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Mathieu Maret bffe30c2a2 deal with shift keys		5 years ago
core	fix status line dsplay when scrolling	5 years ago
drivers	deal with shift keys	5 years ago
Makefile	Folder reorg	5 years ago
Readme.md	Add Readme doc	5 years ago
linker.ld	Put 32bits code after 1sector and load it	5 years ago
mbr.asm	deal with shift keys	5 years ago

Instruction

Build with make

Run with make test

Debug with qemu-system-x86_64 -boot a -fda mbr -s -S then gdb

 target remote localhost:1234
 layout asm
 b *0x7c00
 c

ASM reg

There is 4 main 16bits reg: AX, BX, CX, DX. You can access the 8 MSB from AX with AH and the 8 LSB with AL.( BH,BL, CH, CL)

SI and DI are 16bits index register often used for pointer but can contains data.

SP is stack pointer, BP is base pointer

AX(AH, AL), BX(BH, BL), CX(CH, CL), DX(DH, DL), SI, DI, SP, BP

Main register are "Extended" to 32bits but 16bits of 8bits direct access is not possible anymore.

EAX, EBX, ECX, EDX, ESI, EDI, ESP, EBP

Prefixed by R RAX, RBX, RCX, RDX, RSI, RDI, RSP, RBP

INT_NUM	Short Description PM
0x00	Division by zero
0x01	Debugger
0x02	NMI
0x03	Breakpoint
0x04	Overflow
0x05	Bounds
0x06	Invalid Opcode
0x07	Coprocessor not available
0x08	Double fault
0x09	Coprocessor Segment Overrun (386 or earlier only)
0x0A	Invalid Task State Segment
0x0B	Segment not present
0x0C	Stack Fault
0x0D	General protection fault
0x0E	Page fault
0x0F	reserved
0x10	Math Fault
0x11	Alignment Check
0x12	Machine Check
0x13	SIMD Floating-Point Exception
0x14	Virtualisation Exception
0x15	Control Protection Exception