C29 supports a number of instructions that find use in optimizing specific types of functions. Key examples are listed below:

• SVGEN - space vector generation can be optimized with the QUADF instruction, leveraged using the intrinsic 'float __builtin_c29_quadf32(unsigned int * tdm_w_uip0, float * rw_fp1, float * rw_fp2)'.
  Note: Optimized implementations of the SVGEN (including those that can be applied to a 3-level inverter) are planned in the F29x Motor Control SDK.
• CRC - Cyclic Redundancy Check implementations can be optimized with the CRC instruction. Examples are provided in the F29x SDK. An intrinsic is also available 'unsigned int __builtin_c29_i32_crc(unsigned int ui0, unsigned int ui1, unsigned int ui2, unsigned int ui3)'.
• Limiting (Saturation) operations - can be optimized using the MINMAXF instruction.
  • The compiler generates the MINMAXF instruction and an optimal implementation if the C code is written using the ternary operator, if min and max are constants, and the code is compiled with -O3 and -ffast-math options. This implementation is the fastest as it involves 2 MV instructions in parallel, followed by the MINMAXF instruction. If min and max are constants, but only -O3 is used, MINMAXF is not generated, instead CMPF and SELECT instruction pairs are generated. If min and max are not constant, with -O3 and -ffast-math options, the compiler generates LDs to read from memory, CMPF, SELECT, and MAXF.

    float saturation(float in)
    { 
       float out; 
       out = (in > max)? max:((in < min)? min:in); 
       return out;
    }

  • With if.else conditionals and either of the implementations below, the behavior is exactly the same as above.

    float saturation(float in)
    {
       float out;
       if(in > max) 
       { 
          out = max; 
       } else if(in < min) 
       { 
          out = min; 
       } else { 
          out = in; 
       }
       return out;
    }

    float saturation(float in)
    {
       float out = in;
       if(in > max) 
       { 
          out = max; 
       } else if(in < min) 
       { 
          out = min; 
       }
       return out;
    }

    float saturation(float in)
    {
       float out = in;
       if(in > max) 
       { 
          out = max; 
       } 
       if(in < min) 
       { 
          out = min; 
       }
       return out;
    }

• Deadzone operations - the compiler generates the most efficient code when min and max are constants, with the -O3 option, and with the C code written using either the ternary operator or if..else as shown in the code blocks below.

  float deadzone(float in)
  {
     float out; 
     out = (in>1.0f)?(in-1.0f):((in>-1.0f)?0.0f:(in+1.0f));
     return out;
  }

  float deadzone(float in)
  {
      float out;
      if(in >1.0f)
      { 
          out = in-1.0f; 
      } else if(in >-1.0f){ 
          out =0.0f; 
      } else { 
          out = in+1.0f; 
      }
      return out;
  }