posted May 29, 2002 06:21 AM            

a)When we write an inline assembler routine which of the registers that we use we MUST save ?

b)The following subs are a small simple cipher routines i wrote using pb statements only in the Cipher sub and inline asm in the CipherAsm sub
trying to make it faster.Is there anything that i can do to make the ChipherAsm sub even faster ?

'Save it as Cipher.Bas
Sub Cipher(InString As String,PassWord As String)
    Register i            As Dword
    Register Len_PassWord As Dword
    Local    Init_y       As Dword 'I edited this line after Semens Post.It was Declared as Register
    Local x               As Byte Ptr
    Local y               As Byte Ptr
    x            = StrPtr(InString)
    Init_y       = StrPtr(PassWord)
    y            = Init_y
    Len_PassWord = Len(PassWord) + Init_y - 1
    For i = 1  To Len(InString)
        @x = @x Xor @y
        Incr x
        If y = Len_PassWord Then
           y = Init_y
        Else
           Incr y
        End If
    Next
End Sub
Sub CipherAsm(InString As String,PassWord As String)
    Local Len_PassWord As Dword
    Local Len_Str      As Dword
    Local Init_y       As Dword
    Local x            As Dword
    
    x            = StrPtr(InString)
    Init_y       = StrPtr(PassWord)-1
             
    Len_PassWord = Len(PassWord) '+ Init_y
    Len_Str      = Len(InString)

    !Push ecx
    !Push esi
    !Push edi
    !Push eax
    !Push ebx
    
    
    !Mov  ecx,Len_Str
    !Mov  esi,Init_Y
    !Mov  edi,x
    !Mov  eax,Len_PassWord
    !Add  eax,esi
l1:
    !Inc  esi
    !Mov  bh,[esi]
    !Mov  bl,[edi]
    !Xor  bl,bh
    !Mov  [edi],bl
    !Inc  edi
    !Cmp  esi,eax
    !Jne  n1
    !Mov  esi,Init_Y
n1:
'    !Loop l1 This line was rem out and replaced with the 2 lines below after Berns suggestion.
    !Dec ecx  
    !Jnz l1
      
    !Pop ebx
    !Pop eax
    !Pop edi
    !Pop esi
    !Pop ecx
    
End Sub

This is a simple PB/CC code for benchmarks

#COMPILE EXE
#REGISTER NONE
#INCLUDE "cipher.bas"

FUNCTION PBMAIN()
     REGISTER i AS DWORD
      DIM a AS STRING
      DIM pass AS STRING
      DIM bt AS DOUBLE
      DIM et AS DOUBLE
      pass = "this is a password"
      a=STRING$(LEN(pass)*6,0) 'i initialize it to a string of nulls
                               '   so i can check that if len(InString) > len(Password)
                               '   the cipher routine works well.
      cipherasm a,pass
      PRINT "Encode=";a
      cipherasm a,pass
      PRINT "Decode=";a
      bt=TIMER
      FOR i=1 TO 400000
          cipherasm a,pass
      NEXT
      et=TIMER
      PRINT "With CipherAsm 400,000 interactions in (sec):"STR$(et-bt)
      
 
      bt=TIMER
      FOR i=1 TO 400000
          cipher a,pass
      NEXT
      et=TIMER
      PRINT "With Cipher 400,000 interactions in (sec):"STR$(et-bt)
      
      a=WAITKEY$

END FUNCTION
                                       

Thank you

Stavros

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posted May 29, 2002 06:45 AM            

You should PUSH registers when mixing ASM code with PB code to ensure
that :

1) your ASM code doesn't corrupt the values in the registers specified
in the PB Docs/Help file under saving registers.

2) any PB statements/functions mixed in with your ASM code don't change
the contents of the registers that you are using.

posted May 29, 2002 06:54 AM            

Regards
Stavros

posted May 29, 2002 06:59 AM            

Can someone verify this please ?
I am using PB/CC 2.11 on Win98SE

Regards
Stavros

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posted May 29, 2002 07:25 AM            

Push/pop in:
w/ CipherASM secs: 1.7699...
w/ Cipher secs: 2.1399...

PB/CC 2.10 on Win98

Brad

posted May 29, 2002 07:47 AM            

BTW on my computer the speed difference betwen Cipher and CipherAsm is biger:
CipherAsm 0.65 - 0.70...
Cipher 3.00 - 3.20 ...

Stavros

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posted May 29, 2002 08:18 AM            

and mine are
CipherAsm sec 0.65 To 0.70...
Cipher secs 3.00 To 3.20 ...

In my case CipherAsm looks like its runing ~5 times faster than Chipher
But in your case it looks like it is runing just a litle faster.

Stavros

posted May 29, 2002 08:31 AM            

Stavros

posted May 29, 2002 08:40 AM            

CipherAsm 0,720 sec
Cipher 0,989 sec

Those numbers are familiar to yours.So i think that there is some kind
of difference to pre 2.11 compilers.
Lets wait and see what will happen in PB/CC 3

posted May 29, 2002 09:09 AM            

Regards

Stavros

posted May 29, 2002 09:14 AM            

Stavros

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