Motorola DSP96002 User Manual page 680

;
; Round toward -infinity
;
_rminf jclr
_addone move
add
jcc
inc
_acar jcc
lsr
ror
inc
;
; Check if Result is Infinity
;
move
move
and
cmp
jne
move
move
ori
ori
ori
jmp
;
; Get Result in D1
;
_lmove move
_emove move
_done nop
nop
nop
rts
endsec
B.4.2 IEEE Double Precision Subtraction
;
; Double Precision IEEE floating-point Subtraction
;
; D0 - D1
;
;
;
; Alters Data ALU Registers
; d0.h
; d1.h
;
;
MOTOROLA
#31,d6.l,_lmove ; no rounding if positive
#$800,d7.l ; get increment number
d7,d1 ; add one to lsb
_acar ; jump if no carry
d3 ; increment mantr.high
_lmove ; jump if result normalized
d3 ; shift right mantr.high
d1 ; shift right mantr.low
d6 ; increment expr
#emsk,d7.l ; get exp mask
d6.l,d5.l ; get expr
d7,d5 ; delete tags
d7,d5 ; check for max exp
_lmove ; jump if no overflow
#0,d1.l ; set result to infinity
#0,d1.m ;
#$10,ccr ; set infinity bit
#$09,ier ; set OVF and INX bits in IER
#$09,er ; set OVF and INX bits in ER
_emove ; get infinity exponent
d3.l,d1.m ; move mantr.high to d1
d6.l,d1.h ; move expr to d1
;
;
;
; end of subroutine
D1
d0.m d0.l
d1.m d1.l
d2.m d2.l
d3.l
DSP96002 USER'S MANUAL
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B-161