108 lines
1.6 KiB
NASM
108 lines
1.6 KiB
NASM
cpu 8086
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org 0x0700
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%include "inc/bpb.asm"
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%include "inc/mbr.asm"
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%include "inc/dpt.asm"
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init: cli
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xor ax, ax
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mov ds, ax
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mov es, ax
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mov ss, ax
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mov sp, ax
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mov si, 0x7C00
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; relocate to 00700
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mov di, text_start
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mov cx, text_length + rodata_length + data_length
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rep movsb
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; clear out bss section
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mov cx, bss_length
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rep stosb
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; jump to copy
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call 0:relinit
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section .rodata
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%define V 0x %+ VERSION
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version: dd V
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section .text
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relinit: ; print banner
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push word [version]
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push word [version+2]
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call printf
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db "RDOS ",2,2, 0x0A, 0x0D, 0
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; initialize the disk i/o
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call dinit
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; init 21h vector
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mov word [0x21*4], int21
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mov word [0x21*4+2], cs
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; set current PSP, directly after us
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mov ax, stack
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mov cl, 4
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shr ax, cl
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mov word [curpsp], ax
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; also the DTA
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mov bx, dta
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call setdta
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; set current drive to boot drive
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mov al, dl
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rol al, 1
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rol al, 1
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or dl, al
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and dl, 3
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call setdd
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mov bx, testfcb
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call fndfst
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restart:
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hlt: hlt
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jmp hlt
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%include "kernel/psp.asm"
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%include "kernel/syscall.asm"
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%include "kernel/char.asm"
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%include "kernel/fcb.asm"
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%include "kernel/drive.asm"
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%include "kernel/printf.asm"
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section .bss
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dta: resb 128
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section .data
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testfcb: db 0
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db "HELLO ", "COM"
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times 30 db 0
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section .text
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text_start equ $$
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text_length equ $-$$
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section .rodata
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rodata_start equ $$
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rodata_length equ $-$$
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section .data
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data_start equ $$
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data_length equ $-$$
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section .bss
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resw 256 ; 512b kern stack
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alignb 16
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stack: ; stack grows into this ^
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; this is also the end marker
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; programs with their psp start here
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bss_start equ $$
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bss_length equ $-$$
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