34 lines
451 B
ArmAsm
34 lines
451 B
ArmAsm
|
.define Mli4
|
||
|
|
|
||
|
|
! This subroutine multiplies two signed fourbyte integers
|
||
|
|
! For more detail see mli.s
|
||
|
|
! The only difference is that zeropage locations are twice as big.
|
||
|
|
|
||
|
|
|
||
|
|
Mli4:
|
||
|
|
ldy #1
|
||
|
|
sty UNSIGN
|
||
|
|
jsr Pop
|
||
|
|
stx ARTH
|
||
|
|
sta ARTH+1
|
||
|
|
jsr Pop
|
||
|
|
stx ARTH+2
|
||
|
|
sta ARTH+3 ! multiplier
|
||
|
|
jsr Pop
|
||
|
|
stx ARTH+4
|
||
|
|
sta ARTH+5
|
||
|
|
jsr Pop
|
||
|
|
stx ARTH+6
|
||
|
|
sta ARTH+7 ! multiplicand
|
||
|
|
lda ARTH+3
|
||
|
|
bpl 3f
|
||
|
|
lda #0
|
||
|
|
ldx #ARTH
|
||
|
|
jsr Ngi4
|
||
|
|
lda #0
|
||
|
|
ldx #ARTH+4
|
||
|
|
jsr Ngi4
|
||
|
|
3: jmp Mul4
|
||
|
|
|
||
|
|
|