| C64 ROM | Routines |
| Prev: E518 | Up: Map | Next: E566 |
|
Used by the routine at E716.
|
||||
| E544 | AD 88 02 | LDA $0288 | get the screen memory page | |
| E547 | 09 80 | ORA #$80 | set the high bit, flag every line is a logical line start | |
| E549 | A8 | TAY | copy to Y | |
| E54A | A9 00 | LDA #$00 | clear the line start low byte | |
| E54C | AA | TAX | clear the index | |
| E54D | 94 D9 | STY $D9,X | save the start of line X pointer high byte | |
| E54F | 18 | CLC | clear carry for add | |
| E550 | 69 28 | ADC #$28 | add the line length to the low byte | |
| E552 | 90 01 | BCC $E555 | if no rollover skip the high byte increment | |
| E554 | C8 | INY | else increment the high byte | |
| E555 | E8 | INX | increment the line index | |
| E556 | E0 1A | CPX #$1A | compare it with the number of lines + 1 | |
| E558 | D0 F3 | BNE $E54D | loop if not all done | |
| E55A | A9 FF | LDA #$FF | set the end of table marker | |
| E55C | 95 D9 | STA $D9,X | mark the end of the table | |
| E55E | A2 18 | LDX #$18 | set the line count, 25 lines to do, 0 to 24 | |
| E560 | 20 FF E9 | JSR $E9FF | clear screen line X | |
| E563 | CA | DEX | decrement the count | |
| E564 | 10 FA | BPL $E560 | loop if more to do | |
| Prev: E518 | Up: Map | Next: E566 |