board/MAI/bios_emulator/scitech/src/common/gtfcalc.c - uboot/windcharger - Git at Google

 /****************************************************************************
 *
 *                   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 */
	/****************************************************************************
	*
	* 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 + (2topMarginLines) + 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 */