mirror of
https://github.com/holub/mame
synced 2025-05-23 22:20:01 +03:00
228 lines
8.4 KiB
C++
228 lines
8.4 KiB
C++
// license:BSD-3-Clause
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// copyright-holders:Olivier Galibert
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/* DONE:
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* Support auto-identification heuristics for determining disk image speed,
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capture clock rate, and number of multireads per image.
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* TODO:
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* Scale captured data based on the guessed clock rate and samplerate to match
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the internal 200mhz representation
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* Handle 0xFF bytes properly
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* Correctly note exact index timing.
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*/
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#include "emu.h" // fatalerror
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#include "dfi_dsk.h"
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#include <zlib.h>
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#define NUMBER_OF_MULTIREADS 3
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// threshholds for brickwall windowing
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//define DFI_MIN_CLOCKS 65
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// number_please apple2 wants 40 min
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#define DFI_MIN_CLOCKS 60
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//define MAX_CLOCKS 260
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#define DFI_MAX_CLOCKS 270
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#define MIN_THRESH (DFI_MIN_CLOCKS*(clock_rate/25000000))
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#define MAX_THRESH (DFI_MAX_CLOCKS*(clock_rate/25000000))
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// constants to help guess clockrate and rpm
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// constant is 25mhz / 6 revolutions per second (360rpm) = 4166667 +- 2.5%
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#define REV25_MIN 4062500
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#define REV25_MAX 4270833
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// define the following to show a histogram per track
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//define TRACK_HISTOGRAM 1
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#undef TRACK_HISTOGRAM
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dfi_format::dfi_format() : floppy_image_format_t()
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{
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}
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const char *dfi_format::name() const
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{
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return "dfi";
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}
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const char *dfi_format::description() const
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{
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return "DiscFerret flux dump format";
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}
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const char *dfi_format::extensions() const
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{
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return "dfi";
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}
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bool dfi_format::supports_save() const
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{
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return false;
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}
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int dfi_format::identify(io_generic *io, UINT32 form_factor)
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{
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char sign[4];
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io_generic_read(io, sign, 0, 4);
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if (memcmp(sign, "DFER", 4)==0)
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fatalerror("Old type Discferret image detected; the mess Discferret decoder will not handle this properly, bailing out!\n");
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return memcmp(sign, "DFE2", 4) ? 0 : 100;
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}
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bool dfi_format::load(io_generic *io, UINT32 form_factor, floppy_image *image)
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{
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UINT64 size = io_generic_size(io);
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UINT64 pos = 4;
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dynamic_buffer data;
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int onerev_time = 0; // time for one revolution, used to guess clock and rpm for DFE2 files
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unsigned long clock_rate = 100000000; // sample clock rate in megahertz
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int rpm=360; // drive rpm
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while(pos < size) {
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UINT8 h[10];
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io_generic_read(io, h, pos, 10);
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UINT16 track = (h[0] << 8) | h[1];
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UINT16 head = (h[2] << 8) | h[3];
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// Ignore sector
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UINT32 tsize = (h[6] << 24) | (h[7] << 16) | (h[8] << 8) | h[9];
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// if the position-so-far-in-file plus 10 (for the header) plus track size
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// is larger than the size of the file, free buffers and bail out
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if(pos+tsize+10 > size) {
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return false;
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}
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// reallocate the data array if it gets too small
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data.resize(tsize);
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pos += 10; // skip the header, we already read it
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io_generic_read(io, &data[0], pos, tsize);
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pos += tsize; // for next time we read, increment to the beginning of next header
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int index_time = 0; // what point the last index happened
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int index_count = 0; // number of index pulses per track
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//int index_polarity = 1; // current polarity of index, starts high
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int total_time = 0; // total sampled time per track
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for(int i=0; i<tsize; i++) {
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UINT8 v = data[i];
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if (v == 0xFF) { fprintf(stderr,"DFI stream contained a 0xFF at t%d, position%d, THIS SHOULD NEVER HAPPEN! Bailing out!\n", track, i); exit(1); }
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if((v & 0x7f) == 0x7f)
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total_time += 0x7f;
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else if(v & 0x80) {
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total_time += v & 0x7f;
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index_time = total_time;
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//index_polarity ^= 1;
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//fprintf(stderr,"index state changed to %d at time=%d\n", index_polarity, total_time);
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//fprintf(stderr,"index rising edge seen at time=%d\n", total_time);
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if (onerev_time == 0) onerev_time = total_time;
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index_count += 1;//index_polarity;
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} else // (v & 0x80) == 0
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total_time += v & 0x7f;
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}
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// its possible on single read images for there to be no index pulse during the image at all!
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if (onerev_time == 0) onerev_time = total_time;
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if(!track && !head)
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fprintf(stderr, "%02d:%d tt=%10d it=%10d\n", track, head, total_time, index_time);
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if(!track && !head) {
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fprintf(stderr, "index_count: %d, onerev_time: %d\n", index_count, onerev_time);
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if ((onerev_time > REV25_MIN) && (onerev_time < REV25_MAX)) {
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fprintf(stderr, "Guess: speed: 360rpm, clock 25MHz\n");
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clock_rate = 25000000; rpm = 360;
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} else if ((onerev_time > REV25_MIN*1.2) && (onerev_time < REV25_MAX*1.2)) {
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fprintf(stderr, "Guess: speed: 300rpm, clock 25MHz\n");
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clock_rate = 25000000; rpm = 300;
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} else if ((onerev_time > REV25_MIN*2) && (onerev_time < REV25_MAX*2)) {
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fprintf(stderr, "Guess: speed: 360rpm, clock 50MHz\n");
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clock_rate = 50000000; rpm = 360;
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} else if ((onerev_time > (REV25_MIN*2)*1.2) && (onerev_time < (REV25_MAX*2)*1.2)) {
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fprintf(stderr, "Guess: speed: 300rpm, clock 50MHz\n");
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clock_rate = 50000000; rpm = 300;
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} else if ((onerev_time > REV25_MIN*4) && (onerev_time < REV25_MAX*4)) {
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fprintf(stderr, "Guess: speed: 360rpm, clock 100MHz\n");
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clock_rate = 100000000; rpm = 360;
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} else if ((onerev_time > (REV25_MIN*4)*1.2) && (onerev_time < (REV25_MAX*4)*1.2)) {
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fprintf(stderr, "Guess: speed: 300rpm, clock 100MHz\n");
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clock_rate = 100000000; rpm = 300;
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} else
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fprintf(stderr, "WARNING: Cannot Guess Speed! Assuming 360rpm, 100Mhz clock!\n");
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fprintf(stderr,"Actual rpm based on index: %f\n", ((double)clock_rate/(double)onerev_time)*60);
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}
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rpm += 0; // HACK: prevent GCC 4.6+ from warning "variable set but unused"
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if(!index_time)
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index_time = total_time;
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std::vector<UINT32> &buf = image->get_buffer(track, head);
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buf.resize(tsize);
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int cur_time = 0;
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int prev_time = 0;
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#ifdef TRACK_HISTOGRAM
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// histogram
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int time_buckets[4096];
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for (int i = 0; i < 4096; i++)
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time_buckets[i] = 0;
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#endif
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index_count = 0;
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//index_polarity = 0;
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UINT32 mg = floppy_image::MG_A;
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int tpos = 0;
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buf[tpos++] = mg;
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for(int i=0; i<tsize; i++) {
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UINT8 v = data[i];
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if((v & 0x7f) == 0x7f) // 0x7F : no transition, but a carry (FF is a board-on-fire error and is checked for above)
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cur_time += 0x7f;
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else if(v & 0x80) { // 0x80 set, note the index (TODO: actually do this!) and add number to count
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cur_time += v & 0x7f;
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//index_polarity ^= 1;
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index_count += 1;//index_polarity;
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//if (index_count == NUMBER_OF_MULTIREADS) break;
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}
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else if((v & 0x80) == 0) { // 0x00-0x7E: not an index or carry, add the number and store transition
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cur_time += v & 0x7f;
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int trans_time = cur_time - prev_time;
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#ifdef TRACK_HISTOGRAM
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time_buckets[(trans_time<4096)?trans_time:4095]++;
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#endif
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// cur_time and onerev_time need to be converted to something standard, so we'll stick with 300rpm at the standard 200mhz rate that mfi uses internally
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// TODO for 4/22/2012: ACTUALLY DO THIS RESCALING STEP
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// filter out spurious crap
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//if (trans_time <= MIN_THRESH) fprintf(stderr, "DFI: Throwing out short transition of length %d\n", trans_time);
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// the normal case: write the transition at the appropriate time
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if ((prev_time == 0) || ((trans_time > MIN_THRESH) && (trans_time <= MAX_THRESH))) {
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mg = mg == floppy_image::MG_A ? floppy_image::MG_B : floppy_image::MG_A;
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buf[tpos++] = mg | UINT32((200000000ULL*cur_time)/index_time);
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prev_time = cur_time;
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}
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// the long case: we probably missed a transition, stuff an extra guessed one in there to see if it helps
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if (trans_time > MAX_THRESH) {
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mg = mg == floppy_image::MG_A ? floppy_image::MG_B : floppy_image::MG_A;
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if (((track%2)==0)&&(head==0)) fprintf(stderr,"missed transition, total time for transition is %d\n",trans_time);
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#ifndef FAKETRANS_ONE
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buf[tpos++] = mg | UINT32((200000000ULL*(cur_time-(trans_time/2)))/index_time); // generate imaginary transition at half period
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#else
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buf[tpos++] = mg | UINT32((200000000ULL*(cur_time-((trans_time*2)/3)))/index_time);
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mg = mg == floppy_image::MG_A ? floppy_image::MG_B : floppy_image::MG_A;
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buf[tpos++] = mg | UINT32((200000000ULL*(cur_time-(trans_time/3)))/index_time);
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#endif
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mg = mg == floppy_image::MG_A ? floppy_image::MG_B : floppy_image::MG_A;
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buf[tpos++] = mg | UINT32(200000000ULL*cur_time/index_time); // generate transition now
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prev_time = cur_time;
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}
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}
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}
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#ifdef TRACK_HISTOGRAM
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if (((track%2)==0)&&(head==0)) {
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for (int i = 0; i < 4096; i++) {
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fprintf(stderr,"%4d:%4d ", i, time_buckets[i]);
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if (((i+1)%10)==0) fprintf(stderr,"\n");
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}
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}
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fprintf(stderr,"\n");
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#endif
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index_count = 0;
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buf.resize(tpos);
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}
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return true;
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}
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const floppy_format_type FLOPPY_DFI_FORMAT = &floppy_image_format_creator<dfi_format>;
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