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path: root/emu/6522.c
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#include "6522.h"

#include <stdio.h>
#include <stdbool.h>

static device_vtable_t const via_6522_vtable = {
	via_6522_read,
	via_6522_write,
#ifdef WITH_GUI
	via_6522_draw,
#endif
	via_6522_deinit
};

void via_6522_init( via_6522_t *via, uint16_t addr, bool initialize )
{
	device_init( &via->base, "via_6522" );
	via->base.vtable = (device_vtable_t *)&via_6522_vtable;

	via->addr = addr;
	via->debug = false;
	
	if( initialize ) {
		via->ddra = 0x00;
		via->ddrb = 0x00;
		via->pcr = 0x00;
		via->ier = 0x00;
	}
	
	bus_init( &via->busa );
	bus_init( &via->busb );
}

void via_6522_reset( via_6522_t *via )
{
	via->ddra = 0x00;
	via->ddrb = 0x00;
	via->pcr = 0x00;
	via->ier = 0x00;
}

void via_6522_register( via_6522_t *via, int bus, device_t *device )
{
	switch( bus ) {
		case PORTA:
			bus_register( &via->busa, device, 0, 0 );
			break;

		case PORTB:
			bus_register( &via->busb, device, 0, 0 );
			break;

		default:
			fprintf( stderr, "ERROR: unable to register to VIA 6522 bus, use PORTA or PORTB\n" );
	}
}

uint8_t via_6522_read( void *obj, uint16_t addr )
{
	return 0;
}

void via_6522_write( void *obj, uint16_t addr, uint8_t data )
{
	via_6522_t *via = (via_6522_t *)obj;

	switch( addr - via->addr ) {
		case PORTA:
			data &= via->ddra;
			for( int i = 0; i < via->busa.nof_devices; i++ ) {
				device_t *device = via->busa.devices[i].device;
				device->vtable->write( device, 0, data );
			}
			break;

		case PORTB:
			data &= via->ddrb;
			for( int i = 0; i < via->busb.nof_devices; i++ ) {
				device_t *device = via->busb.devices[i].device;
				device->vtable->write( device, 0, data );
			}
			break;

		case DDRB:
			via->ddrb = data;
			break;
			
		case DDRA:
			via->ddra = data;
			break;
		
		case PCR:
			via->pcr = data;
			break;
			
		case IER:
			via->ier = data;
			break;
				
		default:
			fprintf( stderr, "ERROR: VIA 6522 not implemented address '%04X', data: '%02X'\n", addr, data );
			break;
	}
}

#ifdef WITH_GUI
void via_6522_draw( void *obj, SDL_Renderer *renderer )
{
	via_6522_t *via = (via_6522_t *)obj;

	via->busa.base.vtable->draw( &via->busa, renderer );
	via->busb.base.vtable->draw( &via->busb, renderer );
}
#endif

void via_6522_deinit( void *obj )
{
	via_6522_t *via = (via_6522_t *)obj;

	bus_deinit( &via->busa );
	bus_deinit( &via->busb );
	
	device_deinit( &via->base );
}