Data commit

Task/Apply-a-callback-to-an-array/6502-Assembly/apply-a-callback-to-an-array.6502

@@ -0,0 +1,54 @@
+define SRC_LO  $00
+define SRC_HI  $01
+
+define DEST_LO $02
+define DEST_HI $03
+
+define temp $04		;temp storage used by foo
+
+;some prep work since easy6502 doesn't allow you to define arbitrary bytes before runtime.
+
+SET_TABLE:
+TXA
+STA $1000,X
+INX
+BNE SET_TABLE	
+;stores the identity table at memory address $1000-$10FF
+
+CLEAR_TABLE:
+LDA #0
+STA $1200,X
+INX
+BNE CLEAR_TABLE
+;fills the range $1200-$12FF with zeroes.
+
+
+LDA #$10
+STA SRC_HI
+LDA #$00
+STA SRC_LO
+;store memory address $1000 in zero page
+
+LDA #$12
+STA DEST_HI
+LDA #$00
+STA DEST_LO
+;store memory address $1200 in zero page
+
+
+loop:
+LDA (SRC_LO),y  ;load accumulator from memory address $1000+y
+JSR foo		;multiplies accumulator by 3.
+STA (DEST_LO),y ;store accumulator in memory address $1200+y
+
+INY
+CPY #$56 ;alternatively you can store a size variable and check that here instead.
+BCC loop
+BRK
+
+foo:
+STA temp
+ASL		;double accumulator
+CLC
+ADC temp	;2a + a = 3a
+RTS