The Hobbit: Routine at 7249

7249: Input: Wait For A Key

Used by the routine at ReadTheInputLine. Counts down the input delay while polling the keyboard. A key raises the next delay by 01F4, up to 0BB8, and is returned. If the delay runs out, 7291 is printed into the buffer, ENTER is returned, and the next delay is cleared.
Input_WaitForAKey	7249	PUSH HL	Read the input delay.
	724A	LD HL,($B714)	Read the input delay.
Input_WaitForAKey_Poll	724D	CALL GetKey	Poll the keyboard.
	7250	AND A	Jump to Input_WaitForAKey_AddToTheDelay if a key is waiting.
	7251	JR NZ,Input_WaitForAKey_AddToTheDelay
	7253	DEC HL	Loop back to Input_WaitForAKey_Poll to keep polling until the delay runs out.
	7254	LD A,H
	7255	OR L
	7256	JR NZ,Input_WaitForAKey_Poll
	7258	POP HL	Rub out the characters typed so far.
	7259	PUSH HL
	725A	CALL Input_RubOutCharacters
	725D	LD DE,$7291	Point at the letters W, A, I, T.
	7260	LD B,$04	Four letters.
Input_WaitForAKey_Wait	7262	LD A,(DE)	Store the next letter of 7291 in the input buffer.
	7263	LD (HL),A
	7264	INC HL
	7265	INC DE
	7266	CALL Print_Character	Print that letter.
	7269	DJNZ Input_WaitForAKey_Wait	Loop back to Input_WaitForAKey_Wait until 7291 is done.
	726B	EX (SP),HL	Remember the pointer after 7291, and prepare ENTER. The next delay is FE0C plus 01F4, which is zero.
	726C	LD B,$7C
	726E	LD A,$0D
	7270	LD HL,$FE0C
Input_WaitForAKey_AddToTheDelay	7273	PUSH AF	Add 01F4 to the delay. A key raises the current delay; the timeout path adds it to zero.
	7274	XOR A
	7275	LD DE,$01F4
	7278	ADC HL,DE
	727A	LD DE,$0BB8	The cap is 0BB8.
	727D	JR C,Input_WaitForAKey_Cap	Jump to Input_WaitForAKey_Cap if the sum overflowed, and use the cap.
	727F	CALL Input_CompareTwoTotals	Call Input_CompareTwoTotals to compare the delay with the cap.
	7282	JR C,Input_WaitForAKey_Store	Jump to Input_WaitForAKey_Store if the delay is still under the cap.
Input_WaitForAKey_Cap	7284	EX DE,HL	Use the cap instead.
Input_WaitForAKey_Store	7285	LD ($B714),HL	Store the next input delay.
	7288	POP AF	Restore AF and HL from the stack.
	7289	POP HL	Restore AF and HL from the stack.
	728A	RET	Return.