Motorola DSP96002 User Manual page 679

move
ori
ori
ori
jmp
;
; Begin Rounding the Result
;
;
; Check for Denormalized Numbers
;
_rnd move
move
move
and
cmp
jne
tst
dec
;
; Remove Bits to Right of the Sticky Bit
;
_remst move
and
;
; Check GRS Bits Equal Zero
;
move
move
and
tst
jeq
ori
ori
;
; Check Rounding Mode
;
jset
jset
;
; Round to nearest even
;
jclr
bclr
tst
jne
jset
jmp
_r1chk jclr
;
; Round toward +infinity
;
jclr
jmp
B-160
d6.l,d1.h ;
#$10,ccr ; set infinity bit
#$09,ier ; set OVF and INX bits in IER
#$09,er ; set OVF and INX bits in ER
_done ; result is infinity
#eden,d7.l ; get denorm exponent
d6.l,d5.l ; get expr
#emsk,d4.l ; get exponent mask
d4,d5 ; delete tags and sign
d7,d5 ; compare exponents
_remst ; jump if not a denorm
d3 ; test mantr.high
d6 ifpl.u ; decrement expr if no int bit
#smsk,d7.l ; get sticky mask
d7,d1 ; remove bits right of sticky
d1.l,d5.l ; get register with GRS bits
#grsmsk,d7.l ; get GRS mask
d7,d5 ; get GRS bits
d5 ; check GRS bits = zero
_lmove ; jump if no rounding required
#$1,ier ; set inexact result bit
#$1,er ; set inexact result bit
#21,sr,_r1chk ; jump if rounding bit r0 = 1
#22,sr,_rminf ; jump if round toward -infinity
#10,d5.l,_lmove ; check guard bit
#10,d5.l ; delete G bit
d5 ; check sticky and round bits
_addone ; jump if S or R bits = 1
#11,d1.l,_addone ; add one if LSB of result = 1
_lmove ; no rounding required
#22,sr,_lmove ; jump if round toward zero
#31,d6.l,_addone ; add one if positive
_lmove ; get result in d1
DSP96002 USER'S MANUAL
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MOTOROLA