Bit Fields tutorial

Suppose the source text looked like this:

void out_operand(int opnum, int flags);

// 'flags' parameter is combination of the following bits:
// (don't use OOF_SIGNMASK and OOF_WIDTHMASK, they are for the kernel)

#define OOF_SIGNMASK    0x0003      // sign output:
#define   OOFS_IFSIGN   0x0000      //   output sign if needed
#define   OOFS_NOSIGN   0x0001      //   should not out sign     ()
#define   OOFS_NEEDSIGN 0x0002      //   always out sign         (+-)
#define OOF_SIGNED      0x0004      // output as signed if 


// This function output the first 2 operands of instruction
void out_operands(void)
{
  // the first operand is a signed value
  out_operand(0, OOFS_IFSIGN