Routines
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A536: Wait For A Key With Timeout
Used by the routine at ReadCommandLine_CommandLinePrints.
Waits for a key until the timer at A039+02 runs out. GetKeypress sets bit 7 when a key is pressed. When the timer expires, DeleteInputCharacter runs. Either way the timer is reset to 0BB8.
WaitForKeyWithTimeout A536 PUSH HL Save the pointer and read the timeout at A039+02.
A537 LD HL,($A03B)
WaitForKeyWithTimeout_Loop A53A CALL GetKeypress Jump ahead to WaitForKeyWithTimeout_KeyPressed if GetKeypress reports a key.
A53D BIT 7,A
A53F JR NZ,WaitForKeyWithTimeout_KeyPressed
A541 LD A,$00 Start the delay at zero.
WaitForKeyWithTimeout_0 A543 DEC A Spin until the delay runs out.
A544 PUSH HL
A545 POP HL
A546 JR NZ,WaitForKeyWithTimeout_0
A548 DEC HL Count the timeout down.
A549 LD A,H
A54A OR L
A54B JR NZ,WaitForKeyWithTimeout_Loop
A54D POP HL Restore the pointer from the stack.
A54E PUSH HL Call DeleteInputCharacter, keeping the pointer.
A54F CALL DeleteInputCharacter
A552 XOR A Clear the key code.
WaitForKeyWithTimeout_KeyPressed A553 AND $7F Clear bit 7 and reset the timeout to 0BB8.
A555 LD HL,$0BB8
A558 LD ($A03B),HL
A55B POP HL Restore the saved pointer from the stack.
A55C RET Return.
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