#pragma TEST_CODE: Check Generated Code

Function Definition

  #pragma TEST_CODE CompareOperator <Size> [<HashCode>] 
  

  CompareOperator: ==|!=|<|>|<=|>= 
  

<Size>: Size of the function to be used in a compare operation

<HashCode>: optional value specifying one specific code pattern.

None

This pragma checks the generated code. If the check fails, the message C3601 is issued.

The following parts are tested:

• Size of the function

  The compare operator and the size given as arguments are compared with the size of the function.

  This feature checks that the compiler generates less code than a given boundary. Or, to be sure that certain code it can also be checked that the compiler produces more code than specified. To only check the hashcode, use a condition which is always TRUE, such as != 0.

• Hashcode

  The compiler produces a 16-bit hashcode from the produced code of the next function. This hashcode considers:

  • The code bytes of the generated functions
  • The type, offset, and addend of any fixup.

    To get the hashcode of a certain function, compile the function with an active #pragma TEST_CODE which will intentionally fail. Then copy the computed hashcode out of the body of the message C3601.

    Note: The code generated by the compiler may change. If the test fails, it is often not certain that the topic chosen to be checked was wrong.

The following listing and Listing: Using a Test_Code pragma with the hashcode option present two examples of the TEST_CODE pragma.

/* check that an empty function is smaller */ 
/* than 10 bytes */ 
#pragma TEST_CODE < 10 
void main(void) { 
} 

You can also use the TEST_CODE pragma to detect when a different code is generated (refer to the following listing).

/* If the following pragma fails, check the code. */ 
/* If the code is OK, add the hashcode to the */ 
/* list of allowed codes : */ 
#pragma TEST_CODE != 0 25645 37594 
/* check code patterns : */ 
/* 25645 : shift for *2 */ 
/* 37594 : mult for *2 */ 
void main(void) { 
 f(2*i); 
} 

Message C3601 in the Online Help