Routines
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46304: Pause Game
Used by the routine at RunGame.
Pauses the game while CAPS SHIFT or SPACE is held down on its own. A click is made to say that the game has been paused, and the game then waits for the key to be released, pressed and released again before another click and returning.
Interrupts are enabled while the game is paused, and the system variable pointer in IY is set up to what the ROM interrupt routine expects.
Return unless CAPS SHIFT or SPACE is the only key being pressed.
PauseGame 46304 LD A,126 Read from the keyboard, with a call to ReadKeyboardPort that returns the pressed keys as set bits;
Port Number Bit
0 1 2 3 4
126 CAPS SHIFT or SPACE Z or SYMBOL SHIFT X or M C or N V or B
46306 CALL ReadKeyboardPort
46309 BIT 0,A Return if neither CAPS SHIFT nor SPACE is pressed.
46311 RET Z
46312 AND %00011110 Keep only the keys other than CAPS SHIFT and SPACE.
46314 RET NZ Return if another key is pressed.
46315 CALL PlayClick Call PlayClick to make a click.
Wait for the key to be released.
PauseGame_WaitRelease 46318 LD A,126 Read the keyboard rows that hold CAPS SHIFT and SPACE.
46320 CALL ReadKeyboardPort
46323 BIT 0,A Jump to PauseGame_WaitRelease if CAPS SHIFT or SPACE is still pressed.
46325 JR NZ,PauseGame_WaitRelease
46327 LD IY,23610 Set up the system variables for the ROM interrupt routine.
46331 EI Enable interrupts.
The game is paused: wait for the key to be pressed.
PauseGame_WaitPress 46332 LD A,126 Read the keyboard rows that hold CAPS SHIFT and SPACE.
46334 CALL ReadKeyboardPort
46337 BIT 0,A Jump to PauseGame_WaitPress if neither is pressed.
46339 JR Z,PauseGame_WaitPress
Wait for the key to be released again.
PauseGame_WaitResume 46341 LD A,126 Read the keyboard rows that hold CAPS SHIFT and SPACE.
46343 CALL ReadKeyboardPort
46346 BIT 0,A Jump to PauseGame_WaitResume if CAPS SHIFT or SPACE is still pressed.
46348 JR NZ,PauseGame_WaitResume
46350 DI Disable interrupts.
46351 CALL PlayClick Call PlayClick to make a click.
46354 RET Return.
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