PMI Functions

A PMI function is defined as a PMI Section with a user-defined name other 
than one of the predefined Section names. 

PMI functions have the following characteristics: 

   *  Argument passing is performed using registers. 

   *  Functions can be of either the VOID type (no return value) or of the 
      APIRET type (return 0 for success and nonzero for failure). 

   *  Function prototypes are not explicitly declared; the calling section 
      has to understand how many and which registers need to be set and 
      set them before calling the function. 

   *  Functions are invoked by specifying the function name in a section. 

   *  Functions must be declared prior to their use. 

   *  A function may be called from within a function. 

   *  Recursions are not allowed. 

   *  There is no explicit exit or return command from functions. 

   *  The last command or assignment in the function's section is 
      considered its exit point. 
 

 PMI functions should be used extensively to create commonality and to 
 encapsulate related operations. This use will reduce development costs, 
 support more adapter-specific variations, reduce the size of the .PMI 
 file, and improve performance. 

 The VIDEO_ADAPTER structure is passed by PMI procedural callers at every 
 PMI entry point and is available to all of the PMI functions other than 
 IdentifyAdapter. All PMI functions have addressability to the current 
 state of the PMI registers and care should be taken in using the 
 registers.