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Routines |
| Prev: 21746 | Up: Map | Next: 22000 |
| BC | 256 |
| DE | 33024 |
| HL | 23296 |
| 21920 | LDIR | Copy 256 bytes from 23296 to 33024 |
| 21922 | LD H,88 | INK 1: PAPER 1 |
| 21924 | LD B,3 | |
| 21926 | LD D,H | |
| 21927 | INC E | |
| 21928 | LD (HL),9 | |
| 21930 | LDIR | |
| 21932 | LD HL,23611 | Reset bit 5 at 23611, ready for future keypresses |
| 21935 | RES 5,(HL) | |
| 21937 | EXX | Point HL' at the last byte of the graphic data for the digit "9" in the ROM |
| 21938 | LD HL,15823 | |
| 21941 | EXX | |
| 21942 | LD DE,1084 | Wait approximately one second |
| 21945 | DJNZ 21945 | |
| 21947 | DEC DE | |
| 21948 | LD A,D | |
| 21949 | OR E | |
| 21950 | JR NZ,21945 | |
| 21952 | LD HL,23020 | 23020 is the attribute file address where the bottom row of "big pixels" will be drawn |
| 21955 | LD DE,65496 | DE=-40 |
| 21958 | LD C,8 | There are 8 pixel rows per countdown digit |
| 21960 | EXX | |
| 21961 | BIT 7,L | Set the zero flag when HL' hits 15743 |
| 21963 | LD A,(HL) | Pick up a digit pixel row byte |
| 21964 | DEC HL | Move HL' to the next pixel row up |
| 21965 | EXX | |
| 21966 | JP Z,21737 | Jump to start the game if we've already printed "0" |
| 21969 | LD B,8 | There are 8 bits per pixel row |
| 21971 | LD (HL),9 | INK 1: PAPER 1 (blue) for a reset pixel |
| 21973 | RLCA | Is this a reset pixel? |
| 21974 | JR NC,21978 | Jump if so |
| 21976 | LD (HL),36 | INK 4: PAPER 4 (green) for a set pixel |
| 21978 | INC HL | Move HL along to the next attribute file address |
| 21979 | DJNZ 21971 | Jump back until all 8 "big pixels" have been drawn |
| 21981 | ADD HL,DE | Move HL back 8 spaces and up one row of the attribute file |
| 21982 | DEC C | Next pixel row |
| 21983 | JR NZ,21960 | Jump back until all 8 pixel rows have been drawn |
| 21985 | CALL 29012 | Make a ticking sound effect |
| 21988 | LD HL,23611 | |
| 21991 | BIT 5,(HL) | Reset the zero flag if a key was pressed |
| 21993 | RES 5,(HL) | Reset bit 5 at 23611, ready for future keypresses |
| 21995 | JP NZ,21425 | Jump if a key was pressed |
| 21998 | JR 21942 | Wait roughly one second, then print the next digit |
| Prev: 21746 | Up: Map | Next: 22000 |