commit whatever is in my worktree rn
This commit is contained in:
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1dea0c40bc
commit
a3ef693059
@ -7,11 +7,8 @@ banner: db "RDOS KERNEL ", V, 0x0A, 0x0D, '$', 0x1A
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%include "kernel/far.asm"
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%include "kernel/char.asm"
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%include "inc/bpb.asm"
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%include "kernel/drive.asm"
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%include "kernel/fcb.asm"
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%include "kernel/rootdir.asm"
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%include "kernel/cluster.asm"
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%include "kernel/fat.asm"
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section .text
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@ -21,32 +18,15 @@ init: call rstseg
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mov dx, banner
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call puts
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call rstseg
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mov dx, testdta
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push ds
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call norm
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call setdta
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pop ds
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mov dl, 0
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call select
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mov dx, testfcb
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call norm
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call open
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call read
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mov ax, [cs:testdta]
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mov cx, [cs:testdta+2]
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int 3
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mov dx, 3
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call setclus
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call rdfat
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mov dx, bx
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inc dx
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call wdfat
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hlt: hlt
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jmp hlt
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section .data
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testfcb db 0, "HELLO ","COM"
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times FCBSIZ db 0
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section .bss
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testdta resb 128
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163
com/a86.asm
163
com/a86.asm
@ -43,10 +43,6 @@ dmpdx3: int 0x10
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free dw 0 ; free ram size
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lncnt dw 0 ; line count
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rdptr dw 0xFFFF ; infile blk ptr
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symbol dw 0 ; symbol of current line
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offset dw 0 ; byte offset in outfile
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len db 0 ; len for wrd (must be before it)
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wrd dw 0,0,0,0,0,0,0,0 ; 16 byte word buf
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getc mov bx, [rdptr]
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cmp bx, 0x80
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@ -72,12 +68,6 @@ l02 mov al, 0x1A
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l03 cmp al, eof
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ret
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;getc2 call peek
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; cmp al, eof
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; jne getc_
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; inc word [rdptr]
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;getc_ ret
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newlin mov dl, 0x0A
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mov ah, 2
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int 0x21
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@ -99,145 +89,32 @@ error mov dl, [bx]
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e_eof db "EOF "
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e_dup db "DUPSYM "
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; scan word
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scawrd mov si, wrd
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l04 call getc
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; EOF is fatal
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mov bx, e_eof
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jz error
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; tab=end
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cmp al, 9
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je pad
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; space=end
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cmp al, 0x20
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je pad
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; if lbl full, continue eating
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cmp si, wrd+0x10
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jnc l04
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; insert
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mov [si], al
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inc si
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jmp l04
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; pad with spaces
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pad mov cx, si
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sub cx, wrd
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mov [len], cl
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cmp si, wrd+0x10
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jnc l06
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mov ah, 0x20
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xchg ah, [si]
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inc si
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cmp ah, 0x20
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jne pad
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l06 ret
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tok1:
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s_ws db " " ; also used for tabs
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s_com db ","
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s_obr db "["
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s_cbr db "]"
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s_plu db "+"
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s_min db "-"
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; print wrd
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dmpwrd mov si, wrd
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mov cx, 0x10
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mov ah, 2
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l05 mov dl, [si]
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cmp dl, 0x20
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je l07
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inc si
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int 0x21
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loop l05
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l07 call newlin
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ret
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align 2
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tok2:
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reg8 db "AL","CL","DL","BL","AH","CH","DH","BH"
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reg16 db "AX","CX","DX","BX","SP","BP","SI","DI"
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sreg db "ES","CS","SS","DS"
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s_db db "DB"
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s_dw db "DW"
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; create symbol table entry
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; name is read from [wrd]
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; offset is written to [symbol]
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symins cmp byte [wrd], 0x20
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je nosym
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mov bx, init ; walk ptr
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mov bp, [free]
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add bp, bx ; end addr
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jmp l09
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l08 add bx, 8
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l09 mov al, [bx]
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cmp al, 0
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je l10
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call symcmp
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jnz l08
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mov bx, e_dup
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jmp error
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; copy str to table
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l10 mov si, wrd
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mov di, bx
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movsw
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movsw
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movsw
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xor ax, ax
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stosw
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mov byte [bx+8], 0
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mov [symbol], bx
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ret
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tok3:
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s_org db "ORG"
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s_equ db "EQU"
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nosym xor ax, ax
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mov [symbol], ax
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ret
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; compares 6 bytes [bx] with [wrd]
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; bit 7 of each byte is ignored
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symcmp mov si, wrd
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xor ax, ax
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mov dx, [wrd]
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xor dx, [bx]
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or ax, dx
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mov dx, [wrd+2]
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xor dx, [bx+2]
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or ax, dx
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mov dx, [wrd+4]
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xor dx, [bx+4]
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or ax, dx
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test ax, 0x8F8F
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ret
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; look up keyword in wrd
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; result is stored in bx
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lookup mov ch, 0
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mov bx, s_org
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l11 mov si, bx
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mov di, len ; wrd immediately follows
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mov cl, [bx]
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test cx, cx
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jz l13
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inc cl
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mov dx, cx
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rep cmpsb
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je l12
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add bx, dx
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jmp l11
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; found!
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l12 clc
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ret
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; give up
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l13 xor bx, bx
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stc
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ret
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s_org db 3, "org"
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s_equ db 3, "equ"
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db 0
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; TODO: parse a line into wordlist of tokens and ptrs to strings
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rline: ret
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; clear symbol table
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main mov byte [init], 0
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; scan and create label
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mloop call scawrd
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call symins
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; scan instruction word
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call scawrd
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call lookup
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; special stuff
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cmp bx, s_org
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je iorg
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mov ax, bx
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call dumpax
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int 0x20
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; org pseudo instruction
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iorg mov ax, 0x5A5A
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call dumpax
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call rline
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int 0x20
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align 16
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@ -5,6 +5,34 @@
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; - dirty: inform that dskbuf has been written to
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; access is done by accessing dskbuf directly
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BPBOFF equ 0xB
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; DOS 2.0 BPB
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BPBSS equ 0 ; word
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BPBSC equ 2 ; byte
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BPBRSC equ 3 ; word
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BPBFN equ 5 ; byte
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BPBRDE equ 6 ; word
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BPBTS equ 8 ; word
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BPBMD equ 10 ; byte
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BPBFS equ 11 ; word
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BPBSIZ2 equ 13 ; size constant
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; DOS 3.31 BPB
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BPBSPT equ 0x0D ; word
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BPBNOS equ 0x0F ; word
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BPBHS equ 0x11 ; dword
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BPBLTS equ 0x15 ; dword
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BPBSIZ3 equ 25 ; size constant
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; DOS 3.4 EBPB
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BPBDN equ 0x19 ; byte
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BPBFALG equ 0x1A ; byte
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BPBSIG equ 0x1B ; byte
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BPBSER equ 0x1C ; dword serial number
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BPBSIZ4 equ 32 ; size constant
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; Disk parameter table (int 1E)
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DPTSIZE equ 11
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DPTSPT equ 4
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@ -94,10 +122,10 @@ getprm test byte [dskflag], 4
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call lodfar
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.ret ret
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; log in drive
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; select a drive for io
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; IN dl drive number
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; dont do anything if drive already selected
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logdrv cmp dl, [dsknum]
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select cmp dl, [dsknum]
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je logfdd.ret
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; clear out current contents
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push dx
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@ -191,35 +219,42 @@ loghdd sub dl, 2
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logerr stc
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ret
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; count from partition start
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; map sector into dskbuf
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; sector number from partition start
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; IN dx:ax sector number
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maprel add ax, [bpb+BPBHS]
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map add ax, [bpb+BPBHS]
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add dx, [bpb+BPBHS+2]
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; absolute sector count
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; skip doing a read if sector number matches
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; IN dx:ax sector number
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mapabs cmp ax, [dskseek]
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jne dskread
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jne l003
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cmp dx, [dskseek+2]
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jne dskread
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ret
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dskread push ax
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je l002
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; flush and read other sector
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l003 push ax
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push dx
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call flush
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pop dx
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pop ax
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; store the sector number
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mov [cs:dskseek], ax
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mov [cs:dskseek+2], dx
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; do the actual read
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mov [dskseek], ax
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mov [dskseek+2], dx
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jmp _read
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; mark dskbuf as containing unwritten changes
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dirty or byte [cs:dskflag], 1 ; dirty
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l002 ret
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; flush buffer if dirty
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flush test byte [cs:dskflag], 1
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jz l002
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; low level read and write
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; call again to retry, no input registers
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; read or write is configured in cx
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_read mov ch, 2
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db 0x3D ; cmp ax, imm16: causes next instr to be skipped
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_write mov ch, 3
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db 0x3D ; cmp ax, imm16: causes next 2 bytes to be skipped
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_read mov ch, 2
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mov cl, 1 ; read len
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; DS := ES := CS
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mov ax, cs
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@ -286,14 +321,3 @@ _write mov ch, 3
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; exit with carry flag set
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stc
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ret
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; mark dskbuf as containing unwritten changes
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dirty or byte [cs:dskflag], 1 ; dirty
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ret
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; flush buffer if dirty
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flush test byte [cs:dskflag], 1
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jz .ret
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; TODO: error handling & retries
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jmp _write
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.ret ret
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125
kernel/fat.asm
Normal file
125
kernel/fat.asm
Normal file
@ -0,0 +1,125 @@
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section .bss
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clus resw 1
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section .text
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; Set cluster for next operations
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; IN dx cluster number
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setclus mov [clus], dx
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ret
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; get ptr to single byte in fat table
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; IN dx position byte in fat table
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; OUT bx ptr to byte in dskbuf
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_fat1 push dx
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mov ax, dx
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xor dx, dx
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mov cl, 9
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shr ax, cl
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add ax, [bpb+BPBRSC]
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adc dx, 0
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call map
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pop dx
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mov bx, dx
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and bx, 0x1FF
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add bx, dskbuf
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ret
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; get ptr to word in fat table
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_fat2 push dx
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mov ax, dx
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xor dx, dx
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mov cl, 8
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shr ax, cl
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add ax, [bpb+BPBRSC]
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adc dx, 0
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call map
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pop dx
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mov bl, dl
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mov bh, 0
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add bx, bx
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add bx, dskbuf
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ret
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; read value from fat table
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; index given with setclus
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; OUT bx value
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; carry set if EOF marker
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rdfat mov dx, [clus]
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mov ax, dx
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shr ax, 1
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add dx, ax
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call _fat1
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push word [bx]
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inc dx
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call _fat1
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mov si, bx
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pop bx
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mov bh, [si]
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test word [clus], 1
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jz l001
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mov cl, 4
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shr bx, cl
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l001 and bx, 0xFFF
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cmp bx, 0xFF0
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cmc
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ret
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; set value in FAT table
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; IN dx value
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wrfat and dh, 0x0F
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push dx
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; DX = index * 1.5
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mov dx, [clus]
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mov ax, dx
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shr dx, 1
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add dx, ax
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call _fat1
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pop ax
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test [clus], 1
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jnz l004
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; even, first byte full
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mov [bx], al
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push ax
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call dirty
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; DX = index * 1.5
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mov dx, [clus]
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mov ax, dx
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shr dx, 1
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add dx, ax
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inc dx
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call _fat1
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pop ax
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mov al, [bx]
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and al, 0xF0
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or al, ah
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mov [bx], al
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call dirty
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jmp l005
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; odd, second byte full
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l004: mov ch, [bx]
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; concat existing and our nib
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and ch, 0x0F
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mov cl, 4
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shl ax, cl
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or al, ch
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; write back lower 4 bits
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mov [bx], al
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call dirty
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push ax
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; re-calculate offset
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mov ax, dx
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shr dx, 1
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add dx, ax
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inc dx
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; map second byte
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call _fat1
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pop ax
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; write higher 8 bits
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mov [bx], ah
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call dirty
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l005: ret
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; wrfat from above, FAT16 flavour
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wf16: ret
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8
kernel/main.asm
Normal file
8
kernel/main.asm
Normal file
@ -0,0 +1,8 @@
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org 0
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jmp init
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init: mov ax, 0x0e37
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int 0x10
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hlt: hlt
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jmp hlt
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Block a user