10. Simplification

 
Introduction
Porting tools
Relogix
Technical tour
  How Relogix works
  Simple example
  Relogix translation
  Header and Includes
  Function definitions
  Local variables
  Variable types
  Variable names
  Code flow
  Simplification
  Comments
  User header files
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As it translates code, Relogix is often able to combine several assembler instructions into one C statement or expression. In our example, the lines:

    BEQ.S    DONE
    TST.L    TOKBUF(A0)
    BEQ.S    DONE

have been combined into a single if clause:

	if (i != 0 && tok_ptr->tokbuf != NULL)

This simplification of the code may sometimes result in the elimination of local variables. For example, in a routine like this:

MUL10:
    MOVEM.L    D1/D2,-(A7)
    MOVE.L     D1,D2	
    LSL.L      #3,D1
    LSL.L      #1,D2
    ADD.L      D2,D1
    MOVE.L     D1,(A0)
    MOVEM.L    (A7)+,D1/D2
    RTS

D2 represents a temporary local variable which Relogix will be able to eliminate. The final translation is greatly simplified:

void mul10 (long val, long *ptr)
{
    *ptr = val * 10;  
}