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authorWilly Tarreau <w@1wt.eu>2020-02-24 22:23:51 +0100
committerJens Axboe <axboe@kernel.dk>2020-03-16 15:26:57 +0100
commit76dabe79605bebce6f34ca65c0e42e411e4ccb7b (patch)
treefd7356094acaf86264bfde1a697f9cb302bf941e /drivers/block/floppy.c
parentfloppy: cleanup: expand macro DRWE (diff)
downloadlinux-76dabe79605bebce6f34ca65c0e42e411e4ccb7b.tar.xz
linux-76dabe79605bebce6f34ca65c0e42e411e4ccb7b.zip
floppy: cleanup: expand the R/W / format command macros
Various macros were used to access raw_cmd for R/W or format commands without making it obvious that raw_cmd->cmd[] was used. Let's expand the macros to make this more obvious. Link: https://lore.kernel.org/r/20200224212352.8640-10-w@1wt.eu Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '')
-rw-r--r--drivers/block/floppy.c194
1 files changed, 98 insertions, 96 deletions
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index d771579df57e..0d5333570544 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -309,23 +309,23 @@ static bool initialized;
#define PH_HEAD(floppy, head) (((((floppy)->stretch & 2) >> 1) ^ head) << 2)
#define STRETCH(floppy) ((floppy)->stretch & FD_STRETCH)
-/* read/write */
-#define COMMAND (raw_cmd->cmd[0])
-#define DR_SELECT (raw_cmd->cmd[1])
-#define TRACK (raw_cmd->cmd[2])
-#define HEAD (raw_cmd->cmd[3])
-#define SECTOR (raw_cmd->cmd[4])
-#define SIZECODE (raw_cmd->cmd[5])
-#define SECT_PER_TRACK (raw_cmd->cmd[6])
-#define GAP (raw_cmd->cmd[7])
-#define SIZECODE2 (raw_cmd->cmd[8])
+/* read/write commands */
+#define COMMAND 0
+#define DR_SELECT 1
+#define TRACK 2
+#define HEAD 3
+#define SECTOR 4
+#define SIZECODE 5
+#define SECT_PER_TRACK 6
+#define GAP 7
+#define SIZECODE2 8
#define NR_RW 9
-/* format */
-#define F_SIZECODE (raw_cmd->cmd[2])
-#define F_SECT_PER_TRACK (raw_cmd->cmd[3])
-#define F_GAP (raw_cmd->cmd[4])
-#define F_FILL (raw_cmd->cmd[5])
+/* format commands */
+#define F_SIZECODE 2
+#define F_SECT_PER_TRACK 3
+#define F_GAP 4
+#define F_FILL 5
#define NR_F 6
/*
@@ -2124,28 +2124,28 @@ static void setup_format_params(int track)
FD_RAW_NEED_DISK | FD_RAW_NEED_SEEK);
raw_cmd->rate = _floppy->rate & 0x43;
raw_cmd->cmd_count = NR_F;
- COMMAND = FM_MODE(_floppy, FD_FORMAT);
- DR_SELECT = UNIT(current_drive) + PH_HEAD(_floppy, format_req.head);
- F_SIZECODE = FD_SIZECODE(_floppy);
- F_SECT_PER_TRACK = _floppy->sect << 2 >> F_SIZECODE;
- F_GAP = _floppy->fmt_gap;
- F_FILL = FD_FILL_BYTE;
+ raw_cmd->cmd[COMMAND] = FM_MODE(_floppy, FD_FORMAT);
+ raw_cmd->cmd[DR_SELECT] = UNIT(current_drive) + PH_HEAD(_floppy, format_req.head);
+ raw_cmd->cmd[F_SIZECODE] = FD_SIZECODE(_floppy);
+ raw_cmd->cmd[F_SECT_PER_TRACK] = _floppy->sect << 2 >> raw_cmd->cmd[F_SIZECODE];
+ raw_cmd->cmd[F_GAP] = _floppy->fmt_gap;
+ raw_cmd->cmd[F_FILL] = FD_FILL_BYTE;
raw_cmd->kernel_data = floppy_track_buffer;
- raw_cmd->length = 4 * F_SECT_PER_TRACK;
+ raw_cmd->length = 4 * raw_cmd->cmd[F_SECT_PER_TRACK];
- if (!F_SECT_PER_TRACK)
+ if (!raw_cmd->cmd[F_SECT_PER_TRACK])
return;
/* allow for about 30ms for data transport per track */
- head_shift = (F_SECT_PER_TRACK + 5) / 6;
+ head_shift = (raw_cmd->cmd[F_SECT_PER_TRACK] + 5) / 6;
/* a ``cylinder'' is two tracks plus a little stepping time */
track_shift = 2 * head_shift + 3;
/* position of logical sector 1 on this track */
n = (track_shift * format_req.track + head_shift * format_req.head)
- % F_SECT_PER_TRACK;
+ % raw_cmd->cmd[F_SECT_PER_TRACK];
/* determine interleave */
il = 1;
@@ -2153,27 +2153,27 @@ static void setup_format_params(int track)
il++;
/* initialize field */
- for (count = 0; count < F_SECT_PER_TRACK; ++count) {
+ for (count = 0; count < raw_cmd->cmd[F_SECT_PER_TRACK]; ++count) {
here[count].track = format_req.track;
here[count].head = format_req.head;
here[count].sect = 0;
- here[count].size = F_SIZECODE;
+ here[count].size = raw_cmd->cmd[F_SIZECODE];
}
/* place logical sectors */
- for (count = 1; count <= F_SECT_PER_TRACK; ++count) {
+ for (count = 1; count <= raw_cmd->cmd[F_SECT_PER_TRACK]; ++count) {
here[n].sect = count;
- n = (n + il) % F_SECT_PER_TRACK;
+ n = (n + il) % raw_cmd->cmd[F_SECT_PER_TRACK];
if (here[n].sect) { /* sector busy, find next free sector */
++n;
- if (n >= F_SECT_PER_TRACK) {
- n -= F_SECT_PER_TRACK;
+ if (n >= raw_cmd->cmd[F_SECT_PER_TRACK]) {
+ n -= raw_cmd->cmd[F_SECT_PER_TRACK];
while (here[n].sect)
++n;
}
}
}
if (_floppy->stretch & FD_SECTBASEMASK) {
- for (count = 0; count < F_SECT_PER_TRACK; count++)
+ for (count = 0; count < raw_cmd->cmd[F_SECT_PER_TRACK]; count++)
here[count].sect += FD_SECTBASE(_floppy) - 1;
}
}
@@ -2303,32 +2303,32 @@ static void rw_interrupt(void)
drive_state[current_drive].first_read_date = jiffies;
nr_sectors = 0;
- ssize = DIV_ROUND_UP(1 << SIZECODE, 4);
+ ssize = DIV_ROUND_UP(1 << raw_cmd->cmd[SIZECODE], 4);
if (ST1 & ST1_EOC)
eoc = 1;
else
eoc = 0;
- if (COMMAND & 0x80)
+ if (raw_cmd->cmd[COMMAND] & 0x80)
heads = 2;
else
heads = 1;
- nr_sectors = (((R_TRACK - TRACK) * heads +
- R_HEAD - HEAD) * SECT_PER_TRACK +
- R_SECTOR - SECTOR + eoc) << SIZECODE >> 2;
+ nr_sectors = (((R_TRACK - raw_cmd->cmd[TRACK]) * heads +
+ R_HEAD - raw_cmd->cmd[HEAD]) * raw_cmd->cmd[SECT_PER_TRACK] +
+ R_SECTOR - raw_cmd->cmd[SECTOR] + eoc) << raw_cmd->cmd[SIZECODE] >> 2;
if (nr_sectors / ssize >
DIV_ROUND_UP(in_sector_offset + current_count_sectors, ssize)) {
DPRINT("long rw: %x instead of %lx\n",
nr_sectors, current_count_sectors);
- pr_info("rs=%d s=%d\n", R_SECTOR, SECTOR);
- pr_info("rh=%d h=%d\n", R_HEAD, HEAD);
- pr_info("rt=%d t=%d\n", R_TRACK, TRACK);
+ pr_info("rs=%d s=%d\n", R_SECTOR, raw_cmd->cmd[SECTOR]);
+ pr_info("rh=%d h=%d\n", R_HEAD, raw_cmd->cmd[HEAD]);
+ pr_info("rt=%d t=%d\n", R_TRACK, raw_cmd->cmd[TRACK]);
pr_info("heads=%d eoc=%d\n", heads, eoc);
pr_info("spt=%d st=%d ss=%d\n",
- SECT_PER_TRACK, fsector_t, ssize);
+ raw_cmd->cmd[SECT_PER_TRACK], fsector_t, ssize);
pr_info("in_sector_offset=%d\n", in_sector_offset);
}
@@ -2366,11 +2366,11 @@ static void rw_interrupt(void)
probing = 0;
}
- if (CT(COMMAND) != FD_READ ||
+ if (CT(raw_cmd->cmd[COMMAND]) != FD_READ ||
raw_cmd->kernel_data == bio_data(current_req->bio)) {
/* transfer directly from buffer */
cont->done(1);
- } else if (CT(COMMAND) == FD_READ) {
+ } else if (CT(raw_cmd->cmd[COMMAND]) == FD_READ) {
buffer_track = raw_cmd->track;
buffer_drive = current_drive;
INFBOUND(buffer_max, nr_sectors + fsector_t);
@@ -2429,13 +2429,13 @@ static void copy_buffer(int ssize, int max_sector, int max_sector_2)
min(max_sector, max_sector_2),
blk_rq_sectors(current_req));
- if (current_count_sectors <= 0 && CT(COMMAND) == FD_WRITE &&
+ if (current_count_sectors <= 0 && CT(raw_cmd->cmd[COMMAND]) == FD_WRITE &&
buffer_max > fsector_t + blk_rq_sectors(current_req))
current_count_sectors = min_t(int, buffer_max - fsector_t,
blk_rq_sectors(current_req));
remaining = current_count_sectors << 9;
- if (remaining > blk_rq_bytes(current_req) && CT(COMMAND) == FD_WRITE) {
+ if (remaining > blk_rq_bytes(current_req) && CT(raw_cmd->cmd[COMMAND]) == FD_WRITE) {
DPRINT("in copy buffer\n");
pr_info("current_count_sectors=%ld\n", current_count_sectors);
pr_info("remaining=%d\n", remaining >> 9);
@@ -2470,16 +2470,16 @@ static void copy_buffer(int ssize, int max_sector, int max_sector_2)
fsector_t, buffer_min);
pr_info("current_count_sectors=%ld\n",
current_count_sectors);
- if (CT(COMMAND) == FD_READ)
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_READ)
pr_info("read\n");
- if (CT(COMMAND) == FD_WRITE)
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_WRITE)
pr_info("write\n");
break;
}
if (((unsigned long)buffer) % 512)
DPRINT("%p buffer not aligned\n", buffer);
- if (CT(COMMAND) == FD_READ)
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_READ)
memcpy(buffer, dma_buffer, size);
else
memcpy(dma_buffer, buffer, size);
@@ -2497,7 +2497,7 @@ static void copy_buffer(int ssize, int max_sector, int max_sector_2)
/* work around a bug in pseudo DMA
* (on some FDCs) pseudo DMA does not stop when the CPU stops
* sending data. Hence we need a different way to signal the
- * transfer length: We use SECT_PER_TRACK. Unfortunately, this
+ * transfer length: We use raw_cmd->cmd[SECT_PER_TRACK]. Unfortunately, this
* does not work with MT, hence we can only transfer one head at
* a time
*/
@@ -2506,18 +2506,18 @@ static void virtualdmabug_workaround(void)
int hard_sectors;
int end_sector;
- if (CT(COMMAND) == FD_WRITE) {
- COMMAND &= ~0x80; /* switch off multiple track mode */
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_WRITE) {
+ raw_cmd->cmd[COMMAND] &= ~0x80; /* switch off multiple track mode */
- hard_sectors = raw_cmd->length >> (7 + SIZECODE);
- end_sector = SECTOR + hard_sectors - 1;
- if (end_sector > SECT_PER_TRACK) {
+ hard_sectors = raw_cmd->length >> (7 + raw_cmd->cmd[SIZECODE]);
+ end_sector = raw_cmd->cmd[SECTOR] + hard_sectors - 1;
+ if (end_sector > raw_cmd->cmd[SECT_PER_TRACK]) {
pr_info("too many sectors %d > %d\n",
- end_sector, SECT_PER_TRACK);
+ end_sector, raw_cmd->cmd[SECT_PER_TRACK]);
return;
}
- SECT_PER_TRACK = end_sector;
- /* make sure SECT_PER_TRACK
+ raw_cmd->cmd[SECT_PER_TRACK] = end_sector;
+ /* make sure raw_cmd->cmd[SECT_PER_TRACK]
* points to end of transfer */
}
}
@@ -2550,10 +2550,10 @@ static int make_raw_rw_request(void)
raw_cmd->cmd_count = NR_RW;
if (rq_data_dir(current_req) == READ) {
raw_cmd->flags |= FD_RAW_READ;
- COMMAND = FM_MODE(_floppy, FD_READ);
+ raw_cmd->cmd[COMMAND] = FM_MODE(_floppy, FD_READ);
} else if (rq_data_dir(current_req) == WRITE) {
raw_cmd->flags |= FD_RAW_WRITE;
- COMMAND = FM_MODE(_floppy, FD_WRITE);
+ raw_cmd->cmd[COMMAND] = FM_MODE(_floppy, FD_WRITE);
} else {
DPRINT("%s: unknown command\n", __func__);
return 0;
@@ -2561,16 +2561,16 @@ static int make_raw_rw_request(void)
max_sector = _floppy->sect * _floppy->head;
- TRACK = (int)blk_rq_pos(current_req) / max_sector;
+ raw_cmd->cmd[TRACK] = (int)blk_rq_pos(current_req) / max_sector;
fsector_t = (int)blk_rq_pos(current_req) % max_sector;
- if (_floppy->track && TRACK >= _floppy->track) {
+ if (_floppy->track && raw_cmd->cmd[TRACK] >= _floppy->track) {
if (blk_rq_cur_sectors(current_req) & 1) {
current_count_sectors = 1;
return 1;
} else
return 0;
}
- HEAD = fsector_t / _floppy->sect;
+ raw_cmd->cmd[HEAD] = fsector_t / _floppy->sect;
if (((_floppy->stretch & (FD_SWAPSIDES | FD_SECTBASEMASK)) ||
test_bit(FD_NEED_TWADDLE_BIT, &drive_state[current_drive].flags)) &&
@@ -2578,7 +2578,7 @@ static int make_raw_rw_request(void)
max_sector = _floppy->sect;
/* 2M disks have phantom sectors on the first track */
- if ((_floppy->rate & FD_2M) && (!TRACK) && (!HEAD)) {
+ if ((_floppy->rate & FD_2M) && (!raw_cmd->cmd[TRACK]) && (!raw_cmd->cmd[HEAD])) {
max_sector = 2 * _floppy->sect / 3;
if (fsector_t >= max_sector) {
current_count_sectors =
@@ -2586,23 +2586,24 @@ static int make_raw_rw_request(void)
blk_rq_sectors(current_req));
return 1;
}
- SIZECODE = 2;
+ raw_cmd->cmd[SIZECODE] = 2;
} else
- SIZECODE = FD_SIZECODE(_floppy);
+ raw_cmd->cmd[SIZECODE] = FD_SIZECODE(_floppy);
raw_cmd->rate = _floppy->rate & 0x43;
- if ((_floppy->rate & FD_2M) && (TRACK || HEAD) && raw_cmd->rate == 2)
+ if ((_floppy->rate & FD_2M) &&
+ (raw_cmd->cmd[TRACK] || raw_cmd->cmd[HEAD]) && raw_cmd->rate == 2)
raw_cmd->rate = 1;
- if (SIZECODE)
- SIZECODE2 = 0xff;
+ if (raw_cmd->cmd[SIZECODE])
+ raw_cmd->cmd[SIZECODE2] = 0xff;
else
- SIZECODE2 = 0x80;
- raw_cmd->track = TRACK << STRETCH(_floppy);
- DR_SELECT = UNIT(current_drive) + PH_HEAD(_floppy, HEAD);
- GAP = _floppy->gap;
- ssize = DIV_ROUND_UP(1 << SIZECODE, 4);
- SECT_PER_TRACK = _floppy->sect << 2 >> SIZECODE;
- SECTOR = ((fsector_t % _floppy->sect) << 2 >> SIZECODE) +
+ raw_cmd->cmd[SIZECODE2] = 0x80;
+ raw_cmd->track = raw_cmd->cmd[TRACK] << STRETCH(_floppy);
+ raw_cmd->cmd[DR_SELECT] = UNIT(current_drive) + PH_HEAD(_floppy, raw_cmd->cmd[HEAD]);
+ raw_cmd->cmd[GAP] = _floppy->gap;
+ ssize = DIV_ROUND_UP(1 << raw_cmd->cmd[SIZECODE], 4);
+ raw_cmd->cmd[SECT_PER_TRACK] = _floppy->sect << 2 >> raw_cmd->cmd[SIZECODE];
+ raw_cmd->cmd[SECTOR] = ((fsector_t % _floppy->sect) << 2 >> raw_cmd->cmd[SIZECODE]) +
FD_SECTBASE(_floppy);
/* tracksize describes the size which can be filled up with sectors
@@ -2610,24 +2611,24 @@ static int make_raw_rw_request(void)
*/
tracksize = _floppy->sect - _floppy->sect % ssize;
if (tracksize < _floppy->sect) {
- SECT_PER_TRACK++;
+ raw_cmd->cmd[SECT_PER_TRACK]++;
if (tracksize <= fsector_t % _floppy->sect)
- SECTOR--;
+ raw_cmd->cmd[SECTOR]--;
/* if we are beyond tracksize, fill up using smaller sectors */
while (tracksize <= fsector_t % _floppy->sect) {
while (tracksize + ssize > _floppy->sect) {
- SIZECODE--;
+ raw_cmd->cmd[SIZECODE]--;
ssize >>= 1;
}
- SECTOR++;
- SECT_PER_TRACK++;
+ raw_cmd->cmd[SECTOR]++;
+ raw_cmd->cmd[SECT_PER_TRACK]++;
tracksize += ssize;
}
- max_sector = HEAD * _floppy->sect + tracksize;
- } else if (!TRACK && !HEAD && !(_floppy->rate & FD_2M) && probing) {
+ max_sector = raw_cmd->cmd[HEAD] * _floppy->sect + tracksize;
+ } else if (!raw_cmd->cmd[TRACK] && !raw_cmd->cmd[HEAD] && !(_floppy->rate & FD_2M) && probing) {
max_sector = _floppy->sect;
- } else if (!HEAD && CT(COMMAND) == FD_WRITE) {
+ } else if (!raw_cmd->cmd[HEAD] && CT(raw_cmd->cmd[COMMAND]) == FD_WRITE) {
/* for virtual DMA bug workaround */
max_sector = _floppy->sect;
}
@@ -2639,12 +2640,12 @@ static int make_raw_rw_request(void)
(current_drive == buffer_drive) &&
(fsector_t >= buffer_min) && (fsector_t < buffer_max)) {
/* data already in track buffer */
- if (CT(COMMAND) == FD_READ) {
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_READ) {
copy_buffer(1, max_sector, buffer_max);
return 1;
}
} else if (in_sector_offset || blk_rq_sectors(current_req) < ssize) {
- if (CT(COMMAND) == FD_WRITE) {
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_WRITE) {
unsigned int sectors;
sectors = fsector_t + blk_rq_sectors(current_req);
@@ -2655,7 +2656,7 @@ static int make_raw_rw_request(void)
}
raw_cmd->flags &= ~FD_RAW_WRITE;
raw_cmd->flags |= FD_RAW_READ;
- COMMAND = FM_MODE(_floppy, FD_READ);
+ raw_cmd->cmd[COMMAND] = FM_MODE(_floppy, FD_READ);
} else if ((unsigned long)bio_data(current_req->bio) < MAX_DMA_ADDRESS) {
unsigned long dma_limit;
int direct, indirect;
@@ -2706,7 +2707,7 @@ static int make_raw_rw_request(void)
}
}
- if (CT(COMMAND) == FD_READ)
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_READ)
max_size = max_sector; /* unbounded */
/* claim buffer track if needed */
@@ -2714,7 +2715,7 @@ static int make_raw_rw_request(void)
buffer_drive != current_drive || /* bad drive */
fsector_t > buffer_max ||
fsector_t < buffer_min ||
- ((CT(COMMAND) == FD_READ ||
+ ((CT(raw_cmd->cmd[COMMAND]) == FD_READ ||
(!in_sector_offset && blk_rq_sectors(current_req) >= ssize)) &&
max_sector > 2 * max_buffer_sectors + buffer_min &&
max_size + fsector_t > 2 * max_buffer_sectors + buffer_min)) {
@@ -2726,7 +2727,7 @@ static int make_raw_rw_request(void)
raw_cmd->kernel_data = floppy_track_buffer +
((aligned_sector_t - buffer_min) << 9);
- if (CT(COMMAND) == FD_WRITE) {
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_WRITE) {
/* copy write buffer to track buffer.
* if we get here, we know that the write
* is either aligned or the data already in the buffer
@@ -2748,10 +2749,10 @@ static int make_raw_rw_request(void)
raw_cmd->length <<= 9;
if ((raw_cmd->length < current_count_sectors << 9) ||
(raw_cmd->kernel_data != bio_data(current_req->bio) &&
- CT(COMMAND) == FD_WRITE &&
+ CT(raw_cmd->cmd[COMMAND]) == FD_WRITE &&
(aligned_sector_t + (raw_cmd->length >> 9) > buffer_max ||
aligned_sector_t < buffer_min)) ||
- raw_cmd->length % (128 << SIZECODE) ||
+ raw_cmd->length % (128 << raw_cmd->cmd[SIZECODE]) ||
raw_cmd->length <= 0 || current_count_sectors <= 0) {
DPRINT("fractionary current count b=%lx s=%lx\n",
raw_cmd->length, current_count_sectors);
@@ -2762,9 +2763,10 @@ static int make_raw_rw_request(void)
current_count_sectors);
pr_info("st=%d ast=%d mse=%d msi=%d\n",
fsector_t, aligned_sector_t, max_sector, max_size);
- pr_info("ssize=%x SIZECODE=%d\n", ssize, SIZECODE);
+ pr_info("ssize=%x SIZECODE=%d\n", ssize, raw_cmd->cmd[SIZECODE]);
pr_info("command=%x SECTOR=%d HEAD=%d, TRACK=%d\n",
- COMMAND, SECTOR, HEAD, TRACK);
+ raw_cmd->cmd[COMMAND], raw_cmd->cmd[SECTOR],
+ raw_cmd->cmd[HEAD], raw_cmd->cmd[TRACK]);
pr_info("buffer drive=%d\n", buffer_drive);
pr_info("buffer track=%d\n", buffer_track);
pr_info("buffer_min=%d\n", buffer_min);
@@ -2783,9 +2785,9 @@ static int make_raw_rw_request(void)
fsector_t, buffer_min, raw_cmd->length >> 9);
pr_info("current_count_sectors=%ld\n",
current_count_sectors);
- if (CT(COMMAND) == FD_READ)
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_READ)
pr_info("read\n");
- if (CT(COMMAND) == FD_WRITE)
+ if (CT(raw_cmd->cmd[COMMAND]) == FD_WRITE)
pr_info("write\n");
return 0;
}
@@ -3253,7 +3255,7 @@ static int set_geometry(unsigned int cmd, struct floppy_struct *g,
(int)g->head <= 0 ||
/* check for overflow in max_sector */
(int)(g->sect * g->head) <= 0 ||
- /* check for zero in F_SECT_PER_TRACK */
+ /* check for zero in raw_cmd->cmd[F_SECT_PER_TRACK] */
(unsigned char)((g->sect << 2) >> FD_SIZECODE(g)) == 0 ||
g->track <= 0 || g->track > drive_params[drive].tracks >> STRETCH(g) ||
/* check if reserved bits are set */