|
Routines |
| Prev: CF39 | Up: Map | Next: CF5F |
|
Used by the routine at compare_along_y.
Part of compare_next_obj. Along X (centre +$01, half-size +$04) the code adds 0 if the candidate's low-X edge is at or beyond IY's high-X edge -- IY lies wholly further back -- 18 if the candidate lies wholly further back, and 9 if they overlap.
|
||||
| compare_along_x | CF3C | LD A,(IY+$01) | L = IY's high-X edge | |
| CF3F | ADD A,(IY+$04) | |||
| CF42 | LD L,A | candidate's low-X edge at or beyond it: add 0 | ||
| CF43 | LD A,(IX+$01) | |||
| CF46 | SUB (IX+$04) | |||
| CF49 | SUB L | |||
| CF4A | JR NC,act_on_comparison | |||
| CF4C | LD A,(IX+$01) | L = the candidate's high-X edge | ||
| CF4F | ADD A,(IX+$04) | |||
| CF52 | LD L,A | IY's low-X edge at or beyond it: add 18, otherwise 9 | ||
| CF53 | LD A,(IY+$01) | |||
| CF56 | SUB (IY+$04) | |||
| CF59 | SUB L | |||
| CF5A | LD A,C | |||
| CF5B | JR C,add_x_code | |||
| CF5D | ADD A,$09 | |||
| Prev: CF39 | Up: Map | Next: CF5F |