source: buchla-68k/ram/wscalc.c@ fa38804

/*
   =============================================================================
        wscalc.c -- MIDAS-VII waveshape editor harmonic functions
        Version 9 -- 1988-09-09 -- D.N. Lynx Crowe
   =============================================================================
*/

#include "ram.h"

#define WAVESMAX        1023
#define WAVESMIN        1023

#include "knmtab.h"             /* short knmtab[NUMHARM][NUMWPCAL]; */

/*
   =============================================================================
        adj() -- adjust the coefficients in vknm[wshar][] for a new value
   =============================================================================
*/

void adj(int16_t wshar)
{
        register int16_t wspnt;
        register int32_t harval;
        register int16_t *kp;
        register int32_t *vp;

        vp = &vknm[wshar][0];

        harval = vmtab[wshar];

        if (harval) {

                kp = &knmtab[wshar][0];

                for (wspnt = 0; wspnt < NUMWPCAL; wspnt++)
                        *vp++ = *kp++ * harval;

        } else {

                for (wspnt = 0; wspnt < NUMWPCAL; wspnt++)
                        *vp++ = 0;
        }
}

/*
   =============================================================================
        wadj() -- adjust the coefficients for all harmonics
   =============================================================================
*/

void wadj(void)
{
        register int16_t wshar;

        for (wshar = 0; wshar < NUMHARM; wshar++)
                adj(wshar);
}

/*
   =============================================================================
        clrwsa() -- clear waveshape table harmonic work areas
   =============================================================================
*/

void clrwsa(void)
{
        memsetw(offsets, 0, NUMWPCAL);
        memsetw(vknm,    0, (NUMHARM * NUMWPCAL) << 1);
        memsetw(vmtab,   0, NUMHARM);
}

/*
   =============================================================================
        wscalc() -- calculate a waveshape from its harmonics and offsets
   =============================================================================
*/

void wscalc(void)
{
        register int16_t wspnt, wshar;
        register int32_t hfac, hmax, temp;

        hmax = WAVESMIN;        /* set minimum scaling value */

        for (wspnt = 0; wspnt < NUMWPCAL; wspnt++) {

                temp = 0;       /* sum up the harmonics */

                for (wshar = 0; wshar < NUMHARM; wshar++)
                        temp += vknm[wshar][wspnt];

                /* add in the offsets */

                hwave[wspnt] = (temp / 100) + offsets[wspnt];

                /* adjust the maximum value seen */

                if ((temp = abs(hwave[wspnt])) > hmax)
                        hmax = temp;
        }

        /* calculate the scale factor */

        hfac = ((int32_t)WAVESMAX << 16) / hmax;

        /* scale the waveshape */

        for (wspnt = 0; wspnt < NUMWPCAL; wspnt++)
                wsbuf[wspnt] = (hwave[wspnt] * hfac) >> 16;
}