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Routines |
| Prev: E7E6 | Up: Map | Next: E80D |
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| E7E8 | XOR A | Set A=0 initially to indicate that we are copying a row of attribute bytes first | ||||||||
| E7E9 | PUSH HL | Save the source attribute file address | ||||||||
| E7EA | PUSH DE | Save the destination attribute file address | ||||||||
| E7EB | LD BC,$001F | The operand of this instruction is set to 001F by the routines at E80E and E845, and to 0020 by the routines at E87C, E8B7 and FC6A | ||||||||
| E7EE | LDDR | This instruction is set to LDIR by the routines at E80E, E87C, E8B7 and FC6A, and to LDDR by the routine at E845; it copies the source row of attribute bytes or pixels to the destination row | ||||||||
| E7F0 | POP DE | Restore the destination attribute file address to DE | ||||||||
| E7F1 | POP HL | Restore the source attribute file address to HL | ||||||||
| E7F2 | AND A | Have we just copied a row of attribute bytes? | ||||||||
| E7F3 | JR Z,$E7FB | Jump if so to point DE and HL at the corresponding display file bytes | ||||||||
| E7F5 | INC D | Otherwise point DE and HL at the next destination and source rows of pixels | ||||||||
| E7F6 | INC H | |||||||||
| E7F7 | DEC A | Have we copied 8 rows of pixels yet? | ||||||||
| E7F8 | JR NZ,$E7E9 | Jump back if not | ||||||||
| E7FA | RET | |||||||||
| E7FB | LD A,H | Set HL to the display file address that corresponds to the source attribute file address | ||||||||
| E7FC | AND $0B | |||||||||
| E7FE | ADD A,A | |||||||||
| E7FF | ADD A,A | |||||||||
| E800 | ADD A,A | |||||||||
| E801 | LD H,A | |||||||||
| E802 | LD A,D | Set DE to the display file address that corresponds to the destination attribute file address | ||||||||
| E803 | AND $0B | |||||||||
| E805 | ADD A,A | |||||||||
| E806 | ADD A,A | |||||||||
| E807 | ADD A,A | |||||||||
| E808 | LD D,A | |||||||||
| E809 | LD A,$08 | There are 8 rows of pixels to copy | ||||||||
| E80B | JR $E7E9 | Jump back to copy them | ||||||||
| Prev: E7E6 | Up: Map | Next: E80D |