changed background handling

git-svn-id: svn://kolibrios.org@546 a494cfbc-eb01-0410-851d-a64ba20cac60

kernel/trunk/core/heap.inc

@@ -20,6 +20,7 @@ struc MEM_BLOCK
 MEM_LIST_OFFSET equ  8
 FREE_BLOCK      equ  4
 USED_BLOCK      equ  8
+DONT_FREE_BLOCK equ  10h
 
 virtual at 0
   MEM_BLOCK MEM_BLOCK
@@ -728,8 +729,10 @@ proc user_free stdcall, base:dword
            sub esi, 4096
            shr esi, 12
            mov eax, [page_tabs+esi*4]
-           test eax, USED_BLOCK
+           test al, USED_BLOCK
            jz .not_used
+           test al, DONT_FREE_BLOCK
+           jnz .cantfree
 
            and eax, not 4095
            mov ecx, eax
@@ -765,6 +768,9 @@ proc user_free stdcall, base:dword
            xor eax, eax
            inc eax
            ret
+.cantfree:
+           xor eax, eax
+           ret
 endp
 
 user_normalize:
@@ -836,6 +842,8 @@ user_realloc:
         xor     eax, eax
         ret
 @@:
+        test    edx, DONT_FREE_BLOCK
+        jnz     .ret0
         add     ebx, 0x1FFF
         shr     edx, 12
         shr     ebx, 12

kernel/trunk/core/sys32.inc

@@ -720,6 +720,11 @@ term9:
         mov     [flp_status], 0
 @@:
         pop     esi
+        cmp     [bgrlockpid], esi
+        jnz     @f
+        and     [bgrlockpid], 0
+        mov     [bgrlock], 0
+@@:
 
     pusha ; remove all irq reservations
     mov   eax,esi

kernel/trunk/docs/sysfuncr.txt

@@ -1,4 +1,4 @@
-<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> Kolibri 0.6.5.0
+<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> Kolibri 0.7.0.0
 
 <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20>㭪樨 <20><><EFBFBD><EFBFBD>頥<EFBFBD><E9A0A5><EFBFBD> <20> ॣ<><E0A5A3><EFBFBD><EFBFBD> eax.
 <EFBFBD>맮<EFBFBD> <20><><EFBFBD>⥬<EFBFBD><E2A5AC><EFBFBD> <20>㭪樨 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⢫<EFBFBD><E2A2AB><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> "int 0x40".
@@ -574,6 +574,34 @@
   * <20><><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><>࠭<EFBFBD> (<28><>᫥ <20><><EFBFBD><EFBFBD><EFBFBD>襭<EFBFBD><E8A5AD> <20><>ਨ <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>, ࠡ<><E0A0A1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20>
     䮭<><E4AEAD>) <20><><EFBFBD>뢠<EFBFBD><EBA2A0><EFBFBD> <20><><EFBFBD><EFBFBD>㭪<EFBFBD><E3ADAA><EFBFBD> 3 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ᮢ<EFBFBD><E1AEA2> 䮭<>.
 
+======================================================================
+====================== <20>㭪<EFBFBD><E3ADAA><EFBFBD> 15, <20><><EFBFBD><EFBFBD>㭪<EFBFBD><E3ADAA><EFBFBD> 6 ======================
+==== <20><>஥<EFBFBD><E0AEA5>஢<EFBFBD><E0AEA2><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> 䮭<> <20><> <20><><EFBFBD><EFBFBD>᭮<EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD>࠭<EFBFBD>⢮ <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>. ====
+======================================================================
+<EFBFBD><EFBFBD>ࠬ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>:
+  * eax = 15 - <20><><EFBFBD><EFBFBD><EFBFBD> <20>㭪樨
+  * ebx = 6 - <20><><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>㭪樨
+<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>頥<EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>祭<EFBFBD><E7A5AD>:
+  * eax = 㪠<><E3AAA0>⥫<EFBFBD> <20><> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> 䮭<>, 0 <20><><EFBFBD> <20>訡<EFBFBD><E8A8A1>
+<EFBFBD><EFBFBD><EFBFBD><EFBFBD>砭<EFBFBD><EFBFBD>:
+  * <20><>஥<EFBFBD><E0AEA5>஢<EFBFBD><E0AEA2><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>㯭<EFBFBD> <20><> <20>⥭<EFBFBD><E2A5AD> <20> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>.
+  * <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> 䮭<> ࠢ<><E0A0A2> 3*xsize*ysize. <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> ࠧ<><E0A0A7>஢ 䮭<>
+    <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><> <20>६<EFBFBD> ࠡ<><E0A0A1><EFBFBD> <20> <20><>஥<EFBFBD><E0AEA5>஢<EFBFBD><E0AEA2><EFBFBD>묨 <20><><EFBFBD><EFBFBD>묨.
+  * <20><><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>ᥫ<EFBFBD> <20>࠭<EFBFBD><E0A0AD><EFBFBD><EFBFBD> <20><><EFBFBD> 3-<2D><><EFBFBD>⮢<EFBFBD><E2AEA2> <20><><EFBFBD><EFBFBD>稭<EFBFBD> BBGGRR.
+  * <20><><EFBFBD>ᥫ<EFBFBD> 䮭<><E4AEAD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>ࠦ<EFBFBD><E0A0A6><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD>뢠<EFBFBD><EBA2A0><EFBFBD><EFBFBD> <20><>᫥<EFBFBD><E1ABA5><EFBFBD><EFBFBD>⥫쭮
+    ᫥<><E1ABA5> <20><><EFBFBD>ࠢ<EFBFBD>, ᢥ<><E1A2A5><EFBFBD> <20><><EFBFBD><EFBFBD>.
+
+======================================================================
+====================== <20>㭪<EFBFBD><E3ADAA><EFBFBD> 15, <20><><EFBFBD><EFBFBD>㭪<EFBFBD><E3ADAA><EFBFBD> 7 ======================
+=== <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20>஥<EFBFBD><E0AEA5><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> 䮭<> <20><> <20><><EFBFBD><EFBFBD>᭮<EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD>࠭<EFBFBD>⢮ <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>. ==
+======================================================================
+<EFBFBD><EFBFBD>ࠬ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>:
+  * eax = 15 - <20><><EFBFBD><EFBFBD><EFBFBD> <20>㭪樨
+  * ebx = 7 - <20><><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>㭪樨
+  * ecx = 㪠<><E3AAA0>⥫<EFBFBD> <20><> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> 䮭<>
+<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>頥<EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>祭<EFBFBD><E7A5AD>:
+  * eax = 1 <20><><EFBFBD> <20>ᯥ<EFBFBD><E1AFA5>, 0 <20><><EFBFBD> <20>訡<EFBFBD><E8A8A1>
+
 ======================================================================
 ============= <20>㭪<EFBFBD><E3ADAA><EFBFBD> 16 - <20><><EFBFBD>࠭<EFBFBD><E0A0AD><EFBFBD> ࠬ<><E0A0AC><EFBFBD><EFBFBD> <20><> <20><>᪥<EFBFBD><E1AAA5>. =============
 ======================================================================
@@ -839,7 +867,7 @@
 <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>:
 db a,b,c,d <20><><EFBFBD> <20><><EFBFBD>ᨨ a.b.c.d
 db UID_xxx: <20><><EFBFBD><EFBFBD> <20><> UID_NONE=0, UID_MENUET=1, UID_KOLIBRI=2
-dd REV - <20><><EFBFBD><EFBFBD><EFBFBD> svn ॢ<EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>
+dd REV - <20><><EFBFBD><EFBFBD><EFBFBD> svn-ॢ<EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>
 <EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD> Kolibri 0.7.0.0:
 db 0,7,0,0
 db 2
@@ -2305,12 +2333,11 @@ dword-
 <EFBFBD><EFBFBD>ࠬ<EFBFBD><EFBFBD><EFBFBD><EFBFBD>:
   * eax = 48 - <20><><EFBFBD><EFBFBD><EFBFBD> <20>㭪樨
   * ebx = 8 - <20><><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>㭪樨
-  * ecx = 㪠<><E3AAA0>⥫<EFBFBD> <20><> <20><><EFBFBD><EFBFBD> <20><><EFBFBD> <20>㭪樨 58, <20> <20><><EFBFBD><EFBFBD>஬ <20><>⠭<EFBFBD><E2A0AD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
+  * ecx = 㪠<><E3AAA0>⥫<EFBFBD> <20><> <20><><EFBFBD> 䠩<><E4A0A9> ᪨<EFBFBD><EFBFBD>
-    <20><><EFBFBD><EFBFBD> <20>஬<EFBFBD><E0AEAC><EFBFBD><EFBFBD><EFBFBD>筮<EFBFBD><E7ADAE> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20> 㪠<><E3AAA0><EFBFBD><EFBFBD> <20><><EFBFBD> 䠩<><E4A0A9>
 <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>頥<EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>祭<EFBFBD><E7A5AD>:
   * eax = 0 - <20>ᯥ譮
-  * <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> eax = <20><><EFBFBD> <20>訡<EFBFBD><E8A8A1> 䠩<><E4A0A9><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>⥬<EFBFBD>; <20>᫨ 䠩<> <20><> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD> ᪨<>,
+  * eax = 1 - <20><> 㤠<><E3A4A0><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>㧨<EFBFBD><E3A7A8> 䠩<>
-    <20><> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>頥<EFBFBD><E9A0A5><EFBFBD> <20>訡<EFBFBD><E8A8A1> 3 (<28><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⭠<EFBFBD> 䠩<><E4A0A9><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>⥬<EFBFBD>).
+  * eax = 2 - 䠩<> <20><> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> 䠩<><E4A0A9><EFBFBD> ᪨<EFBFBD><EFBFBD>
 <EFBFBD><EFBFBD><EFBFBD><EFBFBD>砭<EFBFBD><EFBFBD>:
   * <20><><EFBFBD> <20>ᯥ譮<E1AFA5> <20><><EFBFBD><EFBFBD>㧪<EFBFBD> ᪨<><E1AAA8> <20><><EFBFBD> <20><><EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <20> <20><><EFBFBD><EFBFBD>室<EFBFBD><E5AEA4><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
     <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ᮢ<EFBFBD><E1AEA2> (ᮡ<>⨥ 1).
@@ -4064,11 +4091,14 @@ Architecture Software Developer's Manual, Volume 3, Appendix B);
   * /CD0/1, /CD1/1, /CD2/1, /CD3/1 <20><><EFBFBD> <20><><EFBFBD><EFBFBD>㯠 ᮮ⢥<E1AEAE><E2A2A5>⢥<EFBFBD><E2A2A5><EFBFBD>
     <20> CD <20><> IDE0 (Primary Master), IDE1 (Primary Slave),
     IDE2 (Secondary Master), IDE3 (Secondary Slave)
+  * /SYS - <20><>।<EFBFBD><E0A5A4><EFBFBD><EFBFBD><EFBFBD> <20><><EFBFBD>⥬<EFBFBD><E2A5AC><EFBFBD> <20><><EFBFBD><EFBFBD><EFBFBD>; <20><><EFBFBD> <20><><EFBFBD>筮<EFBFBD> <20><><EFBFBD><EFBFBD>㧪<EFBFBD> <20><><EFBFBD>⥬<EFBFBD>
+    <20> <20><>᪥<EFBFBD><E1AAA5> <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>⭮ /RD/1
 <EFBFBD>ਬ<EFBFBD><EFBFBD><EFBFBD>:
   * '/rd/1/kernel.asm',0
   * '/HD0/1/kernel.asm',0
   * '/hd0/2/menuet/pics/tanzania.bmp',0
   * '/hd0/1/Program files/NameOfProgram/SomeFile.SomeExtension',0
+  * '/sys/MySuperApp.ini',0
 <EFBFBD><EFBFBD><EFBFBD><EFBFBD>㯭<EFBFBD><EFBFBD> <20><><EFBFBD><EFBFBD>㭪樨:
   * <20><><EFBFBD><EFBFBD>㭪<EFBFBD><E3ADAA><EFBFBD> 0 - <20>⥭<EFBFBD><E2A5AD> 䠩<><E4A0A9>
   * <20><><EFBFBD><EFBFBD>㭪<EFBFBD><E3ADAA><EFBFBD> 1 - <20>⥭<EFBFBD><E2A5AD> <20><><EFBFBD><EFBFBD><EFBFBD>

kernel/trunk/docs/sysfuncs.txt

@@ -1,4 +1,4 @@
-SYSTEM FUNCTIONS of OS Kolibri 0.6.5.0
+SYSTEM FUNCTIONS of OS Kolibri 0.7.0.0
 
 Number of the function is located in the register eax.
 The call of the system function is executed by "int 0x40" command.
@@ -567,6 +567,33 @@ Remarks:
   * For update of the screen (after completion of a series of commands
     working with a background) call subfunction 3.
 
+======================================================================
+===================== Function 15, subfunction 6 =====================
+======== Map background data to the address space of process. ========
+======================================================================
+Parameters:
+  * eax = 15 - function number
+  * ebx = 6 - subfunction number
+Returned value:
+  * eax = pointer to background data, 0 if error
+Remarks:
+  * Mapped data are available for read and write.
+  * Size of background data is 3*xsize*ysize. The system blocks
+    changes of background sizes while process works with mapped data.
+  * Color of each pixel is stored as 3-bytes value BBGGRR.
+  * Pixels of the background image are written sequentially
+    from left to right, from up to down.
+
+======================================================================
+===== Function 15, subfunction 7 - close mapped background data. =====
+======================================================================
+Parameters:
+  * eax = 15 - function number
+  * ebx = 7 - subfunction number
+  * ecx = pointer to mapped data
+Returned value:
+  * eax = 1 - success, 0 - error
+
 ======================================================================
 =============== Function 16 - save ramdisk on a floppy. ==============
 ======================================================================
@@ -4025,11 +4052,14 @@ one of
   * /CD0/1, /CD1/1, /CD2/1, /CD3/1 to access accordingly to
     CD on IDE0 (Primary Master), IDE1 (Primary Slave),
     IDE2 (Secondary Master), IDE3 (Secondary Slave)
+  * /SYS means system folder; with the usual boot (from floppy)
+    is equivalent to /RD/1
 Examples:
   * '/rd/1/kernel.asm',0
   * '/HD0/1/kernel.asm',0
   * '/hd0/2/menuet/pics/tanzania.bmp',0
   * '/hd0/1/Program files/NameOfProgram/SomeFile.SomeExtension',0
+  * '/sys/MySuperApp.ini',0
 Available subfunctions:
   * subfunction 0 - read file
   * subfunction 1 - read folder

kernel/trunk/kernel.asm

@@ -2346,6 +2346,8 @@ sys_cachetodiskette:
 
 uglobal
 ;  bgrchanged  dd  0x0
+bgrlock db 0
+bgrlockpid dd 0
 endg
 
 sys_background:
@@ -2356,6 +2358,14 @@ sys_background:
     je    sbgrr
     cmp   ecx,0
     je    sbgrr
+@@:
+        mov     al, 1
+        xchg    [bgrlock], al
+        test    al, al
+        jz      @f
+        call    change_task
+        jmp     @b
+@@:
     mov   [BgrDataWidth],ebx
     mov   [BgrDataHeight],ecx
 ;    mov   [bgrchanged],1
@@ -2379,12 +2389,13 @@ sys_background:
     lea  eax,[eax*3]
     mov  [mem_BACKGROUND],eax
 ; get memory for new background
-    stdcall kernel_alloc, [mem_BACKGROUND]
+    stdcall kernel_alloc, eax
     test eax, eax
     jz .exit_mem
     mov [img_background], eax
 .exit_mem:
     popad
+        mov     [bgrlock], 0
 
   sbgrr:
     ret
@@ -2444,6 +2455,84 @@ draw_background_temp:
     ret
   nosb5:
 
+        cmp     eax, 6
+        jnz     nosb6
+@@:
+        mov     al, 1
+        xchg    [bgrlock], al
+        test    al, al
+        jz      @f
+        call    change_task
+        jmp     @b
+@@:
+        mov     eax, [CURRENT_TASK]
+        mov     [bgrlockpid], eax
+        stdcall user_alloc, [mem_BACKGROUND]
+        mov     [esp+36], eax
+        test    eax, eax
+        jz      .nomem
+        mov     ebx, eax
+        shr     ebx, 12
+        or      dword [page_tabs+(ebx-1)*4], DONT_FREE_BLOCK
+        mov     esi, [img_background]
+        shr     esi, 12
+        mov     ecx, [mem_BACKGROUND]
+        add     ecx, 0xFFF
+        shr     ecx, 12
+.z:
+        mov     eax, [page_tabs+ebx*4]
+        test    al, 1
+        jz      @f
+        call    free_page
+@@:
+        mov     eax, [page_tabs+esi*4]
+        or      al, PG_UW
+        mov     [page_tabs+ebx*4], eax
+        mov     eax, ebx
+        shl     eax, 12
+        invlpg  [eax]
+        inc     ebx
+        inc     esi
+        loop    .z
+        ret
+.nomem:
+        and     [bgrlockpid], 0
+        mov     [bgrlock], 0
+nosb6:
+        cmp     eax, 7
+        jnz     nosb7
+        cmp     [bgrlock], 0
+        jz      .err
+        mov     eax, [CURRENT_TASK]
+        cmp     [bgrlockpid], eax
+        jnz     .err
+        mov     eax, ebx
+        shr     eax, 12
+        mov     ecx, [page_tabs+(eax-1)*4]
+        test    cl, USED_BLOCK+DONT_FREE_BLOCK
+        jz      .err
+        jnp     .err
+        push    eax
+        shr     ecx, 12
+@@:
+        and     dword [page_tabs+eax*4], 0
+        mov     edx, eax
+        shl     edx, 12
+        invlpg  [edx]
+        inc     eax
+        loop    @b
+        pop     eax
+        and     dword [page_tabs+(eax-1)*4], not DONT_FREE_BLOCK
+        stdcall user_free, ebx
+        mov     [esp+36], eax
+        and     [bgrlockpid], 0
+        mov     [bgrlock], 0
+        ret
+.err:
+        and     dword [esp+36], 0
+        ret
+
+nosb7:
     ret
 
 

kernel/trunk/video/vesa20.inc

@@ -862,20 +862,24 @@ vesa20_drawbackground_stretch:
         call    [disable_mouse]
         pushad
 ; Helper variables
+; calculate 2^32*(BgrDataWidth-1) mod (ScreenWidth-1)
         mov     eax, [BgrDataWidth]
+        dec     eax
         xor     edx, edx
-        mov     ecx, [ScreenWidth]
+        div     dword [ScreenWidth]
-        inc     ecx
+        push    eax     ; high
-        div     ecx
+        xor     eax, eax
-        push    eax     ; quo
+        div     dword [ScreenWidth]
-        push    edx     ; rem
+        push    eax     ; low
+; the same for height
         mov     eax, [BgrDataHeight]
+        dec     eax
         xor     edx, edx
-        mov     ecx, [ScreenHeight]
+        div     dword [ScreenHeight]
-        inc     ecx
+        push    eax     ; high
-        div     ecx
+        xor     eax, eax
-        push    eax
+        div     dword [ScreenHeight]
-        push    edx
+        push    eax     ; low
 ; External loop for all y from start to end
         mov     ebx, [draw_data+32+RECT.top]    ; y start
         mov     ebp, [draw_data+32+RECT.left]   ; x start
@@ -897,83 +901,76 @@ vesa20_drawbackground_stretch:
         xchg    edi, ebp
 ; Now eax=x, ebx=y, edi->output, ebp=offset in WinMapAddress
         push    ebx
+        push    eax
 ; 2) Calculate offset in background memory block
-        push    eax
         mov     eax, ebx
-        mul     dword [BgrDataHeight]
+        imul    ebx, dword [esp+12]
-        mov     ecx, [ScreenHeight]
+        mul     dword [esp+8]
-        inc     ecx
+        add     edx, ebx        ; edx:eax = y * 2^32*(BgrDataHeight-1)/(ScreenHeight-1)
-        div     ecx             ; eax := y * BgrDataHeight / ScreenHeight
+        mov     esi, edx
-                                ; edx := (y * BgrDataHeight) mod ScreenHeight
+        imul    esi, [BgrDataWidth]
-        mov     esi, eax
-        pop     eax
-        push    edx             ; dword [esp] = (y * BgrDataHeight) mod ScreenHeight
-                                ; dword [esp+4] = y * BgrDataHeight / ScreenHeight
-        push    eax
-        mov     ecx, [BgrDataWidth]
-        lea     edx, [ecx*3]
-        imul    edx, [BgrDataHeight]
-        add     edx, [img_background]
         push    edx
-        mul     ecx
+        push    eax
-        imul    esi, ecx
+        mov     eax, [esp+8]
-        dec     ecx
+        mul     dword [esp+28]
-        push    ecx
+        push    eax
-        mov     ecx, [ScreenWidth]
+        mov     eax, [esp+12]
-        inc     ecx
+        mul     dword [esp+28]
-        div     ecx             ; eax := x * BgrDataWidth / ScreenWidth
+        add     [esp], edx
-                                ; edx := (x * BgrDataWidth) mod ScreenWidth
+        pop     edx             ; edx:eax = x * 2^32*(BgrDataWidth-1)/(ScreenWidth-1)
-        add     esi, eax
+        add     esi, edx
         lea     esi, [esi*3]
         add     esi, [img_background]
-        push    ecx edx esi
+        mov     ecx, eax
+        push    eax edx esi
 ; 3) Loop through redraw rectangle and copy background data
 ; Registers meaning:
-; ecx = (x * BgrDataWidth) / ScreenWidth
+; edx:ecx = x * 2^32 * (BgrDataWidth-1) / (ScreenWidth-1)
-; edx = (x * BgrDataWidth) mod ScreenWidth (used to fast recalculating of ecx,esi)
 ; esi -> bgr memory, edi -> output
 ; ebp = offset in WinMapAddress
 ; dword [esp] = saved esi
 ; dword [esp+4] = saved edx
 ; dword [esp+8] = saved ecx
-; dword [esp+12] = BgrDataWidth-1, x-limit for overlapping of points
+; qword [esp+12] = y * 2^32 * (BgrDataHeight-1) / (ScreenHeight-1)
-; dword [esp+16] = end of bgr memory (defines y-limit for overlapping of points)
 ; dword [esp+20] = x
-; dword [esp+24] = (y * BgrDataHeight) mod ScreenHeight (used to fast recalculating of esi)
+; dword [esp+24] = y
-; dword [esp+28] = y
 ; precalculated constants:
-; dword [esp+32] = BgrDataHeight mod ScreenHeight
+; qword [esp+28] = 2^32*(BgrDataHeight-1)/(ScreenHeight-1)
-; dword [esp+36] = BgrDataHeight div ScreenHeight
+; qword [esp+36] = 2^32*(BgrDataWidth-1)/(ScreenWidth-1)
-; dword [esp+40] = BgrDataWidth mod ScreenWidth
-; dword [esp+44] = BgrDataWidth div ScreenWidth
 sdp3:
-        add     edx, [esp+40]
         cmp     [ebp+WinMapAddress], byte 1
         jnz     snbgp
         mov     al, [esi+2]
         shl     eax, 16
         mov     ax, [esi]
-        cmp     ecx, [esp+12]
+        test    ecx, ecx
-        jae     @f
+        jz      @f
-        cmp     edx, [ScreenWidth]
-        jb      @f
         mov     ebx, [esi+2]
         shr     ebx, 8
         call    overlapping_of_points
 @@:
-        mov     ebx, [esp+24]
+        cmp     dword [esp+12], 0
-        add     ebx, [esp+32]
+        jz      .novert
-        cmp     ebx, [ScreenHeight]
-        jbe     @f
         mov     ebx, [BgrDataWidth]
         lea     ebx, [ebx*3]
         add     ebx, esi
-        cmp     ebx, [esp+16]
+        push    eax
-        jae     @f
+        mov     al, [ebx+2]
-        mov     ebx, [ebx-1]
+        shl     eax, 16
+        mov     ax, [ebx]
+        test    ecx, ecx
+        jz      .nohorz
+        mov     ebx, [ebx+2]
         shr     ebx, 8
         call    overlapping_of_points
-@@:
+.nohorz:
+        mov     ebx, eax
+        pop     eax
+        push    ecx
+        mov     ecx, [esp+4+12]
+        call    overlapping_of_points
+        pop     ecx
+.novert:
         mov     [edi], ax
         shr     eax, 16
         mov     [edi+2], al
@@ -986,23 +983,18 @@ snbgp:
         mov     [esp+20], eax
         cmp     eax, [draw_data+32+RECT.right]
         ja      sdp4
-        mov     eax, [esp+44]
+        add     ecx, [esp+36]
-        add     ecx, eax
+        mov     eax, edx
+        adc     edx, [esp+40]
+        sub     eax, edx
         lea     eax, [eax*3]
-        add     esi, eax
+        sub     esi, eax
-;        add     edx, [esp+40]
-        cmp     edx, [ScreenWidth]
-        jbe     sdp3
-        sub     edx, [ScreenWidth]
-        add     ecx, 1
-        add     esi, 3
-        sub     edx, 1
         jmp     sdp3
 sdp4:
 ; next y
-        mov     ebx, [esp+28]
+        mov     ebx, [esp+24]
         add     ebx, 1
-        mov     [esp+28], ebx
+        mov     [esp+24], ebx
         cmp     ebx, [draw_data+32+RECT.bottom]
         ja      sdpdone
 ; advance edi, ebp to next scan line
@@ -1019,56 +1011,55 @@ sdp4:
 @@:
         add     edi, [BytesPerScanLine]
 ; restore ecx,edx; advance esi to next background line
+        mov     eax, [esp+28]
+        mov     ebx, [esp+32]
+        add     [esp+12], eax
+        mov     eax, [esp+16]
+        adc     [esp+16], ebx
         pop     esi edx ecx
         push    ecx edx
-        xor     ebx, ebx
+        sub     eax, [esp+16-4]
-        mov     eax, [esp+24-4]
+        lea     eax, [eax*3]
-        add     eax, [esp+32-4]
+        imul    eax, [BgrDataWidth]
-        cmp     eax, [ScreenHeight]
+        sub     esi, eax
-        jbe     @f
-        sub     eax, [ScreenHeight]
-        mov     ebx, 1
-        sub     eax, ebx
-@@:
-        mov     [esp+24-4], eax
-        add     ebx, [esp+36-4]
-        lea     ebx, [ebx*3]
-        imul    ebx, [BgrDataWidth]
-        add     esi, ebx
         push    esi
         mov     eax, [draw_data+32+RECT.left]
         mov     [esp+20], eax
         jmp     sdp3
 sdpdone:
-        add     esp, 48
+        add     esp, 44
         popad
         mov     [EGA_counter],1
         call    VGA_drawbackground
         ret
 
 overlapping_of_points:
-        push    ecx edx edi
+        push    ecx edx
-        mov     ecx, eax
+        mov     edx, eax
-        mov     edx, ebx
+        push    esi
+        shr     ecx, 24
+        mov     esi, ecx
+        mov     ecx, ebx
+        movzx   ebx, dl
+        movzx   eax, cl
+        sub     eax, ebx
+        movzx   ebx, dh
+        imul    eax, esi
+        add     dl, ah
+        movzx   eax, ch
+        sub     eax, ebx
+        imul    eax, esi
+        add     dh, ah
+        ror     ecx, 16
+        ror     edx, 16
         movzx   eax, cl
         movzx   ebx, dl
-        add     eax, ebx
+        sub     eax, ebx
-        rcr     eax, 1
+        imul    eax, esi
-        movzx   edi, ax
+        pop     esi
-        movzx   eax, ch
+        add     dl, ah
-        movzx   ebx, dh
+        mov     eax, edx
-        add     eax, ebx
+        pop     edx
-        rcr     eax, 1
-        ror     edi, 8
-        add     edi, eax
-        shr     ecx, 8
-        shr     edx, 8
-        movzx   eax, ch
-        movzx   ebx, dh
-        add     eax, ebx
-        rcr     eax, 1
-        ror     edi, 8
-        add     eax, edi
         ror     eax, 16
-        pop     edi edx ecx
+        pop     ecx
         ret