123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436 |
- /****************************************************************************
- *
- * VESA Generalized Timing Formula (GTF)
- * Version 1.1
- *
- * ========================================================================
- *
- * The contents of this file are subject to the SciTech MGL Public
- * License Version 1.0 (the "License"); you may not use this file
- * except in compliance with the License. You may obtain a copy of
- * the License at http://www.scitechsoft.com/mgl-license.txt
- *
- * Software distributed under the License is distributed on an
- * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
- * implied. See the License for the specific language governing
- * rights and limitations under the License.
- *
- * The Original Code is Copyright (C) 1991-1998 SciTech Software, Inc.
- *
- * The Initial Developer of the Original Code is SciTech Software, Inc.
- * All Rights Reserved.
- *
- * ========================================================================
- *
- * Developed by: SciTech Software, Inc.
- *
- * Language: ANSI C
- * Environment: Any.
- *
- * Description: C module for generating GTF compatible timings given a set
- * of input requirements. Translated from the original GTF
- * 1.14 spreadsheet definition.
- *
- * Compile with #define TESTING to build a command line test
- * program.
- *
- * NOTE: The code in here has been written for clarity and
- * to follow the original GTF spec as closely as
- * possible.
- *
- ****************************************************************************/
- #include "gtf.h"
- #ifndef __WIN32_VXD__
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <ctype.h>
- #include <math.h>
- #endif
- /*------------------------- Global Variables ------------------------------*/
- static GTF_constants GC = {
- 1.8, /* Margin size as percentage of display */
- 8, /* Character cell granularity */
- 1, /* Minimum front porch in lines/chars */
- 3, /* Width of V sync in lines */
- 8, /* Width of H sync as percent of total */
- 550, /* Minimum vertical sync + back porch (us) */
- 600, /* Blanking formula gradient */
- 40, /* Blanking formula offset */
- 128, /* Blanking formula scaling factor */
- 20, /* Blanking formula scaling factor weight */
- };
- /*-------------------------- Implementation -------------------------------*/
- #ifdef __WIN32_VXD__
- /* These functions are not supported in a VxD, so we stub them out so this
- * module will at least compile. Calling the functions in here will do
- * something wierd!
- */
- double sqrt(double x)
- { return x; }
- double floor(double x)
- { return x; }
- double pow(double x,double y)
- { return x*y; }
- #endif
- static double round(double v)
- {
- return floor(v + 0.5);
- }
- static void GetInternalConstants(GTF_constants *c)
- /****************************************************************************
- *
- * Function: GetInternalConstants
- * Parameters: c - Place to store the internal constants
- *
- * Description: Calculates the rounded, internal set of GTF constants.
- * These constants are different to the real GTF constants
- * that can be set up for the monitor. The calculations to
- * get these real constants are defined in the 'Work Area'
- * after the constants are defined in the Excel spreadsheet.
- *
- ****************************************************************************/
- {
- c->margin = GC.margin;
- c->cellGran = round(GC.cellGran);
- c->minPorch = round(GC.minPorch);
- c->vSyncRqd = round(GC.vSyncRqd);
- c->hSync = GC.hSync;
- c->minVSyncBP = GC.minVSyncBP;
- if (GC.k == 0)
- c->k = 0.001;
- else
- c->k = GC.k;
- c->m = (c->k / 256) * GC.m;
- c->c = (GC.c - GC.j) * (c->k / 256) + GC.j;
- c->j = GC.j;
- }
- void GTF_calcTimings(double hPixels,double vLines,double freq,
- int type,ibool wantMargins,ibool wantInterlace,GTF_timings *t)
- /****************************************************************************
- *
- * Function: GTF_calcTimings
- * Parameters: hPixels - X resolution
- * vLines - Y resolution
- * freq - Frequency (Hz, KHz or MHz depending on type)
- * type - 1 - vertical, 2 - horizontal, 3 - dot clock
- * margins - True if margins should be generated
- * interlace - True if interlaced timings to be generated
- * t - Place to store the resulting timings
- *
- * Description: Calculates a set of GTF timing parameters given a specified
- * resolution and vertical frequency. The horizontal frequency
- * and dot clock will be automatically generated by this
- * routines.
- *
- * For interlaced modes the CRTC parameters are calculated for
- * a single field, so will be half what would be used in
- * a non-interlaced mode.
- *
- ****************************************************************************/
- {
- double interlace,vFieldRate,hPeriod;
- double topMarginLines,botMarginLines;
- double leftMarginPixels,rightMarginPixels;
- double hPeriodEst,vSyncBP,vBackPorch;
- double vTotalLines,vFieldRateEst;
- double hTotalPixels,hTotalActivePixels,hBlankPixels;
- double idealDutyCycle,hSyncWidth,hSyncBP,hBackPorch;
- double idealHPeriod;
- double vFreq,hFreq,dotClock;
- GTF_constants c;
- /* Get rounded GTF constants used for internal calculations */
- GetInternalConstants(&c);
- /* Move input parameters into appropriate variables */
- vFreq = hFreq = dotClock = freq;
- /* Round pixels to character cell granularity */
- hPixels = round(hPixels / c.cellGran) * c.cellGran;
- /* For interlaced mode halve the vertical parameters, and double
- * the required field refresh rate.
- */
- vFieldRate = vFreq;
- interlace = 0;
- if (wantInterlace)
- dotClock *= 2;
- /* Determine the lines for margins */
- if (wantMargins) {
- topMarginLines = round(c.margin / 100 * vLines);
- botMarginLines = round(c.margin / 100 * vLines);
- }
- else {
- topMarginLines = 0;
- botMarginLines = 0;
- }
- if (type != GTF_lockPF) {
- if (type == GTF_lockVF) {
- /* Estimate the horizontal period */
- hPeriodEst = ((1/vFieldRate) - (c.minVSyncBP/1000000)) /
- (vLines + (2*topMarginLines) + c.minPorch + interlace) * 1000000;
- /* Find the number of lines in vSync + back porch */
- vSyncBP = round(c.minVSyncBP / hPeriodEst);
- }
- else if (type == GTF_lockHF) {
- /* Find the number of lines in vSync + back porch */
- vSyncBP = round((c.minVSyncBP * hFreq) / 1000);
- }
- /* Find the number of lines in the V back porch alone */
- vBackPorch = vSyncBP - c.vSyncRqd;
- /* Find the total number of lines in the vertical period */
- vTotalLines = vLines + topMarginLines + botMarginLines + vSyncBP
- + interlace + c.minPorch;
- if (type == GTF_lockVF) {
- /* Estimate the vertical frequency */
- vFieldRateEst = 1000000 / (hPeriodEst * vTotalLines);
- /* Find the actual horizontal period */
- hPeriod = (hPeriodEst * vFieldRateEst) / vFieldRate;
- /* Find the actual vertical field frequency */
- vFieldRate = 1000000 / (hPeriod * vTotalLines);
- }
- else if (type == GTF_lockHF) {
- /* Find the actual vertical field frequency */
- vFieldRate = (hFreq / vTotalLines) * 1000;
- }
- }
- /* Find the number of pixels in the left and right margins */
- if (wantMargins) {
- leftMarginPixels = round(hPixels * c.margin) / (100 * c.cellGran);
- rightMarginPixels = round(hPixels * c.margin) / (100 * c.cellGran);
- }
- else {
- leftMarginPixels = 0;
- rightMarginPixels = 0;
- }
- /* Find the total number of active pixels in image + margins */
- hTotalActivePixels = hPixels + leftMarginPixels + rightMarginPixels;
- if (type == GTF_lockVF) {
- /* Find the ideal blanking duty cycle */
- idealDutyCycle = c.c - ((c.m * hPeriod) / 1000);
- }
- else if (type == GTF_lockHF) {
- /* Find the ideal blanking duty cycle */
- idealDutyCycle = c.c - (c.m / hFreq);
- }
- else if (type == GTF_lockPF) {
- /* Find ideal horizontal period from blanking duty cycle formula */
- idealHPeriod = (((c.c - 100) + (sqrt((pow(100-c.c,2)) +
- (0.4 * c.m * (hTotalActivePixels + rightMarginPixels +
- leftMarginPixels) / dotClock)))) / (2 * c.m)) * 1000;
- /* Find the ideal blanking duty cycle */
- idealDutyCycle = c.c - ((c.m * idealHPeriod) / 1000);
- }
- /* Find the number of pixels in blanking time */
- hBlankPixels = round((hTotalActivePixels * idealDutyCycle) /
- ((100 - idealDutyCycle) * c.cellGran)) * c.cellGran;
- /* Find the total number of pixels */
- hTotalPixels = hTotalActivePixels + hBlankPixels;
- /* Find the horizontal back porch */
- hBackPorch = round((hBlankPixels / 2) / c.cellGran) * c.cellGran;
- /* Find the horizontal sync width */
- hSyncWidth = round(((c.hSync/100) * hTotalPixels) / c.cellGran) * c.cellGran;
- /* Find the horizontal sync + back porch */
- hSyncBP = hBackPorch + hSyncWidth;
- if (type == GTF_lockPF) {
- /* Find the horizontal frequency */
- hFreq = (dotClock / hTotalPixels) * 1000;
- /* Find the number of lines in vSync + back porch */
- vSyncBP = round((c.minVSyncBP * hFreq) / 1000);
- /* Find the number of lines in the V back porch alone */
- vBackPorch = vSyncBP - c.vSyncRqd;
- /* Find the total number of lines in the vertical period */
- vTotalLines = vLines + topMarginLines + botMarginLines + vSyncBP
- + interlace + c.minPorch;
- /* Find the actual vertical field frequency */
- vFieldRate = (hFreq / vTotalLines) * 1000;
- }
- else {
- if (type == GTF_lockVF) {
- /* Find the horizontal frequency */
- hFreq = 1000 / hPeriod;
- }
- else if (type == GTF_lockHF) {
- /* Find the horizontal frequency */
- hPeriod = 1000 / hFreq;
- }
- /* Find the pixel clock frequency */
- dotClock = hTotalPixels / hPeriod;
- }
- /* Return the computed frequencies */
- t->vFreq = vFieldRate;
- t->hFreq = hFreq;
- t->dotClock = dotClock;
- /* Determine the vertical timing parameters */
- t->h.hTotal = (int)hTotalPixels;
- t->h.hDisp = (int)hTotalActivePixels;
- t->h.hSyncStart = t->h.hTotal - (int)hSyncBP;
- t->h.hSyncEnd = t->h.hTotal - (int)hBackPorch;
- t->h.hFrontPorch = t->h.hSyncStart - t->h.hDisp;
- t->h.hSyncWidth = (int)hSyncWidth;
- t->h.hBackPorch = (int)hBackPorch;
- /* Determine the vertical timing parameters */
- t->v.vTotal = (int)vTotalLines;
- t->v.vDisp = (int)vLines;
- t->v.vSyncStart = t->v.vTotal - (int)vSyncBP;
- t->v.vSyncEnd = t->v.vTotal - (int)vBackPorch;
- t->v.vFrontPorch = t->v.vSyncStart - t->v.vDisp;
- t->v.vSyncWidth = (int)c.vSyncRqd;
- t->v.vBackPorch = (int)vBackPorch;
- if (wantInterlace) {
- /* Halve the timings for interlaced modes */
- t->v.vTotal /= 2;
- t->v.vDisp /= 2;
- t->v.vSyncStart /= 2;
- t->v.vSyncEnd /= 2;
- t->v.vFrontPorch /= 2;
- t->v.vSyncWidth /= 2;
- t->v.vBackPorch /= 2;
- t->dotClock /= 2;
- }
- /* Mark as GTF timing using the sync polarities */
- t->interlace = (wantInterlace) ? 'I' : 'N';
- t->hSyncPol = '-';
- t->vSyncPol = '+';
- }
- void GTF_getConstants(GTF_constants *constants)
- { *constants = GC; }
- void GTF_setConstants(GTF_constants *constants)
- { GC = *constants; }
- #ifdef TESTING_GTF
- void main(int argc,char *argv[])
- {
- FILE *f;
- double xPixels,yPixels,freq;
- ibool interlace;
- GTF_timings t;
- if (argc != 5 && argc != 6) {
- printf("Usage: GTFCALC <xPixels> <yPixels> <freq> [[Hz] [KHz] [MHz]] [I]\n");
- printf("\n");
- printf("where <xPixels> is the horizontal resolution of the mode, <yPixels> is the\n");
- printf("vertical resolution of the mode. The <freq> value will be the frequency to\n");
- printf("drive the calculations, and will be either the vertical frequency (in Hz)\n");
- printf("the horizontal frequency (in KHz) or the dot clock (in MHz). To generate\n");
- printf("timings for an interlaced mode, add 'I' to the end of the command line.\n");
- printf("\n");
- printf("For example to generate timings for 640x480 at 60Hz vertical:\n");
- printf("\n");
- printf(" GTFCALC 640 480 60 Hz\n");
- printf("\n");
- printf("For example to generate timings for 640x480 at 31.5KHz horizontal:\n");
- printf("\n");
- printf(" GTFCALC 640 480 31.5 KHz\n");
- printf("\n");
- printf("For example to generate timings for 640x480 with a 25.175Mhz dot clock:\n");
- printf("\n");
- printf(" GTFCALC 640 480 25.175 MHz\n");
- printf("\n");
- printf("GTFCALC will print a summary of the results found, and dump the CRTC\n");
- printf("values to the UVCONFIG.CRT file in the format used by SciTech Display Doctor.\n");
- exit(1);
- }
- /* Get values from command line */
- xPixels = atof(argv[1]);
- yPixels = atof(argv[2]);
- freq = atof(argv[3]);
- interlace = ((argc == 6) && (argv[5][0] == 'I'));
- /* Compute the CRTC timings */
- if (toupper(argv[4][0]) == 'H')
- GTF_calcTimings(xPixels,yPixels,freq,GTF_lockVF,false,interlace,&t);
- else if (toupper(argv[4][0]) == 'K')
- GTF_calcTimings(xPixels,yPixels,freq,GTF_lockHF,false,interlace,&t);
- else if (toupper(argv[4][0]) == 'M')
- GTF_calcTimings(xPixels,yPixels,freq,GTF_lockPF,false,interlace,&t);
- else {
- printf("Unknown command line!\n");
- exit(1);
- }
- /* Dump summary info to standard output */
- printf("CRTC values for %.0fx%.0f @ %.2f %s\n", xPixels, yPixels, freq, argv[4]);
- printf("\n");
- printf(" hTotal = %-4d vTotal = %-4d\n",
- t.h.hTotal, t.v.vTotal);
- printf(" hDisp = %-4d vDisp = %-4d\n",
- t.h.hDisp, t.v.vDisp);
- printf(" hSyncStart = %-4d vSyncStart = %-4d\n",
- t.h.hSyncStart, t.v.vSyncStart);
- printf(" hSyncEnd = %-4d vSyncEnd = %-4d\n",
- t.h.hSyncEnd, t.v.vSyncEnd);
- printf(" hFrontPorch = %-4d vFrontPorch = %-4d\n",
- t.h.hFrontPorch, t.v.vFrontPorch);
- printf(" hSyncWidth = %-4d vSyncWidth = %-4d\n",
- t.h.hSyncWidth, t.v.vSyncWidth);
- printf(" hBackPorch = %-4d vBackPorch = %-4d\n",
- t.h.hBackPorch, t.v.vBackPorch);
- printf("\n");
- printf(" Interlaced = %s\n", (t.interlace == 'I') ? "Yes" : "No");
- printf(" H sync pol = %c\n", t.hSyncPol);
- printf(" V sync pol = %c\n", t.vSyncPol);
- printf("\n");
- printf(" Vert freq = %.2f Hz\n", t.vFreq);
- printf(" Horiz freq = %.2f KHz\n", t.hFreq);
- printf(" Dot Clock = %.2f Mhz\n", t.dotClock);
- /* Dump to file in format used by SciTech Display Doctor */
- if ((f = fopen("UVCONFIG.CRT","w")) != NULL) {
- fprintf(f, "[%.0f %.0f]\n", xPixels, yPixels);
- fprintf(f, "%d %d %d %d '%c' %s\n",
- t.h.hTotal, t.h.hDisp,
- t.h.hSyncStart, t.h.hSyncEnd,
- t.hSyncPol, (t.interlace == 'I') ? "I" : "NI");
- fprintf(f, "%d %d %d %d '%c'\n",
- t.v.vTotal, t.v.vDisp,
- t.v.vSyncStart, t.v.vSyncEnd,
- t.vSyncPol);
- fprintf(f, "%.2f\n", t.dotClock);
- fclose(f);
- }
- }
- #endif /* TESTING */
|