Donate Now Goal amount for this month: 100 USD, Received: 0 USD (0%)
Donate to support this site and ThinBASIC project development

Results 1 to 10 of 10

Thread: OK, I need help from ASM men

  1. #1
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10

    OK, I need help from ASM men

    Hi all,

    it is some days I'm struggled trying to find a fix on how to dynamically correctly call external CDECL functions.
    Asper posted a bug in support area: http://www.thinbasic.com/community/p...r=all#note2246
    He is trying to use Blitz3d SDK library that is defined as CDECL.
    I've created a PowerBasic application that use that library and all is fine but in thinBasic calling that library produces a GPF on function exit.
    I'm quite sure I'm making something wrong or missing something in releasing stack used for function parameters when functions are CDECL.

    As you may know I'm not an expert in ASM, so I need some help.
    Can some ASM men out there help me to understand what to do in ASM for calling a CDECL function?

    Attached full PB and TB examples with library.

    Thanks a lot
    Eros
    Attached Files Attached Files
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

  2. #2
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10
    I realize that without some code from my side it is quite difficult to get help, isn't it?

    The following is part of the method I use to call external functions (API functions or functions contained in 3rd part libraries).
    The code mainly push parameters (previously collected) into the stack and than call the external function pointer.
    Code is written into PowerBasic with some inline ASM. Somewhere in there I'm missing something.

    Added: code changed after Charles suggestion

      '----------------------------------------------------------------------------
      'Generic function for API function calling
      'Parameters:
      '  lError    : return code error
      '              2 = Error calling function
      '              3 = Error loading library
      '----------------------------------------------------------------------------
      Function DllApi_Call( ByVal lptr_tFunction As tFunction Ptr, ByRef lResultExt As Ext) As Quad
        Local ApiCall_pCount            As Long
        Local hLib                      As Long   
        Local hProc                     As Long   
        Local RetVal                    As Long   
        Local ApiCall_PushParam         As Long   
        Local ApiCall_PushParam_Single  As Single 
        Local glApiLib                  As tAPILIB
        Local ptr_lApiLib               As tAPILIB Ptr 
        Local ApiCall_WhereFound        As Long
        'Local HowManyBytesPushed        As Long
        Local savedSP                   As Long
    
    
        '---Save current stack pointer
        ! mov savedSP,esp
        '---
            
        '---Get the lib and proc address from function just in case they were already defined
        hProc = @lptr_tFunction.hProc
    
    
        If @lptr_tFunction.IsAPI Then
          hLib = @lptr_tFunction.hLib
    
    
          If hLib = 0& Then
            '---Search if library is already loaded    
            ptr_lApiLib = HashTable_KeyFind(gScript.APILIB_Dict, @lptr_tFunction.LibName & "")
            
            '---If not, try to load the library
            If ptr_lApiLib Then
              '---If already loaded, just get its handle
              hLib = @ptr_lApiLib.LibHandle
            Else
              hLib = thinBasic_LoadLibrary(@lptr_tFunction.LibName, ApiCall_WhereFound)
              If hLib Then                 
                glApiLib.LibName   = @lptr_tFunction.LibName
                glApiLib.LibHandle = hLib
                APILIB_Add(VarPtr(glApiLib))
              End If
            End If
            
            If hLib Then
              @lptr_tFunction.hLib = hLib
            Else
              '---
              'Error loading library
              '---
              RunTimeError(%ERR__API_LIB_NOT_FOUND, "LibName: " & Trim$(@lptr_tFunction.LibName))
              gdwStatus = %OS_ERROR_LOADLIBRARY
    
    
              Exit Function
            
            End If
            
          End If
    
    
          '---Now check hProc
          If hProc = 0& Then 
            hProc = GetProcAddress(hLib, @lptr_tFunction.AliasName )
            If hProc Then
              @lptr_tFunction.hProc = hProc
            Else
              '---
              'Error calling function
              '---
              RunTimeError(%ERR__API_FUNCTION_NOT_FOUND_IN_LIB, "LibName: " & Trim$(@lptr_tFunction.LibName) & " - Alias: " & Trim$(@lptr_tFunction.AliasName))
              gdwStatus = %OS_ERROR_CALLFUNCTION
      
              Exit Function
      
            End If
          End If
          
        End If
    
    
        '---PUSH parameters reverse order
        For ApiCall_pCount = @lptr_tFunction.NumberOfParams To 1& Step -1&
          
    
    
          Select Case Long @lptr_tFunction.params(ApiCall_pCount).ParamMainType
          
            Case %ArrayType_IsNumber
    
    
              If @lptr_tFunction.params(ApiCall_pCount).ParamPassBy = %PARAM_ByVal Then
    
    
                Select Case Long @lptr_tFunction.params(ApiCall_pCount).ParamSubType
    
    
                  Case %ArrayType_Long
                    ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.lLong
                    ! push ApiCall_PushParam 
                    'HowManyBytesPushed += 4
    
    
                  Case %ArrayType_DWord
                    ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.lDWord
                    ! push ApiCall_PushParam
                    'HowManyBytesPushed += 4
    
    
                  Case %ArrayType_Ext
                    ApiCall_PushParam = VarPtr(@lptr_tFunction.params(ApiCall_pCount).DataValue.lExt)
                    !mov eax,ApiCall_PushParam  ;'point EAX To the 8 Byte variable
                    !mov edx,[eax+8]    ;'Get latest 4 bytes
                    !push edx           ;'push them
                    !mov edx,[eax+4]    ;'Get mid    4 bytes
                    !push edx           ;'push them
                    !mov edx,[eax]      ;'Get the 1st 4 bytes
                    !push edx           ;'push them
                    'HowManyBytesPushed += 12
    
    
                  Case %ArrayType_Double
                    ApiCall_PushParam = VarPtr(@lptr_tFunction.params(ApiCall_pCount).DataValue.lDouble)
                    !mov eax,ApiCall_PushParam  ;'point EAX To the 8 Byte variable
                    !mov edx,[eax+4]    ;'Get latest 4 bytes
                    !push edx           ;'push them
                    !mov edx,[eax]      ;'Get the 1st 4 bytes
                    !push edx           ;'push them
                    'HowManyBytesPushed += 8
    
    
                  Case %ArrayType_Single
                    ApiCall_PushParam_Single = @lptr_tFunction.params(ApiCall_pCount).DataValue.lSingle
                    ! push ApiCall_PushParam_Single
                    'HowManyBytesPushed += 4
    
    
                  Case %ArrayType_Byte
                    ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.lByte
                    ! push ApiCall_PushParam
                    'HowManyBytesPushed += 4
      
                  Case %ArrayType_Word
                    ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.lWord
                    ! push ApiCall_PushParam
                    'HowManyBytesPushed += 4
          
                  Case %ArrayType_Integer
                    ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.lInteger
                    ! push ApiCall_PushParam
                    'HowManyBytesPushed += 4
      
      
                  Case %ArrayType_Quad
                    ApiCall_PushParam = VarPtr(@lptr_tFunction.params(ApiCall_pCount).DataValue.lQuad)
                    !mov eax,ApiCall_PushParam  ;'point EAX To the 8 Byte variable
                    !mov edx,[eax+4]    ;'Get latest 4 bytes
                    !push edx           ;'push them
                    !mov edx,[eax]      ;'Get the 1st 4 bytes
                    !push edx           ;'push them
                    'HowManyBytesPushed += 8
    
    
                End Select
                
              Else '---BYREF
    
    
                ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.GenericPtr
                ! push ApiCall_PushParam
                'HowManyBytesPushed += 4
              
              End If
              
            Case %ArrayType_IsString, %ArrayType_IsGUID
    
    
              'IF @lptr_tFunction.params(ApiCall_pCount).ParamPassBy = %PARAM_ByRef THEN
                ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.GenericPtr
                ! push ApiCall_PushParam
              'ELSE
              '  SELECT CASE LONG @lptr_tFunction.params(ApiCall_pCount).ParamSubType
              '    CASE %ArrayType_String, %ArrayType_Asciiz
              '      ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.lString
              '      ! push ApiCall_PushParam
              '  END SELECT
              'END IF
                'HowManyBytesPushed += 4
    
    
            Case %ArrayType_UDT
              ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.GenericPtr
              ! push ApiCall_PushParam
              'HowManyBytesPushed += 4
    
    
            Case %ArrayType_Variant
              If @lptr_tFunction.params(ApiCall_pCount).ParamPassBy = %PARAM_ByRef Then
                ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.GenericPtr
                ! push ApiCall_PushParam
                'HowManyBytesPushed += 4
              Else
    '---ORIGINAL
    '                '---Push 16 bytes into the stack in reverse order
    '                ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.GenericPtr
    '                !mov eax,ApiCall_PushParam  ;point EAX To the 8 Byte variable
    '                !mov edx,[eax+16]    ;Get latest 4 bytes
    '                !push edx           ;push them
    '                !mov edx,[eax+12]    ;Get latest 4 bytes
    '                !push edx           ;push them
    '                !mov edx,[eax+8]    ;Get latest 4 bytes
    '                !push edx           ;push them
    '                !mov edx,[eax+4]    ;Get mid    4 bytes
    '                !push edx           ;push them
    '                !mov edx,[eax]      ;Get the 1st 4 bytes
    '                !push edx           ;push them
    '---NEW
                '---Push 16 bytes into the stack in reverse order
                ApiCall_PushParam = @lptr_tFunction.params(ApiCall_pCount).DataValue.GenericPtr
                !mov eax,ApiCall_PushParam  ;'point EAX To the 16 Byte variable
                !mov edx,[eax+12]   ;'Get latest 4 bytes
                !push edx           ;'push them
                !mov edx,[eax+8]    ;'Get latest 4 bytes
                !push edx           ;'push them
                !mov edx,[eax+4]    ;'Get mid    4 bytes
                !push edx           ;'push them
                !mov edx,[eax]      ;'Get the 1st 4 bytes
                !push edx           ;'push them
    '---                
                'HowManyBytesPushed += 16
              End If                        
          End Select
        Next
        
        '---
        'Call the function and get return code
        If @lptr_tFunction.ReturnMainType = %ArrayType_IsNumber Then
    
    
            Select Case Long @lptr_tFunction.ReturnSubType
              Case %ArrayType_Ext
                Static ve As Extended
                  '---
                  '!Xor eax, eax
                  !Call hProc       
                  '! fstp Qword Ptr ve
                  ! fstp ve
                  lResultExt = ve
    
    
              Case  _
                    %ArrayType_Long   , _
                    %ArrayType_DWord  , _
                    %ArrayType_Word   , _
                    %ArrayType_Integer, _
                    %ArrayType_Byte
                  '---
                  !Xor eax, eax
                  !Call hProc  
                  !mov RetVal, eax
                  lResultExt = RetVal 
                   
              Case %ArrayType_Double
                Static vd As Double
                  '---
                  '!Xor eax, eax
                  !Call hProc       
                  ! fstp Qword Ptr vd
                  lResultExt = vd
    
    
              Case %ArrayType_Single
                Static vs As Single
                  '---
                  '!Xor eax, eax
                  !Call hProc       
                  ! fstp Dword Ptr vs
                  lResultExt = vs
    
    
              Case %ArrayType_Quad
                Static vq As Quad
    '                  '---
    '                  '!Xor eax, eax
    '                  !Call hProc       
    '                  '! fstp Qword Ptr ve
    '                  ! fistp vq
    '                  lResultExt = vq
    
    
                  '---
                  '!Xor eax, eax
                  !Call hProc       
                  ! PUSH EBX
                  ! LEA EBX, vq
                  ! MOV [EBX], EAX
                  ! MOV [EBX + 4], EDX
                  ! POP EBX
                  lResultExt = vq
                            
            End Select 
            
        ElseIf @lptr_tFunction.ReturnMainType = %ArrayType_IsString Then
            '---
            !Xor eax, eax
            !Call hProc  
            !mov RetVal, eax 
            lResultExt = RetVal
            
        End If        
    
    
        '---CDECL
        If @lptr_tFunction.CallingMode = %PA__CDECL Then
          '---Restore previous stack position
          ! mov esp,savedSP
          'If HowManyBytesPushed Then
          '  !Add esp, HowManyBytesPushed
          'End If
        End If
    
    
        Function = RetVal
      End Function
    
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

  3. #3
    Hi Eros,

    Very briefly.

    The easy way to handle CDECL calls is to save the stack pointer before passing parameters and making the call, then restore it immediately after.

    In all other respects it is the same as making a STDCALL.

    dim savedSP as long
    ...
    ! mov savedSP,esp
    'push params here (right to left order)
    'call function here
    ! mov esp,savedSP

    I hope this helps

    Charles

  4. #4
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10
    Thanks a lot Charles.
    I applied your changes but still GPF.
    The strange thing is that if I start thinBasic script in debug mode and execute it using F5, all is working fine while if I run the script without debugger, it GPF just after "Graphics3D(800, 600, 32, 0)"
    There must be something else I missed.

    I'm going to reverse engineer PowerBasic example I did and see what is doing before/during/after external function calling compared to my code.
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

  5. #5
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10
    Maybe different behave between declared procedure is a SUB or a FUNCTION ?
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

  6. #6
    It may be necessary to push all the params then make the call immediately without intervening BASIC code, since you cannot guarantee that BASIC will not alter the stack pointer in all circumstances. This could explain why it only works with the debugger, which keeps a tight grip on the stack pointer itself

    It is not necessary to clear eax. (!xor eax,eax) before calling.

    Charles

  7. #7
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10
    Quote Originally Posted by Charles Pegge View Post
    It may be necessary to push all the params then make the call immediately without intervening BASIC code, since you cannot guarantee that BASIC will not alter the stack pointer in all circumstances.
    Yes I thought about that but this method is working with all standard API calling and with calling any DLL function I've tested so far.

    Quote Originally Posted by Charles Pegge View Post
    This could explain why it only works with the debugger, which keeps a tight grip on the stack pointer itself
    Yes but the debugger not a real debugger but IS MY thinBasic DEBUGGER that just do a stop/go/stop script execution semaphore
    It is not checking anything, it just install a hook into main thinBasic Core engine telling Core "hey I'm with you". If core has such a hook, at every line change pass the control to the debugger.
    Nothing else.

    Quote Originally Posted by Charles Pegge View Post
    It is not necessary to clear eax. (!xor eax,eax) before calling.
    Thanks I will change it.
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

  8. #8
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10
    Here it is the debugger session of the GPF
    Maybe to someone this tells something

    Click image for larger version. 

Name:	DebugGPF_001.png 
Views:	97 
Size:	85.0 KB 
ID:	7859
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

  9. #9
    You could try an experiment, - calling this API in pure Assembler,embedded, and see whether you can get it to work. It will help to isolate the problem.

    Another broader test: create your own dll with a set of CDECL functions displaying all received params. Then you have full control of both sides.

    I know how time-consuming these bugs can be. You just have to grind them down very fine.

    Charles

  10. #10
    thinBasic author ErosOlmi's Avatar
    Join Date
    Sep 2004
    Location
    Milan - Italy
    Age
    47
    Posts
    7,551
    Blog Entries
    2
    Rep Power
    10
    I will got with option "Another broader test"
    Great idea.
    Thanks
    www.thinbasic.com | www.thinbasic.com/community/ | psch.thinbasic.com
    Win7Pro 64bit - 8GB Ram - Intel i7 M620 2.67GHz - NVIDIA Quadro FX1800M 1GB

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •