iodisp.c

利用386保护模式将DOS实模式下的PC总线I/O操作（in/out）实时捕捉到内存并可以显示在屏幕上。可用于ISA/VESA/PCI插卡及相关软件的输入/输出调试、I/O性能/行为分析和反汇编。Ve

/*-----------------------------------------------------------------------
| iodisp.c - Display data captured with I/O Monitor                     |
|            (must compile with -Zp to pack structures)                 |
|	     (Borland C++: Large Model                                  |
|	     		   No Debug info in OBJ                         |
|			   No Standard Stack Frame			|
-----------------------------------------------------------------------*/
#include <bios.h>
#include <dos.h>
#include <stdio.h>
#include <string.h>

#define USER_INT	0x61

#define	PORT_OUTPUT	0x8000		// MSB of address: out - 1; in - 0
#define	PORT_BYTE	0x4000		// Address bit 15: word - 1; byte - 0
#define	PORT_INVALID	-1		// Initial data (marked as empty)
#define	PORT_REPEAT	-2		// Repeat data (io_data = repeat count)
#define	PORT_ADDRESS	0x3fff

struct io_record
{
   unsigned short int io_port;
   unsigned short int io_data;				// repeat or number
};

int main(int argc, char * argv[])
{
   unsigned int port, i, buf_size, buf_total, buf_wrap;
   unsigned long io_total, repeat_count, io_count;
   unsigned far * vector_ptr;
   struct io_record far *buf_ptr, *buf_start, *buf_end;
   union REGS inregs, outregs;

   vector_ptr = (unsigned far *) ((USER_INT << 2) + 2);    // CS of user isr
   if(*vector_ptr == 0)				//if user int not installed
   {
      printf ("\nIOMON not installed."
	      "\n\nUsage:\tIODISP /c\n\t/c - clear buffer after read\n");
      return 1;
   }

   int86(USER_INT, &inregs, &outregs);		// Generate user interrupt

   FP_SEG(buf_start) = outregs.x.dx;		// Get buffer start pointer
   FP_OFF(buf_start) = outregs.x.bx;

   FP_SEG(buf_ptr) = outregs.x.dx;		// Get buffer current pointer
   FP_OFF(buf_ptr) = outregs.x.cx;

   buf_size = outregs.h.al;			// Buffer size in KB
   buf_size <<= 10;				// convert to bytes
   buf_total = buf_size / sizeof(struct io_record);
   buf_end = buf_start + buf_total;

   io_total = buf_total;
   buf_wrap = outregs.h.ah;
   io_total *= buf_wrap;			// Buffer wrap count
   io_total += (outregs.x.cx - outregs.x.bx) / sizeof(struct io_record);

   printf ("%ld I/O records stored in a %dKB buffer\n",
     io_total, outregs.h.al);

#ifdef DEBUG

   /* Debug purpose only */

   printf ("AX: %04X BX: %04X CX: %04X DX: %04X\n",
     outregs.x.ax, outregs.x.bx, outregs.x.cx, outregs.x.dx);

   for(i = 0; i < 64; i++)
      printf ("%04X : %04X\t", buf_ptr[i].io_port, buf_ptr[i].io_data);

#endif

   if(buf_wrap) buf_ptr++;			// Curren record is invalid
   else buf_ptr = buf_start;			// Start from beginning

   for(i = 1, io_count = 0; i < buf_total; )	// Last record is invalid
   {
      if(buf_ptr >=  buf_end) buf_ptr = buf_start;	// Wrap to beginning

      port = buf_ptr->io_port;
      if((int) port == PORT_INVALID) break;	// No more data
      else
      {
	 printf("\n%c %4XH ", (port & PORT_OUTPUT) ? 'O' : 'I', port & PORT_ADDRESS);
	 printf((port & PORT_BYTE) ? "%02X" : "%04X", buf_ptr->io_data);

	 buf_ptr++;				// Next data
	 io_count++;
	 i++;

	 for(repeat_count = 0; i < buf_total; buf_ptr++, i++)	// Add repeat count if any
	 {
	    if(buf_ptr >=  buf_end) buf_ptr = buf_start;	// Wrap to beginning
	    if ((int) buf_ptr->io_port != PORT_REPEAT) break;
	    repeat_count += buf_ptr->io_data;	// Increase repeat count
	 }

	 if(repeat_count) printf(" [%ld]", repeat_count + 1);
	 io_count += repeat_count;
      }
   }

   printf ("\nTotal I/O operations captured: %ld\n", io_count);

   if(argc > 1 && !stricmp(argv[1], "/c"))	// Clear record after display
   {
      memset(buf_start, 0xff, buf_size);

      buf_ptr = buf_end;			// Go to end of buffer
      buf_ptr->io_port = outregs.x.bx;		// io_buf_ptr = buf_start
      buf_ptr->io_data = outregs.x.bx;		// io_repeat_ptr = buf_start

      buf_ptr++;
      * ((char *) buf_ptr) = 0;			// io_buf_wrap = 0
      printf ("\nI/O records purged\n");
   }

   return 0;
}