Add support for the 83kB 5.25" Lanier format.

arch/aeslanier/aeslanier.h

@@ -1,9 +1,19 @@
 #ifndef AESLANIER_H
 #define AESLANIER_H
 
+/* MFM:
+ * 
+ * Raw bits:
+ *    5    5    5    5    5    1    2    2
+ * 0101 0101 0101 0101 0101 0001 0010 0010
+ * 0 0  0 0  0 0  0 0  0 0  0 0  0 1  0 1
+ *        0         0         0         5
+ * Decoded bits.
+ */
+
 #define AESLANIER_RECORD_SEPARATOR 0x55555122
 #define AESLANIER_SECTOR_LENGTH 256
-#define AESLANIER_RECORD_SIZE (AESLANIER_SECTOR_LENGTH + 5)
+#define AESLANIER_RECORD_SIZE (AESLANIER_SECTOR_LENGTH + 4)
 
 extern std::unique_ptr<Decoder> createAesLanierDecoder(
     const DecoderProto& config);

arch/aeslanier/aeslanier.proto

@@ -1,4 +1,4 @@
 syntax = "proto2";
 
-message AesLanierDecoderProto {}
+message AesLanier5DecoderProto {}
 

arch/aeslanier5/aeslanier5.h

@@ -0,0 +1,21 @@
+#ifndef AESLANIER5_H
+#define AESLANIER5_H
+
+/* Format is FM:
+ *
+ *    a    a    a    a    f    b    e    f
+ * 1010 1010 1010 1010 1111 1011 1110 1111
+ *  0 0  0 0  0 0  0 0  1 1  0 1  1 0  1 1
+ *         0         0         d         b
+ * 
+ * However, note that this pattern is _not_ reversed...
+ */
+
+#define AESLANIER5_RECORD_SEPARATOR 0xaaaaaaaaaaaafbefLL
+#define AESLANIER5_SECTOR_LENGTH 151
+#define AESLANIER5_RECORD_SIZE (AESLANIER5_SECTOR_LENGTH + 3)
+
+extern std::unique_ptr<Decoder> createAesLanier5Decoder(
+    const DecoderProto& config);
+
+#endif

arch/aeslanier5/aeslanier5.proto

@@ -0,0 +1,4 @@
+syntax = "proto2";
+
+message AesLanierDecoderProto {}
+

arch/aeslanier5/decoder.cc

@@ -0,0 +1,78 @@
+#include "lib/core/globals.h"
+#include "lib/decoders/decoders.h"
+#include "aeslanier5.h"
+#include "lib/core/crc.h"
+#include "lib/data/fluxmap.h"
+#include "lib/data/fluxmapreader.h"
+#include "lib/data/fluxpattern.h"
+#include "lib/data/sector.h"
+#include "lib/core/bytes.h"
+#include "fmt/format.h"
+#include <string.h>
+
+static const FluxPattern SECTOR_PATTERN(32, AESLANIER5_RECORD_SEPARATOR);
+
+/* This is actually FM, rather than MFM, but it our MFM/FM decoder copes fine
+ * with it. */
+
+class AesLanier5Decoder : public Decoder
+{
+public:
+    AesLanier5Decoder(const DecoderProto& config): Decoder(config) {}
+
+    nanoseconds_t advanceToNextRecord() override
+    {
+        return seekToPattern(SECTOR_PATTERN);
+    }
+
+    void decodeSectorRecord() override
+    {
+        /* Skip ID mark (we know it's a AESLANIER5_RECORD_SEPARATOR). */
+
+        readRawBits(SECTOR_PATTERN.length());
+
+        const auto& rawbits = readRawBits(AESLANIER5_RECORD_SIZE * 16);
+        const auto& bytes =
+            decodeFmMfm(rawbits).slice(0, AESLANIER5_RECORD_SIZE);
+        const auto& reversed = bytes.reverseBits();
+
+        uint8_t encodedTrack = reversed[0];
+        uint8_t encodedSector = reversed[1];
+
+        _sector->logicalTrack = encodedTrack >> 1;
+        _sector->logicalSide = 0;
+        _sector->logicalSector = encodedSector;
+
+        /* Check header 'checksum' (which seems far too simple to mean much). */
+
+        {
+            uint8_t wanted = reversed[2];
+            uint8_t got = reversed[0] + reversed[1];
+            if (wanted != got)
+                return;
+        }
+
+        /* Check data checksum, which also includes the header and is
+         * significantly better. */
+
+        _sector->data = reversed.slice(3, AESLANIER5_SECTOR_LENGTH);
+        uint8_t wanted, got;
+        ByteReader br(_sector->data);
+        if ((encodedSector == 0) || (encodedSector == 8))
+        {
+            wanted = br.seek(17).read_8() + br.seek(150).read_8();
+            got = sumBytes(_sector->data.slice(0, 17)) + sumBytes(_sector->data.slice(18, 132));
+        }
+        else
+        {
+            wanted = br.seek(150).read_8();
+            got = sumBytes(_sector->data.slice(0, AESLANIER5_SECTOR_LENGTH-1));
+        }
+        _sector->status = (wanted == got) ? Sector::OK : Sector::BAD_CHECKSUM;
+    }
+};
+
+std::unique_ptr<Decoder> createAesLanier5Decoder(const DecoderProto& config)
+{
+    return std::unique_ptr<Decoder>(new AesLanier5Decoder(config));
+}

arch/arch.cc

@@ -4,6 +4,7 @@
 #include "lib/config/config.h"
 #include "arch/agat/agat.h"
 #include "arch/aeslanier/aeslanier.h"
+#include "arch/aeslanier5/aeslanier5.h"
 #include "arch/amiga/amiga.h"
 #include "arch/apple2/apple2.h"
 #include "arch/brother/brother.h"
@@ -70,6 +71,7 @@ std::unique_ptr<Decoder> Arch::createDecoder(const DecoderProto& config)
         decoders = {
             {DecoderProto::kAgat,       createAgatDecoder       },
             {DecoderProto::kAeslanier,  createAesLanierDecoder  },
+            {DecoderProto::kAeslanier5, createAesLanier5Decoder  },
             {DecoderProto::kAmiga,      createAmigaDecoder      },
             {DecoderProto::kApple2,     createApple2Decoder     },
             {DecoderProto::kBrother,    createBrotherDecoder    },

arch/build.py

@@ -5,6 +5,7 @@ proto(
     name="proto",
     srcs=[
         "./aeslanier/aeslanier.proto",
+        "./aeslanier5/aeslanier5.proto",
         "./agat/agat.proto",
         "./amiga/amiga.proto",
         "./apple2/apple2.proto",
@@ -36,6 +37,7 @@ cxxlibrary(
     srcs=[
         "./arch.cc",
         "./aeslanier/decoder.cc",
+        "./aeslanier5/decoder.cc",
         "./agat/agat.cc",
         "./agat/decoder.cc",
         "./agat/encoder.cc",
@@ -83,6 +85,7 @@ cxxlibrary(
         "arch/f85/f85.h": "./f85/f85.h",
         "arch/mx/mx.h": "./mx/mx.h",
         "arch/aeslanier/aeslanier.h": "./aeslanier/aeslanier.h",
+        "arch/aeslanier5/aeslanier5.h": "./aeslanier5/aeslanier5.h",
         "arch/northstar/northstar.h": "./northstar/northstar.h",
         "arch/brother/data_gcr.h": "./brother/data_gcr.h",
         "arch/brother/brother.h": "./brother/brother.h",

doc/disk-aeslanier.md

@@ -31,13 +31,16 @@ based on what looks right. If anyone knows _anything_ about these disks,
 
 ## Options
 
-(no options)
+  - Format variants:
+      - `8`: use the format found on 8" disks
+      - `5`: use the format found on 5.25" disks
 
 ## Examples
 
 To read:
 
-  - `fluxengine read aeslanier -s drive:0 -o aeslanier.img`
+  - `fluxengine read aeslanier --8 -s drive:0 -o aeslanier.img`
+  - `fluxengine read aeslanier --5 -s drive:0 -o aeslanier.img`
 
 ## References
 

lib/data/fluxpattern.h

@@ -33,6 +33,11 @@ public:
 
     bool matches(const unsigned* intervals, FluxMatch& match) const override;
 
+    unsigned length() const
+    {
+        return _bits;
+    }
+
     unsigned intervals() const override
     {
         return _intervals.size();

lib/decoders/decoders.proto

@@ -2,6 +2,7 @@ syntax = "proto2";
 
 import "arch/agat/agat.proto";
 import "arch/aeslanier/aeslanier.proto";
+import "arch/aeslanier5/aeslanier5.proto";
 import "arch/amiga/amiga.proto";
 import "arch/apple2/apple2.proto";
 import "arch/brother/brother.proto";
@@ -22,7 +23,7 @@ import "arch/zilogmcz/zilogmcz.proto";
 import "lib/fluxsink/fluxsink.proto";
 import "lib/config/common.proto";
 
-//NEXT: 33
+//NEXT: 34
 message DecoderProto {
 	optional double pulse_debounce_threshold = 1 [default = 0.30,
 		(help) = "ignore pulses with intervals shorter than this, in fractions of a clock"];
@@ -37,6 +38,7 @@ message DecoderProto {
 
 	oneof format {
 		AesLanierDecoderProto aeslanier = 7;
+		AesLanier5DecoderProto aeslanier5 = 33;
 		AgatDecoderProto agat = 28;
 		AmigaDecoderProto amiga = 8;
 		Apple2DecoderProto apple2 = 13;

src/formats/aeslanier.textpb

@@ -14,6 +14,8 @@ of nearly £50,000 in 2018!).
 processing software off twin 5.25" drive units, but apparently other software
 was available.
 
+**Note:** the following is wrong and needs to be updated.
+
 The disk format is exceptionally weird. They used 77 track, 32 sector, single-sided
 _hard_ sectored disks, where there were multiple index holes,
 indicating to the hardware where the sectors start. The encoding scheme
@@ -46,21 +48,56 @@ image_writer {
 	type: IMAGETYPE_IMG
 }
 
-decoder {
-	aeslanier {}
-}
+option_group {
+	comment: "$formats"
 
-layout {
-	format_type: FORMATTYPE_80TRACK
-	tracks: 77
-	sides: 1
-	layoutdata {
-		sector_size: 256
-		physical {
-			start_sector: 0
-			count: 32
+	option {
+		name: '8'
+		comment: 'use the format found on 8" disks'
+		set_by_default: true
+
+		config {
+			decoder {
+				aeslanier {}
+			}
+
+			layout {
+				format_type: FORMATTYPE_80TRACK
+				tracks: 77
+				sides: 1
+				layoutdata {
+					sector_size: 256
+					physical {
+						start_sector: 0
+						count: 32
+					}
+				}
+			}
+		}
+	}
+
+	option {
+		name: '83'
+		comment: '83kB 5.25" 35-track 16-sector SSSD'
+
+		config {
+			decoder {
+				aeslanier5 {}
+			}
+
+			layout {
+				format_type: FORMATTYPE_40TRACK
+				tracks: 35
+				sides: 1
+				layoutdata {
+					sector_size: 150
+					physical {
+						start_sector: 0
+						count: 16
+						skew: 3
+					}
+				}
+			}
 		}
 	}
 }
-
-

src/gui/fluxviewercontrol.cc

@@ -246,12 +246,13 @@ void FluxViewerControl::OnPaint(wxPaintEvent&)
             dc.SetTextForeground(*wxBLACK);
             for (auto& sector : trackdata->sectors)
             {
-                nanoseconds_t sr = sector->dataEndTime;
-                if (!sr)
-                    sr = sector->headerEndTime;
+                nanoseconds_t tl = sector->headerStartTime;
+                nanoseconds_t tr = sector->dataEndTime;
+                if (!tl && !sector->headerEndTime)
+                    tl = sector->dataStartTime;
 
-                int sp = sector->headerStartTime / _nanosecondsPerPixel;
-                int sw = (sr - sector->headerStartTime) / _nanosecondsPerPixel;
+                int sp = tl / _nanosecondsPerPixel;
+                int sw = (tr - tl) / _nanosecondsPerPixel;
 
                 wxRect rect = {x + sp, t1y - ch2, sw, ch};
                 bool hovered = rect.Contains(_mouseX, _mouseY);