speedtst.cpp

精工打印头LTP3445的使用范例。有原理图和源码

#include <dos.h>
#include <time.h>
#include <stdio.h>
void main(void)
{
   static unsigned long first, second;
   printf("\nThe program calculates time interval to perform 10 million of writes to 0x378\nTakes about 20 seconds. Please wait...\n");

   first = *(long*)MK_FP(0x40, 0x6c);  /* Gets system
                           time */
   for(unsigned long i=0;i<10000000L;i++)
      outportb(0x378, i&0xff);

   second = *(long*)MK_FP(0x40, 0x6c); /* Gets system time
                           again */

   static int in = second-first;
   static float f = (second-first)/18.2;
   printf("10 million of writes to 0x378 took %d timer ticks (%5.3f seconds)\n",in, f);
   printf("About %5.3f us per write\n", f/10.);
}