; Test adding, and subtracting. ; ; Written by mr b0nk 500 ; Main Program. .org 0 reset: cps ; Clear the processor status register. ldx.w #$FFFF ; Reset the stack pointer. txs ; lsr #16 ; Reset A. tab ; Reset B. tax ; Reset X. up: inc ; Increment the counter. cmp #$FF ; Did the accumulator overflow? bcs down ; Yes, so start decrementing. jmp up ; No, so keep incrementing. down: dec ; Did the accumulator underflow? beq up ; Yes, so start incrementing. jmp down ; No, so keep decrementing. .org $FFC0 .qword reset a d