wok view runcom/description.txt @ rev 15838

Up: fox to 1.6.49.
author Christopher Rogers <slaxemulator@gmail.com>
date Mon Jan 27 05:11:58 2014 +0000 (2014-01-27)
parents 5d74983842db
children
line source
1 Runcom support DOS .com binary files and boot sector files.
2
3 1- The DOS .com support
4
5 Runcom provides few BIOS and DOS (int 21H) interrupt handlers. Many .com files
6 may not work. DOS .exe are also supported.
7 You can test it with the file /usr/bin/debug.com, with the command line :
8 $ debug.com
9
10 2- The boot sector image support
11
12 A boot sector image is a 512 bytes file ending with the 0xAA and 0x55 bytes
13 with the .bin extension.
14 Bios disk (int 13H) are emulated (CHS or LBA) with an image file :
15 - hard disk are image ./hd0, ./hd1, ... for disk 0x80, 0x81...
16 - floppy disk are image ./fd0, ./fd1 ... or /dev/fd0, /dev/fd1 if not found.
17 You can test it with the file /usr/bin/debug.bin, with the command line :
18 $ debug.bin
19
20 3- The 512 bytes boot sector debugger /usr/bin/debug.bin
21
22 Usage:
23
24 f DX:CX load one CHS sector to 0000:7C00
25 t trace one step
26 g <address> go to adrs
27 d <address> display 16 bytes, CR for next 16 bytes...
28 e <address> <words>... enter memory byte/word/dword
29 m <segment> self move
30 + <segment> default segment offset
31
32 seqment and offset are hexadecimal values in 0..FFFF range
33 address is linear hexadecimal value in 0..FFFFF range or seqment:offset
34 words are bytes in 0..FF range or words in 000..FFFF range or double words
35 CX and DX are used by INT13H/AL=01 BIOS interrupt.
36
37 Example:
38 m 0FC0 move debugger to 0FC0:0000 0FC0:01FF
39 f 1 read floppy boot sector to 0000:7C00
40 f 80:1 read hard disk master boot sector to 0000:7C00
41 g 7C0E ...