mirror of https://github.com/KarolS/millfork.git
60 lines
1.1 KiB
Plaintext
60 lines
1.1 KiB
Plaintext
// mouse driver for Commodore 1531 mouse on Commodore 64
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import mouse
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import c64_hardware
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sbyte _c1531_calculate_delta (byte old, byte new) {
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byte mouse_delta
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mouse_delta = (new - old)
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mouse_delta &= $3f
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if mouse_delta >= $20 {
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mouse_delta |= $c0
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}
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return mouse_delta
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}
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byte _c1531_handle_x() {
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static byte _c1531_old_pot_x
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sbyte mouse_delta
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byte new_pot_x
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new_pot_x = sid_paddle_x >> 1
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mouse_delta = _c1531_calculate_delta(_c1531_old_pot_x, new_pot_x)
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_c1531_old_pot_x = new_pot_x
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mouse_x += mouse_delta
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mouse_x.hi &= 1
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if mouse_x > 319 {
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if mouse_delta > 0 {
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mouse_x = 319
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} else {
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mouse_x = 0
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}
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}
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}
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byte _c1531_handle_y() {
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static byte _c1531_old_pot_y
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byte new_pot_y
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sbyte mouse_delta
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new_pot_y = sid_paddle_y >> 1
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mouse_delta = _c1531_calculate_delta(_c1531_old_pot_y, new_pot_y)
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_c1531_old_pot_y = new_pot_y
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mouse_y -= mouse_delta
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if mouse_y > 199 {
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if mouse_delta > 0 {
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mouse_y = 0
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} else {
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mouse_y = 199
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}
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}
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}
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void c1531_mouse () {
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cia1_pra = ($3f & cia1_pra) | $40
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_c1531_handle_x()
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_c1531_handle_y()
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} |