Data commit

Task/Josephus-problem/6502-Assembly/josephus-problem.6502

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+JSEPHS: STA  $D0        ; n
+        STX  $D1        ; k
+        LDA  #$FF
+        LDX  #$00
+SETUP:  STA  $1000,X    ; populate array with hex FF
+        INX
+        CPX  $D0
+        BEQ  KILL
+        JMP  SETUP
+KILL:   LDA  #$00       ; number killed so far
+        STA  $D2
+        LDX  #$00       ; position within array
+        LDY  #$01       ; counting up to k
+FIND:   INY
+SCAN:   INX
+        CPX  $D0
+        BMI  TEST
+        LDX  #$00       ; circle back around
+TEST:   LDA  $1000,X
+        CMP  #$FF
+        BNE  SCAN       ; already been killed
+        CPY  $D1
+        BMI  FIND       ; if y < k keep going round
+        LDA  $D2
+        STA  $1000,X    ; mark as dead
+        CLC
+        ADC  #$01
+        STA  $D2
+        CMP  $D0        ; have we killed all but 1?
+        BPL  RETURN
+        LDY  #$00
+        JMP  FIND
+RETURN: TXA             ; a <- index of survivor
+        RTS