Routines
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E32C: Pause Game
Used by the routine at StartGame.
Pauses the game if CAPS SHIFT or SPACE is pressed on its own. The game continues when the key has been pressed again.
Return unless CAPS SHIFT or SPACE is pressed on its own.
PauseGame E32C LD A,$7E Read from the keyboard;
Port Number Bit
0 1 2 3 4
7E SHIFT / SPACE Z / SYM X / M C / N V / B
E32E CALL ReadKeyboardPort
E331 BIT 0,A Return if neither of the keys CAPS SHIFT or SPACE is pressed.
E333 RET Z
Return if any of the other keys is pressed too.
E334 AND %00011110 Keep bits 1 to 4.
E336 RET NZ Return if any of them is set.
Wait for the key to be let go of, then pressed and let go of again.
PauseGame_Release E337 LD A,$7E Read the keys.
E339 CALL ReadKeyboardPort
E33C BIT 0,A Jump to PauseGame_Release if bit 0 is set.
E33E JR NZ,PauseGame_Release
Wait for a key to be pressed.
PauseGame_Press E340 LD A,$7E Read the keys.
E342 CALL ReadKeyboardPort
E345 BIT 0,A Jump to PauseGame_Press if bit 0 is not set.
E347 JR Z,PauseGame_Press
Wait for the key to be released.
PauseGame_ReleaseAgain E349 LD A,$7E Read the keys.
E34B CALL ReadKeyboardPort
E34E BIT 0,A Jump to PauseGame_ReleaseAgain if bit 0 is set.
E350 JR NZ,PauseGame_ReleaseAgain
E352 RET Return.
View the equivalent code in;
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