C166: Using sbit in Embedded C++

Information in this article applies to:

• C166 Version 5
• EC166 Version 1

QUESTION

I have used the sbit constructs in the C166 Compiler for several years and I am now converting my program to Embedded C++. It appears that the following construct does not work:

unsigned int bdata ival;
sbit b0 = ival^0;
sbit b1 = ival^1;
sbit b2 = ival^2;
sbit b3 = ival^3;

What can I do to achieve bit-level access in the Embedded C++ Compiler?

ANSWER

The Embedded C++ Compiler uses standard C syntax for this. Just rewrite your program, so it uses a bit-field that is located to the bdata memory type.

struct bits {
  unsigned int b0: 1;
  unsigned int b1: 1;
  unsigned int b2: 1;
  unsigned int b3: 1;
  unsigned int b4: 1;
  unsigned int b5: 1;
  unsigned int b6: 1;
  unsigned int b7: 1;
};

union bacc  {
  unsigned int uc;
  struct bits   b;
};

union bacc bdata v1;    // bdata variables can be accessed using bit instructions

int main()  {
  if (v1.b.b0) {
    v1.b.b1 = 1;
  }
}

SEE ALSO

• C166: Declaring bdata and sbit Variables

Last Reviewed: Thursday, February 25, 2021