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path: root/src/iemlib1/sigiem_sqrt4.c
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/* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt," in this distribution.

iemlib1 written by Thomas Musil, Copyright (c) IEM KUG Graz Austria 2000 - 2003 */

#ifdef NT
#pragma warning( disable : 4244 )
#pragma warning( disable : 4305 )
#endif


#include "m_pd.h"
#include "iemlib.h"
#include <math.h>
#include <stdio.h>
#include <string.h>

#define IEMSQRT4TAB1SIZE 256
#define IEMSQRT4TAB2SIZE 1024

/* ------------------------ iem_sqrt4~ ----------------------------- */

float *iem_sqrt4_exptab=(float *)0L;
float *iem_sqrt4_mantissatab=(float *)0L;

static t_class *sigiem_sqrt4_class;

typedef struct _sigiem_sqrt4
{
	t_object x_obj;
	float x_msi;
} t_sigiem_sqrt4;

static t_int *sigiem_sqrt4_perform(t_int *w)
{
	t_float *in = (t_float *)(w[1]);
	t_float *out = (t_float *)(w[2]);
	t_int n = (t_int)(w[3])/4;

	while(n--)
	{	
		float f = *in;
		float g, h;
		long l = *(long *)(in);
		
		if(f < 0.0f)
		{
			*out++ = 0.0f;
			*out++ = 0.0f;
			*out++ = 0.0f;
			*out++ = 0.0f;
		}
		else
		{
			g = iem_sqrt4_exptab[(l >> 23) & 0xff] * iem_sqrt4_mantissatab[(l >> 13) & 0x3ff];
			h = f * (1.5f * g - 0.5f * g * g * g * f);
			*out++ = h;
			*out++ = h;
			*out++ = h;
			*out++ = h;
		}
		in += 4;
	}
	return(w+4);
}

static void sigiem_sqrt4_dsp(t_sigiem_sqrt4 *x, t_signal **sp)
{
	dsp_add(sigiem_sqrt4_perform, 3, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
}

static void sigiem_sqrt4_maketable(void)
{
	int i;
	float f;
	long l;

	if(!iem_sqrt4_exptab)
	{
		iem_sqrt4_exptab = (float *)getbytes(sizeof(float) * IEMSQRT4TAB1SIZE);
		for(i=0; i<IEMSQRT4TAB1SIZE; i++)
    {
			l = (i ? (i == IEMSQRT4TAB1SIZE-1 ? IEMSQRT4TAB1SIZE-2 : i) : 1)<< 23;
			*(long *)(&f) = l;
			iem_sqrt4_exptab[i] = 1.0f/sqrt(f);	
    }
	}
	if(!iem_sqrt4_mantissatab)
	{
		iem_sqrt4_mantissatab = (float *)getbytes(sizeof(float) * IEMSQRT4TAB2SIZE);
		for(i=0; i<IEMSQRT4TAB2SIZE; i++)
    {
			f = 1.0f + (1.0f/(float)IEMSQRT4TAB2SIZE) * (float)i;
			iem_sqrt4_mantissatab[i] = 1.0f/sqrt(f);	
    }
	}
}

static void *sigiem_sqrt4_new(void)
{
	t_sigiem_sqrt4 *x = (t_sigiem_sqrt4 *)pd_new(sigiem_sqrt4_class);

	outlet_new(&x->x_obj, gensym("signal"));
	x->x_msi = 0;
	return (x);
}

void sigiem_sqrt4_setup(void)
{
	sigiem_sqrt4_class = class_new(gensym("iem_sqrt4~"), (t_newmethod)sigiem_sqrt4_new, 0,
				 sizeof(t_sigiem_sqrt4), 0, 0);
	CLASS_MAINSIGNALIN(sigiem_sqrt4_class, t_sigiem_sqrt4, x_msi);
	class_addmethod(sigiem_sqrt4_class, (t_method)sigiem_sqrt4_dsp, gensym("dsp"), 0);
	sigiem_sqrt4_maketable();
	class_sethelpsymbol(sigiem_sqrt4_class, gensym("iemhelp/help-iem_sqrt4~"));
}