What's New in C51 Version 9.52

• [Cx51 Compiler]
  • Modified: the warning C294: unreachable code will be issued instead of a compiler error for unreachable code statements. Example:
    

    int foo = 1 ;
    int bar ;
    
    int main( void )
    {
      switch( foo )
      {
        bar = 0 ;   // warning C294: unreachable code
        case 1:
          bar = 1 ;
          break ;
        case 2:
          bar = 2 ;
          break ;
      }
      return( 0 ) ;
    }
    

  • Corrected: wrong XDATA address calculation which may occurs with combined pointer and int arithmetic. Example:
    

    unsigned char xdata b[256];  // Problem does not exist when array size > 256
    void xdata *p;
    unsigned int i = 256;
    
    void main (void) {
      p = &b[256-i];     // Correct result.
      p = b + 256 - i;   // Incorrect result. Only the LOW BYTE of i has been used for the calculation.
    }
    

  • Corrected: an ignored pointer cast which occurs under some circumstances with far and generic pointers. Example:
    

    unsigned short foo (char far *farPtr) {
    
      return (unsigned char) farPtr;  // Explicite cast is ignored.
    }
    

• [LX51 Linker/Locater]
  • Corrected: a wrong address calculation which occurs when const in code banks combined with linker code packing.
  • Added: Error 144: OVERLAY GROUP SEGMENT CANNOT HAVE 'LAST' ADDRESS ASSIGNMENT message. The LAST attribute cannot be used to locate segments that collect overlayable segments.
• [AX51 Assembler]
  • Corrected: an erroneously issued error A57 'REGISTER USAGE' REQUIRES A PUBLIC CODE SYMBOL which occurs when REGUSE directive is used by mixed-case (composed by upper and lower case characters) symbols.
• [New Supported Devices]
  • Texas Instruments
    CC2541F128 and CC2541F256.
• [ULink2]
  • Wiht this release the firmware of the ULINK2 target debuger will be updated to version 2 which will not work with older C51 installations.
    The .\C51\ULINK\Utilities\UL2_Configure.exe tool allows to switch back to an older firmware version when backward compatibility is needed.
• [µVision4]
  • This C51 release comes with µVision V4.72.9.0.