Calling exported string functions - PB 4.2 beta 2

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Fred
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Post by Fred »

Could you post the code generated by TailBite ?
srod
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Post by srod »

Here's the PB source :

Code: Select all

ProcedureDLL.s HeyHo(a) 
  Protected a$ 
  a$=Str(a) 
  ProcedureReturn a$ 
EndProcedure
Here's the PB generated ASM for the HeyHo function :

Code: Select all

; :
; ProcedureDLL.s HeyHo(a) 
macro MP0{
_Procedure0:
  PS0=8
  XOR    eax,eax
  PUSH   eax                                                                                                                                                                                                                             
; Protected a$ 
; a$=Str(a) 
  PUSH   dword [_PB_StringBasePosition]
  PUSH   dword [_PB_StringBasePosition]
  PUSH   dword [esp+PS0+8]
  CALL  _PB_Str@8
  LEA    ecx,[esp+4]
  POP    edx
  CALL   SYS_AllocateString
; ProcedureReturn a$ 
  MOV    edx,dword [esp]
  PUSH   dword [_PB_StringBasePosition]
  CALL  _SYS_CopyString@0
  POP    eax
  ADD    eax,[PB_StringBase]
  JMP   _EndProcedure1
; EndProcedure
  MOV    eax,[_PB_StringBasePosition]
  ADD    eax,[PB_StringBase]
  MOV    byte [eax],0
_EndProcedure1:
  PUSH   dword [esp]
  CALL  _SYS_FreeString@4
  ADD    esp,4
  RET    4
}
and here's the tailbite generated source for the HeyHo function:

Code: Select all

format MS COFF

Public PB_HeyHo


Extrn _PB_Str@8
Extrn SYS_AllocateString
Extrn _SYS_CopyString@0
Extrn _SYS_FreeString@4
Extrn _PB_StringBasePosition
Extrn PB_StringBase


section '.text' code readable executable

PB_HeyHo:
PS0=8
XOR    eax,eax
PUSH   eax
; Protected a$
; a$=Str(a)
PUSH   dword [_PB_StringBasePosition]
PUSH   dword [_PB_StringBasePosition]
PUSH   dword [esp+PS0+8]
CALL  _PB_Str@8
LEA    ecx,[esp+4]
POP    edx
CALL   SYS_AllocateString
; ProcedureReturn a$
MOV    edx,dword [esp]
PUSH   dword [_PB_StringBasePosition]
CALL  _SYS_CopyString@0
POP    eax
ADD    eax,[PB_StringBase]
JMP   _EndProcedure1
; EndProcedure
MOV    eax,[_PB_StringBasePosition]
ADD    eax,[PB_StringBase]
MOV    byte [eax],0
_EndProcedure1:
PUSH   dword [esp]
CALL  _SYS_FreeString@4
ADD    esp,4
RET    4
Here's the desc file :

Code: Select all

ASM
;
1
KERNEL32
;
LIB
;
2
String
StringExtension
;
heyho.chm
;
HeyHo, Long (a)
String | StdCall
;
heyho_Init 
InitFunction | StdCall
;
I may look like a mule, but I'm not a complete ass.
ABBKlaus
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Post by ABBKlaus »

I think its how PB calls the TailBiten function.

Here the commented ASM output when using the TailBiten function from PB:

Code: Select all

; MessageRequester("",HeyHo(1))
  MOV    eax,[_PB_StringBasePosition]
  PUSH   eax
  PUSH   eax
  PUSH   dword [_PB_StringBasePosition]
  PUSH   dword 1
  CALL   PB_HeyHo
  INC    dword [_PB_StringBasePosition]
  PUSH   dword _S1
  MOV    edx,[PB_StringBase]
  ADD    [esp+4],edx
  CALL  _PB_MessageRequester@8
  POP    dword [_PB_StringBasePosition]
Here the commented ASM output using the lib as includefile:

Code: Select all

; XIncludeFile("Srod_String_Bug_1.pb")
; ProcedureDLL.s HeyHo(a)
macro MP0{
_Procedure0:
  PS0=8
  XOR    eax,eax
  PUSH   eax                                                                                                                                                                                                                             
; Protected a$
; a$=Str(a)
  MOV    eax,[_PB_StringBasePosition]
  PUSH   eax
  PUSH   eax
  PUSH   dword [esp+PS0+8]
  CALL  _PB_Str@8
  LEA    ecx,[esp+4]
  POP    edx
  CALL   SYS_AllocateString
; ProcedureReturn a$
  MOV    edx,dword [esp]
  PUSH   dword [_PB_StringBasePosition]
  CALL  _SYS_CopyString@0
  POP    eax
  ADD    eax,[PB_StringBase]
  JMP   _EndProcedure1
; EndProcedure
  MOV    eax,[_PB_StringBasePosition]
  ADD    eax,[PB_StringBase]
  MOV    byte [eax],0
_EndProcedure1:
  PUSH   dword [esp]
  CALL  _SYS_FreeString@4
  ADD    esp,4
  RET    4
}
; 
; MessageRequester("",HeyHo(1))
  MOV    eax,[_PB_StringBasePosition]
  PUSH   eax
  PUSH   eax
  PUSH   dword 1
  CALL  _Procedure0
  MOV    edx,[esp]
  MOV    dword [_PB_StringBasePosition],edx
  MOV    edx,eax
  CALL  _SYS_CopyString@0
  INC    dword [_PB_StringBasePosition]
  PUSH   dword _S1
  MOV    edx,[PB_StringBase]
  ADD    [esp+4],edx
  CALL  _PB_MessageRequester@8
  POP    dword [_PB_StringBasePosition]
and the function itself (TailBiten with PB4.20B4) :

Code: Select all

format MS COFF

Public PB_HeyHo


Extrn _PB_Str@8
Extrn SYS_AllocateString
Extrn _SYS_CopyString@0
Extrn _SYS_FreeString@4
Extrn _PB_StringBasePosition
Extrn PB_StringBase


section '.text' code readable executable

PB_HeyHo:
PS0=8
XOR    eax,eax
PUSH   eax
; Protected a$
; a$=Str(a)
MOV    eax,[_PB_StringBasePosition]
PUSH   eax
PUSH   eax
PUSH   dword [esp+PS0+8]
CALL  _PB_Str@8
LEA    ecx,[esp+4]
POP    edx
CALL   SYS_AllocateString
; ProcedureReturn a$
MOV    edx,dword [esp]
PUSH   dword [_PB_StringBasePosition]
CALL  _SYS_CopyString@0
POP    eax
ADD    eax,[PB_StringBase]
JMP   _EndProcedure1
; EndProcedure
MOV    eax,[_PB_StringBasePosition]
ADD    eax,[PB_StringBase]
MOV    byte [eax],0
_EndProcedure1:
PUSH   dword [esp]
CALL  _SYS_FreeString@4
ADD    esp,4
RET    4
Fact is : the procedure is in both cases the same, only the calling is different.
Since i am not an ASM guru like you (Fred and Freak) it would be nice if you could help get TailBite running again.

Thanks in advance.
Klaus
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Post by Mistrel »

This bug is still preventing TailBite from functioning properly with PureBasic 4.20. Is this a PureBasic bug or a TailBite bug?

http://www.purebasic.fr/english/viewtopic.php?t=32585
Fred
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Post by Fred »

It's definitely a tailbite bug, how could it be a PB one ?
gnozal
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Post by gnozal »

<Asks humbly> Some hint on how to fix this tailbite issue would be great !
I am no asm guru myself.
For free libraries and tools, visit my web site (also home of jaPBe V3 and PureFORM).
Fred
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Post by Fred »

The tailbite function should change the 'Ret' line to:

Code: Select all

RET    X+4 
Only when a string is returned. It should work then.
srod
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Post by srod »

Fred wrote:The tailbite function should change the 'Ret' line to:

Code: Select all

RET    X+4 
Only when a string is returned. It should work then.
Yes - it works! :) (Tested with coffIT, manually editing the ASM files and creating the DESC file by hand. Tailbite should easily follow suit.)

Thanks Fred. Looking at it, the damn solution was obvious!!!

Can I ask why PB passes an extra parameter when calling compiled user lib functions?
I may look like a mule, but I'm not a complete ass.
gnozal
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Post by gnozal »

It seems to work yes (I only made a few tests).
1. only add 'RET X + 4' to the exported functions, not the private functions
2. don't use exported functions in the library

I have just updated the custom Tailbite for jaPBe V3 : http://freenet-homepage.de/gnozal/TailBite.zip
Source included, search for 'PB4.20 fix'. It seems to work.
Sorry, it's not the ABBKlaus source, but I am more confortable with the old ElChoni source :oops:
Last edited by gnozal on Tue May 27, 2008 2:44 pm, edited 1 time in total.
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srod
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Post by srod »

gnozal wrote:2. don't use exported functions in the library
That should be fine Gnozal. I see no reason why that should be a problem.
I may look like a mule, but I'm not a complete ass.
gnozal
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Post by gnozal »

srod wrote:
gnozal wrote:2. don't use exported functions in the library
That should be fine Gnozal. I see no reason why that should be a problem.
I made some tests, and it crashed.
I am probably doing something wrong, but imho the '+ 4' fix is only for the exported functions when called from the outside (PB), it's not right if the function is called from the library itself.
But then again, I am no asm guru.
For free libraries and tools, visit my web site (also home of jaPBe V3 and PureFORM).
srod
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Post by srod »

Right, I'll have a crack at it! :)
I may look like a mule, but I'm not a complete ass.
srod
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Post by srod »

gnozal wrote:
srod wrote:
gnozal wrote:2. don't use exported functions in the library
That should be fine Gnozal. I see no reason why that should be a problem.
I made some tests, and it crashed.
I am probably doing something wrong, but imho the '+ 4' fix is only for the exported functions when called from the outside (PB), it's not right if the function is called from the library itself.
But then again, I am no asm guru.
Confirmed. Crashes if one exported string function calls another! :( Yes, thinking about it -and considering the code posted by Klaus above, it's obvious now.

Mind you, in this case you'll just have to ensure that no function within a library calls a string function from the same library which is to be exported. Just add a 'dummy' function through which the exported string function operates.
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gnozal
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Post by gnozal »

srod wrote:Mind you, in this case you'll just have to ensure that no function within a library calls a string function from the same library which is to be exported. Just add a 'dummy' function through which the exported string function operates.
Yes, that's what I did for one test library.
I will check all my libs for this before recompiling them with PB4.20 final.
For free libraries and tools, visit my web site (also home of jaPBe V3 and PureFORM).
ABBKlaus
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Post by ABBKlaus »

Thanks Fred, i´m going to donate now :D
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