_SIMULATION AND TESTBOARD FOR EMBEDDED SYSTEM DESIGN_
by Michael Kutter


[LISTING ONE]

FILE *serial_in,*serial_out;

void outbyte(unsigned char dest,value)
     {
     static long command;
     /* check to make sure dest indicates SERIAL_DEVICE. */
     if (dest != SERIAL_DEVICE)
          {
          printf("Error in Hardware destination address\n");
          return;
          }
     /* reconstruct the command by shifting bits into the */
     /* command variable. */
     if (control bit in value indicates a new command bit
               has been sent)
          {
          command += new input bit in "value";
          command <= 1;
          }
     /* record the command after it is complete */
     if (latch bit in value indicates the command is complete)
          {
          fprintf(serial_out,"serial command: %lx",command);

          command = 0;
          }
     }
unsigned char inbyte(unsigned char source)
     {
     static long status;
     unsigned char return_byte = 0;

     /* check to make sure dest indicates SERIAL_DEVICE. */
     if (source != SERIAL_DEVICE)
          {
          printf("Error in Hardware destination address\n");
          return;
          }
     /* get a new status word */
     if (latch bit in value indicates a new status read)

          fscanf(serial_in,"%lx",&status);
     /* send the status one bit at time, shifting bits  */
     /* out of the status variable */
     if (control bit in status indicates a new statu bit
               has been requested)
          {
          return_byte = status & 0x01;
          status >= 1;
          }
     return(return_byte);
     }



Example 1: Basic RPSC macros

#define inbyte(b)     (*((unsigned char *)b))
#define outbyte(a,b)  (*((unsigned char *)a)=(unsigned char)b)




Example 2: You can replace macros with subroutines like these 
that read from and write to text files

FILE *sim_out;      /* opened at beginning of simulation */
                    /* closed at end. */
FILE *sim_in[ONE_FOR_EACH_REGISTER];

unsigned char inbyte(unsigned char address)
     {
     int invalue;

     fscanf(sim_in[address],"%x",&invalue);
     return(0xFF & invalue);
     }

void outbyte(unsigned char dest,value);
     {
     fprintf(sim_out,"%x <-- %x\n",dest,value);

     }