visetxscale.c 2.78 KB

/*====================================================================
 * visetxscale.c
 *
 * Copyright 1995, Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This is UNPUBLISHED PROPRIETARY SOURCE CODE of Silicon Graphics,
 * Inc.; the contents of this file may not be disclosed to third
 * parties, copied or duplicated in any form, in whole or in part,
 * without the prior written permission of Silicon Graphics, Inc.
 *
 * RESTRICTED RIGHTS LEGEND:
 * Use, duplication or disclosure by the Government is subject to
 * restrictions as set forth in subdivision (c)(1)(ii) of the Rights
 * in Technical Data and Computer Software clause at DFARS
 * 252.227-7013, and/or in similar or successor clauses in the FAR,
 * DOD or NASA FAR Supplement. Unpublished - rights reserved under the
 * Copyright Laws of the United States.
 *====================================================================*/

/**************************************************************************
 *
 *  $Revision: 1.1.1.2 $
 *  $Date: 2002/10/29 08:06:43 $
 *  $Source: /root/leakn64/depot/rf/sw/bbplayer/libultra/monegi/vi/visetxscale.c,v $
 *
 **************************************************************************/


#include "osint.h"
#include "rcp.h"
#include "viint.h"
#include "assert.h"


/*
 * Name:   osViSetXScale
 *
 * Description:
 *	Calculate the X-offset based on the X-scaling factor.
 *	X-scaling can be applied to any of the 28 modes. The input parameter
 *	"value" can only be within 0.25 <= value <= 1.0.
 *
 * Globals Referenced: 
 *	__osViNext
 */
void
osViSetXScale(f32 value)
{
    register u32 nomValue;
    register u32 saveMask;

#ifdef _DEBUG
    /* Check that VI manager is running */
    if (!__osViDevMgr.active) {
	__osError(ERR_OSVISETXSCALE_VIMGR, 0);
	return;
    }

    /* Check for valid value range */
    if ((value < 0.25F) || (value > 1.0F)) {
	__osError(ERR_OSVISETXSCALE_VALUE, 1, OS_LOG_FLOAT(value));

	if (value < 0.25F) 
	  {
	    value = 0.25F;
	  }
	
	else
	  {
	    value = 1.0F;
	  }			     
    }
#endif

    /*
     * x_scale = value * (nomimal x_scale in mode);
     * x_offset= (7 * 0x400) / x_scale;
     */

    saveMask = __osDisableInt();

    __osViNext->x.factor = value;
    __osViNext->state |= VI_STATE_X_SCALE;

    /* Get nominal X_SCALE value (mask bit [11:0] from VI_X_SCALE reg) */
    nomValue = __osViNext->modep->comRegs.xScale & 0x0FFF;

    /* Calculate new x-scale value based on factor value */
    __osViNext->x.scale = ((u32)(__osViNext->x.factor*(float)nomValue))& 0x0FFF;

    /* Calculate new offset based on new x-scale value */

    /*
     * Don't do this; it just affects subpixel position, and is apparently
     * wrong.
    __osViNext->x.offset = (u16)((7 * VI_NOMINAL_X_SCALE) /__osViNext->x.scale);
    */

    __osRestoreInt(saveMask);

}  /* osViSetXScale */