Routines
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B8C4: Print an FF terminated string, processing control characters
Used by the routines at 80E5, B2F1, B3C3, B451 and ED2A.
Input
C The attribute to display
HL The address of the start of the string
D The y co-ordinate of the first character
E The x co-ordinate of the first character
B8C4 LD A,(HL) Get the current byte.
B8C5 INC HL Point HL to the next one.
B8C6 CP $80 Is the current byte less than 80?
B8C8 JR C,$B8E7 Jump forward if so.
B8CA CP $FF Is the current byte an end marker? (FF)
B8CC RET Z Return if it is, it's the end of the string.
Process a special character.
B8CD CP $FE Is the current byte an attribute marker? (FE)
B8CF JR NZ,$B8D5 Jump forward if it isn't.
B8D1 LD C,(HL) Otherwise put the next byte as an attribute in C.
Process an attribute character.
B8D2 INC HL Point HL to the next place in the buffer.
B8D3 JR $B8C4 Jump back to draw some more.
Process more special characters.
B8D5 CP $A8 If the current byte isn't between A8 and E8 then it's an unrecognised character, so ignore it.
B8D7 JR C,$B8E7
B8D9 CP $E8
B8DB JR NC,$B8E7
Process position / movement characters.
B8DD SUB $C8 Subtract C8 to get the actual offset (which may be negative).
B8DF ADD A,E Add this to the x co-ordinate.
B8E0 LD E,A
B8E1 LD A,D Use the next byte as an offset for the y co-ordinate.
B8E2 ADD A,(HL)
B8E3 LD D,A
B8E4 INC HL Point HL to the next place in the buffer.
B8E5 JR $B8C4 Jump back to draw some more.
This is a simple ASCII character.
B8E7 CALL $B715 Print the graphic.
B8EA INC E Move forward one column.
B8EB JR $B8C4 Jump back to draw some more.
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