Home Page Forums MAME MAME Playing with the Atari 2600 POP

static int compumate_output_bit(int16_t *buffer, int sample_pos, bool bit)
{
	int samples = 0;
	int samples_per[] = {8, 5};  // 10,5 works, 8,5 is close to actual timing (samples per half cycle)
	int cycles_per[] = {1, 2};   // compumate has 1 cycle for a 0 bit, 2 cycles for a 1 bit

	for (int i = 0; i < cycles_per[bit]; i++)
	{
		samples += compumate_put_samples(buffer, sample_pos + samples, samples_per[bit], WAVEENTRY_LOW);
		samples += compumate_put_samples(buffer, sample_pos + samples, samples_per[bit], WAVEENTRY_HIGH);
	}
	return samples;
}

static int compumate_output_byte(int16_t *buffer, int sample_pos, uint8_t byte)
{
	int samples = 0;
	uint8_t i;

	samples += compumate_output_bit (buffer, sample_pos + samples, 0);  // 1 start bit of zero

	/* data */
	for (i = 0; i<8; i++)
		samples += compumate_output_bit (buffer, sample_pos + samples, ((byte >> i) & 1));

	for (i = 0; i<4; i++)
		samples += compumate_output_bit (buffer, sample_pos + samples, 1);  // 4 stop bits

	return samples;
}

static int compumate_bin_handle_cassette(int16_t *buffer, const uint8_t *bytes)
{
	uint32_t sample_count = 0;

	/* start */
	for (int i = 0; i < HEADER_LENGTH; i++)  // roughly 900 bytes of 0xff as header for 10 seconds (can be much much less)
		sample_count += compumate_output_byte(buffer, sample_count, 0xff);

	/* data */
	for (int i = 0; i < compumate_image_size; i++)
	{
		sample_count += compumate_output_byte(buffer, sample_count, bytes[i]);
	}	

	if (buffer)
	{
		FILE* fp=fopen("RAWDATA","wb");
		if(fp)
		{	
			fwrite(buffer,sample_count*2,1,fp);
			fclose(fp);
		}
	}
	return sample_count;
}