What's New in C251 Version 5.58

• [C251 Compiler]
  • Corrected: the variable attribute __attribute__((aligned)) was overruled by the linker directive NOSORTSIZE. Example:

    unsigned char ucValg __attribute__((aligned(4)));   /* The variable ucValg must be aligned on 4-byte boundary */
    
    void main (void)
    {
    :::::::::::
    }
    

    The MAP file for the above definition shows that the variable 'ucValg' was located at address 00000009H which is not a 4-byte boundary.

    00000009H   EDATA    BYTE      ucValg
    

  • Corrected: under some circumstances wrong code will be generated in case of the following expression and high optimization levels:

    unsigned char GetByte(unsigned char i);
    unsigned short value;
    
    value = (GetByte(0) * 256) + GetByte(1);        /* Wrong result */
    

    Generated assembler code:

    ---- Assembler code for : (GetByte(0) * 256) -----
    000016 E4             CLR      A                ; Parameter passing via R11=A to the callee function GetByte.
    000017 9A000000    R  ECALL    GetByte?         ;
                                                    ; The GetByte return value (unsigned char) is passed to the caller function via R11.
    
    ---- Load word registers WR14 and WR12 for the upcoming multiplication ----
    00001B 0A7B           MOVZ     WR14,R11         ; WR14 = | 00  | R11 |
    00001D 7E640100       MOV      WR12,#0100H      ; WR12 = | 01  | 00  |
    000021 AD67           MUL      WR12,WR14        ; The result is stored in the double word register DR12 = | WR12 | WR14 |, DR12 = | 00  |  00  | R11 | 00  |
    
    ---- Assembler code for : GetByte(1) -----
    000023 7401           MOV      A,#01H           ;
    000025 9A000000    R  ECALL    GetByte?         ;
    
    000029 0A7B           MOVZ     WR14,R11         ; Overwrites previous result in word register WR14
    00002B 2D76           ADD      WR14,WR12        ;
    

  • Corrected: Unexpected warning C98 "'&': different levels of indirection. Example:

    typedef unsigned char   byte;
    typedef unsigned short  word;
    
    typedef struct {
      byte     data1;
      word     data2;
    } struct_type;
    
    byte processStruct(byte xdata*xdata* structPtr);
    
    void main(void) {
      struct_type xdata myStruct;
      struct_type xdata*xdata myStructPtr = &myStruct;  /* The compiler throws erroneously the warning C98 "'&': different levels of indirection */
    
      processStruct((byte xdata*xdata*)&myStructPtr);
    }
    

  • Corrected: reentrant function has wrong name when userclass Compiler directive is used. Example:

    #pragma USERCLASS(ecode=user)
    
    int foobar(int x) reentrant {   /* The name of the generated segment is "?PR?FOOBAR?TC_0" instead of "?PR?FOOBAR_?TC_0" */
      return x ? foobar(x) : x-1;
    }
    

• [L251 Linker/Locater]
  • Corrected: under some circumstances the L251 ingnores the NOJMPTAB directive and and throws erroneously the following error:

    *** ERROR L210: I/O ERROR ON INPUT FILE:
        EXCEPTION 0021H: PATH OR FILE NOT FOUND
        FILE: C:\KEIL\C51\LIB\L51_BANK.OBJ
    

  • Corrected: Error L138 while optimizing a function at the end of a 2K or 64K segment.
• [A251 Macro Assembler]
  • Corrected: under some circumstances the assembler shows wrong line numbers if an $include file cannot be found. The root cause for this behavior is the erroneous line number generation by the preprocessor. Example:

    NAME xxx
    S       SEGMENT  CODE
            RSEG  S
    #line                 ; The preprocessor generates wrong line numbers if an $include file cannot be found.
    PUT:    MOV   A,#x    ; The assembler shows these wrong line numbers inside the build output window as part of a warning or error message.
            RET
            END
    
    

• [µVision4]
  • This C251 release comes with µVision4 V5.16.2.0.