| Alien (BUGFIX 1.7) | Routines |
| Prev: 43141 | Up: Map | Next: 43242 |
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XOR-toggles the attribute colour of the currently selected menu row, used by GameModeScreen to highlight or erase the cursor. Loads the base attribute address $59E9 (row 15, col 9), steps 64 bytes per row (selection × 64), then XORs 15 consecutive attribute bytes with 36 (flipping ink/paper to show highlight).
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| 43216 | LD HL,23017 | attribute address of the mode-0 row (row 15, col 9) | ||
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This entry point is used by the routine at 43610.
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| 43219 | LD DE,64 | 64 = two attribute rows per menu line | ||
| 43222 | LD A,(33683) | A = selected mode (0-2) | ||
| 43225 | AND A | |||
| 43226 | JR Z,43232 | |||
| 43228 | LD B,A | |||
| 43229 | ADD HL,DE | step down to the selected line | ||
| 43230 | DJNZ 43229 | |||
| 43232 | LD B,15 | 15 cells wide | ||
| 43234 | LD A,(HL) | XOR 36 swaps green-paper/black-ink to | ||
| 43235 | XOR 36 | black-paper/green-ink: inverse video | ||
| 43237 | LD (HL),A | |||
| 43238 | INC HL | |||
| 43239 | DJNZ 43234 | |||
| 43241 | RET | |||
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