//---------------------------------------------------------------------------
// L362.C
// Using the 80C188XL internal DMA channel 0 for implementing an 
// 'unsynchronized' Memory to Memory tansfer, i.e., copy one
// string to another.
// An interrupt is generated on terminal count.
// 
// C/C++ code for the SBC188 board.
// C.P. Diduch, March 1999.
//---------------------------------------------------------------------------
#define TRUE    1

#define D0SRCL  0xFFC0          // 80C188 DMA0 SRC address: lo 16-bits.
#define D0SRCH  0xFFC2          // 80C188 DMA0 SRC address: hi 4-bits.
#define D0DSTL  0xFFC4          // 80C188 DMA0 DST address: lo 16-bits.
#define D0DSTH  0xFFC6          // 80C188 DMA0 DST address: hi 4-bits.
#define D0TC    0xFFC8          // 80C188 DMA0 terminal count register.
#define D0CON   0xFFCA          // 80C188 DMA0 control register.

#define D0TYPE  10              // 80C188 Interrupt TYPE number for DMA0.
#define DMA0CON 0xFF34          // 80C188 Interrupt control reg for DMA0.      
#define EOI     0xFF22          // 80C188 End of interrupt register.

#define KEY_PC  0x013C          // 8255A PPI Port addresses.
#define KEY_CON 0x013E

#include <dos.h>
#include <conio.h>

void int_vect_init(void);       // Function prototypes.
void timer_init(unsigned MICROSECS);
void interrupt isr_0(void);
void delay(unsigned MILLISECS);
void dma_mem_mem(char *x, char *y, unsigned z, unsigned NO_BYTES);

//---------------------------------------------------------------------------
void main(void)
{
char DATA[] = {1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3, \
               4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,6,6,6,6,6,6,6,6,6,6};
char BUFF[60];
unsigned SA;
disable();                      // Clear 80C188 interrupts.
outportb(KEY_CON, 0x92);        // Initialize KEY_PC as an output port.
int_vect_init();                // Initialize interrupt vector table.
asm{
   mov SA, ds                   // Get segment address of BUFF[] and DATA[].
   }

// Initialize and arm DMA0 to transfer 60 bytes from array DATA[]
// to array BUFF[].

dma_mem_mem(&BUFF[0], &DATA[0], SA, 60); 
enable();                       // Enable 80C188 interrupts.
asm hlt                         // Wait for a DMA interrupt on
                                // terminal count.
delay(1000);
}

//---------------------------------------------------------------------------     
void dma_mem_mem(char *DST, char *SRC, unsigned SA, unsigned NO_BYTES)
{
long PA;
unsigned LO, HI;

PA = (16* (long) SA) + (unsigned) SRC;
LO = (unsigned) PA;
HI = (unsigned) (PA >> 16);
outport(D0SRCL, LO);
outport(D0SRCH, HI);

PA = (16* (long) SA) + (unsigned) DST;
LO = (unsigned) PA;
HI = (unsigned) (PA >> 16);
outport(D0DSTL, LO); 
outport(D0DSTH, HI);

outport(D0TC, NO_BYTES);
outport(D0CON, 0xB706);    	// Unsynchronize transfer terminates
                           	// with interrupt.
outport(DMA0CON, 0);
}

//---------------------------------------------------------------------------     
void int_vect_init(void)
{
asm {                           // Initialize the Interrupt Vector
   push ax                      // Table entry for the 80C188XL
   push bx                      // DMA0.
   push ds
   mov ax, 0
   mov ds, ax
   mov bx, D0TYPE*4
   mov word ptr[bx], offset isr_0
   mov word ptr[bx+2], seg isr_0
   pop ds
   pop bx
   pop bx
   }
}

//---------------------------------------------------------------------------
// DMA0 Terminal Count Interrupt Service Routine

void interrupt isr_0(void)
{
   outportb(KEY_PC, 0xAA);
   outport(EOI, 0x000A);        // Specific End of Interrupt for TIMER2.
                                // Reqired TYPE = 10D for all TIMERS.
}

//---------------------------------------------------------------------------
void delay(unsigned MILLISECS)
{
unsigned M;
while (MILLISECS != 0) {
   M = 1000;
   while (M != 0) {M--;}
   MILLISECS--;
   }
}