Systems Guide
Memory Map
Page 2 Continued
by James Capparell
Memory Map is an on-going feature of ANTIC. We intend to publish the function of all the low memory RAM locations. The format for our description is:
| 12 | $C | 2 | DOSINI | The Operating System variable called DOSINI uses 2 contiguous locations starting at address 12 (decimal) or C (hexidecimal). |
| 566 | $236 | 4 | SPARE | No Operating System Function. |
| 570 | $23A | 1 | CDEVIC | ??? |
| 571 | $23B | 1 | CCOMND | ??? |
| 572 | $23C | 1 | CAUX1 | ??? |
| 573 | $23D | 1 | CAUX2 | Command auxiliary byte. |
| 574 | $23E | 1 | TEMP | Receives one-byte responses from serial bus controllers. |
| 575 | $23F | 1 | ERRFLG | Error flag any device error except timeout errors. |
| 576 | $240 | 1 | DFLAGS | Disk flags from sector 1, contains value of first byte of boot file. |
| 577 | $241 | 1 | DBSECT | Number of disk boot sectors. |
| 578 | $242 | 2 | BOOTAD | Address where disk boot loader will be put. |
| 580 | $244 | 1 | COLDST | Coldstart flag when = 1 then powerup in progress. When = 0 then S / RESET in progress. If set = 1 during norm program execution then S / RESET will act like powerup giving some protection. |
| 581 | $245 | 1 | SPARE | No Operating System Function. |
| 582 | $246 | 1 | DSKTIM | Disk timeout register. |
| 583 | $247 | 40 | LINBUF | Character line buffer used to temporarily buffer one physical line of text when screen editor is moving screen data |
| 626 | $26F | 1 | GPRIOR | Global priority shadow for PRIOR [$DOlB] controls priority of player/missile/playfield. |
| 627 | $270 | 8 | PADDL0- | |
| PADDL7 | Potentiometer 0 - 7 storage. | |||
| 635 | $278 | 4 | STICK0 | |
| STICK3 | Joystick 0 - 3 values. | |||
| 636 | $27C | 8 | PTRIG0 | |
| PTRIG7 | Paddle trigger 0 - 7. | |||
| 644 | $284 | 4 | STRIG0 | Joystick trigger 0 - 3. |
| 648 | $288 | 1 | CSTAT | No Operating System Function. |
| 649 | $28 | 1 | WMODE | Used by cassette handler as read/write mode flag. 0 = read; $80 = write. |
| 650 | $28A | 1 | BLIM | Cassette record data size Count of # of data bytes being read range 1-128 depends on record control byte. |
| 651 | $28B | 4 | SPARE | No Operating System Function. |
| 656 | $290 | 1 | TXTROW | Text row cursor range 0-3. |
| 657 | $291 | 2 | TXTCOL | Text column cursor range 0-39 used in split screen. These two variables give cursor position. |
| 659 | $293 | 1 | TINDEX | Split screen text window index always = 0 when SWPFLG[78] = 0 equivalent of DINDEX. |
| 660 | $294 | 2 | TXTMSC | Split screen text window version SAVMSC[58]. |
| 662 | $296 | 6 | TXTOLD | Oldrow and old column for text and then some split screen cursor data. |
| 668 | $29C | 1 | TMPXI | ? ? |
| 669 | $29D | 1 | HOLD3 | Used by the display handler to hold scroll loop counter. |
| 670 | $29E | 1 | SUBTMP | ? ? |
| 671 | $29F | 1 | HOLD2 | ? ? |
| 672 | $2A0 | 1 | DMASK | ? ? |