|
Routines |
| Prev: 48018 | Up: Map | Next: 48081 |
|
Used by the routine at 47193.
|
||||
| 48027 | LD BC,(23408) | Load BC with the coordinates of the top-left corner of the area to fill | ||
| 48031 | CALL 63219 | Load HL with attribute file address for coordinates (C, B) | ||
|
The operand of the instruction at 48034 is an attribute value. This is modified by the instruction at 47267.
|
||||
| 48034 | LD A,0 | Load attribute to place into A | ||
| 48036 | LD (HL),A | Apply attribute data to attribute file address in HL | ||
| 48037 | LD A,(23410) | Load A with x-coordinate of right side of area to fill | ||
| 48040 | CP C | Check if left and right edges are at same x-coordinate (i.e. zero width)... | ||
| 48041 | JP Z,48057 | ...and if so, skip to 48057 | ||
| 48044 | INC C | Increase C | ||
| 48045 | LD A,C | Copy C into A | ||
| 48046 | AND 31 | Ensure current x-coordinate doesn't exceed 31 (i.e. width of screen) | ||
| 48048 | LD C,A | Place back into C | ||
| 48049 | LD A,L | Get LSB of attribute file address | ||
| 48050 | AND 224 | Decrease to nearest multiple of 32 (i.e. start of character row in attribute file) | ||
| 48052 | ADD A,C | Add x-offset (i.e. current x-coordinate, C) | ||
| 48053 | LD L,A | Update HL with x-offset | ||
| 48054 | JP 48034 | Loop back to 48034 to print next attribute block | ||
| 48057 | LD A,(23408) | Get x-coordinate of left of area to fill | ||
| 48060 | LD C,A | Store in C | ||
| 48061 | LD A,(23411) | Get y-coordinate of bottom of area to fill | ||
| 48064 | CP B | Compare with y-coordinate of top of area to fill | ||
| 48065 | RET Z | If no difference between current y-coordinate and y-coordinate of bottom of area to fill then exit function and return | ||
| 48066 | INC B | Advance current y-coordinate down one unit | ||
| 48067 | LD A,B | Copy current y-coordinate into A... | ||
| 48068 | CP 24 | ...and ensure it doesn't exceed 24 (i.e. height of screen)... | ||
| 48070 | JP NZ,48075 | ...if it doesn't then skip ahead to 48075... | ||
| 48073 | LD B,0 | ...else set current y-coordinate to zero (top of screen) | ||
| 48075 | CALL 63219 | Load HL with attribute file address for coordinates (C, B) | ||
| 48078 | JP 48034 | Loop back to print next attribute block row | ||
| Prev: 48018 | Up: Map | Next: 48081 |