Programming Embedded Systems in C and C++
by Michael Barr


The following changes were made in the 6/00 reprint:


[69] 2nd paragraph:

The following was added to the end of the paragraph:

	If the address bus test fails, the address at which the 
        first error was detected will be returned.  Otherwise, this 
        function returns NULL to indicate success.

The code used to read:

datum *
memTestAddressBus(volatile datum * baseAddress, unsigned long nBytes)
{
     unsigned long offset;
     unsigned long testOffset;    
 
     datum pattern     = 0xAA;

     datum antipattern = 0x55;
 
     /*
      * Set the address mask that will be used as a stop condition.
      */
     unsigned long addressMask = (nBytes - 1);
     int busWidth = 8 * sizeof(datum);
 
     switch (busWidth)
     {
       case  8: break;
       case 16: addressMask >>= 1; break;
       case 32: addressMask >>= 2; break;
       case 64: addressMask >>= 3; break;
     }
 
     /*
      * Write the default pattern at each of the power-of-two offsets.
      */


It now reads:

datum*
memTestAddressBus(volatile datum * baseAddress, unsigned long nBytes)
{
    unsigned long addressMask = (nBytes - 1);
    unsigned long offset;
    unsigned long testOffset;

    datum pattern     = (datum) 0xAAAAAAAA;
    datum antipattern = (datum) 0x55555555;

    /*
     * Write the default pattern at each of the power-of-two offsets.
     */ 



{69-72} All instances of:

	 /*(Text)*/ 
        
 in the code were changed back to:

	 /*
          * (Text)
          */

as they were in the original printing.
         



NOTE that these changes undo some of the changes that were made in
the 3/00 reprint. Those previous changes broke the code, and are now
corrected.