Routines
Prev: 37376 Up: Map Next: 37434
37417: Screen Address One Pixel Below
Used by the routines at DrawBackground, 37434 and Yin_Yang_Copy.
Input
HL Current position
Output
HL Address for new position
Calculates the new address for writing a sprite pixel, in a downward direction, taking into consideration the screen memory layout.
ScreenPos1PixelBelow 37417 INC H Increment H by one to move down one pixel on screen.
37418 LD A,H Stash H in A temporarily.
37419 AND %00000111 Keep only bits 0-2.
37421 JR NZ,ScreenPos1PixelBelow_Return If a character line has not been crossed then jump to ScreenPos1PixelBelow_Return to return.
37423 LD A,32 L+=32.
37425 ADD A,L
37426 LD L,A
37427 JR C,ScreenPos1PixelBelow_Return If a new section of the screen has not been crossed, jump to ScreenPos1PixelBelow_Return to return.
37429 LD A,H H-=8.
37430 SUB 8
37432 LD H,A
ScreenPos1PixelBelow_Return 37433 RET Return.
Prev: 37376 Up: Map Next: 37434