Routines
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7145: End Of Pass
The housekeeping which is done at the end of every pass through the objects: this pauses the game while "SHIFT" is held down, adds one to the game timer and updates the random number. In the fast pass the instruction at 714F is changed to jump to ResetModifiedInFrame instead.
Holding "SHIFT" pauses the game.
Pause_Loop 7145 LD A,$FE Read from the keyboard;
Port Number Bit
0 1 2 3 4
FE SHIFT Z X C V
7147 OUT ($FD),A
7149 IN A,($FE)
714B BIT 0,A Jump to Pause_Loop if the "SHIFT" key has been pressed.
714D JR Z,Pause_Loop
714F LD HL,($5E17) HL=see 711E.
7152 INC HL Increment the game timer by one.
7153 LD ($5E17),HL Write the game timer back to GameTimer.
The random number is the old random number added to the byte of the ROM found using the low byte of the game timer, and added to the refresh register.
7156 LD H,$00 H=00.
7158 LD A,R A=the refresh register.
715A LD C,A C=A.
715B LD A,($5E19) A=RandomNumber.
715E ADD A,(HL) Add the byte from the ROM.
715F ADD A,C Add the refresh register.
7160 LD ($5E19),A Write the new random number to RandomNumber.
7163 EX AF,AF' Keep a copy of the random number in AF'.
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