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Routines |
| Prev: 6AE3 | Up: Map | Next: 6B1A |
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| 6AE4 | PUSH DE | Save the attribute file address temporarily | ||||||||
| 6AE5 | LD A,$03 | There are 3 rows of character squares | ||||||||
| 6AE7 | LD BC,$0008 | There are 8 character squares in each row | ||||||||
| 6AEA | LDIR | Copy one row of attribute bytes to the screen | ||||||||
| 6AEC | LD C,$18 | Point DE at the start of the next row down | ||||||||
| 6AEE | EX DE,HL | |||||||||
| 6AEF | ADD HL,BC | |||||||||
| 6AF0 | EX DE,HL | |||||||||
| 6AF1 | DEC A | |||||||||
| 6AF2 | JR NZ,$6AE7 | Jump back to copy the remaining attributes to the screen | ||||||||
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The attribute bytes have been copied to the screen. Now for the graphic bytes.
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| 6AF4 | POP DE | Restore the attribute file address to DE | ||||||||
| 6AF5 | LD A,D | Set DE to the appropriate display file address | ||||||||
| 6AF6 | SUB $50 | |||||||||
| 6AF8 | ADD A,A | |||||||||
| 6AF9 | ADD A,A | |||||||||
| 6AFA | ADD A,A | |||||||||
| 6AFB | LD D,A | |||||||||
| 6AFC | LD C,$03 | There are 3 rows of character squares | ||||||||
| 6AFE | LD A,$08 | There are 8 rows of pixels per character square | ||||||||
| 6B00 | PUSH BC | Save the character square row counter | ||||||||
| 6B01 | PUSH DE | |||||||||
| 6B02 | LD C,$08 | There are 8 bytes in each row of pixels | ||||||||
| 6B04 | LDIR | Copy one row of pixels to the screen | ||||||||
| 6B06 | POP DE | |||||||||
| 6B07 | INC D | Point to the display file address of the next pixel row | ||||||||
| 6B08 | DEC A | |||||||||
| 6B09 | JR NZ,$6B01 | Jump back to fill in the remaining pixel rows for this row of character squares | ||||||||
| 6B0B | LD A,E | Set DE to the start address of the first pixel row in the next row of character squares | ||||||||
| 6B0C | ADD A,$20 | |||||||||
| 6B0E | LD E,A | |||||||||
| 6B0F | JR C,$6B15 | |||||||||
| 6B11 | LD A,D | |||||||||
| 6B12 | SUB $08 | |||||||||
| 6B14 | LD D,A | |||||||||
| 6B15 | POP BC | Restore the character square row counter to C | ||||||||
| 6B16 | DEC C | |||||||||
| 6B17 | JR NZ,$6AFE | Jump back to fill in the remaining rows of character squares | ||||||||
| 6B19 | RET | |||||||||
| Prev: 6AE3 | Up: Map | Next: 6B1A |