machine/t10mmc: Implement T10MMC_CMD_SCAN

src/devices/machine/t10mmc.cpp

@@ -571,6 +571,51 @@ void t10mmc::ExecCommand()
 		m_transfer_length = m_blocks * m_sector_bytes;
 		break;
 
+	case T10MMC_CMD_SCAN:
+	{
+		const int direction = BIT(command[1], 4); // 0 = forward, 1 = reverse
+		const uint32_t start_addr = get_u32be(&command[2]);
+		const int scan_type = BIT(command[9], 6, 2); // 0 = lba, 1 = msf, 2 = track num, 3 = reserved
+
+		m_device->logerror("T10MMC: SCAN direction %d type %d addr %06x\n", direction, scan_type, start_addr);
+
+		uint32_t lba = 0;
+		switch (scan_type)
+		{
+			case 0: // lba
+				lba = start_addr;
+				break;
+			case 1: // msf
+				lba = to_lba(start_addr & 0xffffff);
+				break;
+			case 2: // track number
+				lba = m_image->get_track_start(start_addr & 0xff);
+				break;
+			default:
+				m_device->logerror("T10MMC: unsupported scan type! %d\n", scan_type);
+				break;
+		}
+
+		const int trk = m_image->get_track(m_lba);
+		if (m_image->get_track_type(trk) != cdrom_file::CD_TRACK_AUDIO)
+		{
+			m_device->logerror("T10MMC: scan target track is NOT audio!\n");
+			set_sense(SCSI_SENSE_KEY_ILLEGAL_REQUEST, SCSI_SENSE_ASC_ASCQ_ILLEGAL_MODE_FOR_THIS_TRACK);
+			m_status_code = SCSI_STATUS_CODE_CHECK_CONDITION;
+		}
+		else
+		{
+			const uint32_t disc_end_lba = m_image->get_track_start(m_image->get_last_track());
+			m_cdda->start_audio(lba, disc_end_lba - lba);
+			m_cdda->set_audio_scan(direction ? -150 : 190); // recommended values in t10 docs for forward and reverse
+
+			m_audio_sense = SCSI_SENSE_ASC_ASCQ_AUDIO_PLAY_OPERATION_IN_PROGRESS;
+			m_status_code = SCSI_STATUS_CODE_GOOD;
+		}
+
+		break;
+	}
+
 	case T10MMC_CMD_SET_CD_SPEED:
 		m_device->logerror("T10MMC: SET CD SPEED to %d kbytes/sec.\n", get_u16be(&command[2]));
 		m_phase = SCSI_PHASE_STATUS;
@@ -1172,7 +1217,8 @@ void t10mmc::ReadData( uint8_t *data, int dataLength )
 				data[0]= 0x00;
 
 				const int audio_active = m_cdda->audio_active();
-				if (audio_active)
+				const int audio_is_scanning = m_cdda->is_scanning();
+				if (audio_active || audio_is_scanning)
 				{
 					// if audio is playing, get the latest LBA from the CDROM layer
 					m_last_lba = m_cdda->get_audio_lba();

src/devices/sound/cdda.cpp

@@ -38,6 +38,9 @@ void cdda_device::device_start()
 	m_audio_length = 0;
 	m_audio_samples = 0;
 	m_audio_bptr = 0;
+	m_audio_scan_offset = 0;
+	m_audio_scan_next_lba = 0;
+	m_audio_scan_play_length = 0;
 	m_sequence_counter = 0;
 
 	save_item( NAME(m_audio_playing) );
@@ -49,7 +52,9 @@ void cdda_device::device_start()
 	save_item( NAME(m_audio_samples) );
 	save_item( NAME(m_audio_bptr) );
 	save_item( NAME(m_sequence_counter) );
-
+	save_item( NAME(m_audio_scan_offset) );
+	save_item( NAME(m_audio_scan_play_length) );
+	save_item( NAME(m_audio_scan_next_lba) );
 }
 
 
@@ -67,6 +72,8 @@ void cdda_device::start_audio(uint32_t startlba, uint32_t numblocks)
 	m_audio_lba = startlba;
 	m_audio_length = numblocks;
 	m_audio_samples = 0;
+
+	stop_audio_scan();
 }
 
 
@@ -80,6 +87,8 @@ void cdda_device::stop_audio()
 	m_stream->update();
 	m_audio_playing = false;
 	m_audio_ended_normally = true;
+
+	stop_audio_scan();
 }
 
 
@@ -92,6 +101,8 @@ void cdda_device::pause_audio(int pause)
 {
 	m_stream->update();
 	m_audio_pause = pause;
+
+	stop_audio_scan();
 }
 
 
@@ -142,6 +153,40 @@ int cdda_device::audio_ended()
 }
 
 
+/*-------------------------------------------------
+    set_audio_scan - enable scanning mode.
+    the offset can be negative for reverse
+    scanning or positive for forward scanning,
+    or 0 to disable scanning. the optional play
+    length value controls how many frames of audio
+    to play between each scan.
+
+    t10 spec recommendations:
+    forward scan offset = 190
+    reverse scan offset = -150
+    play length = 6
+-------------------------------------------------*/
+
+void cdda_device::set_audio_scan(int32_t offset, uint32_t play_length)
+{
+	m_audio_scan_offset = offset;
+	m_audio_length = m_audio_scan_play_length = play_length;
+	m_audio_scan_next_lba = m_audio_lba + play_length;
+}
+
+
+/*-------------------------------------------------
+    stop_audio_scan - stop and reset scan parameters
+-------------------------------------------------*/
+
+void cdda_device::stop_audio_scan()
+{
+	m_audio_scan_offset = 0;
+	m_audio_scan_play_length = 0;
+	m_audio_scan_next_lba = 0;
+}
+
+
 /*-------------------------------------------------
     get_audio_data - reads Red Book data off
     the disc if playback is in progress and
@@ -153,6 +198,23 @@ void cdda_device::get_audio_data(write_stream_view &bufL, write_stream_view &buf
 	int i;
 	int16_t *audio_cache = (int16_t *) m_audio_cache.get();
 
+	if (m_audio_scan_offset != 0 && m_audio_lba >= m_audio_scan_next_lba)
+	{
+		const uint32_t end_lba = m_disc->get_track_start(m_disc->get_last_track());
+
+		m_audio_lba = std::min(std::max(0, int32_t(m_audio_lba) + m_audio_scan_offset), int32_t(end_lba));
+		m_audio_length = m_audio_scan_play_length;
+		m_audio_scan_next_lba = m_audio_lba + m_audio_scan_play_length;
+		m_audio_samples = 0;
+
+		const int track_type = m_disc->get_track_type(m_disc->get_track(m_audio_lba));
+		if (m_audio_lba == 0 || m_audio_lba >= end_lba || track_type != cdrom_file::CD_TRACK_AUDIO)
+		{
+			// stop if very start, very end, or non-audio track is reached
+			m_audio_length = m_audio_samples = m_audio_scan_offset = 0;
+		}
+	}
+
 	for (int sampindex = 0; sampindex < bufL.samples(); )
 	{
 		/* if no file, audio not playing, audio paused, or out of disc data,

src/devices/sound/cdda.h

@@ -18,9 +18,13 @@ class cdda_device : public device_t, public device_sound_interface
 	void start_audio(uint32_t startlba, uint32_t numblocks);
 	void stop_audio();
 	void pause_audio(int pause);
+	void set_audio_scan(int32_t offset, uint32_t play_length = 6);
+	void stop_audio_scan();
 	int16_t get_channel_sample(int channel);
 
 	uint32_t get_audio_lba();
+	int is_scanning() { return m_audio_scan_offset != 0; }
+
 	int audio_active();
 	int audio_paused();
 	int audio_ended();
@@ -52,6 +56,10 @@ class cdda_device : public device_t, public device_sound_interface
 
 	uint32_t              m_sequence_counter;
 
+	int32_t               m_audio_scan_offset;
+	uint32_t              m_audio_scan_play_length;
+	uint32_t              m_audio_scan_next_lba;
+
 	devcb_write_line m_audio_end_cb;
 };