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;;                                                              ;;

;; Copyright (C) KolibriOS team 2007-2015. All rights reserved. ;;

;; Distributed under terms of the GNU General Public License    ;;

;;                                                              ;;

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$Revision: 6333 $

; Virtual-8086 mode manager

; diamond, 2007, 2008

DEBUG_SHOW_IO = 0

struct  V86_machine

; page directory

        process         dd ?

; mutex to protect all data from writing by multiple threads at one time

        mutex           dd ?

; i/o permission map

        iopm            dd ?

ends

; Create V86 machine

; in: nothing

; out: eax = handle (pointer to struc V86_machine)

;      eax = NULL => failure

; destroys: ebx, ecx, edx (due to malloc)

v86_create:

; allocate V86_machine structure

        mov     eax, sizeof.V86_machine

        call    malloc

        test    eax, eax

        jz      .fail

; initialize mutex

        and     dword [eax+V86_machine.mutex], 0

; allocate tables

        mov     ebx, eax

        stdcall create_process, 4096

        test    eax, eax

        jz      .fail2

        mov     [eax+PROC.mem_used], 4096

        mov     [ebx+V86_machine.process], eax

        push    2000h

        call    kernel_alloc

        test    eax, eax

        jz      .fail2

        mov     [ebx+V86_machine.iopm], eax

; initialize tables

        push    edi

        mov     edi, eax

        mov     eax, -1

        mov     ecx, 2000h/4

        rep stosd

        mov     eax, [ebx+V86_machine.process]

        mov     eax, [eax+PROC.pdt_0_phys]

        pushfd

        cli

        mov     cr3, eax

; now V86 specific: initialize known addresses in first Mb

; first page - BIOS data (shared between all machines!)

; physical address = 0

; linear address = OS_BASE

; page before 0xA0000 - Extended BIOS Data Area (shared between all machines!)

; physical address = 0x9C000

; linear address = 0x8009C000

; (I have seen one computer with EBDA segment = 0x9D80,

; all other computers use less memory)

        mov     eax, PG_UWR

        mov     [page_tabs], eax

        invlpg  [eax]

        mov     byte [0x500], 0xCD

        mov     byte [0x501], 0x13

        mov     byte [0x502], 0xF4

        mov     byte [0x503], 0xCD

        mov     byte [0x504], 0x10

        mov     byte [0x505], 0xF4

        mov     eax, 0x98000+PG_UWR

        mov     edi, page_tabs+0x98*4

        mov     edx, 0x1000

        mov     ecx, 8

@@:

        stosd

        add     eax, edx

        loop    @b

; addresses 0xC0000 - 0xFFFFF - BIOS code (shared between all machines!)

; physical address = 0xC0000

        mov     eax, 0xC0000+PG_UWR

        mov     edi, page_tabs+0xC0*4

        mov     ecx, 64

@@:

        stosd

        add     eax, edx

        loop    @b

        mov     eax, [sys_proc+PROC.pdt_0_phys]

        mov     cr3, eax

        popfd

        pop     edi

        mov     eax, ebx

        ret

.fail2:

        mov     eax, ebx

        call    free

.fail:

        xor     eax, eax

        ret

;not used

; Destroy V86 machine

; in: eax = handle

; out: nothing

; destroys: eax, ebx, ecx, edx (due to free)

;v86_destroy:

;        push    eax

;        stdcall kernel_free, [eax+V86_machine.pagedir]

;        pop     eax

;        jmp     free

; Translate V86-address to linear address

; in: eax=V86 address

;     esi=handle

; out: eax=linear address

; destroys: nothing

v86_get_lin_addr:

        push    ecx edx

        mov     ecx, eax

        shr     ecx, 12

        mov     edx, [page_tabs+ecx*4]

        and     eax, 0xFFF

        and     edx, 0xFFFFF000

        or      eax, edx

        pop     edx ecx

        ret

;not used

; Sets linear address for V86-page

; in: eax=linear address (must be page-aligned)

;     ecx=V86 page (NOT address!)

;     esi=handle

; out: nothing

; destroys: nothing

;v86_set_page:

;        push    eax ebx

;        mov     ebx, [esi+V86_machine.pagedir]

;        mov     [ebx+ecx*4+0x1800], eax

;        call    get_pg_addr

;        or      al, 111b

;        mov     [ebx+ecx*4+0x1000], eax

;        pop     ebx eax

;        ret

; Allocate memory in V86 machine

; in: eax=size (in bytes)

;     esi=handle

; out: eax=V86 address, para-aligned (0x10 multiple)

; destroys: nothing

; недописана!!!

;v86_alloc:

;        push    ebx ecx edx edi

;        lea     ebx, [esi+V86_machine.mutex]

;        call    wait_mutex

;        add     eax, 0x1F

;        shr     eax, 4

;        mov     ebx, 0x1000  ; start with address 0x1000 (second page)

;        mov     edi, [esi+V86_machine.tables]

;.l:

;        mov     ecx, ebx

;        shr     ecx, 12

;        mov     edx, [edi+0x1000+ecx*4] ; get linear address

;        test    edx, edx                ; page allocated?

;        jz      .unalloc

;        mov     ecx, ebx

;        and     ecx, 0xFFF

;        add     edx, ecx

;        cmp     dword [edx], 0          ; free block?

;        jnz     .n

;        cmp     dword [edx+4],

;        and     [esi+V86_machine.mutex], 0

;        pop     edi edx ecx ebx

;        ret

uglobal

sys_v86_machine dd      ?

endg

; Called from kernel.asm at first stages of loading

; Initialize system V86 machine (used to simulate BIOS int 13h)

init_sys_v86:

        call    v86_create

        mov     [sys_v86_machine], eax

        test    eax, eax

        jz      .ret

        mov     esi, eax

if ~DEBUG_SHOW_IO

; allow access to all ports

        mov     ecx, [esi+V86_machine.iopm]

        xor     eax, eax

        mov     edi, ecx

        mov     ecx, 10000h/8/4

        rep stosd

end if

.ret:

        ret

struct  v86_regs

; don't change the order, it is important

        edi             dd ?