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en:docs:kernel:doskrnl [2023/11/26 14:33] – prokushev | en:docs:kernel:doskrnl [2024/05/25 02:43] (current) – prokushev | ||
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+ | {{page> | ||
+ | |||
====== DOSKRNL ====== | ====== DOSKRNL ====== | ||
- | DOSKRNL is a specialized | + | DOSKRNL is a specialized |
+ | |||
+ | ===== Initialization ===== | ||
+ | |||
+ | DOSKRNL loaded at address differ from standard DOS 0060:0000 address. On test environment it was loaded to 0280:00, but [[https:// | ||
+ | |||
+ | On DOSKRNL startup registers are following: | ||
+ | |||
+ | * CS:IP - starting point | ||
+ | * SS:BP - pointer to the DOSKRNL init structure (also referenced as VDOS init in IBM documents) | ||
+ | * SS:SP - stack pointer (size around 800 bytes) | ||
- | ===== Startup ===== | + | Interrupts disabled. |
- | On DOSKRNL | + | DOSKRNL |
^ Offset ^ Size ^ Description ^ | ^ Offset ^ Size ^ Description ^ | ||
Line 11: | Line 23: | ||
| 2 | 2 | Size of memory - first free segment (paragraphs) | | | 2 | 2 | Size of memory - first free segment (paragraphs) | | ||
| 4 | 2 | Size of init area (paragraphs)| | | 4 | 2 | Size of init area (paragraphs)| | ||
- | | ???? | ??? | + | | 6 |
- | | 22 | 4 | Pointer | + | | 8 | 2 | Value of DOS setting | |
- | | 25 | 1 | Current drive (0-A, 1-B,...)| | + | | 10 | 4 | Far pointer to list of DOS DEVICE setting | |
- | | 26 | 1 | Boot drive (0-A, 1-B,...) | | + | | 14 | 4 | Far pointer to SHELL (filepath only) | |
+ | | 18 | 4 | Far pointer to SHELL (arguments) | ||
+ | | 22 | 4 | Far pointer | ||
+ | | 26 | 1 | Current drive (1-A, 2-B, 3-C, ...)| | ||
+ | | 27 | 1 | Boot drive (1-A, 2-B, 3-C, ...) | | ||
+ | | 28 | 1 | Last drive (1-A, 2-B, 3-C, ...) | | ||
+ | | ??? | ??? | ??? | | ||
+ | DEVICES is ASCIIZ string with list of DOS devices to be loaded divided by 0AH | ||
- | Memory map on DOSKRNL start: | + | SHELL is ASCIIZ string. |
- | | Init area | [BP+0+BP+2-BP+4]: | + | SHELL arguments is ASCIIZ string (first byte is a string length, string ends with 0dh) |
- | | Free | [BP+0]:0 | | + | |
- | | DOSKRNL | + | |
- | | CMOS Data | 40:0 | | + | |
- | | Interrupt vectors | 0:0 | | + | |
- | As in most DOS kernels, DOSKRNL moves initialization code to higher memory. But uses init structure, not BIOS INT 12h, for memory information. | + | VDD is linked list of structures: |
- | VDDs linked list (in init area) in standard DOS Device drivers format | + | VDDs linked list in standard DOS Device drivers format. Entry can be placed in HMA, so need to be sure A20 enabled for such entries. Named as DOSDDTYPE in DDK |
^ offset ^ Size ^ Description ^ | ^ offset ^ Size ^ Description ^ | ||
Line 34: | Line 49: | ||
| ::: | ::: | Bit 15 = 1 if char device 0 if blk | | | ::: | ::: | Bit 15 = 1 if char device 0 if blk | | ||
| ::: | ::: | if bit 15 is 1 | | | ::: | ::: | if bit 15 is 1 | | ||
- | | ::: | ::: | Bit 0 = 1 if Current | + | | ::: | ::: | Bit 0 = 1 if Current |
- | | ::: | ::: | Bit 1 = 1 if Current | + | | ::: | ::: | Bit 1 = 1 if Current |
- | | ::: | ::: | Bit 2 = 1 if Current | + | | ::: | ::: | Bit 2 = 1 if Current |
- | | ::: | ::: | Bit 3 = 1 if Current CLOCK dev | | + | | ::: | ::: | Bit 3 = 1 if Current CLOCK device |
| ::: | ::: | Bit 4 = 1 if SPECIAL | | ::: | ::: | Bit 4 = 1 if SPECIAL | ||
| ::: | ::: | Bit 14 is the IOCTL bit | | | ::: | ::: | Bit 14 is the IOCTL bit | | ||
Line 44: | Line 59: | ||
| 8 | | 8 | ||
| 10 | 8 | character device name field. Character devices set a device name. For block devices the first byte is the number of units | | | 10 | 8 | character device name field. Character devices set a device name. For block devices the first byte is the number of units | | ||
+ | |||
+ | Memory map on DOSKRNL start: | ||
+ | |||
+ | | Init area | [BP+0+BP+2-BP+4]: | ||
+ | | Free | [BP+0]:0 | | ||
+ | | DOSKRNL | ||
+ | | Some data (VDD entries was found here) | ??? | | ||
+ | | CMOS Data | 40:0 | | ||
+ | | Interrupt vectors | 0:0 | | ||
+ | |||
+ | As in most DOS kernels, DOSKRNL moves initialization code to higher conventional memory. But uses init structure, not BIOS INT 12h, for memory information. | ||
DOSKRNL search and initialize XMS driver and moves some parts to HMA. Most other initialization things is same. DOSKRNL initializes standard device drivers and adds and initializes VDDs, passed via init structure. Some things (at least COMMAND.COM, | DOSKRNL search and initialize XMS driver and moves some parts to HMA. Most other initialization things is same. DOSKRNL initializes standard device drivers and adds and initializes VDDs, passed via init structure. Some things (at least COMMAND.COM, | ||
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* SHELL | * SHELL | ||
* DOS | * DOS | ||
+ | * BREAK | ||
+ | * FCBS | ||
+ | * LASTDRIVE | ||
todo add more info here | todo add more info here | ||
+ | Also most of these setting can be adjusted via DOS Properties (aka DOS Settings). Refer [[https:// | ||
+ | |||
+ | ===== Properties ===== | ||
+ | |||
+ | * COM_DIRECT_ACCESS | ||
+ | * COM_HOLD | ||
+ | * COM_RECEIVE_BUFFER_FLUSH | ||
+ | * COM_SELECT | ||
+ | * DOS_AUTOEXEC | ||
+ | * DOS_BACKGROUND_EXECUTION | ||
+ | * DOS_BREAK | ||
+ | * DOS_DEVICE | ||
+ | * DOS_FCBS | ||
+ | * DOS_FCBS_KEEP | ||
+ | * DOS_FILES | ||
+ | * DOS_HIGH | ||
+ | * DOS_LASTDRIVE | ||
+ | * DOS_RMSIZE | ||
+ | * DOS_SHELL | ||
+ | * DOS_STARTUP_DRIVE | ||
+ | * DOS_UMB | ||
+ | * DOS_VERSION | ||
+ | * DPMI_DOS_API | ||
+ | * DPMI_MEMORY_LIMIT | ||
+ | * DPMI_NETWORK_BUFF_SIZE | ||
+ | * EMS_FRAME_LOCATION | ||
+ | * EMS_HIGH_OS_MAP_REGION | ||
+ | * EMS_LOW_OS_MAP_REGION | ||
+ | * EMS_MEMORY_LIMIT | ||
+ | * HW_NOSOUND | ||
+ | * HW_ROM_TO_RAM | ||
+ | * HW_TIMER | ||
+ | * IDLE_SECONDS | ||
+ | * IDLE_SENSITIVITY | ||
+ | * INT_DURING_IO | ||
+ | * KBD_ALTHOME_BYPASS | ||
+ | * KBD_BUFFER_EXTEND | ||
+ | * KBD_CTRL_BYPASS | ||
+ | * KBD_RATE_LOCK | ||
+ | * MEM_EXCLUDE_REGION | ||
+ | * MEM_INCLUDE_REGION | ||
+ | * MOUSE_EXCLUSIVE_ACCESS | ||
+ | * PRINT_SEPARATE_OUTPUT | ||
+ | * PRINT_TIMEOUT | ||
+ | * SESSION_PRIORITY | ||
+ | * VIDEO_8514A_XGA_IOTRAP | ||
+ | * VIDEO_FASTPASTE | ||
+ | * VIDEO_MODE_RESTRICTIONS | ||
+ | * VIDEO_ONDEMAND_MEMORY | ||
+ | * VIDEO_RETRACE_EMULATION | ||
+ | * VIDEO_ROM_EMULATION | ||
+ | * VIDEO_SWITCH_NOTIFICATION | ||
+ | * VIDEO_WINDOW_REFRESH | ||
+ | * XMS_HANDLES | ||
+ | * XMS_MEMORY_LIMIT | ||
+ | * XMS_MINIMUM_HMA | ||
===== API ===== | ===== API ===== |