| C64 ROM | Routines |
| Prev: B6EC | Up: Map | Next: B72C |
|
|
||||
| B700 | 20 61 B7 | JSR $B761 | pull string data and byte parameter from stack. return pointer in descriptor, byte in A (and X), Y=0 | |
| B703 | D1 50 | CMP ($50),Y | compare byte parameter with string length | |
| B705 | 98 | TYA | clear A | |
|
This entry point is used by the routine at B72C.
|
||||
| B706 | 90 04 | BCC $B70C | branch if string length > byte parameter | |
| B708 | B1 50 | LDA ($50),Y | else make parameter = length | |
| B70A | AA | TAX | copy to byte parameter copy | |
| B70B | 98 | TYA | clear string start offset | |
| B70C | 48 | PHA | save string start offset | |
|
This entry point is used by the routine at B737.
|
||||
| B70D | 8A | TXA | copy byte parameter (or string length if <) | |
|
This entry point is used by the routine at B737.
|
||||
| B70E | 48 | PHA | save string length | |
| B70F | 20 7D B4 | JSR $B47D | make string space A bytes long | |
| B712 | A5 50 | LDA $50 | get descriptor pointer low byte | |
| B714 | A4 51 | LDY $51 | get descriptor pointer high byte | |
| B716 | 20 AA B6 | JSR $B6AA | pop (YA) descriptor off stack or from top of string space. returns with A = length, X = pointer low byte, Y = pointer high byte | |
| B719 | 68 | PLA | get string length back | |
| B71A | A8 | TAY | copy length to Y | |
| B71B | 68 | PLA | get string start offset back | |
| B71C | 18 | CLC | clear carry for add | |
| B71D | 65 22 | ADC $22 | add start offset to string start pointer low byte | |
| B71F | 85 22 | STA $22 | save string start pointer low byte | |
| B721 | 90 02 | BCC $B725 | branch if no overflow | |
| B723 | E6 23 | INC $23 | else increment string start pointer high byte | |
| B725 | 98 | TYA | copy length to A | |
| B726 | 20 8C B6 | JSR $B68C | store string from pointer to utility pointer | |
| B729 | 4C CA B4 | JMP $B4CA | check space on descriptor stack then put string address and length on descriptor stack and update stack pointers | |
| Prev: B6EC | Up: Map | Next: B72C |