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|
bits 16
jmp kmain
%include "constants.asm"
%include "string.asm"
%include "isr.asm"
%include "disk.asm"
%include "console.asm"
%include "stdio.asm"
%include "terminal.asm" ; eventually will become its own "program"
kmain:
cli ; disable interrupts
mov ax, cs ; get code segment
mov ds, ax ; set data segment
mov es, ax ; set extra segment
mov ax, 8000h
mov ss, ax ; set stack segment
mov sp, 0ffffh ; set stack pointer (~64k)
sti ; enable interrupts
mov [drive0], dx ; store bootloader's drive number
; reset general purpose registers
xor ax, ax
xor bx, bx
xor cx, cx
xor dx, dx
xor di, di
xor si, si
xor bp, bp
mov dl, 0 ; select video page 0
call console_set_video_page ; set video page
call cls ; clear console
push 0 ; home the cursor
call setcursor
add sp, 2
push banner
call puts
add sp, 2
push word [drive0]
push sp
push ss
push sp
push ss
push kend
push cs
push kmain
push cs
push kend
push cs
push kmain
push cs
push msg_entry_point_fmt
call printf
add sp, 2 * 11
mov cx, 0ffh - 80h
mov dx, 80h
.extloop:
push dx
call disk_info
add sp, 2
inc dx
dec cx
jne .extloop
.mainloop:
call isr_inject
call terminal
jmp .mainloop
cli
jmp $
isr_inject:
push bp
mov bp, sp
push es
push ax
push bx
push bp
mov ax, 0000h ; set ES to Interrupt Vector Table
; (start of RAM)
mov es, ax
mov bp, 20h * 4 ; Set vector (v = es:offset * 4))
lea bx, [int22] ; Load address of ISR routine
mov ax, cs ; Load code segment into AX
mov word [es:bp], bx ; Store address of ISR routine
mov word [es:bp+2], ax ; Store code segment of ISR routine
push bx
push ax
push msg_isr_fmt
call printf ; print injected ISR address
add sp, 2 * 3 ; cleanup stack
pop bp
pop bx
pop ax
pop es
int 20h ; test new ISR
mov sp, bp
pop bp
ret
panic:
; Hang system with supplied error message
push bp
mov bp, sp
push error_msg_panic ; i.e. 'PANIC:'
call puts
add sp, 2
push word [bp + 4] ; address of error string buffer
call puts ; print error
add sp, 2
cli ; disable interrupts
jmp $ ; hang (no return)
; stack is dead
; data
banner: db "+========================+", ASCII_CR
db "| Welcome to MINOS 0.0.1 |", ASCII_CR
db "+========================+", ASCII_CR
db ASCII_CR, 0
msg_entry_point_fmt: db 'Kernel address: %x:%x - %x:%x (%d:%d - %d:%d)', ASCII_CR
db 'Stack address : %x:%x (%d:%d)', ASCII_CR
db 'Boot device : %x', ASCII_CR, ASCII_CR, 0
msg_isr_fmt: db "ISR %x:%x", ASCII_CR, 0
; Error messages
error_msg_panic: db "PANIC: ", 0
kend: dw 0xefbe ; The "BEEF" signature is a visual "end of kernel"
times (0200h * 20h) db 0 ; Until we have a file system just reserve 32k
|
