Motorola DSP96002 User Manual page 676

jmp
;
; Set Sticky Bit for Shift > 55 Bits
;
_setst0 move
move
jmp
;
; *** Case: Exp1 > Exp0 ***
;
;
; Align Mantissas
;
_pos sub
move
cmp
jgt
do
lsr
ror
jclr
move
_cclr2 nop
;
; Calculate Sticky Bit
;
_end2 move
and
jclr
bset
jmp
;
; Set Sticky Bit for Shift > 55 Bits
;
_setst1 move
move
;
; Check the Signs of the Addends
;
_add jset
jset
jmp
;
; *** Case: Addend 0 is Negative,
; Addend 1 is Positive ***
;
_neg1 jset
sub
subc
jcc
bset
move
not
not
MOTOROLA
_add ;
#0,d3.l ; get number for addition
#inum,d1.l ;
_add ;
d4,d5 d1.h,d6.l
#55,d7.l
d7,d5 ; check for shift > 55
_setst1 ; jump if shift > 55
d5.l,_end2 ; align mantissas
d2 ; shift right m0.h
d0 ; shift right m0.l and GRS0
#8,d0.l,_cclr2 ; jump if sticky bit clear
#1,d2.m ; set sticky bit
;
#grmsk,d7.l ; get GR mask
d7,d0 ; remove bits right of round bit
#0,d2.m,_add ; jump if sticky = 0
#8,d1.l ; put in sticky bit
_add ;
#0,d2.l ; get number for addition
#inum,d0.l ;
#31,d0.h,_neg1 ; jump if a0 negative
#31,d1.h,_neg2 ; jump if a1 negative
_fadd ; jump to addition for a0+,a1+
#31,d1.h,_nset ; jump if a1 negative
d0,d1 ; subtract for case: a0-,a1+
d2,d3 ;
_zchk ; jump if result is positive
#31,d6.l ; set result as negative
#inum,d7.l ; get increment number
d1 ; get 2's comp of result
d3 ;
DSP96002 USER'S MANUAL
"
; get shift, get expr
; get number of bits
"
"
"
B-157