-Onbf: Disable Optimize Bitfields

Group

OPTIMIZATIONS

Scope

Function

Syntax

  -Onbf

Arguments

None

Default

None

Defines

None

Pragmas

None

Description

This option prevents the Compiler from combining sequences of bitfield assignments containing constants. This simplifies debugging and makes the code more readable.

Example

Listing: Example Bitfield Definition



struct {
  b0:1;

  b1:1;

  b2:1;

} bf;

void main(void) {

  bf.b0 = 0;

  bf.b1 = 0;

  bf.b2 = 0;

}

Without -Onbf (pseudo intermediate code):

  BITCLR  bf, #7  // all 3 bits (the mask is 7)

                  // are cleared

With -Onbf (pseudo intermediate code):

  BITCLR  bf, #1  // clear bit 1 (mask 1)

  BITCLR  bf, #2  // clear bit 2 (mask 2)

  BITCLR  bf, #4  // clear bit 3 (mask 4)

Example

  -Onbf