From c26b5dadc48ad48d8a8cbbad082cb951dfca08e1 Mon Sep 17 00:00:00 2001
From: Robbbert <pac0446@bigpond.net.au>
Date: Sun, 24 May 2015 13:58:21 +1000
Subject: [PATCH] (MESS) camplynx: added TAP cassette format.

---
 scripts/src/lib.lua            |   2 +
 src/lib/formats/camplynx_cas.c | 205 +++++++++++++++++++++++++++++++++
 src/lib/formats/camplynx_cas.h |  15 +++
 src/mess/drivers/camplynx.c    |   3 +
 4 files changed, 225 insertions(+)
 create mode 100644 src/lib/formats/camplynx_cas.c
 create mode 100644 src/lib/formats/camplynx_cas.h

diff --git a/scripts/src/lib.lua b/scripts/src/lib.lua
index d4738644375..54540f0f630 100644
--- a/scripts/src/lib.lua
+++ b/scripts/src/lib.lua
@@ -168,6 +168,8 @@ project "formats"
 		MAME_DIR .. "src/lib/formats/c4040_dsk.h",
 		MAME_DIR .. "src/lib/formats/c8280_dsk.c",
 		MAME_DIR .. "src/lib/formats/c8280_dsk.h",
+		MAME_DIR .. "src/lib/formats/camplynx_cas.c",
+		MAME_DIR .. "src/lib/formats/camplynx_cas.h",
 		MAME_DIR .. "src/lib/formats/cbm_crt.c",
 		MAME_DIR .. "src/lib/formats/cbm_crt.h",
 		MAME_DIR .. "src/lib/formats/cbm_tap.c",
diff --git a/src/lib/formats/camplynx_cas.c b/src/lib/formats/camplynx_cas.c
new file mode 100644
index 00000000000..9da4d856dbf
--- /dev/null
+++ b/src/lib/formats/camplynx_cas.c
@@ -0,0 +1,205 @@
+// license:BSD-3-Clause
+// copyright-holders:Robbbert
+/********************************************************************
+
+Support for Camputers Lynx cassette images
+
+
+We support TAP files used by the Pale and Jynx emulators.
+
+Tape format:
+- about 7 seconds of zeroes
+- A5 byte
+- 22 byte
+- program name
+- 22 byte
+- about 7 seconds of zeroes
+- A5 byte
+- header
+- main program
+- checksum
+
+Each byte is 8 bits (MSB first) with no start or stop bits.
+
+********************************************************************/
+
+#include <assert.h>
+
+#include "camplynx_cas.h"
+
+#define WAVEENTRY_LOW  -32768
+#define WAVEENTRY_HIGH  32767
+
+#define LYNX48K_WAV_FREQUENCY   4000
+#define LYNX128K_WAV_FREQUENCY  8000
+
+
+// image size
+static int camplynx_image_size;
+
+static int camplynx_put_samples(INT16 *buffer, int sample_pos, int count, int level)
+{
+	if (buffer)
+	{
+		for (int i=0; i<count; i++)
+			buffer[sample_pos + i] = level;
+	}
+
+	return count;
+}
+
+static int camplynx_output_bit(INT16 *buffer, int sample_pos, bool bit)
+{
+	int samples = 0;
+
+	if (bit)
+	{
+		samples += camplynx_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH);
+		samples += camplynx_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW);
+	}
+	else
+	{
+		samples += camplynx_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH);
+		samples += camplynx_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW);
+	}
+
+	return samples;
+}
+
+static int camplynx_output_byte(INT16 *buffer, int sample_pos, UINT8 byte)
+{
+	int samples = 0;
+	UINT8 i;
+
+	/* data */
+	for (i = 0; i<8; i++)
+		samples += camplynx_output_bit (buffer, sample_pos + samples, (byte >> (7-i)) & 1);
+
+	return samples;
+}
+
+static int camplynx_handle_cassette(INT16 *buffer, const UINT8 *bytes)
+{
+	UINT32 sample_count = 0;
+	UINT32 byte_count = 1;
+	UINT32 i;
+
+
+	/* header zeroes */
+	for (i=0; i<555; i++)
+		sample_count += camplynx_output_byte(buffer, sample_count, 0);
+
+	sample_count += camplynx_output_byte(buffer, sample_count, 0xA5);
+	sample_count += camplynx_output_byte(buffer, sample_count, bytes[0]); // should be 0x22
+
+	/* program name - include protection in case tape is corrupt */
+	for (int i=1; bytes[i]!=0x22; i++)
+	{
+		if (i < camplynx_image_size)
+			sample_count += camplynx_output_byte(buffer, sample_count, bytes[i]);
+		else
+			return sample_count;
+		byte_count++;
+	}
+
+	sample_count += camplynx_output_byte(buffer, sample_count, bytes[byte_count++]); // should be 0x22
+
+	/* data zeroes */
+	for (i=0; i<555; i++)
+		sample_count += camplynx_output_byte(buffer, sample_count, 0);
+
+	sample_count += camplynx_output_byte(buffer, sample_count, 0xA5);
+
+	/* data */
+	for (i=byte_count; i<camplynx_image_size; i++)
+		sample_count += camplynx_output_byte(buffer, sample_count, bytes[i]);
+
+	return sample_count;
+}
+
+
+/*******************************************************************
+   Generate samples for the tape image
+********************************************************************/
+
+static int camplynx_cassette_fill_wave(INT16 *buffer, int length, UINT8 *bytes)
+{
+	return camplynx_handle_cassette(buffer, bytes);
+}
+
+/*******************************************************************
+   Calculate the number of samples needed for this tape image
+********************************************************************/
+
+static int camplynx_cassette_calculate_size_in_samples(const UINT8 *bytes, int length)
+{
+	camplynx_image_size = length;
+
+	return camplynx_handle_cassette(NULL, bytes);
+}
+
+static const struct CassetteLegacyWaveFiller lynx48k_legacy_fill_wave =
+{
+	camplynx_cassette_fill_wave,                 /* fill_wave */
+	-1,                                     /* chunk_size */
+	0,                                      /* chunk_samples */
+	camplynx_cassette_calculate_size_in_samples, /* chunk_sample_calc */
+	LYNX48K_WAV_FREQUENCY,                      /* sample_frequency */
+	0,                                      /* header_samples */
+	0                                       /* trailer_samples */
+};
+
+static const struct CassetteLegacyWaveFiller lynx128k_legacy_fill_wave =
+{
+	camplynx_cassette_fill_wave,                 /* fill_wave */
+	-1,                                     /* chunk_size */
+	0,                                      /* chunk_samples */
+	camplynx_cassette_calculate_size_in_samples, /* chunk_sample_calc */
+	LYNX128K_WAV_FREQUENCY,                      /* sample_frequency */
+	0,                                      /* header_samples */
+	0                                       /* trailer_samples */
+};
+
+static casserr_t lynx48k_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts)
+{
+	return cassette_legacy_identify(cassette, opts, &lynx48k_legacy_fill_wave);
+}
+
+static casserr_t lynx128k_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts)
+{
+	return cassette_legacy_identify(cassette, opts, &lynx128k_legacy_fill_wave);
+}
+
+static casserr_t lynx48k_cassette_load(cassette_image *cassette)
+{
+	return cassette_legacy_construct(cassette, &lynx48k_legacy_fill_wave);
+}
+
+static casserr_t lynx128k_cassette_load(cassette_image *cassette)
+{
+	return cassette_legacy_construct(cassette, &lynx128k_legacy_fill_wave);
+}
+
+static const struct CassetteFormat lynx48k_cassette_image_format =
+{
+	"tap",
+	lynx48k_cassette_identify,
+	lynx48k_cassette_load,
+	NULL
+};
+
+static const struct CassetteFormat lynx128k_cassette_image_format =
+{
+	"tap",
+	lynx128k_cassette_identify,
+	lynx128k_cassette_load,
+	NULL
+};
+
+CASSETTE_FORMATLIST_START(lynx48k_cassette_formats)
+	CASSETTE_FORMAT(lynx48k_cassette_image_format)
+CASSETTE_FORMATLIST_END
+
+CASSETTE_FORMATLIST_START(lynx128k_cassette_formats)
+	CASSETTE_FORMAT(lynx128k_cassette_image_format)
+CASSETTE_FORMATLIST_END
diff --git a/src/lib/formats/camplynx_cas.h b/src/lib/formats/camplynx_cas.h
new file mode 100644
index 00000000000..d8148682edf
--- /dev/null
+++ b/src/lib/formats/camplynx_cas.h
@@ -0,0 +1,15 @@
+// license:BSD-3-Clause
+// copyright-holders:Robbbert
+/*********************************************************************
+
+    camplynx_cas.h
+
+    Format code for Camputers Lynx cassette images (TAP format)
+
+*********************************************************************/
+
+
+#include "cassimg.h"
+
+CASSETTE_FORMATLIST_EXTERN(lynx48k_cassette_formats);
+CASSETTE_FORMATLIST_EXTERN(lynx128k_cassette_formats);
diff --git a/src/mess/drivers/camplynx.c b/src/mess/drivers/camplynx.c
index 144c45d8c3b..84822d66fd0 100644
--- a/src/mess/drivers/camplynx.c
+++ b/src/mess/drivers/camplynx.c
@@ -95,6 +95,7 @@
 #include "sound/dac.h"
 #include "imagedev/cassette.h"
 #include "sound/wave.h"
+#include "formats/camplynx_cas.h"
 
 class camplynx_state : public driver_device
 {
@@ -573,6 +574,7 @@ static MACHINE_CONFIG_START( lynx48k, camplynx_state )
 	MCFG_MC6845_UPDATE_ROW_CB(camplynx_state, lynx48k_update_row)
 
 	MCFG_CASSETTE_ADD("cassette")
+	MCFG_CASSETTE_FORMATS(lynx48k_cassette_formats)
 	MCFG_CASSETTE_DEFAULT_STATE(CASSETTE_PLAY | CASSETTE_SPEAKER_ENABLED | CASSETTE_MOTOR_DISABLED)
 	//MCFG_CASSETTE_INTERFACE("camplynx_cass")
 MACHINE_CONFIG_END
@@ -611,6 +613,7 @@ static MACHINE_CONFIG_START( lynx128k, camplynx_state )
 	MCFG_MC6845_OUT_HSYNC_CB(WRITE8(camplynx_state, lynx128k_irq))
 
 	MCFG_CASSETTE_ADD("cassette")
+	MCFG_CASSETTE_FORMATS(lynx128k_cassette_formats)
 	MCFG_CASSETTE_DEFAULT_STATE(CASSETTE_PLAY | CASSETTE_SPEAKER_ENABLED | CASSETTE_MOTOR_DISABLED)
 	//MCFG_CASSETTE_INTERFACE("camplynx_cass")
 MACHINE_CONFIG_END