FF.CFG: Get rid of single quotes around example config values

Single quotes are not accepted by the parser, so the extra punctuation
is unnecessary and confusing verbiage.

Refs #865

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
 
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - name: Set environment variables
       id: vars
@@ -43,7 +43,7 @@ jobs:
         mv flashfloppy-$VER.zip _cidist/
 
     - name: Upload artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: FlashFloppy.CI.${{ steps.vars.outputs.sha_short }}
         path: _cidist

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
 
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - name: Set environment variables
       id: vars

RELEASE_NOTES

@@ -3,6 +3,11 @@
 ** Keir Fraser <keir.xen@gmail.com>
 ************************************
 
+** v3.42 - 11 January 2024
+ - HFEv3: Various read/write improvements
+ - WDATA: Merge short write pulses, and apply de-jitter/precomp
+ - IMG, EDSK: Stream large sector writes to flash
+
 ** v3.41 - 14 July 2023
  - AT32F415: Fix timer handling since clock speed increase (v3.39).
  - LCD: Faster power-on initialisation. Don't wait for display to clear.

examples/FF.CFG

@@ -13,11 +13,11 @@
 # jc: Specified by jumper JC (open: shugart, closed: ibmpc)
 # shugart: P2=DSKCHG, P34=RDY (Amiga, Atari ST, many others)
 # ibmpc: P2=unused, P34=DSKCHG (IBM PC interface)
-# ibmpc-hdout: P2=HD_OUT, P34=DSKCHG (not generally needed: prefer 'ibmpc')
+# ibmpc-hdout: P2=HD_OUT, P34=DSKCHG (not generally needed: prefer ibmpc)
 # jppc: P2=unused, P34=RDY (Japanese PC standard)
-# jppc-hdout: P2=HD_OUT, P34=RDY (Japanese PC alternate: prefer 'jppc')
-# akai-s950: Legacy alias of 'jppc-hdout', previously used for Akai S950
-# amiga: P2=DSKCHG, P34=DRIVE_ID (not generally needed: prefer 'shugart')
+# jppc-hdout: P2=HD_OUT, P34=RDY (Japanese PC alternate: prefer jppc)
+# akai-s950: Legacy alias of jppc-hdout, previously used for Akai S950
+# amiga: P2=DSKCHG, P34=DRIVE_ID (not generally needed: prefer shugart)
 interface = jc
 
 # Host platform: Improves image-format detection for generic types such as IMG
@@ -172,9 +172,9 @@ twobutton-action = zero
 # Input sensor type at the rotary-encoder inputs (pins PC10 and PC11):
 #  [full | half | quarter]:
 #    Rotary encoder, identified by fraction of a Gray-code cycle performed
-#    per detent/click. If default value ('full') requires multiple
-#    clicks/detents to move position then change to 'half' (if 2 clicks
-#    per move) or 'quarter' (if 4 clicks).
+#    per detent/click. If default value (full) requires multiple
+#    clicks/detents to move position then change to half (if 2 clicks
+#    per move) or quarter (if 4 clicks).
 #  [trackball]:
 #    Blackberry-style trackball (eg. using Hall-effect sensors).
 #  [buttons]:
@@ -220,15 +220,15 @@ oled-font = 6x13
 oled-contrast = 143
 
 # Text height and arrangement on LCD/OLED and on OSD, respectively.
-# 'default', or a comma-separated list (one entry per LCD/OLED row, top down).
-# Each list item is a digit plus optional height specifier: <content-row>[d]
-#  content-row: '0-3' = specified content row, '7' = blank
+# Comma-separated list, one entry per display row, top down.
+# Each list item is a digit plus optional height specifier: [0-7][d]
+#  content-row: 0-3 = specified content, 7 = blank
 #    0: Current image name
 #    1: Status
 #    2: Image/Volume info
 #    3: Current subfolder name
-#  height specifier: 'd' = double height (32px, OLED only; ignored for LCD)
-# 'default' depends on display, eg.: oled-128x32='0,1' ; oled-128x64='3,0d,1'
+#  height-specifier: d = double height (32px, OLED only; ignored for LCD)
+# Default depends on display, eg.: oled-128x32 -> 0,1 ; oled-128x64 -> 3,0d,1
 # Values: [0-7][d] | default
 display-order = default
 osd-display-order = default

examples/Host/GRiD/IMG.CFG

@@ -0,0 +1,17 @@
+## IMG.CFG for machines produced by GRiD Systems Corp.
+
+# NOTE: The tags match on filesize alone. If you wish to define an explicit
+# tagname match, you can for example add 'flex' to the square-bracketed tags
+# to limit matches to filenames of the form *.flex.{img,ima,dsk}
+
+# 360k 40-cylinder DS/DD format used by GRiD Compass
+[::368640]
+cyls = 40
+heads = 2
+bps = 512
+secs = 9
+mode = mfm
+interleave = 5
+id = 1
+tracks = 0-39.1
+  id = 10

examples/Host/Sinclair_ZX_Spectrum/Sandy_FDD2/IMG.CFG

@@ -0,0 +1,45 @@
+## IMG.CFG for the Sandy FDD2 interface.
+
+# Sandy FDD2 is a clone of the FDC-1 by Technology Research Ltd.
+# Using a 1771 controller chip, it supports single-density (FM) recording
+# only, unlike the later Beta Disk interfaces.
+
+# *.ss40.img: Single-sided 40 cylinders.
+[ss40::102400]
+cyls = 40
+heads = 1
+secs = 10
+bps = 256
+mode = fm
+interleave = 2
+
+# *.ss80.img: Single-sided 80 cylinders.
+[ss80::204800]
+cyls = 80
+heads = 1
+secs = 10
+bps = 256
+mode = fm
+interleave = 2
+
+# *.ds40.img: Double-sided 40 cylinders.
+[ds40::204800]
+cyls = 40
+heads = 2
+secs = 10
+bps = 256
+mode = fm
+interleave = 2
+tracks = 0-39.1
+  h = 0
+
+# *.ds80.img: Double-sided 80 cylinders.
+[ds80::409600]
+cyls = 80
+heads = 2
+secs = 10
+bps = 256
+mode = fm
+interleave = 2
+tracks = 0-79.1
+  h = 0

inc/util.h

@@ -69,6 +69,8 @@ int snprintf(char *str, size_t size, const char *format, ...)
 #define htobe16(x) _rev16(x)
 #define htobe32(x) _rev32(x)
 
+uint32_t udiv64(uint64_t dividend, uint32_t divisor);
+
 /* Arena-based memory allocation */
 void *arena_alloc(uint32_t sz);
 uint32_t arena_total(void);

src/floppy_generic.c

@@ -674,7 +674,7 @@ static void IRQ_wdata_dma(void)
     bc_dat = image->write_bc_window;
     for (cons = dma_wr->cons; cons != prod; cons = (cons+1) & buf_mask) {
         next = dma_wr->buf[cons];
-        curr = (uint16_t)(next - prev) - (cell >> 1);
+        curr = (int16_t)(next - prev) - (cell >> 1);
         if (unlikely(curr < 0)) {
             /* Runt flux, much shorter than bitcell clock. Merge it forward. */
             continue;
@@ -686,6 +686,8 @@ static void IRQ_wdata_dma(void)
             if (!(bc_prod&31))
                 bc_buf[((bc_prod-1) / 32) & bc_bufmask] = htobe32(bc_dat);
         }
+        curr += cell >> 1; /* remove the 1/2-cell bias */
+        prev -= curr >> 2; /* de-jitter/precomp: carry 1/4 of phase error */
         bc_dat = (bc_dat << 1) | 1;
         bc_prod++;
         switch (sync) {

src/image/adf.c

@@ -41,6 +41,7 @@ static bool_t adf_open(struct image *im)
     im->tracklen_bc = DD_TRACKLEN_BC;
     im->ticks_per_cell = ((sampleclk_stk(im->stk_per_rev) * 16u)
                           / im->tracklen_bc);
+    im->write_bc_ticks = im->ticks_per_cell / 16u;
 
     im->nr_cyls = f_size(&im->fp) / (2 * 11 * 512);
 

src/image/dsk.c

@@ -271,15 +271,17 @@ static void dsk_setup_track(
     im->cur_ticks = im->cur_bc * im->ticks_per_cell;
     im->ticks_since_flux = 0;
 
-    decode_off = calc_start_pos(im);
-
     rd->prod = rd->cons = 0;
     bc->prod = bc->cons = 0;
 
     if (start_pos) {
+        decode_off = calc_start_pos(im);
+
         image_read_track(im);
         bc->cons = decode_off * 16;
         *start_pos = start_ticks;
+    } else {
+        im->dsk.decode_pos = 0;
     }
 }
 
@@ -481,10 +483,9 @@ static bool_t dsk_write_track(struct image *im)
     unsigned int bufmask = (wr->len / 2) - 1;
     uint8_t *wrbuf = (uint8_t *)im->bufs.write_data.p + 512; /* skip DIB/TIB */
     uint32_t c = wr->cons / 16, p = wr->prod / 16;
-    unsigned int i;
+    unsigned int i, off;
     time_t t;
-    uint16_t crc, off;
-    uint8_t x;
+    uint16_t crc = im->dsk.crc;
 
     /* If we are processing final data then use the end index, rounded up. */
     barrier();
@@ -494,77 +495,103 @@ static bool_t dsk_write_track(struct image *im)
 
     while ((int16_t)(p - c) > 128) {
 
-        uint32_t sc = c;
+        if (im->dsk.decode_pos == 0) {
 
-        if (be16toh(buf[c++ & bufmask]) != 0x4489)
-            continue;
-        if ((x = mfmtobin(buf[c & bufmask])) == 0xa1)
-            continue;
-        c++;
+            uint8_t x;
 
-        switch (x) {
+            if (be16toh(buf[c++ & bufmask]) != 0x4489)
+                continue;
+            if ((x = mfmtobin(buf[c & bufmask])) == 0xa1)
+                continue;
+            c++;
 
-        case 0xfe: /* IDAM */
-            for (i = 0; i < 3; i++)
-                wrbuf[i] = 0xa1;
-            wrbuf[i++] = x;
-            for (; i < 10; i++)
-                wrbuf[i] = mfmtobin(buf[c++ & bufmask]);
-            crc = crc16_ccitt(wrbuf, i, 0xffff);
-            if (crc != 0) {
-                log("IDAM Bad CRC: %04x, %02x\n", crc, wrbuf[6]);
+            switch (x) {
+
+            case 0xfe: /* IDAM */
+                for (i = 0; i < 3; i++)
+                    wrbuf[i] = 0xa1;
+                wrbuf[i++] = x;
+                for (; i < 10; i++)
+                    wrbuf[i] = mfmtobin(buf[c++ & bufmask]);
+                crc = crc16_ccitt(wrbuf, i, 0xffff);
+                if (crc != 0) {
+                    log("IDAM Bad CRC: %04x, %02x\n", crc, wrbuf[6]);
+                    break;
+                }
+                /* Convert logical sector number -> rotational number. */
+                for (i = 0; i < tib->nr_secs; i++)
+                    if (wrbuf[6] == tib->sib[i].r)
+                        break;
+                im->dsk.write_sector = i;
+                if (im->dsk.write_sector >= tib->nr_secs) {
+                    log("IDAM Bad Sector: %02x\n", wrbuf[6]);
+                    im->dsk.write_sector = -2;
+                }
+                break;
+
+            case 0xfb: /* DAM */
+                im->dsk.decode_pos = 1;
+                im->dsk.decode_data_pos = 0;
                 break;
             }
-            /* Convert logical sector number -> rotational number. */
-            for (i = 0; i < tib->nr_secs; i++)
-                if (wrbuf[6] == tib->sib[i].r)
-                    break;
-            im->dsk.write_sector = i;
-            if (im->dsk.write_sector >= tib->nr_secs) {
-                log("IDAM Bad Sector: %02x\n", wrbuf[6]);
-                im->dsk.write_sector = -2;
-            }
-            break;
 
-        case 0xfb: /* DAM */ {
-            unsigned int nr, todo, sec_sz;
+        } else {
+
+            /* Data record, shy address mark */
+            unsigned int sec_sz;
             int sec_nr = im->dsk.write_sector;
 
+            ASSERT(im->dsk.decode_pos == 1);
+
             if (sec_nr < 0) {
-                if (sec_nr == -1)
+                if (sec_nr == -1) {
                     sec_nr = dsk_find_first_write_sector(im, write, tib);
+                    im->dsk.write_sector = sec_nr;
+                }
                 if (sec_nr < 0) {
                     log("DAM Unknown\n");
-                    goto dam_out;
+                    goto data_complete;
                 }
             }
 
             sec_sz = data_sz(&tib->sib[sec_nr]);
-            if ((int16_t)(p - c) < (sec_sz + 2)) {
-                c = sc;
-                goto out;
-            }
-
-            crc = MFM_DAM_CRC;
-
-            log("Write %u[%02x]/%u... ",
-                sec_nr, tib->sib[sec_nr].r, tib->nr_secs);
-            t = time_now();
 
             for (i = off = 0; i < sec_nr; i++)
                 off += tib->sib[i].actual_length;
-            F_lseek(&im->fp, im->dsk.trk_off + off);
+            off += im->dsk.trk_off;
+            off += im->dsk.decode_data_pos;
 
-            for (todo = sec_sz; todo != 0; todo -= nr) {
-                nr = min_t(unsigned int, todo, CHUNK_SIZE);
+            if (im->dsk.decode_data_pos < sec_sz) {
+                unsigned int nr = sec_sz - im->dsk.decode_data_pos;
+                nr = min_t(unsigned int, nr, CHUNK_SIZE - (off & 511));
+                if ((int16_t)(p - c) < nr)
+                    break;
+
+                if (!im->dsk.decode_data_pos) {
+                    crc = MFM_DAM_CRC;
+                    log("Write %d[%02x]/%u...",
+                            sec_nr, tib->sib[sec_nr].r, tib->nr_secs);
+                    F_lseek(&im->fp, off);
+                }
+
+                t = time_now();
                 mfm_ring_to_bin(buf, bufmask, c, wrbuf, nr);
                 c += nr;
                 crc = crc16_ccitt(wrbuf, nr, crc);
                 F_write(&im->fp, wrbuf, nr, NULL);
+                printk(" %u us", time_diff(t, time_now()) / TIME_MHZ);
+                im->dsk.decode_data_pos += nr;
+                if (im->dsk.decode_data_pos < sec_sz)
+                    printk("...");
+                else
+                    printk("\n");
             }
 
-            printk("%u us\n", time_diff(t, time_now()) / TIME_MHZ);
+            if (im->dsk.decode_data_pos < sec_sz)
+                continue;
 
+            if ((int16_t)(p - c) < 2)
+                break;
             mfm_ring_to_bin(buf, bufmask, c, wrbuf, 2);
             c += 2;
             crc = crc16_ccitt(wrbuf, 2, crc);
@@ -573,15 +600,14 @@ static bool_t dsk_write_track(struct image *im)
                     crc, sec_nr, tib->sib[sec_nr].r);
             }
 
-            dam_out:
+        data_complete:
             im->dsk.write_sector = -2;
-            break;
-        }
+            im->dsk.decode_pos = 0;
 
         }
     }
 
-out:
+    im->dsk.crc = crc;
     wr->cons = c * 16;
     return flush;
 }

src/image/hfe.c

@@ -128,9 +128,10 @@ static void hfe_seek_track(struct image *im, uint16_t track)
     im->hfe.trk_off = le16toh(thdr.offset);
     im->hfe.trk_len = le16toh(thdr.len) / 2;
     im->tracklen_bc = im->hfe.trk_len * 8;
-    /* Opcodes in v3 make it difficult to predict the track's length. Keep the
-     * previous track's value if this isn't the first seek. */
-    if (!(im->hfe.is_v3 && im->tracklen_ticks)) {
+    if (im->hfe.is_v3 && im->tracklen_ticks) {
+        /* Opcodes in v3 make it difficult to predict the track's length. Keep
+         * the previous track's value since this isn't the first seek. */
+    } else {
         im->tracklen_ticks = im->tracklen_bc * im->ticks_per_cell;
         im->stk_per_rev = stk_sampleclk(im->tracklen_ticks / 16);
     }
@@ -152,13 +153,16 @@ static void hfe_setup_track(
         hfe_seek_track(im, track);
 
     start_ticks = start_pos ? *start_pos : get_write(im, im->wr_cons)->start;
-    im->cur_bc = (start_ticks * 16) / im->ticks_per_cell;
-    if (im->cur_bc >= im->tracklen_bc)
-        im->cur_bc = 0;
-    im->cur_ticks = im->cur_bc * im->ticks_per_cell;
-    im->ticks_since_flux = 0;
 
-    start_ticks = im->cur_ticks / 16;
+    im->cur_ticks = start_ticks * 16;
+    im->cur_bc = udiv64((uint64_t)im->cur_ticks * im->tracklen_bc,
+                        im->tracklen_ticks);
+    if ((im->cur_ticks >= im->tracklen_ticks) ||
+        (im->cur_bc >= im->tracklen_bc)) {
+        im->cur_ticks = 0;
+        im->cur_bc = 0;
+    }
+    im->ticks_since_flux = 0;
 
     rd->prod = rd->cons = 0;
     bc->prod = bc->cons = 0;
@@ -172,10 +176,16 @@ static void hfe_setup_track(
         im->hfe.trk_pos = (im->cur_bc/8) & ~255;
         image_read_track(im);
         bc->cons = im->cur_bc & 2047;
-        *start_pos = start_ticks;
     } else {
         /* Write mode. */
         im->hfe.trk_pos = im->cur_bc / 8;
+        if (im->hfe.is_v3) {
+            /* Provide context to the write to avoid corrupting an opcode. */
+            if ((im->hfe.trk_pos & 255) == 0 && im->hfe.trk_pos != 0)
+                im->hfe.trk_pos--;
+            else if ((im->hfe.trk_pos & 255) == 1)
+                im->hfe.trk_pos = (im->hfe.trk_pos+1) % im->hfe.trk_len;
+        }
         im->hfe.write.start = im->hfe.trk_pos;
         im->hfe.write.wrapped = FALSE;
         im->hfe.write_batch.len = 0;
@@ -270,6 +280,7 @@ static uint16_t hfe_rdata_flux(struct image *im, uint16_t *tbuf, uint16_t nr)
                 x = _rbit32(bc_b[(bc_c/8) & bc_mask]) >> 24;
                 im->ticks_per_cell = ticks_per_cell = 
                     (sampleclk_us(2) * 16 * x) / 72;
+                im->write_bc_ticks = ticks_per_cell / 16;
                 bc_c += 8;
                 im->cur_bc += 8;
                 continue;
@@ -330,6 +341,7 @@ static bool_t hfe_write_track(struct image *im)
     unsigned int bufmask = wr->len - 1;
     uint8_t *w, *wrbuf = im->bufs.write_data.p;
     uint32_t i, space, c = wr->cons / 8, p = wr->prod / 8;
+    bool_t is_v3 = im->hfe.is_v3;
     bool_t writeback = FALSE;
     time_t t;
 
@@ -381,11 +393,62 @@ static bool_t hfe_write_track(struct image *im)
             + (im->cur_track & 1) * 256
             + batch_off - im->hfe.write_batch.off
             + (off & 255);
-        for (i = 0; i < nr; i++)
-            *w++ = _rbit32(buf[c++ & bufmask]) >> 24;
+
+        i = 0;
+
+        if (is_v3 && off == im->hfe.write.start && off != 0) {
+            /* Avoid starting write in the middle of an opcode. */
+            if (w[-2] == OP_SkipBits) {
+                i++;
+            } else {
+                switch (w[-1]) {
+                case OP_SkipBits:
+                    i += 2;
+                    break;
+                case OP_Bitrate:
+                    i++;
+                    break;
+                default:
+                    break;
+                }
+            }
+        }
+
+        while (i < nr) {
+            if (is_v3 && (w[i] & 0xf) == 0xf) {
+                switch (w[i]) {
+                case OP_SkipBits:
+                    /* Keep the write byte-aligned. This changes the length of
+                     * the track by 8+skip bitcells, but overwriting OP_SkipBits
+                     * should be rare. */
+                    w[i++] = OP_Nop;
+                    continue;
+
+                case OP_Bitrate:
+                    /* Assume bitrate does not change significantly for the
+                     * entire track, and write_bc_ticks already adjusted when
+                     * reading. */
+                    i += 2;
+                    continue;
+
+                case OP_Nop:
+                case OP_Index:
+                default:
+                    /* Preserve opcode. But making sure not to write past end of
+                     * buffer. */
+                    i++;
+                    continue;
+
+                case OP_Rand:
+                    /* Replace with data. */
+                    break;
+                }
+            }
+            w[i++] = _rbit32(buf[c++ & bufmask]) >> 24;
+        }
         im->hfe.write_batch.dirty = TRUE;
 
-        im->hfe.trk_pos += nr;
+        im->hfe.trk_pos += i; /* i may be larger than nr due to opcodes. */
         if (im->hfe.trk_pos >= im->hfe.trk_len) {
             ASSERT(im->hfe.trk_pos == im->hfe.trk_len);
             im->hfe.trk_pos = 0;

src/image/img.c

@@ -1876,15 +1876,17 @@ static void raw_setup_track(
     im->cur_ticks = im->cur_bc * im->ticks_per_cell;
     im->ticks_since_flux = 0;
 
-    decode_off = calc_start_pos(im);
-
     rd->prod = rd->cons = 0;
     bc->prod = bc->cons = 0;
 
     if (start_pos) {
+        decode_off = calc_start_pos(im);
+
         image_read_track(im);
         bc->cons = decode_off * 16;
         *start_pos = start_ticks;
+    } else {
+        im->img.decode_pos = 0;
     }
 }
 
@@ -1963,8 +1965,8 @@ static bool_t raw_write_track(struct image *im)
     struct raw_sec *sec;
     unsigned int i, off;
     time_t t;
-    uint16_t crc;
-    uint8_t idam_r, x;
+    uint16_t crc = im->img.crc;
+    uint8_t idam_r;
 
     /* If we are processing final data then use the end index, rounded up. */
     barrier();
@@ -1974,110 +1976,137 @@ static bool_t raw_write_track(struct image *im)
 
     while ((int16_t)(p - c) > 128) {
 
-        uint32_t sc = c;
+        if (im->img.decode_pos == 0) {
 
-        if (im->sync == SYNC_fm) {
+            uint8_t x;
 
-            uint16_t sync;
-            if (buf[c++ & bufmask] != 0xaaaa)
-                continue;
-            sync = buf[c & bufmask];
-            if (mfmtobin(sync >> 1) != FM_SYNC_CLK)
-                continue;
-            x = mfmtobin(sync);
-            c++;
-
-        } else { /* MFM */
-
-            if (be16toh(buf[c++ & bufmask]) != 0x4489)
-                continue;
-            if ((x = mfmtobin(buf[c & bufmask])) == 0xa1)
-                continue;
-            c++;
-
-        }
-
-        switch (x) {
-
-        case 0xfe: /* IDAM */
             if (im->sync == SYNC_fm) {
-                wrbuf[0] = x;
-                for (i = 1; i < 7; i++)
-                    wrbuf[i] = mfmtobin(buf[c++ & bufmask]);
-                idam_r = wrbuf[3];
+
+                uint16_t sync;
+                if (buf[c++ & bufmask] != 0xaaaa)
+                    continue;
+                sync = buf[c & bufmask];
+                if (mfmtobin(sync >> 1) != FM_SYNC_CLK)
+                    continue;
+                x = mfmtobin(sync);
+                c++;
+
             } else { /* MFM */
-                for (i = 0; i < 3; i++)
-                    wrbuf[i] = 0xa1;
-                wrbuf[i++] = x;
-                for (; i < 10; i++)
-                    wrbuf[i] = mfmtobin(buf[c++ & bufmask]);
-                idam_r = wrbuf[6];
+
+                if (be16toh(buf[c++ & bufmask]) != 0x4489)
+                    continue;
+                if ((x = mfmtobin(buf[c & bufmask])) == 0xa1)
+                    continue;
+                c++;
+
             }
-            crc = crc16_ccitt(wrbuf, i, 0xffff);
-            if (crc != 0) {
-                log("IDAM Bad CRC: %04x, %u\n", crc, idam_r);
+
+            switch (x) {
+
+            case 0xfe: /* IDAM */
+                if (im->sync == SYNC_fm) {
+                    wrbuf[0] = x;
+                    for (i = 1; i < 7; i++)
+                        wrbuf[i] = mfmtobin(buf[c++ & bufmask]);
+                    idam_r = wrbuf[3];
+                } else { /* MFM */
+                    for (i = 0; i < 3; i++)
+                        wrbuf[i] = 0xa1;
+                    wrbuf[i++] = x;
+                    for (; i < 10; i++)
+                        wrbuf[i] = mfmtobin(buf[c++ & bufmask]);
+                    idam_r = wrbuf[6];
+                }
+                crc = crc16_ccitt(wrbuf, i, 0xffff);
+                if (crc != 0) {
+                    log("IDAM Bad CRC: %04x, %u\n", crc, idam_r);
+                    break;
+                }
+                /* Search by sector id for this sector's logical order. */
+                for (i = 0, sec = im->img.sec_info;
+                     (i < trk->nr_sectors) && (sec->r != idam_r);
+                     i++, sec++)
+                    continue;
+                im->img.write_sector = i;
+                if (i >= trk->nr_sectors) {
+                    log("IDAM Bad Sector: %02x\n", idam_r);
+                    im->img.write_sector = -2;
+                }
+                break;
+
+            case 0xfb: /* DAM */
+                im->img.decode_pos = 1;
+                im->img.decode_data_pos = 0;
                 break;
             }
-            /* Search by sector id for this sector's logical order. */
-            for (i = 0, sec = im->img.sec_info;
-                 (i < trk->nr_sectors) && (sec->r != idam_r);
-                 i++, sec++)
-                continue;
-            im->img.write_sector = i;
-            if (i >= trk->nr_sectors) {
-                log("IDAM Bad Sector: %02x\n", idam_r);
-                im->img.write_sector = -2;
-            }
-            break;
 
-        case 0xfb: /* DAM */ {
-            unsigned int nr, todo, sec_sz;
+        } else {
+
+            /* Data record, shy address mark */
+            unsigned int sec_sz;
             int sec_nr = im->img.write_sector;
 
+            ASSERT(im->img.decode_pos == 1);
+
             if (sec_nr < 0) {
-                if (sec_nr == -1)
+                if (sec_nr == -1) {
                     sec_nr = raw_find_first_write_sector(im, write, trk);
+                    im->img.write_sector = sec_nr;
+                }
                 if (sec_nr < 0) {
                     log("DAM Unknown\n");
-                    goto dam_out;
+                    goto data_complete;
                 }
             }
 
             sec_sz = sec_sz(im->img.sec_info[sec_nr].n);
-            if ((int16_t)(p - c) < (sec_sz + 2)) {
-                c = sc;
-                goto out;
-            }
-
-            crc = (im->sync == SYNC_fm) ? FM_DAM_CRC : MFM_DAM_CRC;
 
             sec = &im->img.sec_info[sec_nr];
-            log("Write %u[%02x]/%u... ", sec_nr, sec->r, trk->nr_sectors);
-            t = time_now();
 
             if (im->img.file_sec_offsets) {
                 off = im->img.file_sec_offsets[sec_nr];
             } else if (trk->img_bps != 0) {
                 off = sec_nr * trk->img_bps;
             } else {
-                off = 0;
                 sec = im->img.sec_info;
-                for (i = 0; i < sec_nr; i++)
+                for (i = off = 0; i < sec_nr; i++)
                     off += sec_sz(sec++->n);
             }
-            F_lseek(&im->fp, im->img.trk_off + off);
+            off += im->img.trk_off;
+            off += im->img.decode_data_pos;
 
-            for (todo = sec_sz; todo != 0; todo -= nr) {
-                nr = min_t(unsigned int, todo, CHUNK_SIZE);
+            if (im->img.decode_data_pos < sec_sz) {
+                unsigned int nr = sec_sz - im->img.decode_data_pos;
+                nr = min_t(unsigned int, nr, CHUNK_SIZE - (off & 511));
+                if ((int16_t)(p - c) < nr)
+                    break;
+
+                if (!im->img.decode_data_pos) {
+                    crc = (im->sync == SYNC_fm) ? FM_DAM_CRC : MFM_DAM_CRC;
+                    log("Write %u[%02x]/%u...",
+                            sec_nr, sec->r, trk->nr_sectors);
+                    F_lseek(&im->fp, off);
+                }
+
+                t = time_now();
                 mfm_ring_to_bin(buf, bufmask, c, wrbuf, nr);
                 c += nr;
                 crc = crc16_ccitt(wrbuf, nr, crc);
                 process_data(im, wrbuf, nr);
                 F_write(&im->fp, wrbuf, nr, NULL);
+                printk(" %u us", time_diff(t, time_now()) / TIME_MHZ);
+                im->img.decode_data_pos += nr;
+                if (im->img.decode_data_pos < sec_sz)
+                    printk("...");
+                else
+                    printk("\n");
             }
 
-            printk("%u us\n", time_diff(t, time_now()) / TIME_MHZ);
+            if (im->img.decode_data_pos < sec_sz)
+                continue;
 
+            if ((int16_t)(p - c) < 2)
+                break;
             mfm_ring_to_bin(buf, bufmask, c, wrbuf, 2);
             c += 2;
             crc = crc16_ccitt(wrbuf, 2, crc);
@@ -2085,15 +2114,14 @@ static bool_t raw_write_track(struct image *im)
                 log("Bad CRC: %04x, %u[%02x]\n", crc, sec_nr, sec->r);
             }
 
-            dam_out:
+        data_complete:
             im->img.write_sector = -2;
-            break;
-        }
+            im->img.decode_pos = 0;
 
         }
     }
 
-out:
+    im->img.crc = crc;
     wr->cons = c * 16;
     return flush;
 }

src/image/qd.c

@@ -33,7 +33,7 @@ static bool_t qd_open(struct image *im)
     im->qd.tb = 1;
     im->nr_cyls = 1;
     im->nr_sides = 1;
-    im->write_bc_ticks = sampleclk_us(4) + 66; /* 4.917us */
+    im->write_bc_ticks = sampleclk_ns(4917); /* 4.917us */
     im->ticks_per_cell = im->write_bc_ticks;
     im->sync = SYNC_none;
 

src/util.c

@@ -335,6 +335,18 @@ unsigned int popcount(uint32_t x)
     return (((x + (x >> 4)) & 0x0f0f0f0f) * 0x01010101) >> 24;
 }
 
+
+/* 64:32->32q division requiring 32:32->64 multiply. Cortex M3+ */
+uint32_t udiv64(uint64_t dividend, uint32_t divisor)
+{
+    uint32_t x, q = 0;
+    for (x = 1u<<31; x != 0; x >>= 1) {
+        if (((uint64_t)(q|x)*divisor) <= dividend)
+            q |= x;
+    }
+    return q;
+}
+
 /*
  * Local variables:
  * mode: C