math.c

来自「BLDC_SENSORLESS controller using freeesc」· C语言 代码 · 共 57 行

/*******************************************************************************
*
* Freescale Semiconductor Inc.
* (c) Copyright 2004-2006 Freescale Semiconductor, Inc.
* (c) Copyright 2001-2004 Motorola, Inc.
* ALL RIGHTS RESERVED.
*
********************************************************************************
*
* $File Name: math.c$
*
* $Date:      Jan-19-2007$
*
* $Version:   0.0.2.0$
*
* Description:
*   File contains basic mathematical modules
*
* Modules Included: 
*	  unsigned int umul_16x8 (unsigned int x, unsigned char y)
*
*****************************************************************************/

/*****************************************************************************
*  Included files
*****************************************************************************/

/* SDK system header files */
#include "math.h"


/*****************************************************************************
*
* Module: unsigned int umul_16x8(unsigned int x, unsigned char y)
*
* Description: Unsigned multiplication
*   x(L)*y/256+x(H)*y
*
* Returns: x*y/256
*
* Global Data:None
*
* Arguments:
*   x (in)
*   y (in)
*
* Range Issues: None
*
* Special Issues: None
*
*****************************************************************************/
unsigned int umul_16x8(unsigned int x, unsigned char y)
{
    return (unsigned int)((unsigned int)((unsigned char)(x>>8)*(y))+(unsigned char)(((unsigned char)(x)*(y))>>8));
}