Routines
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48183: Adjust Screen Address at Row Boundary
Used by the routines at Draw_3Wide_Sprite_Column and Draw_2Wide_Sprite_Column.
Adjusts the screen buffer address in HL when a pixel row crosses a character cell boundary.
Input
HL Screen buffer address
Output
HL Adjusted Screen buffer address
Adjust_Screen_Address 48183 LD A,L Load the low byte of the screen address.
48184 DEC H Undo the previous row increment and test if the next character row would cross into the next screen third.
48185 CPL
48186 AND %11100000
48188 JR Z,Next_Screen_Third Jump to Next_Screen_Third if crossing into the next screen third.
48190 LD A,L Add 32 to L to move to the next character row.
48191 ADD A,32
48193 LD L,A
48194 LD A,H Mask H to reset the pixel row bits.
48195 AND %11111000
48197 LD H,A
48198 RET Return.
Next_Screen_Third 48199 LD A,L Mask L to keep only the column bits.
48200 AND %00011111
48202 LD L,A
48203 LD A,H Mask H and add 8 to advance to the next screen third.
48204 AND %11111000
48206 ADD A,8
48208 LD H,A
48209 RET Return.
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