IMG.CFG: New per-track parameter "img_bps"

Specifies bytes occupied per sector in the IMG image file.

Allows padding of short sectors for uniformly-indexed fiels.

Refs #751

Author: keirf

examples/IMG.CFG

@@ -73,6 +73,11 @@ bps = 512
 # The list is comma separated; no white space allowed.
 # bps = 512,512,512,512,512,512,512,512,256
 
+# Bytes per sector within the IMG file. Smaller sectors will be padded.
+# The default is 0: Sectors occupy precisely their data size; No padding.
+# Supported values: 0, 128, 256, 512, 1024, 2048, 4096, 8192.
+# img_bps = 0
+
 # ID of first sector on each track (0-255). Default is 1.
 # Numbers may be expressed in hexadecimal with 0x prefix (eg. 0xab).
 # id = 1

inc/floppy.h

@@ -91,6 +91,7 @@ struct raw_trk {
     uint16_t sec_off;
     uint16_t data_rate;
     uint16_t rpm;
+    uint16_t img_bps; /* could squeeze this field into uint8_t or bitfield */
     int16_t gap_2, gap_3, gap_4a;
     uint8_t interleave, cskew, hskew;
     uint8_t has_iam:1, is_fm:1, invert_data:1;

src/image/img.c

@@ -237,6 +237,7 @@ static bool_t raw_type_open(struct image *im, const struct raw_type *type)
 
 struct tag_layout {
     struct simple_layout s;
+    uint16_t img_bps;
     uint8_t no[256];
 };
 
@@ -262,6 +263,7 @@ static void tag_add_layout(
     trk->cskew = layout->s.cskew;
     trk->hskew = layout->s.hskew;
     trk->head = layout->s.head;
+    trk->img_bps = layout->img_bps;
 
     sec = &im->img.sec_info_base[trk->sec_off];
     for (i = 0; i < layout->s.nr_sectors; i++) {
@@ -280,6 +282,7 @@ static bool_t tag_open(struct image *im, char *tag)
         IMGCFG_step,
         IMGCFG_secs,
         IMGCFG_bps,
+        IMGCFG_img_bps,
         IMGCFG_id,
         IMGCFG_h,
         IMGCFG_mode,
@@ -303,6 +306,7 @@ static bool_t tag_open(struct image *im, char *tag)
         [IMGCFG_step] = { "step" },
         [IMGCFG_secs] = { "secs" },
         [IMGCFG_bps] = { "bps" },
+        [IMGCFG_img_bps] = { "img_bps" },
         [IMGCFG_id] = { "id" },
         [IMGCFG_h] = { "h" },
         [IMGCFG_mode] = { "mode" },
@@ -380,6 +384,7 @@ static bool_t tag_open(struct image *im, char *tag)
                 match = active;
                 reset_all_params(im);
                 heap->d_layout.s = dfl_simple_layout;
+                heap->d_layout.img_bps = 0;
                 memset(heap->d_layout.no, ~0, sizeof(heap->d_layout.no));
                 heap->t_layout = heap->d_layout;
                 nr_t = 0;
@@ -451,6 +456,9 @@ static bool_t tag_open(struct image *im, char *tag)
             memset(&heap->t_layout.no[i], no, sizeof(heap->t_layout.no)-i);
             break;
             }
+        case IMGCFG_img_bps:
+            heap->t_layout.img_bps = strtol(opts.arg, NULL, 0);
+            break;
         case IMGCFG_id:
             heap->t_layout.s.base[0] = strtol(opts.arg, NULL, 0);
             break;
@@ -1763,10 +1771,14 @@ static void raw_seek_track(
                 if (file_idx(im, i, j) >= idx)
                     continue;
                 trk = &im->img.trk_info[im->img.trk_map[i*im->nr_sides + j]];
-                sec = &im->img.sec_info_base[trk->sec_off];
-                for (k = 0; k < trk->nr_sectors; k++) {
-                    off += sec_sz(sec->n);
-                    sec++;
+                if (trk->img_bps != 0) {
+                    off += trk->nr_sectors * trk->img_bps;
+                } else {
+                    sec = &im->img.sec_info_base[trk->sec_off];
+                    for (k = 0; k < trk->nr_sectors; k++) {
+                        off += sec_sz(sec->n);
+                        sec++;
+                    }
                 }
             }
         }
@@ -2041,9 +2053,12 @@ static bool_t raw_write_track(struct image *im)
 
             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 = off = 0; i < sec_nr; i++)
+                for (i = 0; i < sec_nr; i++)
                     off += sec_sz(sec++->n);
             }
             F_lseek(&im->fp, im->img.trk_off + off);
@@ -2101,7 +2116,7 @@ static void raw_dump_info(struct image *im)
            im->ticks_per_cell, im->write_bc_ticks, trk->has_iam);
     printk(" interleave: %u, cskew %u, hskew %u\n ",
            trk->interleave, trk->cskew, trk->hskew);
-    printk(" file-layout: %x\n", im->img.layout);
+    printk(" file_layout: %x, img_bps: %u\n", im->img.layout, trk->img_bps);
     for (i = 0; i < trk->nr_sectors; i++) {
         struct raw_sec *sec = &im->img.sec_info[im->img.sec_map[i]];
         int hd = trk->head ? trk->head-1 : im->cur_track&1;
@@ -2114,19 +2129,22 @@ static void raw_dump_info(struct image *im)
 static void img_fetch_data(struct image *im)
 {
     struct image_buf *rd = &im->bufs.read_data;
+    struct raw_trk *trk = im->img.trk;
     uint8_t *buf = rd->p;
     struct raw_sec *sec, *s;
     uint8_t sec_i;
     uint16_t off, len;
 
-    if ((im->img.trk->nr_sectors == 0) || (rd->prod != rd->cons))
+    if ((trk->nr_sectors == 0) || (rd->prod != rd->cons))
         return;
 
     sec_i = im->img.sec_map[im->img.trk_sec];
     sec = &im->img.sec_info[sec_i];
 
     if (im->img.file_sec_offsets) {
         off = im->img.file_sec_offsets[sec_i];
+    } else if (trk->img_bps != 0) {
+        off = sec_i * trk->img_bps;
     } else {
         off = 0;
         for (s = im->img.sec_info; s != sec; s++)
@@ -2143,7 +2161,7 @@ static void img_fetch_data(struct image *im)
         im->img.rd_sec_pos++;
     } else {
         im->img.rd_sec_pos = 0;
-        if (++im->img.trk_sec >= im->img.trk->nr_sectors)
+        if (++im->img.trk_sec >= trk->nr_sectors)
             im->img.trk_sec = 0;
     }