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Diffstat (limited to 'test/add-sub.s')
| -rw-r--r-- | test/add-sub.s | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/test/add-sub.s b/test/add-sub.s new file mode 100644 index 0000000..694931d --- /dev/null +++ b/test/add-sub.s @@ -0,0 +1,27 @@ +; Test adding, and subtracting. +; +; Written by mr b0nk 500 <b0nk@b0nk.xyz> + +; 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 |