mirror of
https://github.com/catseye/SixtyPical.git
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95 lines
1.9 KiB
Plaintext
95 lines
1.9 KiB
Plaintext
buffer[2048] screen @ 1024
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byte joy2 @ $dc00
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pointer ptr @ 254
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word pos
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word delta
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//
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// The constraints on these 2 vectors are kind-of sort-of big fibs.
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// They're only written this way so they can be compatible with our
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// routine. In fact, CINV is an interrupt routine where it doesn't
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// really matter what you trash anyway, because all registers were
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/// saved by the caller (the KERNAL) and will be restored by the end
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// of the code of the saved origin cinv routine that we goto.
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//
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// I wonder if this could be arranged somehow to be less fibby, in
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// a future version of SixtyPical.
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//
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vector cinv
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inputs joy2, pos
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outputs delta, pos, screen
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trashes a, x, y, c, z, n, v, ptr
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@ 788
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vector save_cinv
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inputs joy2, pos
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outputs delta, pos, screen
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trashes a, x, y, c, z, n, v, ptr
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routine read_stick
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inputs joy2
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outputs delta
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trashes a, x, z, n
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{
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ld x, joy2
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ld a, x
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and a, 1 // up
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if z {
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copy $ffd8, delta // -40
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} else {
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ld a, x
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and a, 2 // down
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if z {
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copy word 40, delta
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} else {
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ld a, x
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and a, 4 // left
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if z {
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copy $ffff, delta // -1
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} else {
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ld a, x
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and a, 8 // right
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if z {
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copy word 1, delta
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} else {
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copy word 0, delta
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}
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}
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}
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}
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}
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routine our_cinv
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inputs joy2, pos
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outputs delta, pos, screen
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trashes a, x, y, c, z, n, v, ptr
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{
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call read_stick
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st off, c
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add pos, delta
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copy ^screen, ptr
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st off, c
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add ptr, pos
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ld y, 0
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copy 81, [ptr] + y
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goto save_cinv
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}
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routine main
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inputs cinv
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outputs cinv, save_cinv, pos
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trashes a, n, z
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{
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copy word 0, pos
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with interrupts off {
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copy cinv, save_cinv
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copy our_cinv, cinv
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}
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}
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