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Routines |
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| 59368 | XOR A | Set A=0 initially to indicate that we are copying a row of attribute bytes first | ||||||||
| 59369 | PUSH HL | Save the source attribute file address | ||||||||
| 59370 | PUSH DE | Save the destination attribute file address | ||||||||
| 59371 | LD BC,31 | The operand of this instruction is set to 31 by the routines at 59406 and 59461, and to 32 by the routines at 59516, 59575 and 64618 | ||||||||
| 59374 | LDDR | This instruction is set to LDIR by the routines at 59406, 59516, 59575 and 64618, and to LDDR by the routine at 59461; it copies the source row of attribute bytes or pixels to the destination row | ||||||||
| 59376 | POP DE | Restore the destination attribute file address to DE | ||||||||
| 59377 | POP HL | Restore the source attribute file address to HL | ||||||||
| 59378 | AND A | Have we just copied a row of attribute bytes? | ||||||||
| 59379 | JR Z,59387 | Jump if so to point DE and HL at the corresponding display file bytes | ||||||||
| 59381 | INC D | Otherwise point DE and HL at the next destination and source rows of pixels | ||||||||
| 59382 | INC H | |||||||||
| 59383 | DEC A | Have we copied 8 rows of pixels yet? | ||||||||
| 59384 | JR NZ,59369 | Jump back if not | ||||||||
| 59386 | RET | |||||||||
| 59387 | LD A,H | Set HL to the display file address that corresponds to the source attribute file address | ||||||||
| 59388 | AND 11 | |||||||||
| 59390 | ADD A,A | |||||||||
| 59391 | ADD A,A | |||||||||
| 59392 | ADD A,A | |||||||||
| 59393 | LD H,A | |||||||||
| 59394 | LD A,D | Set DE to the display file address that corresponds to the destination attribute file address | ||||||||
| 59395 | AND 11 | |||||||||
| 59397 | ADD A,A | |||||||||
| 59398 | ADD A,A | |||||||||
| 59399 | ADD A,A | |||||||||
| 59400 | LD D,A | |||||||||
| 59401 | LD A,8 | There are 8 rows of pixels to copy | ||||||||
| 59403 | JR 59369 | Jump back to copy them | ||||||||
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