM = 0. Scale the
|
|
* mantissa the equivalent of forcing in the bcd value:
|
|
*
|
|
* SM = 0 a non-zero digit in the integer position
|
|
* SM = 1 a non-zero digit in Mant0, lsd of the fraction
|
|
*
|
|
* this will insure that any value, regardless of its
|
|
* representation (ex. 0.1E2, 1E1, 10E0, 100E-1), is converted
|
|
* consistently.
|
|
*
|
|
* A4. Calculate the factor 10^exp in FP1 using a table of
|
|
* 10^(2^n) values. To reduce the error in forming factors
|
|
* greater than 10^27, a directed rounding scheme is used with
|
|
* tables rounded to RN, RM, and RP, according to the table
|
|
* in the comments of the pwrten section.
|
|
*
|
|
* A5. Form the final binary number by scaling the mantissa by
|
|
* the exponent factor. This is done by multiplying the
|
|
* mantissa in FP0 by the factor in FP1 if the adjusted
|
|
* exponent sign is positive, and dividing FP0 by FP1 if
|
|
* it is negative.
|
|
*
|
|
* Clean up and return. Check if the final mul or div resulted
|
|
* in an inex2 exception. If so, set inex1 in the fpsr and
|
|
* check if the inex1 exception is enabled. If so, set d7 upper
|
|
* word to $0100. This will signal unimp.sa that an enabled inex1
|
|
* exception occured. Unimp will fix the stack.
|
|
*
|
|
|
|
* 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.
|
|
|
|
* DECBIN IDNT 2,1 Motorola 040 Floating Point Software Package
|
|
|
|
|
|
*
|
|
* PTENRN, PTENRM, and PTENRP are arrays of powers of 10 rounded
|
|
* to nearest, minus, and plus, respectively. The tables include
|
|
* 10**{1,2,4,8,16,32,64,128,256,512,1024,2048,4096}. No rounding
|
|
* is required until the power is greater than 27, however, all
|
|
* tables include the first 5 for ease of indexing.
|
|
*
|
|
|
|
RTABLE dc.b 0,0,0,0
|
|
dc.b 2,3,2,3
|
|
dc.b 2,3,3,2
|
|
dc.b 3,2,2,3
|
|
|
|
*
|
|
FNIBS equ 7
|
|
FSTRT equ 0
|
|
*
|
|
ESTRT equ 4
|
|
EDIGITS equ 2
|
|
*
|
|
* Constants in single precision - removed <1/2/91, JPO>
|
|
;FZERO dc.l $00000000
|
|
;FONE dc.l $3F800000
|
|
;FTEN dc.l $41200000
|
|
|
|
TEN equ 10
|
|
|
|
*
|
|
decbin:
|
|
fmove.l #0,FPCR ;clr real fpcr
|
|
movem.l d2-d5,-(a7)
|
|
*
|
|
* Calculate exponent:
|
|
* 1. Copy bcd value in memory for use as a working copy.
|
|
* 2. Calculate absolute value of exponent in d1 by mul and add.
|
|
* 3. Correct for exponent sign.
|
|
* 4. Subtract 16 to compensate for interpreting the mant as all integer digits.
|
|
* (i.e., all digits assumed left of the decimal point.)
|
|
*
|
|
* Register usage:
|
|
*
|
|
* calc_e:
|
|
* (*) d0: temp digit storage
|
|
* (*) d1: accumulator for binary exponent
|
|
* (*) d2: digit count
|
|
* (*) d3: offset pointer
|
|
* ( ) d4: first word of bcd
|
|
* ( ) a0: pointer to working bcd value
|
|
* ( ) a6: pointer to original bcd value
|
|
* (*) FP_SCR1: working copy of original bcd value
|
|
* (*) L_SCR1: copy of original exponent word
|
|
*
|
|
;calc_e: ; label not referenced <1/2/91, JPO>
|
|
move.l #EDIGITS,d2 ;# of nibbles (digits) in fraction part
|
|
moveq.l #ESTRT,d3 ;counter to pick up digits
|
|
lea.l FP_SCR1(a6),a0 ;load tmp bcd storage address
|
|
move.l ETEMP(a6),(a0) ;save input bcd value
|
|
move.l ETEMP_HI(a6),4(a0) ;save words 2 and 3
|
|
move.l ETEMP_LO(a6),8(a0) ;and work with these
|
|
move.l (a0),d4 ;get first word of bcd
|
|
clr.l d1 ;zero d1 for accumulator
|
|
e_gd:
|
|
mulu.l #TEN,d1 ;mul partial product by one digit place
|
|
bfextu d4{d3:4},d0 ;get the digit and zero extend into d0
|
|
add.l d0,d1 ;d1 = d1 + d0
|
|
addq.b #4,d3 ;advance d3 to the next digit
|
|
dbf.w d2,e_gd ;if we have used all 3 digits, exit loop
|
|
btst #30,d4 ;get SE
|
|
beq.b e_pos ;don't negate if pos
|
|
neg.l d1 ;negate before subtracting
|
|
e_pos:
|
|
sub.l #16,d1 ;sub to compensate for shift of mant
|
|
bge.b e_save ;if still pos, do not neg
|
|
neg.l d1 ;now negative, make pos and set SE
|
|
or.l #$40000000,d4 ;set SE in d4,
|
|
or.l #$40000000,(a0) ;and in working bcd
|
|
e_save:
|
|
move.l d1,L_SCR1(a6) ;save exp in memory
|
|
*
|
|
*
|
|
* Calculate mantissa:
|
|
* 1. Calculate absolute value of mantissa in fp0 by mul and add.
|
|
* 2. Correct for mantissa sign.
|
|
* (i.e., all digits assumed left of the decimal point.)
|
|
*
|
|
* Register usage:
|
|
*
|
|
* calc_m:
|
|
* (*) d0: temp digit storage
|
|
* (*) d1: lword counter
|
|
* (*) d2: digit count
|
|
* (*) d3: offset pointer
|
|
* ( ) d4: words 2 and 3 of bcd
|
|
* ( ) a0: pointer to working bcd value
|
|
* ( ) a6: pointer to original bcd value
|
|
* (*) fp0: mantissa accumulator
|
|
* ( ) FP_SCR1: working copy of original bcd value
|
|
* ( ) L_SCR1: copy of original exponent word
|
|
*
|
|
;calc_m: ; label not referenced <1/2/91, JPO>
|
|
moveq.l #1,d1 ;word counter, init to 1
|
|
; fmove.s FZERO,fp0 ;accumulator <1/2/91, JPO>
|
|
fmove.b #0,fp0 ; <1/2/91, JPO>
|
|
*
|
|
*
|
|
* Since the packed number has a long word between the first & second parts,
|
|
* get the integer digit then skip down & get the rest of the
|
|
* mantissa. We will unroll the loop once.
|
|
*
|
|
bfextu (a0){28:4},d0 ;integer part is ls digit in long word
|
|
fadd.b d0,fp0 ;add digit to sum in fp0
|
|
*
|
|
*
|
|
* Get the rest of the mantissa.
|
|
*
|
|
loadlw:
|
|
move.l (a0,d1.L*4),d4 ;load mantissa lonqword into d4
|
|
moveq.l #FSTRT,d3 ;counter to pick up digits
|
|
moveq.l #FNIBS,d2 ;reset number of digits per a0 ptr
|
|
md2b:
|
|
; fmul.s FTEN,fp0 ;fp0 = fp0 * 10 <1/2/91, JPO>
|
|
fmul.b #TEN,fp0 ; <1/2/91, JPO>
|
|
bfextu d4{d3:4},d0 ;get the digit and zero extend
|
|
fadd.b d0,fp0 ;fp0 = fp0 + digit
|
|
*
|
|
*
|
|
* If all the digits (8) in that long word have been converted (d2=0),
|
|
* then inc d1 (=2) to point to the next long word and reset d3 to 0
|
|
* to initialize the digit offset, and set d2 to 7 for the digit count;
|
|
* else continue with this long word.
|
|
*
|
|
addq.b #4,d3 ;advance d3 to the next digit
|
|
dbf.w d2,md2b ;check for last digit in this lw
|
|
;nextlw: ; label not referenced <1/2/91, JPO>
|
|
addq.l #1,d1 ;inc lw pointer in mantissa
|
|
cmp.l #2,d1 ;test for last lw
|
|
ble.b loadlw ;if not, get last one - short branch <1/2/91, JPO>
|
|
|
|
*
|
|
* Check the sign of the mant and make the value in fp0 the same sign.
|
|
*
|
|
;m_sign: ; label not referenced <1/2/91, JPO>
|
|
btst #31,(a0) ;test sign of the mantissa
|
|
beq.b ap_st_z ;if clear, go to append/strip zeros
|
|
fneg.x fp0 ;if set, negate fp0
|
|
|
|
*
|
|
* Append/strip zeros:
|
|
*
|
|
* For adjusted exponents which have an absolute value greater than 27*,
|
|
* this routine calculates the amount needed to normalize the mantissa
|
|
* for the adjusted exponent. That number is subtracted from the exp
|
|
* if the exp was positive, and added if it was negative. The purpose
|
|
* of this is to reduce the value of the exponent and the possibility
|
|
* of error in calculation of pwrten.
|
|
*
|
|
* 1. Branch on the sign of the adjusted exponent.
|
|
* 2p.(positive exp)
|
|
* 2. Check M16 and the digits in lwords 2 and 3 in decending order.
|
|
* 3. Add one for each zero encountered until a non-zero digit.
|
|
* 4. Subtract the count from the exp.
|
|
* 5. Check if the exp has crossed zero in #3 above; make the exp abs
|
|
* and set SE.
|
|
* 6. Multiply the mantissa by 10**count.
|
|
* 2n.(negative exp)
|
|
* 2. Check the digits in lwords 3 and 2 in decending order.
|
|
* 3. Add one for each zero encountered until a non-zero digit.
|
|
* 4. Add the count to the exp.
|
|
* 5. Check if the exp has crossed zero in #3 above; clear SE.
|
|
* 6. Divide the mantissa by 10**count.
|
|
*
|
|
* *Why 27? If the adjusted exponent is within -28 < expA < 28, than
|
|
* any adjustment due to append/strip zeros will drive the resultane
|
|
* exponent towards zero. Since all pwrten constants with a power
|
|
* of 27 or less are exact, there is no need to use this routine to
|
|
* attempt to lessen the resultant exponent.
|
|
*
|
|
* Register usage:
|
|
*
|
|
* ap_st_z:
|
|
* (*) d0: temp digit storage
|
|
* (*) d1: zero count
|
|
* (*) d2: digit count
|
|
* (*) d3: offset pointer
|
|
* ( ) d4: first word of bcd
|
|
* (*) d5: lword counter
|
|
* ( ) a0: pointer to working bcd value
|
|
* ( ) FP_SCR1: working copy of original bcd value
|
|
* ( ) L_SCR1: copy of original exponent word
|
|
*
|
|
*
|
|
* First check the absolute value of the exponent to see if this
|
|
* routine is necessary. If so, then check the sign of the exponent
|
|
* and do append (+) or strip (-) zeros accordingly.
|
|
* This section handles a positive adjusted exponent.
|
|
*
|
|
ap_st_z:
|
|
move.l L_SCR1(a6),d1 ;load expA for range test
|
|
cmp.l #27,d1 ;test is with 27
|
|
ble.w pwrten ;if abs(expA) <28, skip ap/st zeros
|
|
btst #30,(a0) ;check sign of exp
|
|
bne.b ap_st_n ;if neg, go to neg side
|
|
clr.l d1 ;zero count reg
|
|
move.l (a0),d4 ;load lword 1 to d4
|
|
bfextu d4{28:4},d0 ;get M16 in d0
|
|
bne.b ap_p_fx ;if M16 is non-zero, go fix exp
|
|
addq.l #1,d1 ;inc zero count
|
|
moveq.l #1,d5 ;init lword counter
|
|
move.l (a0,d5.L*4),d4 ;get lword 2 to d4
|
|
bne.b ap_p_cl ;if lw 2 is zero, skip it
|
|
addq.l #8,d1 ;and inc count by 8
|
|
addq.l #1,d5 ;inc lword counter
|
|
move.l (a0,d5.L*4),d4 ;get lword 3 to d4
|
|
ap_p_cl:
|
|
clr.l d3 ;init offset reg
|
|
moveq.l #7,d2 ;init digit counter
|
|
ap_p_gd:
|
|
bfextu d4{d3:4},d0 ;get digit
|
|
bne.b ap_p_fx ;if non-zero, go to fix exp
|
|
addq.l #4,d3 ;point to next digit
|
|
addq.l #1,d1 ;inc digit counter
|
|
dbf.w d2,ap_p_gd ;get next digit
|
|
ap_p_fx:
|
|
move.l d1,d0 ;copy counter to d2
|
|
move.l L_SCR1(a6),d1 ;get adjusted exp from memory
|
|
sub.l d0,d1 ;subtract count from exp
|
|
bge.b ap_p_fm ;if still pos, go to pwrten
|
|
neg.l d1 ;now its neg; get abs
|
|
move.l (a0),d4 ;load lword 1 to d4
|
|
or.l #$40000000,d4 ; and set SE in d4
|
|
or.l #$40000000,(a0) ; and in memory
|
|
*
|
|
* Calculate the mantissa multiplier to compensate for the striping of
|
|
* zeros from the mantissa.
|
|
*
|
|
ap_p_fm:
|
|
; move.l #PTENRN,a1 ;get address of power-of-ten table - deleted <1/2/91, JPO>
|
|
lea PTENRN,a1 ; <1/2/91, JPO>
|
|
clr.l d3 ;init table index
|
|
; fmove.s FONE,fp1 ;init fp1 to 1 <1/2/91, JPO>
|
|
fmove.b #1,fp1 ; <1/2/91, JPO>
|
|
moveq.l #3,d2 ;init d2 to count bits in counter
|
|
ap_p_el:
|
|
asr.l #1,d0 ;shift lsb into carry
|
|
bcc.b ap_p_en ;if 1, mul fp1 by pwrten factor
|
|
fmul.x (a1,d3),fp1 ;mul by 10**(d3_bit_no)
|
|
ap_p_en:
|
|
add.l #12,d3 ;inc d3 to next rtable entry
|
|
tst.l d0 ;check if d0 is zero
|
|
bne.b ap_p_el ;if not, get next bit
|
|
fmul.x fp1,fp0 ;mul mantissa by 10**(no_bits_shifted)
|
|
bra.b pwrten ;go calc pwrten
|
|
*
|
|
* This section handles a negative adjusted exponent.
|
|
*
|
|
ap_st_n:
|
|
clr.l d1 ;clr counter
|
|
moveq.l #2,d5 ;set up d5 to point to lword 3
|
|
move.l (a0,d5.L*4),d4 ;get lword 3
|
|
bne.b ap_n_cl ;if not zero, check digits
|
|
sub.l #1,d5 ;dec d5 to point to lword 2
|
|
addq.l #8,d1 ;inc counter by 8
|
|
move.l (a0,d5.L*4),d4 ;get lword 2
|
|
ap_n_cl:
|
|
move.l #28,d3 ;point to last digit
|
|
moveq.l #7,d2 ;init digit counter
|
|
ap_n_gd:
|
|
bfextu d4{d3:4},d0 ;get digit
|
|
bne.b ap_n_fx ;if non-zero, go to exp fix
|
|
subq.l #4,d3 ;point to previous digit
|
|
addq.l #1,d1 ;inc digit counter
|
|
dbf.w d2,ap_n_gd ;get next digit
|
|
ap_n_fx:
|
|
move.l d1,d0 ;copy counter to d0
|
|
move.l L_SCR1(a6),d1 ;get adjusted exp from memory
|
|
sub.l d0,d1 ;subtract count from exp
|
|
bgt.b ap_n_fm ;if still pos, go fix mantissa
|
|
neg.l d1 ;take abs of exp and clr SE
|
|
move.l (a0),d4 ;load lword 1 to d4
|
|
and.l #$bfffffff,d4 ; and clr SE in d4
|
|
and.l #$bfffffff,(a0) ; and in memory
|
|
*
|
|
* Calculate the mantissa multiplier to compensate for the appending of
|
|
* zeros to the mantissa.
|
|
*
|
|
ap_n_fm:
|
|
; move.l #PTENRN,a1 ;get address of power-of-ten table - deleted <1/2/91, JPO>
|
|
lea PTENRN,a1 ; <1/2/91, JPO>
|
|
clr.l d3 ;init table index
|
|
; fmove.s FONE,fp1 ;init fp1 to 1 <1/2/91, JPO>
|
|
fmove.b #1,fp1 ; <1/2/91, JPO>
|
|
moveq.l #3,d2 ;init d2 to count bits in counter
|
|
ap_n_el:
|
|
asr.l #1,d0 ;shift lsb into carry
|
|
bcc.b ap_n_en ;if 1, mul fp1 by pwrten factor
|
|
fmul.x (a1,d3),fp1 ;mul by 10**(d3_bit_no)
|
|
ap_n_en:
|
|
add.l #12,d3 ;inc d3 to next rtable entry
|
|
tst.l d0 ;check if d0 is zero
|
|
bne.b ap_n_el ;if not, get next bit
|
|
fdiv.x fp1,fp0 ;div mantissa by 10**(no_bits_shifted)
|
|
*
|
|
*
|
|
* Calculate power-of-ten factor from adjusted and shifted exponent.
|
|
*
|
|
* Register usage:
|
|
*
|
|
* pwrten:
|
|
* (*) d0: temp
|
|
* ( ) d1: exponent
|
|
* (*) d2: {FPCR[6:5],SM,SE} as index in RTABLE; temp
|
|
* (*) d3: FPCR work copy
|
|
* ( ) d4: first word of bcd
|
|
* (*) a1: RTABLE pointer
|
|
* calc_p:
|
|
* (*) d0: temp
|
|
* ( ) d1: exponent
|
|
* (*) d3: PWRTxx table index
|
|
* ( ) a0: pointer to working copy of bcd
|
|
* (*) a1: PWRTxx pointer
|
|
* (*) fp1: power-of-ten accumulator
|
|
*
|
|
* Pwrten calculates the exponent factor in the selected rounding mode
|
|
* according to the following table:
|
|
*
|
|
* Sign of Mant Sign of Exp Rounding Mode PWRTEN Rounding Mode
|
|
*
|
|
* ANY ANY RN RN
|
|
*
|
|
* + + RP RP
|
|
* - + RP RM
|
|
* + - RP RM
|
|
* - - RP RP
|
|
*
|
|
* + + RM RM
|
|
* - + RM RP
|
|
* + - RM RP
|
|
* - - RM RM
|
|
*
|
|
* + + RZ RM
|
|
* - + RZ RM
|
|
* + - RZ RP
|
|
* - - RZ RP
|
|
*
|
|
*
|
|
pwrten:
|
|
move.l USER_FPCR(a6),d3 ;get user's FPCR
|
|
bfextu d3{26:2},d2 ;isolate rounding mode bits
|
|
move.l (a0),d4 ;reload 1st bcd word to d4
|
|
asl.l #2,d2 ;format d2 to be
|
|
bfextu d4{0:2},d0 ; {FPCR[6],FPCR[5],SM,SE}
|
|
add.l d0,d2 ;in d2 as index into RTABLE
|
|
lea.l RTABLE,a1 ;load rtable base
|
|
move.b (a1,d2),d0 ;load new rounding bits from table
|
|
clr.l d3 ;clear d3 to force no exc and extended
|
|
bfins d0,d3{26:2} ;stuff new rounding bits in FPCR
|
|
fmove.l d3,FPCR ;write new FPCR
|
|
asr.l #1,d0 ;write correct PTENxx table
|
|
bcc.b not_rp ;to a1
|
|
lea.l PTENRP,a1 ;it is RP
|
|
bra.b calc_p ;go to init section
|
|
not_rp:
|
|
asr.l #1,d0 ;keep checking
|
|
bcc.b not_rm
|
|
lea.l PTENRM,a1 ;it is RM
|
|
bra.b calc_p ;go to init section
|
|
not_rm:
|
|
lea.l PTENRN,a1 ;it is RN
|
|
calc_p:
|
|
move.l d1,d0 ;copy exp to d0;use d0
|
|
bpl.b no_neg ;if exp is negative,
|
|
neg.l d0 ;invert it
|
|
or.l #$40000000,(a0) ;and set SE bit
|
|
no_neg:
|
|
clr.l d3 ;table index
|
|
; fmove.s FONE,fp1 ;init fp1 to 1 <1/2/91, JPO>
|
|
fmove.b #1,fp1 ; <1/2/91, JPO>
|
|
e_loop:
|
|
asr.l #1,d0 ;shift next bit into carry
|
|
bcc.b e_next ;if zero, skip the mul
|
|
fmul.x (a1,d3),fp1 ;mul by 10**(d3_bit_no)
|
|
e_next:
|
|
add.l #12,d3 ;inc d3 to next rtable entry
|
|
tst.l d0 ;check if d0 is zero
|
|
bne.b e_loop ;not zero, continue shifting
|
|
*
|
|
*
|
|
* Check the sign of the adjusted exp and make the value in fp0 the
|
|
* same sign. If the exp was pos then multiply fp1*fp0;
|
|
* else divide fp0/fp1.
|
|
*
|
|
* Register Usage:
|
|
* norm:
|
|
* ( ) a0: pointer to working bcd value
|
|
* (*) fp0: mantissa accumulator
|
|
* ( ) fp1: scaling factor - 10**(abs(exp))
|
|
*
|
|
norm:
|
|
btst #30,(a0) ;test the sign of the exponent
|
|
beq.b mul ;if clear, go to multiply
|
|
;div: ; label not referenced <1/2/91, JPO>
|
|
fdiv.x fp1,fp0 ;exp is negative, so divide mant by exp
|
|
bra.b end_dec
|
|
mul:
|
|
fmul.x fp1,fp0 ;exp is positive, so multiply by exp
|
|
*
|
|
*
|
|
* Clean up and return with result in fp0.
|
|
*
|
|
* If the final mul/div in decbin incurred an inex exception,
|
|
* it will be inex2, but will be reported as inex1 by get_op.
|
|
*
|
|
end_dec:
|
|
fmove.l FPSR,d0 ;get status register
|
|
bclr.l #inex2_bit+8,d0 ;test for inex2 and clear it
|
|
fmove.l d0,FPSR ;return status reg w/o inex2
|
|
; beq.b no_exc ;skip this if no exc - label changed <1/2/91, JPO>
|
|
beq.b dbno_exc ; <1/2/91, JPO>
|
|
or.l #inx1a_mask,USER_FPSR(a6) ;set inex1/ainex
|
|
;no_exc: ; label changed <1/2/91, JPO>
|
|
dbno_exc: ; <1/2/91, JPO>
|
|
movem.l (a7)+,d2-d5
|
|
rts
|
|
|
|
|
|
|