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1 month ago | |
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Makefile | 1 month ago | |
README.md | 1 month ago | |
mon8086.asm | 1 month ago |
A control monitor program for the Intel 8086 in a single sector (512 bytes)
Its main use it to help me debugging disk i/o and boot issues on IBM PC compatibles.
Run make
. Requires the NASM assembler.
You can run make qemu
to make it run in qemu.
If you want to run it on a real machine, you need to write it to the boot sector first:
dd if=mon8086.bs of=/dev/sdb1
.
There is no real line editing - key presses have instant effect.
Several commands allow the user to edit a value. While editing, pressing space results in the value being discarded. The monitor will then return to the prompt. This is useful for the inspection of values.
S 0040
O 0000
D
E B4 08 B2 80 CD 13 CC
G
Replace the 80 with the bios drive number (00, 01 and 80 are common values). The results are spread over the CX and DX registers, check Ralf Browns Interrupt List or your BIOS documentation for INT 13h/AH=8 on how to interpret the results.
O 7BF2
E B8 01 02 B9 01 00 BA 80 00 BB 00 7C CD 13
V IP 7BF2
G
Replace the 80 with the bios drive number (00, 01 and 80 are common values).
V CS FFFF
V IP 0000
G