1 files changed, 75 insertions, 0 deletions
diff --git a/emu/bus.c b/emu/bus.c
new file mode 100644
index 0000000..5bbbcb1
--- /dev/null
+++ b/emu/bus.c
@@ -0,0 +1,75 @@
+#include "bus.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+static device_vtable_t const bus_vtable = {
+	bus_read,
+	bus_write,
+	bus_deinit
+};
+
+void bus_init( bus_t *bus )
+{
+	device_init( &bus->base, "bus" );
+	((device_t *)bus)->vtable = (device_vtable_t *)&bus_vtable;
+	
+	bus->nof_devices = 0;	
+}
+
+void bus_register( bus_t *bus, device_t *device, uint16_t from, uint16_t to )
+{
+	if( bus->nof_devices < MAX_NOF_DEVICES ) {
+		registered_device_t *reg = &bus->devices[bus->nof_devices];
+		reg->device = device;
+		reg->from = from;
+		reg->to = to;
+		bus->nof_devices++;
+	} else {
+		fprintf( stderr, "ERROR: too many devices on bus\n" );
+		exit( EXIT_FAILURE );
+	}
+}
+
+uint8_t bus_read( void *obj, uint16_t addr )
+{
+	bus_t *bus = (bus_t *)obj;
+
+	for( int i = 0; i < bus->nof_devices; i++ ) {
+		registered_device_t *reg = &bus->devices[i];
+		if( reg->from <= addr && addr <= reg->to ) {
+			return reg->device->vtable->read( reg->device, addr );
+		}
+	}
+
+	fprintf( stderr, "ERROR: illegal bus access reading from address %04X\n", addr );
+	
+	return 0;
+}
+
+void bus_write( void *obj, uint16_t addr, uint8_t data )
+{
+	bus_t *bus = (bus_t *)obj;
+
+	for( int i = 0; i < bus->nof_devices; i++ ) {
+		registered_device_t *reg = &bus->devices[i];
+		if( reg->from <= addr && addr <= reg->to ) {
+			return reg->device->vtable->write( reg->device, addr, data );
+		}
+	}
+
+	fprintf( stderr, "ERROR: illegal bus access writing from address %04X\n", addr );
+}
+
+void bus_deinit( void *obj )
+{
+	bus_t *bus = (bus_t *)obj;
+
+	for( int i = bus->nof_devices - 1; i >= 0; i-- ) {
+		registered_device_t *reg = &bus->devices[i];
+		reg->device->vtable->deinit( reg->device );
+	}
+	bus->nof_devices = 0;
+
+	device_deinit( &bus->base );
+}