Data commit

Task/Knuth-shuffle/6502-Assembly/knuth-shuffle.6502

@@ -0,0 +1,69 @@
+define sysRandom $fe
+define tempMask $ff
+define range $00
+define tempX $01
+define tempY $02
+define tempRandIndex $03
+define temp $04
+CreateIdentityTable:
+    txa
+    sta $0200,x
+    sta $1000,x
+    inx
+    bne CreateIdentityTable
+;creates a sorted array from 0-255 starting at addr $1000
+;also creates another one at $0200 for our test input
+
+lda #1
+sta range
+
+ConstrainRNG:
+ldx #255
+;max range of RNG
+lda range
+bne outerloop
+jmp end
+
+outerloop:
+cpx range
+bcc continue	;if X >= range, we need to lower X
+pha
+  txa
+  sta tempX
+
+  lsr
+  cmp range
+  bcc continue2
+
+  tax
+pla
+jmp outerloop
+
+continue2:
+pla
+ldx tempX
+
+continue:
+ldy range
+
+KnuthShuffle:
+lda sysRandom
+and $1000,x	;and with range constrictor
+tay
+
+lda $0200,y
+sty tempRandIndex
+sta temp
+ldy range
+lda $0200,y
+pha
+    lda temp
+    sta $0200,y
+pla
+ldy tempRandIndex
+sta $0200,y
+dec range
+jmp ConstrainRNG
+
+end:
+brk