#include "memory.h"

#include <stdio.h>

void memory_init( memory_t *memory, seg7_t *seg )
{
	memory->read = memory_read;
	memory->write = memory_write;
	memory->seg = seg;
}

uint8_t memory_read( memory_t *memory, uint16_t addr )
{
	if( addr <= 0x3FFF ) {
		// RAM access
		return memory->cell[addr];
	} else if( addr <= 0x8000 ) {
		return seg7_read( memory->seg, addr );
	} else {
		// ROM access
		return memory->cell[addr];
	}
}

void memory_write( memory_t *memory, uint16_t addr, uint8_t data )
{
	if( addr <= 0x3FFF ) {
		// RAM access
		memory->cell[addr] = data;
	} else if( addr <= 0x8000 ) {
		seg7_write( memory->seg, addr, data );
	} else {
		// ignore writes to ROM
	}
}

void memory_load( memory_t *memory, uint16_t addr, uint16_t size, const char *filename )
{
	if( addr >= 0x8000 ) {
		FILE *f = fopen( filename, "rb" );
		if( f == NULL ) {
			fprintf( stderr, "ERROR: Unable to open ROM file '%s'\n", filename );
			exit( EXIT_FAILURE );
		}
		fread( &memory->cell[addr], size, 1, f );
		fclose( f );
		fprintf( stderr, "INFO: Loaded firware from '%s' of size %d starting on address %04X\n",
			filename, size, addr );
	} else {
		fprintf( stderr, "ERROR: Cannot load firmware into RAM at address %04X\n", addr );
	}
}