| C64 ROM | Routines |
| Prev: B487 | Up: Map | Next: B526 |
|
Used by the routine at B47D.
return X = pointer low byte, Y = pointer high byte
|
||||
| B4F4 | 46 0F | LSR $0F | clear garbage collected flag (b7) | |
|
make space for string A long
|
||||
| B4F6 | 48 | PHA | save string length | |
| B4F7 | 49 FF | EOR #$FF | complement it | |
| B4F9 | 38 | SEC | set carry for subtract, two's complement add | |
| B4FA | 65 33 | ADC $33 | add bottom of string space low byte, subtract length | |
| B4FC | A4 34 | LDY $34 | get bottom of string space high byte | |
| B4FE | B0 01 | BCS $B501 | skip decrement if no underflow | |
| B500 | 88 | DEY | decrement bottom of string space high byte | |
| B501 | C4 32 | CPY $32 | compare with end of arrays high byte | |
| B503 | 90 11 | BCC $B516 | do out of memory error if less | |
| B505 | D0 04 | BNE $B50B | if not = skip next test | |
| B507 | C5 31 | CMP $31 | compare with end of arrays low byte | |
| B509 | 90 0B | BCC $B516 | do out of memory error if less | |
| B50B | 85 33 | STA $33 | save bottom of string space low byte | |
| B50D | 84 34 | STY $34 | save bottom of string space high byte | |
| B50F | 85 35 | STA $35 | save string utility ptr low byte | |
| B511 | 84 36 | STY $36 | save string utility ptr high byte | |
| B513 | AA | TAX | copy low byte to X | |
| B514 | 68 | PLA | get string length back | |
| B515 | 60 | RTS | ||
| B516 | A2 10 | LDX #$10 | error code $10, out of memory error | |
| B518 | A5 0F | LDA $0F | get garbage collected flag | |
| B51A | 30 B6 | BMI $B4D2 | if set then do error code X | |
| B51C | 20 26 B5 | JSR $B526 | else go do garbage collection | |
| B51F | A9 80 | LDA #$80 | flag for garbage collected | |
| B521 | 85 0F | STA $0F | set garbage collected flag | |
| B523 | 68 | PLA | pull length | |
| B524 | D0 D0 | BNE $B4F6 | go try again (loop always, length should never be = $00) | |
| Prev: B487 | Up: Map | Next: B526 |