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(MESS) apf : added support for CAS and CPF cassettes [Robbbert]
removed APT support for the moment, it could not have ever worked.
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Robbbert
parent
bc0672544f
commit
c164e73a4b
2 changed files with 84 additions and 85 deletions
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@ -1,119 +1,124 @@
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/* .APT tape images */
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// license:BSD-3-Clause
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// copyright-holders: Original author, Robbbert
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/********************************************************************
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Support for APF Imagination Machine cassette images
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CPF and CAS images consist of the screen and then the program,
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and are exactly 1E00 bytes in length.
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Each byte after conversion becomes bit 7,6,etc to 0, There are
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no start or stop bits.
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An actual tape consists of 6 sections
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a. silence until you press Enter (no offset)
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b. 11secs of high bits then 1 low bit
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c. The screen ram
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d. The program ram
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e. A checksum byte (8-bit addition)
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********************************************************************/
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#include "formats/apf_apt.h"
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#define WAVEENTRY_LOW -32768
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#define WAVEENTRY_HIGH 32767
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#define WAVEENTRY_NULL 0
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/* frequency of wave */
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#define APF_WAV_FREQUENCY 11050
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#define APF_APT_BIT_0_LENGTH ((int)(APF_WAV_FREQUENCY*0.0005))
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#define APF_APT_BIT_1_LENGTH ((int)(APF_WAV_FREQUENCY*0.001))
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struct apf_t
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{
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int cassette_length;
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};
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static apf_t apf;
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#define APF_WAV_FREQUENCY 8000
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/* 500 microsecond of bit 0 and 1000 microsecond of bit 1 */
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static int apf_image_size;
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static INT16 *apf_emit_level(INT16 *p, int count, INT16 wave_state)
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static int apf_put_samples(INT16 *buffer, int sample_pos, int count, int level)
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{
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int i;
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for (i=0; i<count; i++)
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if (buffer)
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{
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*(p++) = wave_state;
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for (int i=0; i<count; i++)
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buffer[sample_pos + i] = level;
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}
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return p;
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return count;
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}
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/* 4 periods at 1200Hz */
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static INT16* apf_output_bit(INT16 *p, UINT8 b)
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static int apf_output_bit(INT16 *buffer, int sample_pos, bool bit)
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{
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if (b)
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int samples = 0;
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if (bit)
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{
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p = apf_emit_level(p, (APF_APT_BIT_1_LENGTH>>1), WAVEENTRY_HIGH);
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p = apf_emit_level(p, (APF_APT_BIT_1_LENGTH>>1), WAVEENTRY_LOW);
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samples += apf_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH);
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samples += apf_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW);
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}
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else
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{
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p = apf_emit_level(p, (APF_APT_BIT_0_LENGTH>>1), WAVEENTRY_HIGH);
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p = apf_emit_level(p, (APF_APT_BIT_0_LENGTH>>1), WAVEENTRY_LOW);
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samples += apf_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH);
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samples += apf_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW);
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}
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return p;
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return samples;
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}
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static int apf_get_bit_size_in_samples(UINT8 b)
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static int apf_output_byte(INT16 *buffer, int sample_pos, UINT8 byte)
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{
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if (b)
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{
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return APF_APT_BIT_1_LENGTH;
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}
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int samples = 0;
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UINT8 i;
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return APF_APT_BIT_0_LENGTH;
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/* data */
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for (i = 0; i<8; i++)
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samples += apf_output_bit (buffer, sample_pos + samples, (byte >> (7-i)) & 1);
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return samples;
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}
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/*************************************************************************************/
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/* each bit in the data represents a "1" or "0" waveform */
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static int apf_cassette_calculate_size_in_samples(const UINT8 *bytes, int length)
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static int apf_handle_cassette(INT16 *buffer, const UINT8 *bytes)
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{
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unsigned i;
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int size;
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int b;
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UINT8 data;
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UINT32 sample_count = 0;
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UINT32 i;
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UINT8 cksm = 0;
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size = 0;
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apf.cassette_length = length;
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// silence
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sample_count += apf_put_samples(buffer, 0, 12000, 0);
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/* start */
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for (i=0; i<10000; i++)
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sample_count += apf_output_bit(buffer, sample_count, 1);
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for (i=0; i<length; i++)
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sample_count += apf_output_bit(buffer, sample_count, 0);
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/* data */
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for (i=0; i<apf_image_size; i++)
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{
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data = bytes[i];
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for (b=0; b<8; b++)
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{
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size += apf_get_bit_size_in_samples((data>>7) & 0x01);
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data = data<<1;
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}
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cksm += bytes[i];
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sample_count += apf_output_byte(buffer, sample_count, bytes[i]);
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}
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return size;
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/* checksum byte */
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sample_count += apf_output_byte(buffer, sample_count, cksm);
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return sample_count;
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}
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/*************************************************************************************/
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/*******************************************************************
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Generate samples for the tape image
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********************************************************************/
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static int apf_cassette_fill_wave(INT16 *buffer, int length, UINT8 *bytes)
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{
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int i;
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INT16 *p;
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UINT8 data;
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int b;
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p = buffer;
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for (i=0; i<apf.cassette_length; i++)
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{
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data = bytes[i];
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for (b=0; b<8; b++)
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{
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p = apf_output_bit(p,(data>>7) & 0x01);
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data = data<<1;
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}
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}
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return p - buffer;
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return apf_handle_cassette(buffer, bytes);
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}
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/*******************************************************************
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Calculate the number of samples needed for this tape image
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********************************************************************/
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static int apf_cassette_calculate_size_in_samples(const UINT8 *bytes, int length)
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{
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apf_image_size = length;
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return apf_handle_cassette(NULL, bytes);
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}
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static const struct CassetteLegacyWaveFiller apf_legacy_fill_wave =
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{
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@ -126,27 +131,21 @@ static const struct CassetteLegacyWaveFiller apf_legacy_fill_wave =
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0 /* trailer_samples */
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};
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static casserr_t apf_apt_identify(cassette_image *cassette, struct CassetteOptions *opts)
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static casserr_t apf_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts)
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{
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return cassette_legacy_identify(cassette, opts, &apf_legacy_fill_wave);
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}
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static casserr_t apf_apt_load(cassette_image *cassette)
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static casserr_t apf_cassette_load(cassette_image *cassette)
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{
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return cassette_legacy_construct(cassette, &apf_legacy_fill_wave);
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}
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static const struct CassetteFormat apf_apt_format =
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{
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"apt",
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apf_apt_identify,
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apf_apt_load,
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"cas,cpf",
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apf_cassette_identify,
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apf_cassette_load,
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NULL
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};
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@ -14,14 +14,14 @@ phc images consist of 5 sections
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5. A 1-byte trailer of FF which we do not pass on
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Each byte after conversion becomes a start bit, bit 0,1,etc to 7,
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then 4 end bits.
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then 4 stop bits.
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An actual tape consists of 6 sections
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a. 2.656secs of silence
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b. 4.862secs of high bits
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c. The header which is parts 1 and 2 above
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d. 0.652secs of high bits
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e. The main program wjich is parts 3 and 4 above
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e. The main program which is parts 3 and 4 above
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f. 1.771secs of silence
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We don't emulate the full silence and high-bits periods, only just
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