Small operating system made in assembly language
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;Affiche le nombre hexa dans %0[dword]
PROC biosprinth FAR
ARG @num:dword
USES ax,bx,cx,edx,si,di
mov edx,[@num]
mov ah,09h
mov di,8
@@hexaize:
rol edx,4
mov si,dx
and si,1111b
mov al,[cs:si+offset @@tab]
mov cx,1
cmp al,32
jb @@control
mov bx,7
mov ah,09h
int 10h
@@control:
mov ah,0Eh
int 10h
dec di
jnz @@hexaize
ret
@@tab db '0123456789ABCDEF'
endp biosprinth
;Affiche le texte ASCIIZ pointé par %0
PROC biosprint FAR
ARG @pointer:word
USES ax,bx,cx,si
mov si,[@pointer]
mov cx,1
mov bx,7
@@again:
lodsb
or al,al
jz @@fin
cmp al,32
jb @@control
mov ah,09h
int 10h
@@control:
mov ah,0Eh
int 10h
jmp @@again
@@fin:
ret
endp biosprint
PROC enablea20 FAR
USES ax
mov al,0d1h
out 64h,al
call a20wait
mov al,0dfh
out 60h,al
call a20wait
;mov al,0ffh
;out 64h,al
;call a20wait
ret
endp enablea20
PROC disablea20 FAR
USES ax
mov al,0d1h
out 64h,al
call a20wait
mov al,0DDh
out 60h,al
call a20wait
;mov al,0ffh
;out 64h,al
;call a20wait
ret
endp disablea20
a20wait:
in al,64h
jmp @@suite
@@suite:
and al,2
jnz a20wait
ret
;par le system control port A
;in al,92h
;or al,2
;out 92h,al
;par le system control port A
;in al,92h
;and al,not 2
;out 92h,al
PROC flatmode FAR
USES eax,bx,ds
push cs
pop ds
; first, calculate the linear address of GDT
xor eax,eax
mov ax,ds
shl eax,4
add [dword ptr offset @@gdt+2],eax ; store as GDT linear base addr
; now load the GDT into the GDTR
lgdt [fword ptr offset @@gdt] ; load GDT base
mov bx,1 * size descriptor ; point to first descriptor
cli ; turn off interrupts
mov eax,cr0 ; prepare to enter protected mode
or al,1 ; flip the PE bit
mov cr0,eax ; we're now in protected mode
jmp @@suite
@@suite:
mov fs,bx ; load the FS segment register
and al,0FEh ; clear the PE bit again
mov cr0,eax ; back to real mode
jmp @@suite2
@@suite2:
sti ; resume handling interrupts
ret ;
@@gdt descriptor <offset @@gdtend - offset @@gdt - 1, offset @@gdt, 0, 0, 0, 0> ; the GDT itself
descriptor <0ffffh, 0, 0, 091h, 0cfh, 0> ; 4G data segment
@@gdtend:
endp flatmode
;Attend l'appuie sur une touche
PROC bioswaitkey FAR
USES ax
xor ax,ax
int 16h
ret
endp bioswaitkey
firstmb dw 0
;Charge les sections du block %0
PROC mbloadsection FAR
ARG @blocks:word
USES ax,bx,cx,si,di,ds,es
LOCAL @@toresov:word:60
mov ax,[@blocks]
mov es,ax
mov ds,ax
cmp [word ptr 0],"EC"
jne @@notace
lea si,[@@toresov]
mov [word ptr ss:si],0FFFFh
mov bx,[ds:exe.sections]
cmp bx,0
je @@finishloading
@@loading:
cmp [dword ptr bx],0
je @@finishloading
mov ax,bx
add ax,4
pushad
call biosprint,ax
popad
call mbcreate,ax,[word ptr bx+2]
jc @@error
inc si
inc si
mov [ss:si],ax
push si
mov si,[bx]
xor di,di
mov es,ax
mov cx,[bx+2]
cld
rep movsb
pop si
add bx,4
@@gonext:
inc bx
cmp [byte ptr bx],0
jne @@gonext
inc bx
jmp @@loading
@@finishloading:
cmp [word ptr ss:si],0FFFFh
je @@finishdepands
call mbloadfuncs,[word ptr ss:si]
jc @@depandserror
dec si
dec si
jmp @@finishloading
@@finishdepands:
ret
@@notace:
stc
ret
@@error:
stc
ret
@@depandserror:
stc
ret
endp mbloadsection
;Initialise les blocs de mémoire en prenant memorystart pour segment de base
PROC mbinit FAR
USES ax,cx,si,di,ds,es
cmp [cs:firstmb],0
jne @@alreadyok
push cs
pop ds
mov [cs:firstmb],memorystart
mov ax,memorystart-2
mov es,ax
mov si,offset afree
xor di,di
mov cx,size mb
rep movsb
clc
ret
@@alreadyok:
stc
ret
endp mbinit
afree mb <"HN",0,0,0,0A000h-memorystart,"Libre">
db 0
;Creér un bloc de nom %0 de taille %1 (octets) -> n°segment dans AX
PROC mbcreate FAR
ARG @blocks:word,@size:word
USES bx,cx,dx,si,di,ds,es
push gs
mov ax,[ss:bp+4]
mov dx,ax
dec dx
dec dx
mov gs,dx
cmp [word ptr gs:0x0],'NH'
je @@oktoset
mov ax,memorystart
@@oktoset:
mov gs,ax
mov cx,[@size]
shr cx,4
inc cx
mov bx,[cs:firstmb]
dec bx
dec bx
mov dl,true
@@searchfree:
cmp dl,false
je @@notenougtmem
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
cmp [es:mb.isnotlast],true
sete dl
cmp [es:mb.reference],free
jne @@notsogood
mov ax,[es:mb.sizes]
cmp cx,ax
ja @@notsogood
mov [word ptr es:mb.check],"NH"
mov [es:mb.isnotlast],true
mov [es:mb.reference],gs
mov [es:mb.isresident],false
lea di,[es:mb.names]
push cx
mov cx,24/4
mov si,[@blocks]
cld
rep movsd
pop cx
inc bx
inc bx
sub ax,cx
cmp ax,0
je @@nofree
dec ax
dec ax
mov [es:mb.sizes],cx
add cx,bx
mov es,cx
mov si,offset afree
xor di,di
mov cx,size mb
push cs
pop ds
cld
rep movsb
mov [es:mb.isnotlast],dl
mov [es:mb.sizes],ax
@@nofree:
mov ax,bx
pop gs
clc
ret
@@notsogood:
inc bx
inc bx
add bx,[es:mb.sizes]
jmp @@searchfree
@@memoryerror:
pop gs
stc
ret
@@notenougtmem:
pop gs
stc
ret
endp mbcreate
;Libère le bloc de mémoire %0 et ses sous blocs
PROC mbfree FAR
ARG @blocks:word
USES ax,bx,cx,si,di,ds,es
mov bx,[@blocks]
mov ax,bx
dec bx
dec bx
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
cmp [es:mb.reference],free
je @@wasfree
cmp [es:mb.isresident],true
je @@wasresident
mov [es:mb.reference],free
push cs
pop ds
mov si,offset @@isfree
lea di,[es:mb.names]
mov cx,6
cld
rep movsb
mov bx,[cs:firstmb]
dec bx
dec bx
@@searchtofree:
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
inc bx
inc bx
add bx,[es:mb.sizes]
cmp [es:mb.sizes],0
je @@nottofree
cmp ax,[es:mb.reference]
jne @@nottofree
mov [es:mb.isresident],false
mov [es:mb.reference],free
mov si,offset @@isfree
lea di,[es:mb.names]
mov cx,6
cld
rep movsb
@@nottofree:
cmp [es:mb.isnotlast],true
je @@searchtofree
call mbclean
ret
@@memoryerror:
stc
ret
@@wasfree:
stc
ret
@@wasresident:
stc
ret
@@isfree db "libre",0
endp mbfree
;Mise a nivo de la mémoire (jonction de blocs libre)
PROC mbclean FAR
USES ax,bx,dx,es,gs
mov bx,[cs:firstmb]
dec bx
dec bx
xor ax,ax
xor dx,dx
@@searchfree:
mov gs,bx
cmp [word ptr gs:mb.check],"NH"
jne @@memoryerror
inc bx
inc bx
add bx,[gs:mb.sizes]
cmp [word ptr gs:mb.sizes],0
je @@notenougtmem
cmp [gs:mb.reference],free
jne @@notfree
cmp ax,0
je @@notmeetfree
add dx,[gs:mb.sizes]
mov [word ptr gs:mb.check],0
mov [dword ptr gs:mb.names],0
inc dx
inc dx
jmp @@nottrigered
@@notmeetfree:
xor dx,dx
mov ax,gs
jmp @@nottrigered
@@notfree:
cmp ax,0
je @@nottrigered
mov es,ax
add [es:mb.sizes],dx
xor ax,ax
@@nottrigered:
cmp [gs:mb.isnotlast],true
je @@searchfree
cmp ax,0
je @@reallyfinish
mov es,ax
add [es:mb.sizes],dx
mov [es:mb.isnotlast],false
@@reallyfinish:
clc
ret
@@notenougtmem:
stc
ret
@@memoryerror:
stc
ret
endp mbclean
;Rend le segment %0 résident
PROC mbresident FAR
ARG @blocks:word
USES bx,es
mov bx,[@blocks]
dec bx
dec bx
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
mov [es:mb.isresident],true
ret
@@memoryerror:
stc
ret
endp mbresident
;Rend le segment %0 non résident
PROC mbnonresident FAR
ARG @blocks:word
USES bx,es
mov bx,[@blocks]
dec bx
dec bx
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
mov [es:mb.isresident],false
ret
@@memoryerror:
stc
ret
endp mbnonresident
;Change le proprietaire de %0 a %1
PROC mbchown FAR
ARG @blocks:word,@owner:word
USES bx,dx,es
mov bx,[@blocks]
dec bx
dec bx
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
cmp [es:mb.reference],free
je @@wasfree
mov dx,[@owner]
mov [es:mb.reference],dx
ret
@@memoryerror:
stc
ret
@@wasfree:
stc
ret
endp mbchown
;Alloue un bloc /data de CX caractere pour le process appelant -> ax
PROC mballoc FAR
ARG @size:word
USES si,ds
push cs
pop ds
call mbcreate,offset @@data,[@size]
call mbchown,ax,[word ptr ss:bp+4]
ret
@@data db '/data',0
endp mballoc
;Renvoie en AX le MB n° %0 carry quand terminé
PROC mbget FAR
ARG @num:word
USES bx,dx,es
mov bx,[cs:firstmb]
dec bx
dec bx
xor dx,dx
@@searchfree:
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
inc bx
inc bx
add bx,[es:mb.sizes]
cmp [es:mb.sizes],0
je @@memoryerror
cmp dx,[@num]
je @@foundmcb
ja @@notfound
inc dx
cmp [es:mb.isnotlast],true
je @@searchfree
@@memoryerror:
stc
ret
@@foundmcb:
mov ax,es
inc ax
inc ax
clc
ret
@@notfound:
stc
ret
endp mbget
;Renvoie en AX le MCB qui correspond a ds:%0
PROC mbfind FAR
ARG @blocks:word
USES bx,si,di,es
mov bx,[cs:firstmb]
dec bx
dec bx
mov si,[@blocks]
@@search:
mov es,bx
lea di,[es:mb.names]
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
inc bx
inc bx
add bx,[es:mb.sizes]
cmp [es:mb.sizes],0
je @@memoryerror
push si di
@@cmpnames:
mov al,[es:di]
cmp al,[ds:si]
jne @@ok
cmp al,0
je @@ok
inc si
inc di
jmp @@cmpnames
@@ok:
pop di si
je @@foundmcb
cmp [es:mb.isnotlast],true
je @@search
@@notfound:
stc
ret
@@memoryerror:
stc
ret
@@foundmcb:
mov ax,es
inc ax
inc ax
clc
ret
endp mbfind
;Renvoie en AX le sous mcb qui correspond a %0 et qui appartien a %1
PROC mbfindsb FAR
ARG @blocks:word,@owner:word
USES bx,dx,si,di,es
mov bx,[cs:firstmb]
dec bx
dec bx
mov si,[@blocks]
lea di,[es:mb.names]
mov dx,[@owner]
@@search:
mov es,bx
cmp [word ptr es:mb.check],"NH"
jne @@memoryerror
inc bx
inc bx
add bx,[es:mb.sizes]
cmp [es:mb.sizes],0
je @@memoryerror
push si di
@@cmpnames:
mov al,[es:di]
cmp al,[ds:si]
jne @@ok
cmp al,0
je @@ok
inc si
inc di
jmp @@cmpnames
@@ok:
pop di si
jne @@notfoundmcb
cmp [es:mb.reference],dx
je @@foundmcb
@@notfoundmcb:
cmp [es:mb.isnotlast],true
je @@search
@@notfound:
stc
ret
@@foundmcb:
mov ax,es
inc ax
inc ax
clc
ret
@@memoryerror:
stc
ret
endp mbfindsb
;Resouds les dépendances du bloc de mémoire %0
PROC mbloadfuncs FAR
ARG @blocks:word
USES ax,bx,cx,dx,si,ds
mov ds,[@blocks]
cmp [word ptr 0],"EC"
jne @@notace
mov si,[ds:exe.imports]
cmp si,0
je @@endofloading
@@loadfuncs:
cmp [word ptr si],0
je @@endofloading
call mbsearchfunc,si
jnc @@toendoftext
mov bx,si
;pushad
;call biosprint,si
;popad
@@findend:
inc bx
cmp [byte ptr bx], ':'
jne @@findend
mov [byte ptr bx],0
call [cs:projfile],si
mov [byte ptr bx],':'
jc @@erroronload
;pushad
;call biosprint,si
;popad
call mbsearchfunc,si
jc @@libnotexist
@@toendoftext:
mov cl,[si]
cmp cl,0
je @@oktonext
inc si
jmp @@toendoftext
@@oktonext:
inc si
mov [si],ax
mov [si+2],dx
add si,4
jmp @@loadfuncs
@@endofloading:
clc
ret
@@notace:
stc
ret
@@libnotexist:
stc
ret
@@erroronload:
stc
ret
endp mbloadfuncs
;Recherche une fonction pointé par DS:%0 en mémoire et renvoie son adresse en DX:AX
PROC mbsearchfunc FAR
ARG @func:word
USES bx,si,di,es
mov bx,[@func]
mov si,bx
@@findend:
inc bx
cmp [byte ptr bx], ':'
jne @@findend
mov [byte ptr bx],0
call mbfind,si
mov [byte ptr bx],':'
jc @@notfoundattallthesb
mov es,ax
cmp [word ptr es:exe.checks],"EC"
jne @@notfoundattallthesb
mov di,[es:exe.exports]
inc bx
inc bx
@@functions:
cmp [word ptr es:di],0
je @@notfoundattallthesb
mov si,bx
@@cmpnamesfunc:
mov al,[es:di]
cmp al,[ds:si]
jne @@notfoundthesb
cmp al,0
je @@seemsok
inc si
inc di
jmp @@cmpnamesfunc
@@notfoundthesb:
mov al,[es:di]
cmp al,0
je @@oktonext
inc di
jmp @@notfoundthesb
@@oktonext:
inc di
inc di
inc di
jmp @@functions
@@seemsok:
mov dx,es
mov ax,[es:di+1]
clc
ret
@@notfoundattallthesb:
stc
ret
endp mbsearchfunc