Kernal
From C64-Wiki
Commodore's low-level Operating System was named the Kernal, mispelled early on from Kernel and repeated thereafter in countless publications. The Kernal was the set of low-level hardware interfaces repeated throughout Commodore's 8-bit computer series, beginning with the Commodore PET.
[edit] Functions
The Kernal consisted of thirty-nine (39) functions ranging from Input/Output control to file management, memory management, console management and time management. These functions formed the basis for higher level routines in the BASIC ROM like LOAD, SAVE, INPUT and PRINT.
Kernal functions are accessible via a jump-table at the end of addressable memory ($FF81-$FFF3). The Kernal ROM occupied the last 8KB of address space in Commodore 8-bit computers ($E000-$FFFF).
| Name | Address | Function | |
| Hexadecimal | Decimal | ||
| ACPTR | $FFA5 | 65445 | Input byte from serial port |
| CHKIN | $FFC6 | 65478 | Open channel for input |
| CHKOUT | $FFC9 | 65481 | Open a channel for output |
| CHRIN | $FFCF | 65487 | Get a character from the input channel |
| CHROUT | $FFD2 | 65490 | Output a character |
| CIOUT | $FFA8 | 65448 | Transmit a byte over the serial bus |
| CINT | $FF81 | 65409 | Initialize the screen editor and VIC-II Chip |
| CLALL | $FFE7 | 65511 | Close all open files |
| CLOSE | $FFC3 | 65475 | Close a logical file |
| CLRCHN | $FFCC | 65484 | Clear all I/O channels |
| GETIN | $FFE4 | 65508 | Get a chatacter |
| IOBASE | $FFF3 | 65523 | Define I/O memory page |
| IOINIT | $FF84 | 65412 | Initialize I/O devices |
| LISTEN | $FFB1 | 65457 | Command a device on the serial bus to talk |
| LOAD | $FFD5 | 65493 | Load RAM from device |
| MEMBOT | $FF9C | 65436 | Set bottom of memory |
| MEMTOP | $FF99 | 65433 | Set the top of RAM |
| OPEN | $FFC0 | 65472 | Open a logical file |
| PLOT | $FFF0 | 65520 | Set or retrieve cursor location |
| RAMTAS | $FF87 | 65415 | Perform RAM test |
| RDTIM | $FFDE | 65502 | Read system clock |
| READST | $FFB7 | 65463 | Read status word |
| RESTOR | $FF8A | 65418 | Set the top of RAM |
| SAVE | $FFD8 | 65496 | Save memory to a device |
| SCNKEY | $FF9F | 65439 | Scan the keyboard |
| SCREEN | $FFED | 65517 | Return screen format |
| SECOND | $FF93 | 65427 | Send secondary address for LISTEN |
| SETLFS | $FFBA | 65466 | Set up a logical file |
| SETMSG | $FF90 | 65424 | Set system message output |
| SETNAM | $FFBD | 65469 | Set up file name |
| SETTIM | $FFDB | 65499 | Set the system clock |
| SETTMO | $FFAE | 65442 | Set IEEE bus card timeout flag |
| STOP | $FFE1 | 65505 | Check if STOP key is pressed |
| TALK | $FFB4 | 65460 | Command a device on the serial bus to talk |
| TKSA | $FF96 | 65430 | Send a secondary address to a device commanded to talk |
| UDTIM | $FFEA | 65514 | Update the system clock |
| UNLSN | $FFAE | 65454 | Send an UNLISTEN command |
| UNTLK | $FFAB | 65451 | Send an UNTALK command |
| VECTOR | $FF8D | 65421 | Manage RAM vectors |
