Motorola DSP96002 User Manual page 689

;
; Round toward -infinity
;
_rminf jclr
_addone move
add
jcc
inc
_acar jcc
lsr
ror
inc
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.4.3 IEEE Double Precision Multiplication
;
;********************************************************************
;********************************************************************
; *** IEEE Double Extended Precision Multiply Operation
; ***
; *** The routine was implemented as a unsigned multiply routine.
; ***
; *** 64-bit input operand format (immediately before multiply):
; ***
; ***
; *** 67-bit intermediate result format (immediately after post norm):
; ***
; ***
; ***
B-170
#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
i.fff...fl
i.fff...flgrs
where
i = integer bit
DSP96002 USER'S MANUAL
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