Subversion Repositories Kolibri OS

if ~defined newprocess_inc

newprocess_inc_fix:

newprocess_inc fix newprocess_inc_fix

include "mem.inc"

include "memmanag.inc"

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;Working with new types of processes.

;;Author: Khalyavin Andrey halyavin@land.ru

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

iglobal

    new_process_loading db 'K : New Process - loading',13,10,0

    new_process_running db 'K : New Process - done',13,10,0

    start_not_enough_memory db 'K : New Process - not enough memory',13,10,0

endg

;-----------------------------------------------------------------------------

find_new_process_place:

;input:

;  none

;result:

;  eax=[new_process_place]<>0 - ok

;      0 - failed.

;This function find least empty slot.

;It doesn't increase [0x3004]!

    mov    eax,0x3000+second_base_address

    push   ebx

    mov    ebx,[0x3004]

    inc    ebx

    shl    ebx,5

    add    ebx,eax               ;ebx - address of process information for (last+1) slot

.newprocessplace:

;eax = address of process information for current slot

    cmp    eax,ebx

    jz     .endnewprocessplace   ;empty slot after high boundary

    add    eax,0x20

    cmp    word [eax+0xa],9      ;check process state, 9 means that process slot is empty

    jnz    .newprocessplace

.endnewprocessplace:

    mov    ebx,eax

    sub    eax,0x3000+second_base_address

    shr    eax,5                 ;calculate slot index

    cmp    eax,256

    jge    .failed               ;it should be <256

    mov    word [ebx+0xa],9      ;set process state to 9 (for slot after hight boundary)

    mov    [new_process_place],eax ;save process slot

    pop    ebx

    ret

.failed:

    xor    eax,eax

    pop    ebx

    ret

;-----------------------------------------------------------------------------

safe_sti:

    cmp    byte [0xe000], 1

    jne    @f

    sti

 @@:ret

new_start_application_floppy:

;input:

;  eax - pointer to filename

;  ebx - parameters to pass

;  edx - flags

;result:

;  eax - pid of new process

;        or 0 if call fails.

    mov    [appl_path],edi

    pushad

    mov    esi,new_process_loading

    call   sys_msg_board_str     ;write to debug board

;wait application_table_status mutex

.table_status:

    cli

    cmp    [application_table_status],0

    jz     .stf

    sti

    call   change_task

    jmp    .table_status

.stf:

    call   set_application_table_status

;we can change system tables now

    push   edi

    push   ebx

    push   eax

    call   find_new_process_place ;find empty process slot

    sti

    test   eax,eax

    jz     .failed

    mov    edi,eax

    shl    edi,8

    add    edi,0x80000

    mov    ecx,256/4

    xor    eax,eax

    cld

    rep    stosd                 ;clean extended information about process

;set new process name

    xor    eax,eax

    mov    [appl_path_size],eax

    mov    eax,[esp]  ;+8]

.find_last_byte:

    cmp    byte [eax],0

    jz     .find_last_byte_end

    inc    eax

    inc    [appl_path_size]

    jmp    .find_last_byte

.find_last_byte_end:

    add    [appl_path_size],24

    sub    eax,11                ;last 11 bytes = application name

;    mov    eax,[esp]             ;eax - pointer to file name

    mov    ebx,[new_process_place]

    shl    ebx,8

    add    ebx,0x80000

    mov    ecx,11

    call   memmove

;read header of file

    mov    eax,[esp]

    mov    ebx,1                 ;index of first block

    mov    ecx,2                 ;number of blocks

    mov    edx,0x90000           ;temp area

    mov    esi,12                ;file name length

    mov    edi,[esp+8]

;    cli

    call   floppy_fileread       ;read file from FD

;    sti

    cmp    eax,0

    jne    .cleanfailed

;check MENUET signature

    cmp    [0x90000],dword 'MENU'

    jnz    .cleanfailed

    cmp    [0x90004],word 'ET'

    jnz    .cleanfailed

    call   get_app_params        ;parse header fields

    cmp    esi,0

    jz     .cleanfailed

    mov    eax,[new_process_place]

    call   create_app_cr3_table   ;create page directory for new process

    test   eax,eax

    jz     .cleanfailed_mem

    call   MEM_Get_Linear_Address ;calculate linear address of it

    mov    ebx,std_application_base_address

    mov    ecx,[app_mem]

    add    ecx,4095

    shr    ecx,12

    mov    edx,eax

    call   mem_alloc_specified_region ;allocate memory for application

    test   eax,eax

    jz     .cleanfailed_mem1

    mov    eax,[edx+(std_application_base_address shr 20)]

    and    eax,not (4096-1)      ;eax - physical address of first (for application memory) page table

    call   MEM_Get_Linear_Address

    mov    edx,eax

;read file

    mov    ebx,1

    mov    esi,12                ;length of file name

.loop1:

;edx = linear address of current page table entry

;ebx = index of current block in file

    push   edx

    mov    eax,[edx]

    and    eax,not (4096-1)

    call   MEM_Get_Linear_Address

    mov    edx,eax               ;read file block to current page

    mov    eax,[esp+4]           ;restore pointer to file name

    mov    ecx,8                 ;number of blocks read

    push   ebx

    mov    edi,[esp+16]

;    cli

    call   floppy_fileread

;ebx=file size

;    sti

    pop    ecx

    shr    ebx,9

    cmp    ecx,ebx

    jg     .endloop1             ;if end of file?

    mov    ebx,ecx

    test   eax,eax

    jnz    .endloop1             ;check io errors

    pop    edx

    add    ebx,8                 ;go to next page

    add    edx,4

    jmp    .loop1

.endloop1:

    add    esp,8+4                 ;pop linear address of page table entry and pointer to file name

    call   new_start_application_fl.add_app_parameters

    mov    [esp+28],eax

    popad

    ret

.cleanfailed_mem1:

;there is mem for directory entry, but there is no mem for pages

;so free directory entry

    mov    eax,[new_process_place]

    shl    eax,8

    mov    eax,[0x80000+eax+0xB8]

    call   MEM_Free_Page

.cleanfailed_mem:

;there is no mem for directory entry, display message.

    mov    esi,start_not_enough_memory

    call   sys_msg_board_str

.cleanfailed:                    ;clean process name

;can't read file, clean process name.

;this avoid problems with panel application.

    mov    edi,[new_process_place]

    shl    edi,8

    add    edi,0x80000

    mov    ecx,11

    mov    eax,' '

    cld

    rep    stosb

.failed:

;no more slots

    add    esp,8+4

    mov    [application_table_status],0

    popad

    sti

    mov    eax,-1

    ret

;-----------------------------------------------------------------------------

new_start_application_fl:

;input:

;  eax - pointer to filename

;  ebx - parameters to pass

;  edx - flags

;result:

;  eax - pid of new process

;        or 0 if call fails.

    mov    [appl_path],edi

    mov    [appl_path_size],36

    pushad

    mov    esi,new_process_loading

    call   sys_msg_board_str     ;write to debug board

;wait application_table_status mutex

.table_status:

    cli

    cmp    [application_table_status],0

    jz     .stf

    sti

    call   change_task

    jmp    .table_status

.stf:

    call   set_application_table_status

;we can change system tables now

    push   ebx

    push   eax

    call   find_new_process_place ;find empty process slot

    call   safe_sti

    test   eax,eax

    jz     .failed

    mov    edi,eax

    shl    edi,8

    add    edi,0x80000

    mov    ecx,256/4

    xor    eax,eax

    cld

    rep    stosd                 ;clean extended information about process

;set new process name

    mov    eax,[esp]             ;eax - pointer to file name

    mov    ebx,[new_process_place]

    shl    ebx,8

    add    ebx,0x80000

    mov    ecx,11

    call   memmove

;read header of file

    mov    ebx,1                 ;index of first block

    mov    ecx,2                 ;number of blocks

    mov    edx,0x90000           ;temp area

    mov    esi,12                ;file name length

    cli

    call   fileread              ;read file from RD

    call   safe_sti

    cmp    eax,0

    jne    .cleanfailed

;check MENUET signature

    cmp    [0x90000],dword 'MENU'

    jnz    .cleanfailed

    cmp    [0x90004],word 'ET'

    jnz    .cleanfailed

    call   get_app_params        ;parse header fields

    cmp    esi,0

    jz     .cleanfailed

    mov    eax,[new_process_place]

    call   create_app_cr3_table   ;create page directory for new process

    test   eax,eax

    jz     .cleanfailed_mem

    call   MEM_Get_Linear_Address ;calculate linear address of it

    mov    ebx,std_application_base_address

    mov    ecx,[app_mem]

    add    ecx,4095

    shr    ecx,12

    mov    edx,eax

    call   mem_alloc_specified_region ;allocate memory for application

    test   eax,eax

    jz     .cleanfailed_mem1

    mov    eax,[edx+(std_application_base_address shr 20)]

    and    eax,not (4096-1)      ;eax - physical address of first (for application memory) page table

    call   MEM_Get_Linear_Address

    mov    edx,eax

;read file

    mov    ebx,1

    mov    esi,12                ;length of file name

.loop1:

;edx = linear address of current page table entry

;ebx = index of current block in file

    push   edx

    mov    eax,[edx]

    and    eax,not (4096-1)

    call   MEM_Get_Linear_Address

    mov    edx,eax               ;read file block to current page

    mov    eax,[esp+4]           ;restore pointer to file name

    mov    ecx,8                 ;number of blocks read

    push   ebx

    cli

    call   fileread

;ebx=file size

    call   safe_sti

    pop    ecx

    shr    ebx,9

    cmp    ecx,ebx

    jg     .endloop1             ;if end of file?

    mov    ebx,ecx

    test   eax,eax

    jnz    .endloop1             ;check io errors

    pop    edx

    add    ebx,8                 ;go to next page

    add    edx,4

    jmp    .loop1

.endloop1:

    add    esp,8                 ;pop linear address of page table entry and pointer to file name

    call   .add_app_parameters

    mov    [esp+28],eax

    popad

    ret

.cleanfailed_mem1:

;there is mem for directory entry, but there is no mem for pages

;so free directory entry

    mov    eax,[new_process_place]

    shl    eax,8

    mov    eax,[0x80000+eax+0xB8]

    call   MEM_Free_Page

.cleanfailed_mem:

;there is no mem for directory entry, display message.

    mov    esi,start_not_enough_memory

    call   sys_msg_board_str

.cleanfailed:                    ;clean process name

;can't read file, clean process name.

;this avoid problems with panel application.

    mov    edi,[new_process_place]

    shl    edi,8

    add    edi,0x80000

    mov    ecx,11

    mov    eax,' '

    cld

    rep    stosb

.failed:

;no more slots

    add    esp,8

    mov    [application_table_status],0

    popad

    call   safe_sti

    mov    eax,-1

    ret

.add_app_parameters:

;input:

;  [esp] - pointer to parameters

;  [esp+4]-[esp+36] pushad registers.

;result

;  eax - pid of new process

;        or zero if failed

    cli

    mov    ebx,[new_process_place]

    cmp    ebx,[0x3004]

    jle    .noinc

    inc    dword [0x3004]        ;update number of processes

.noinc:

;   mov    ebx,[new_process_place]

;set 0x8c field of extended information about process

;(size of application memory)

    shl    ebx,8

    mov    eax,[app_mem]

    mov    [second_base_address+0x80000+0x8c+ebx],eax

;set 0x10 field of information about process

;(application base address)

;    mov    ebx,[new_process_place]

;    shl    ebx,5

    shr    ebx,3

    mov    dword [second_base_address+0x3000+ebx+0x10],std_application_base_address

;add command line parameters

.add_command_line:

    mov    edx,[app_i_param]

    test   edx,edx

    jz     .no_command_line      ;application don't need parameters

    mov    eax,[esp+4]

    test   eax,eax

    jz     .no_command_line      ;no parameters specified

;calculate parameter length

    mov    esi,eax

    xor    ecx,ecx

.command_line_len:

    cmp    byte [esi],0

    jz     .command_line_len_end

    inc    esi

    inc    ecx

    cmp    ecx,256

    jl     .command_line_len

.command_line_len_end:

;ecx - parameter length

;edx - address of parameters in new process address space

    mov    ebx,eax               ;ebx - address of parameters in our address space

    mov    eax,[new_process_place]

    call   write_process_memory  ;copy parameters to new process address space

.no_command_line:

;******************************************************************

    mov    edx,[app_i_icon]

    test   edx,edx

    jz     .no_command_line_1      ;application don't need path of file

    mov    ebx,[appl_path]

    mov    ecx,[appl_path_size]

    mov    eax,[new_process_place]

    call   write_process_memory  ;copy path of file to new process address space

.no_command_line_1:

;******************************************************************

    mov    ebx,[new_process_place]

    mov    eax,ebx

    shl    ebx,5

    add    ebx,0x3000            ;ebx - pointer to information about process

    mov    [ebx+0xe],al          ;set window number on screen = process slot

    mov    [ebx],dword 1+2+4     ;set default event flags (see 40 function)

    inc    dword [process_number]

    mov    eax,[process_number]

    mov    [ebx+4],eax           ;set PID

    mov    ecx,ebx

    add    ecx,draw_data-0x3000  ;ecx - pointer to draw data

;set draw data to full screen

    mov    [ecx+0],dword 0

    mov    [ecx+4],dword 0

    mov    eax,[0xfe00]

    mov    [ecx+8],eax

    mov    eax,[0xfe04]

    mov    [ecx+12],eax

;set window state to 'normal' (non-minimized/maximized/rolled-up) state

    mov    [ecx+WDATA.fl_wstate],WSTATE_NORMAL

;set cr3 register in TSS of application

    mov    ecx,[new_process_place]

    shl    ecx,8

    mov    eax,[0x800B8+ecx]

    add    eax,8+16              ;add flags

    mov    [l.cr3],eax

    mov    eax,[app_start]

    mov    [l.eip],eax           ;set eip in TSS

    mov    eax,[app_esp]

    mov    [l.esp],eax           ;set stack in TSS

;gdt

    ;mov    ebx,[new_process_place]

    ;shl    ebx,3

    mov    ax,app_code           ;ax - selector of code segment

    ;add    ax,bx

    mov    [l.cs],ax

    mov    ax,app_data

    ;add    ax,bx                 ;ax - selector of data segment

    mov    [l.ss],ax

    mov    [l.ds],ax

    mov    [l.es],ax

    mov    [l.fs],ax

    mov    ax,graph_data         ;ax - selector of graphic segment

    mov    [l.gs],ax

    mov    [l.io],word 128

    mov    [l.eflags],dword 0x11202

    mov    [l.ss0],os_data

    mov    ebx,[new_process_place]

    shl    ebx,12

    add    ebx,sysint_stack_data+4096

    mov    [l.esp0],ebx

;copy tss to it place

    mov    eax,tss_sceleton

    mov    ebx,[new_process_place]

    imul   ebx,tss_step

    add    ebx,tss_data          ;ebx - address of application TSS

    mov    ecx,120

    call   memmove

;Add IO access table - bit array of permitted ports

    or     eax,-1

    mov    edi,[new_process_place]

    imul   edi,tss_step

    add    edi,tss_data+128

    mov    ecx,2048

    cld

    rep    stosd                 ;full access to 2048*8=16384 ports

    mov    ecx,ebx               ;ecx - address of application TSS

    mov    edi,[new_process_place]

    shl    edi,3

;set TSS descriptor

    mov    [edi+gdts+tss0+0],word tss_step ;limit (size)

    mov    [edi+gdts+tss0+2],cx  ;part of offset

    mov    eax,ecx

    shr    eax,16

    mov    [edi+gdts+tss0+4],al  ;part of offset

    mov    [edi+gdts+tss0+7],ah  ;part of offset

    mov    [edi+gdts+tss0+5],word 01010000b*256+11101001b ;system flags

;flush keyboard and buttons queue

    mov    [0xf400],byte 0

    mov    [0xf500],byte 0

    mov    edi,[new_process_place]

    shl    edi,5

    add    edi,window_data

    mov    ebx,[new_process_place]

    movzx  esi,word [0xC000+ebx*2]

    lea    esi,[0xC400+esi*2]

    call   windowactivate        ;gui initialization

    mov    ebx,[new_process_place]

    shl    ebx,5

    mov    [0x3000+ebx+0xa],byte 0 ;set process state - running

; set if debuggee

    test   byte [esp+28], 1

    jz     .no_debug

    mov    [0x3000+ebx+0xa],byte 1 ;set process state - suspended

    mov    eax,[0x3000]

    mov    [0x80000+ebx*8+0xac],eax ;set debugger PID - current

.no_debug:

    mov    esi,new_process_running

    call   sys_msg_board_str     ;output information about succefull startup

;    add    esp,4                 ;pop pointer to parameters

;    popad

    mov    eax,[process_number]  ;set result

    mov    [application_table_status],0 ;unlock application_table_status mutex

    call   safe_sti

    ret    4

;-----------------------------------------------------------------------------

new_sys_threads:

;eax=1 - create thread

;   ebx=thread start

;   ecx=thread stack value

;result:

;   eax=pid

    xor    edx,edx	; flags=0

    pushad

    cmp    eax,1

    jnz    .ret                  ;other subfunctions

    mov    esi,new_process_loading

    call   sys_msg_board_str

;lock application_table_status mutex

.table_status:

    cli

    cmp    [application_table_status],0

    je     .stf

    sti

    call   change_task

    jmp    .table_status

.stf:

    call   set_application_table_status

;find free process slot

    call   find_new_process_place

    test   eax,eax

    jz     .failed

;set parameters for thread

    xor    eax,eax

    mov    [app_i_param],eax

    mov    [app_i_icon],eax

    mov    [app_start],ebx

    mov    [app_esp],ecx

    mov    esi,[0x3000]

    shl    esi,8

    add    esi,0x80000

    mov    ebx,esi               ;ebx=esi - pointer to extended information about current thread

    mov    edi,[new_process_place]

    shl    edi,8

    add    edi,0x80000

    mov    edx,edi               ;edx=edi - pointer to extended infomation about new thread

    mov    ecx,256/4

    rep    stosd                 ;clean extended information about new thread

    mov    edi,edx

    mov    ecx,11

    rep    movsb                 ;copy process name

    mov    eax,[ebx+0x8c]

    mov    [app_mem],eax         ;set memory size

    mov    eax,[ebx+0xb8]

    mov    [edx+0xb8],eax        ;copy page directory

;    mov    eax,[new_process_place]

;    mov    ebx,[0x3000]

;    call   addreference_app_cr3_table

    push   0                     ;no parameters

    call    new_start_application_fl.add_app_parameters ;start thread

    mov    [esp+28],eax

    popad

    ret

.failed:

    sti

    popad

    mov    eax,-1

    ret

.ret:

    popad

    ret

;-----------------------------------------------------------------------------

new_mem_resize:

;input:

;  ebx - new size

;result:

;  [esp+36]:=0 - normal

;  [esp+36]:=1 - error

;This function set new application memory size.

    mov    esi,ebx               ;save new size

    add    ebx,4095

    and    ebx,not (4096-1)      ;round up size

    mov    ecx,[0x3000]

    shl    ecx,8

    mov    edx,[0x8008C+ecx]

    add    edx,4095

    and    edx,not (4096-1)      ;old size

    mov    eax,[0x800B8+ecx]

    call   MEM_Get_Linear_Address

;eax - linear address of page directory

    call   MEM_Heap_Lock         ;guarantee that two threads willn't

                                 ;change memory size simultaneously

    cmp    ebx,edx

;    mov    esi,ebx               ;save new size

    jg     .expand

.free:

    sub    edx,ebx

    jz     .unlock               ;do nothing

    mov    ecx,edx

    shr    ecx,12

    add    ebx,std_application_base_address

    call   mem_free_specified_region  ;free unnecessary pages

    jmp    .unlock

.expand:

    sub    ebx,edx

    mov    ecx,ebx

    shr    ecx,12

    mov    ebx,edx

    add    ebx,std_application_base_address

    call   mem_alloc_specified_region ;alloc necessary pages

    test   eax,eax

    jz     .failed               ;not enough memory

.unlock:

    mov    ebx,esi

    mov    eax,[0x3000]

    shl    eax,8

    mov    [eax+0x8008c],ebx     ;write new memory size

;search threads and update

;application memory size infomation

    mov    ecx,[eax+0x800b8]

    mov    eax,2

.search_threads:

;eax = current slot

;ebx = new memory size

;ecx = page directory

    cmp    eax,[0x3004]

    jg     .search_threads_end

    mov    edx,eax

    shl    edx,5

    cmp    word [0x3000+edx+0xa],9 ;if slot empty?

    jz     .search_threads_next

    shl    edx,3

    cmp    [edx+0x800b8],ecx     ;if it is our thread?

    jnz    .search_threads_next

    mov    [edx+0x8008c],ebx     ;update memory size

.search_threads_next:

    inc    eax

    jmp    .search_threads

.search_threads_end:

    call   MEM_Heap_UnLock

    mov    dword [esp+36],0

    ret

.failed:

    call   MEM_Heap_UnLock

    mov    dword [esp+36],1

    ret

;-----------------------------------------------------------------------------

pid_to_slot:

;Input:

;  eax - pid of process

;Output:

;  eax - slot of process or 0 if process don't exists

;Search process by PID.

    push   ebx

    push   ecx

    mov    ebx,[0x3004]

    shl    ebx,5

    mov    ecx,2*32

.loop:

;ecx=offset of current process info entry

;ebx=maximum permitted offset

    cmp    byte [second_base_address+0x3000+ecx+0xa],9

    jz     .endloop              ;skip empty slots

    cmp    [second_base_address+0x3000+ecx+0x4],eax ;check PID

    jz     .pid_found

.endloop:

    add    ecx,32

    cmp    ecx,ebx

    jle    .loop

    pop    ecx

    pop    ebx

    xor    eax,eax

    ret

.pid_found:

    shr    ecx,5

    mov    eax,ecx               ;convert offset to index of slot

    pop    ecx

    pop    ebx

    ret

;-----------------------------------------------------------------------------

is_new_process:

;Input:

;  eax - process slot

;Output:

;  eax=1 - it is new process

;  eax=0 - it is old process

;    shl   eax,5

;    mov   eax,[second_base_address+0x3000+eax+0x10]

;    cmp   eax,std_application_base_address  ;check base address of application

;    jz    .new_process

;    xor   eax,eax

;    ret

;.new_process:

    mov   eax,1

    ret

;-----------------------------------------------------------------------------

write_process_memory:

;Input:

;  eax - process slot

;  ebx - buffer address

;  ecx - buffer size

;  edx - start address in other process

;Output:

;  eax - number of bytes written

    pushad

    shl  eax,8

    mov  eax,[0x80000+eax+0xB8]

    call MEM_Get_Linear_Address

    mov  ebp,eax

;ebp=linear address of page directory of other process.

    add  edx,std_application_base_address  ;convert to linear address

    test ecx,ecx

    jle  .ret

.write_loop:

;ebx = current buffer address

;ecx>0 = current size

;edx = current address in other process

;ebp = linear address of page directory

    call MEM_Heap_Lock           ;cli

    mov  esi,edx

    shr  esi,22

    mov  eax,[ebp+4*esi]         ;find page directory entry

    and  eax,not (4096-1)        ;clear flags

    test eax,eax

    jz   .page_not_found

    call MEM_Get_Linear_Address  ;calculate linear address of page table

    test eax,eax

    jz   .page_not_found

    mov  esi,edx

    shr  esi,12

    and  esi,1023

    mov  eax,[eax+4*esi]         ;find page table entry

    and  eax,not (4096-1)

    test eax,eax

    jz   .page_not_found

    call MEM_Get_Linear_Address  ;calculate linear address of page

    test eax,eax

    jz   .page_not_found

    mov  edi,eax

    call MEM_Add_Reference_Linear;guarantee that page willn't disappear

    call MEM_Heap_UnLock         ;sti

    mov  esi,edx

    and  esi,4095

    add  edi,esi                 ;add offset in page

;edi = linear address corresponding edx in other process

    sub  esi,4096

    neg  esi                     ;esi - number of remaining bytes in page

    cmp  esi,ecx

    jl   .min_ecx

    mov  esi,ecx

.min_ecx:                        ;esi=min(ecx,esi) - number of bytes to write

    sub  ecx,esi

    push ecx

    mov  ecx,esi                 ;ecx - number of bytes to write

    mov  esi,ebx                 ;esi - source, edi - destination

    add  edx,ecx                 ;move pointer in address space of other process

    push edi

;move ecx bytes

    test ecx,3

    jnz  .not_aligned

    shr  ecx,2

    rep  movsd

    jmp  .next_iter

.not_aligned:

    rep  movsb

.next_iter:

    pop  eax

    and  eax,not (4096-1)        ;eax - linear address of current page

    call MEM_Free_Page_Linear    ;free reference

    mov  ebx,esi                 ;new pointer to buffer - movsb automaticaly advance it.

    pop  ecx                     ;restore number of remaining bytes

    test ecx,ecx

    jnz  .write_loop

.ret:

    popad

    mov  eax,ecx

    ret

.page_not_found:

    call MEM_Heap_UnLock         ;error has appeared in critical region

    sub  ecx,[esp+24]            ;[esp+24]<-->ecx

    neg  ecx                     ;ecx=number_of_written_bytes

    mov  [esp+28],ecx            ;[esp+28]<-->eax

    popad

    ret

;-----------------------------------------------------------------------------

syscall_test:

;for testing memory manager from applications.

    mov  edx,ecx

    mov  ecx,ebx

    call trans_address

    mov  ebx,eax

    mov  eax,[0x3000]

    call read_process_memory

    ret

;-----------------------------------------------------------------------------

read_process_memory:

;Input:

;  eax - process slot

;  ebx - buffer address

;  ecx - buffer size

;  edx - start address in other process

;Output:

;  eax - number of bytes read.

    pushad

    shl  eax,8

    mov  eax,[0x80000+eax+0xB8]

    call MEM_Get_Linear_Address

    mov  ebp,eax

    add  edx,std_application_base_address

.read_loop:

;ebx = current buffer address

;ecx>0 = current size

;edx = current address in other process

;ebp = linear address of page directory

    call MEM_Heap_Lock           ;cli

    mov  esi,edx

    shr  esi,22

    mov  eax,[ebp+4*esi]         ;find page directory entry

    and  eax,not (4096-1)

    test eax,eax

    jz   .page_not_found

    call MEM_Get_Linear_Address

    test eax,eax

    jz   .page_not_found

    mov  esi,edx

    shr  esi,12

    and  esi,1023

    mov  eax,[eax+4*esi]         ;find page table entry

    and  eax,not (4096-1)

    test eax,eax

    jz   .page_not_found

    call MEM_Get_Linear_Address  ;calculate linear address of page

    test eax,eax

    jz   .page_not_found

    mov  esi,eax

    call MEM_Add_Reference_Linear;guarantee that page willn't disappear

    call MEM_Heap_UnLock         ;sti

    mov  edi,edx

    and  edi,4095

    add  esi,edi                 ;add offset in page

;esi = linear address corresponding edx in other process

    sub  edi,4096

    neg  edi

;edi=min(edi,ecx) - number of bytes to copy

    cmp  edi,ecx

    jl   .min_ecx

    mov  edi,ecx

.min_ecx:

    sub  ecx,edi                 ;update size of remaining bytes

    add  edx,edi                 ;update current pointer in other address space.

    push ecx

    mov  ecx,edi                 ;ecx - number of bytes to read

    mov  edi,ebx                 ;esi - source, edi - destination

    push esi

;move ecx bytes

    test ecx,3

    jnz  .not_aligned

    shr  ecx,2

    rep  movsd

    jmp  .next_iter

.not_aligned:

    rep  movsb

.next_iter:

    pop  eax

    and  eax,not (4096-1)        ;eax - linear address of current page

    call MEM_Free_Page_Linear    ;free reference

    mov  ebx,edi                 ;new pointer to buffer - movsb automaticaly advance it.

    pop  ecx                     ;restore number of remaining bytes

    test ecx,ecx

    jnz  .read_loop

    popad

    mov  eax,ecx

    ret

.page_not_found:

    call MEM_Heap_UnLock         ;error has appeared in critical region

    sub  ecx,[esp+24]            ;[esp+24]<-->ecx

    neg  ecx                     ;ecx=number_of_read_bytes

    mov  [esp+28],ecx            ;[esp+28]<-->eax

    popad

    ret

;-----------------------------------------------------------------------------

check_region:

;input:

;  ebx - start of buffer

;  ecx - size of buffer

;result:

;  eax = 1 region lays in app memory

;  eax = 0 region don't lays in app memory

    mov  eax,[0x3000]

    jmp  check_process_region

;-----------------------------------------------------------------------------

check_process_region:

;input:

;  eax - slot

;  ebx - start of buffer

;  ecx - size of buffer

;result:

;  eax = 1 region lays in app memory

;  eax = 0 region don't lays in app memory

    test ecx,ecx

    jle  .ok

    shl  eax,5

    cmp  word [0x3000+eax+0xa],0

    jnz  .failed

    shl  eax,3

    mov  eax,[0x80000+eax+0xb8]

    test eax,eax

    jz   .failed

    call MEM_Get_Linear_Address

    push ebx

    push ecx

    push edx

    mov  edx,ebx

    and  edx,not (4096-1)

    sub  ebx,edx

    add  ecx,ebx

    mov  ebx,edx

    add  ecx,(4096-1)

    and  ecx,not (4096-1)

.loop:

;eax - linear address of page directory

;ebx - current page

;ecx - current size

    mov  edx,ebx

    shr  edx,22

    mov  edx,[eax+4*edx]

    and  edx,not (4096-1)

    test edx,edx

    jz   .failed1

    push eax

    mov  eax,edx

    call MEM_Get_Linear_Address

    mov  edx,ebx

    shr  edx,12

    and  edx,(1024-1)

    mov  eax,[eax+4*edx]

    and  eax,not (4096-1)

    test eax,eax

    pop  eax

    jz   .failed1

    add  ebx,4096

    sub  ecx,4096

    jg   .loop

    pop  edx

    pop  ecx

    pop  ebx

.ok:

    mov  eax,1

    ret

.failed1:

    pop  edx

    pop  ecx

    pop  ebx

.failed:

    xor  eax,eax

    ret

;-----------------------------------------------------------------------------

new_sys_ipc:

;input:

;  eax=1 - set ipc buffer area

;    ebx=address of buffer

;    ecx=size of buffer

;  eax=2 - send message

;    ebx=PID

;    ecx=address of message

;    edx=size of message

    cmp  eax,1

    jnz  .no_ipc_def

;set ipc buffer area

    mov  edi,[0x3000]

    shl  edi,8

    add  edi,0x80000

    cli

    mov  [edi+0xA0],ebx          ;set fields in extended information area

    mov  [edi+0xA4],ecx

    sti

    mov  [esp+36],dword 0        ;success

    ret

.no_ipc_def:

    cmp  eax,2

    jnz  .no_ipc_send

;send message

    cli

;obtain slot from PID

    mov  eax,ebx

    call pid_to_slot

    test eax,eax

    jz   .no_pid

    mov  ebp,eax

;ebp = slot of other process

    shl  eax,8

    mov  edi,[eax+0x80000+0xa0]  ;is ipc area defined?

    test edi,edi

    jz   .no_ipc_area

    mov  esi,[eax+0x80000+0xa4]  ;esi - size of buffer

    push dword -1                ;temp variable for read_process_memory

    mov  ebx,esp

    push ecx

    push edx

    mov  ecx,4                   ;read 4 bytes

    mov  eax,ebp

    mov  edx,edi                 ;from beginning of buffer.

    call read_process_memory

    mov  eax,[esp+8]

    test eax,eax

    jnz  .ipc_blocked            ;if dword [buffer]<>0 - ipc blocked now

    add  edx,4                   ;move to next 4 bytes

    mov  eax,ebp

    call read_process_memory     ;read size of occupied space in buffer

    sub  esi,8

    sub  esi,[esp]

    sub  esi,[esp+8]             ;esi=(buffer size)-(occupied size)-(message size)-(header of message size)

    js   .buffer_overflow        ;esi<0 - not enough memory in buffer

    mov  esi,[esp+8]             ;previous offset

    add  dword [esp+8],8

    mov  edi,[esp]

    add  [esp+8],edi             ;add (size of message)+(size of header of message) to [buffer+4]

    mov  eax,ebp

    call write_process_memory

    add  edx,esi

    sub  edx,4                   ;move to beginning of place for our message

    mov  eax,[second_base_address+0x3010]

    mov  eax,[eax+0x4]           ;eax - our PID

    mov  [esp+8],eax

    mov  eax,ebp