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brother/lw30.cpp: Added driver for Brother LW-30 word processor. (#10996)
New working systems --------------------- Brother LW-30
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‎scripts/src/formats.lua

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@@ -1187,6 +1187,18 @@ if opt_tool(FORMATS, "JVC_DSK") then
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}
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end
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--------------------------------------------------
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--
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--@src/lib/formats/lw30_dsk.h,FORMATS["LW30_DSK"] = true
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--------------------------------------------------
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if opt_tool(FORMATS, "LW30_DSK") then
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files {
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MAME_DIR.. "src/lib/formats/lw30_dsk.cpp",
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MAME_DIR.. "src/lib/formats/lw30_dsk.h",
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}
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end
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--------------------------------------------------
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--
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--@src/lib/formats/os9_dsk.h,FORMATS["OS9_DSK"] = true

‎src/lib/formats/lw30_dsk.cpp

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// license:BSD-3-Clause
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// copyright-holders:Bartman/Abyss
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/***************************************************************************
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Brother LW-30 Disk image format
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see https://github.com/BartmanAbyss/brother-diskconv for disk conversion tool
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***************************************************************************/
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#include "lw30_dsk.h"
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#include "ioprocs.h"
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#include <array>
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#include <cassert>
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#include <cstring>
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namespace {
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constexpr uint16_t sync_table[]{
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0xdaef, 0xb7ad, 0xfbbe, 0xeadf, 0xbffa, 0xaeb6, 0xf5d7, 0xdbee, 0xbaab, 0xfdbd,
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0xebde, 0xd5f7, 0xafb5, 0xf6d6, 0xdded, 0xbbaa, 0xedbb, 0xd6dd, 0xb5f6, 0xf7af,
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0xded5, 0xbdeb, 0xabfd, 0xeeba, 0xd7db, 0xb6f5, 0xfaae, 0xdfbf, 0xbeea, 0xadfb,
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0xefb7, 0xdada, 0xb7ef, 0xfbad, 0xeabe, 0xbfdf, 0xaefa, 0xf5b6, 0xdbd7, 0xbaee,
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0xfdab, 0xebbd, 0xd5de, 0xaff7, 0xf6b5, 0xddd6, 0xbbed, 0xaadd, 0xedf6, 0xd6af,
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0xb5d5, 0xf7eb, 0xdefd, 0xbdba, 0xabdb, 0xeef5, 0xd7ae, 0xb6bf, 0xfaea, 0xdffb,
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0xbeb7, 0xadda, 0xefef, 0xdaad, 0xb7be, 0xfbdf, 0xeafa, 0xbfb6, 0xaed7, 0xf5ee,
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0xdbab, 0xbabd, 0xfdde, 0xebf7, 0xd5b5, 0xafd6, 0xf6ed, 0xddaa, 0xd6bb, 0xb5dd
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};
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constexpr uint8_t gcr_table[]{
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0xaa, 0xab, 0xad, 0xae, 0xaf, 0xb5, 0xb6, 0xb7,
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0xba, 0xbb, 0xbd, 0xbe, 0xbf, 0xd5, 0xd6, 0xd7,
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0xda, 0xdb, 0xdd, 0xde, 0xdf, 0xea, 0xeb, 0xed,
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0xee, 0xef, 0xf5, 0xf6, 0xf7, 0xfa, 0xfb, 0xfd,
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0xfe, 0xff // FE, FF are reserved
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};
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// format
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constexpr uint8_t sector_prefix[]{
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0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xab
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};
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// write
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constexpr uint8_t sector_header[]{
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0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
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0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xed
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};
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// write
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constexpr uint8_t sector_footer[]{
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0xf5, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd
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};
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constexpr uint8_t sector_interleave1[]{ // 1-based
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1, 6, 11, 4, 9, 2, 7, 12, 5, 10, 3, 8
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};
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constexpr uint8_t sector_interleave2[]{ // 1-based
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
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};
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constexpr uint8_t sector_interleave3[]{ // 1-based
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1, 4, 7, 10, 6, 9, 12, 3, 11, 2, 5, 8
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};
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void gcr_encode_5_to_8(const uint8_t *input, uint8_t *output)
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{
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// input:
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// 76543210
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// --------
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// 00000111 0
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// 11222223 1
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// 33334444 2
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// 45555566 3
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// 66677777 4
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output[0] = gcr_table[(input[0] >> 3) & 0x1f];
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output[1] = gcr_table[((input[0] << 2) & 0x1f) | ((input[1] >> 6) & 0b00000011)];
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output[2] = gcr_table[(input[1] >> 1) & 0x1f];
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output[3] = gcr_table[((input[1] << 4) & 0x1f) | ((input[2] >> 4) & 0b00001111)];
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output[4] = gcr_table[((input[2] << 1) & 0x1f) | ((input[3] >> 7) & 0b00000001)];
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output[5] = gcr_table[(input[3] >> 2) & 0x1f];
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output[6] = gcr_table[((input[3] << 3) & 0x1f) | ((input[4] >> 5) & 0b00000111)];
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output[7] = gcr_table[input[4] & 0x1f];
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}
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std::array<uint8_t, 3> checksum_256_bytes(const uint8_t *input)
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{
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size_t i = 0;
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uint8_t a = 0;
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uint8_t c = input[i++];
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uint8_t d = input[i++];
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uint8_t e = input[i++];
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for(size_t b = 0; b < 253; b++) {
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a = d;
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if(c & 0b10000000)
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a ^= 1;
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d = c;
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c = a;
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a = (d << 1) ^ e;
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e = d;
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d = a;
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e ^= input[i++];
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}
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return { c, d, e };
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}
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std::array<uint8_t, 416> gcr_encode_and_checksum(const uint8_t *input /* 256 bytes */) {
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std::array<uint8_t, 416> output;
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for(int i = 0; i < 51; i++)
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gcr_encode_5_to_8(&input[i * 5], &output[i * 8]);
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auto checksum = checksum_256_bytes(input);
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std::array<uint8_t, 5> end_and_checksum{ input[255], checksum[0], checksum[1], checksum[2], 0x58 };
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gcr_encode_5_to_8(&end_and_checksum[0], &output[408]);
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return output;
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}
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}
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static constexpr int TRACKS_PER_DISK = 78;
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static constexpr int SECTORS_PER_TRACK = 12;
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static constexpr int SECTOR_SIZE = 256;
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static constexpr int RPM = 300;
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static constexpr int CELLS_PER_REV = 250'000 / (RPM / 60);
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// format track: 0xaa (2), 0xaa (48), 12*sector
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// format sector: sector_prefix (8), track_sync (2), sector_sync (2), predata (19), payload=0xaa (414), postdata (13), 0xaa (42), should come out to ~4,000 bits
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// write sector: (after sector_sync, 0xdd) sector_header (2+14), payload (416), sector_footer (11)
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// from write_format, write_sector_data_header_data_footer
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static constexpr int raw_sector_size = 8/*sector_prefix*/ + 2/*track_sync*/ + 2/*sector_sync*/ + 1/*0xdd*/ + 16/*sector_header*/ + 416/*payload*/ + 11/*sector_footer*/ + 42/*0xaa*/;
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static constexpr int raw_track_size = 2/*0xaa*/ + 48/*0xaa*/ + SECTORS_PER_TRACK * raw_sector_size;
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int lw30_format::identify(util::random_read &io, uint32_t form_factor, const std::vector<uint32_t> &variants) const
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{
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uint64_t size = 0;
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io.length(size);
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if(size == TRACKS_PER_DISK * SECTORS_PER_TRACK * SECTOR_SIZE)
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return 50; // identified by size
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return 0;
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}
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bool lw30_format::load(util::random_read &io, uint32_t form_factor, const std::vector<uint32_t> &variants, floppy_image *image) const
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{
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uint8_t trackdata[SECTORS_PER_TRACK * SECTOR_SIZE], rawdata[CELLS_PER_REV / 8];
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memset(rawdata, 0xaa, sizeof(rawdata));
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for(int track = 0; track < TRACKS_PER_DISK; track++) {
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size_t actual{};
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io.read_at(track * SECTORS_PER_TRACK * SECTOR_SIZE, trackdata, SECTORS_PER_TRACK * SECTOR_SIZE, actual);
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if(actual != SECTORS_PER_TRACK * SECTOR_SIZE)
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return false;
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size_t i = 0;
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for(int x = 0; x < 2 + 48; x++)
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rawdata[i++] = 0xaa;
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auto interleave_offset = (track % 4) * 4;
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for(size_t s = interleave_offset; s < interleave_offset + SECTORS_PER_TRACK; s++) {
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auto sector = sector_interleave1[s % SECTORS_PER_TRACK] - 1;
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// according to check_track_and_sector
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for(const auto& d : sector_prefix) // 8 bytes
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rawdata[i++] = d;
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rawdata[i++] = sync_table[track] & 0xff;
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rawdata[i++] = sync_table[track] >> 8;
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rawdata[i++] = sync_table[sector] & 0xff;
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rawdata[i++] = sync_table[sector] >> 8;
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rawdata[i++] = 0xdd;
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for(const auto& d : sector_header) // 16 bytes
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rawdata[i++] = d;
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auto payload = gcr_encode_and_checksum(trackdata + sector * SECTOR_SIZE); // 256 -> 416 bytes
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for(const auto &d : payload)
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rawdata[i++] = d;
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for(const auto &d : sector_footer) // 11 bytes
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rawdata[i++] = d;
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for(int x = 0; x < 42; x++)
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rawdata[i++] = 0xaa;
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}
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assert(i == raw_track_size);
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assert(i <= CELLS_PER_REV / 8);
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generate_track_from_bitstream(track, 0, rawdata, CELLS_PER_REV, image);
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}
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image->set_variant(floppy_image::SSDD);
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return true;
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}
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const char *lw30_format::name() const
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{
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return "lw30";
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}
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const char *lw30_format::description() const
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{
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return "Brother LW-30 floppy disk image";
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}
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const char *lw30_format::extensions() const
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{
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return "img";
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}
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bool lw30_format::supports_save() const
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{
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// TODO
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return false;
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}
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const lw30_format FLOPPY_LW30_FORMAT;

‎src/lib/formats/lw30_dsk.h

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// license:BSD-3-Clause
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// copyright-holders:Bartman/Abyss
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/***************************************************************************
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Brother LW-30 Disk image format
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see https://github.com/BartmanAbyss/brother-diskconv for disk conversion tool
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***************************************************************************/
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#ifndef MAME_FORMATS_LW30_DSK_H
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#define MAME_FORMATS_LW30_DSK_H
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#pragma once
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#include "flopimg.h"
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class lw30_format : public floppy_image_format_t
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{
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public:
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virtual int identify(util::random_read& io, uint32_t form_factor, const std::vector<uint32_t> &variants) const override;
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virtual bool load(util::random_read &io, uint32_t form_factor, const std::vector<uint32_t>& variants, floppy_image *image) const override;
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virtual const char *name() const override;
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virtual const char *description() const override;
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virtual const char *extensions() const override;
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virtual bool supports_save() const override;
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};
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extern const lw30_format FLOPPY_LW30_FORMAT;
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#endif // MAME_FORMATS_LW30_DSK_H

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