dspfunc.c

DSP中使用PWM模块对电机进行控制

/** ###################################################################
**
**     (c) Freescale Semiconductor
**     2004 All Rights Reserved
**
**
**     (c) Copyright UNIS, spol. s r.o. 1997-2004
**     UNIS, spol. s r.o.
**     Jundrovska 33
**     624 00 Brno
**     Czech Republic
**     http      : www.processorexpert.com
**     mail      : [e-mail]
** ###################################################################*/

#include "port.h"
#include "arch.h"

#include "dspfunc.h"



/*****************************************************************************/
void dspfuncInitialize(void)
{

  /* Set saturation mode, set 2's complement rounding, and reset limit bit */

  archSetSat32();
  archSet2CompRound();
  archResetLimitBit();
}


/*****************************************************************************/
/* Primitives (impyuu, impysu) added to circumvent CW problems */

#if 0
// CW V2 compiler is used to implement these functions for V1 compatibility

#undef add

asm unsigned long impyuu(unsigned short unsigA, unsigned short unsigB)
{  /* y0 = unsigA, y1 = unsigB */
  push  OMR      /* store the status of the OMR register */
  bfclr #0x10,OMR    /* set saturation OFF (SA = 0) */
  bfset #0x0100,OMR   /* set Condition Code bit (CC) bit to 1 */
  move  y0,x0      /* save y0 (unsigA) to x0 */
  andc  #0x7fff,y0    /* mask the sign position - represent the positive sign number */
  mpysu y0,y1,a    /* multiply signed operand (y0) and unsigned operand (unsigB = y1)*/
  tstw  x0        /* test if MSB is 0 or 1 (set N flag in SR reg) */
  bge   OVER      /* jump accordig to N flag - if 1 pass, if 0 jump */
  movei #0x7fff,x0  /* store maximum positive value to x0 */
  macsu x0,y1,a    /* multiply 0x7fff with unsigB and accumulate with the previous product */
  clr   b        /* clear B register, used as a temporary location */
  move  y1,b0      /* move unsigB to the LSP of B */
  add   b,a        /* correct the result, needed two times because of fractional multiplication */
  add   b,a       /*  --||-- */
  OVER:
    asr   a               /* fractional into integer number conversion */
  bge   OVERFLOW        /* branch according to V flag - if 1 jump, if 0 pass */
  bfclr #0x8000,a1    /* correction of the sign position - clear MSB bit in A */
  OVERFLOW:
  pop   OMR             /* restore original contents of OMR */
    rts
}


/* asm Int32 impysu(Int16 sig, UInt16 unsig) */
asm long impysu(short sig, unsigned short unsig)
{
  mpysu y0,y1,a
  asr a
  rts
}

#define add             __add

#else

unsigned long impyuu(unsigned short unsigA, unsigned short unsigB)
{
  return (unsigned long)unsigA * unsigB;
}

long impysu(short sig, unsigned short unsig)
{
  return (long)sig * unsig;
}

#endif