; https://skilldrick.github.io/easy6502/
; Multiplies A by X

define    memory  1040

          JMP MAIN

MULTIPLY: STA memory   ; memory = A
          BEQ MUL_END  ; A = 0
          TXA          ; A = X
          BEQ MUL_END  ; X = 0 -> A = 0
          LDA memory
          CLC
MUL_LOOP: DEX          ; X -= 1
          BEQ MUL_END  ; X = 0 -> A = A * X
          ADC memory   ; A += memory
          JMP MUL_LOOP
MUL_END:  RTS

MAIN:     LDA #50
          LDX #5
          JSR MULTIPLY