Routines
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D671: Find Next Valid Exit
Used by the routine at PrintLocationExitsWithFormatting.
Input
IX Pointer to exit data
BC Exit data length
Output
F Zero flag set if valid exit found
FindNextValidExit D671 ADD IX,BC IX+=BC.
D673 LD A,$FF A=FF.
D675 CP (IX+$00) Compare A with *IX+00.
D678 RET Z Return if A is equal to FF.
D679 XOR A A=00.
D67A CP (IX+$01) Compare A with *IX+01.
D67D JR NZ,FindNextValidExit Jump to FindNextValidExit if A is not equal to FF.
D67F LD A,(IX+$00) A=*IX+00.
D682 AND A Set flags.
D683 JR Z,FindNextValidExit Jump to FindNextValidExit if A is equal to A.
D685 CP $0B Compare A with 0B.
D687 JR NC,FindNextValidExit Jump to FindNextValidExit if A is greater than or equal to 0B.
D689 OR %00000001 Set bit 0.
D68B RET Return.
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