Figured i'd post some school fun I'm having with 8085 ASM using j8085 micro-processor emulator. Of course there is also a second one i think using Booth's algo, i'll post that one later on ..


; Intel 8085 ASM Bit Multiplication
; Multiplies bits in B and C Registers (7 x 3) = 21
;
mvi b, 07 ; Multiplicand (M)
mvi c, 03 ; Multiplier (P)(Q)
mvi d, 00 ; Acculiminator (A)
mvi e, 08 ; Loop Counter

L2:mov a, c ; Move Multiplier to A
rar ; Right Shift
jnc L1 ; Not carry, then L1
mov a, d ; A = A + M
add b ; Add (M)
mov d, a ; Copy Result to (A)

L1:mov a, d ; Move result down (A)
rar ; Shift Right
mov d, a ; Move Result Back
mov a, c ; Move result down (Q)
rar ; Shift Right
mov c, a ; Move Result Back
dcr e ; Decrement loop
jnz L2 ; Counter not zero, continue.

out 00 ; Displays 0001 0101 / 21
hlt

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