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#define DUMTAB1SIZE 256
#define DUMTAB2SIZE 1024
#ifdef ROCKBOX
#include "plugin.h"
#include "../../pdbox.h"
#endif
#include "../src/m_pd.h"
#include "../src/m_fixed.h"
/* sigsqrt - square root good to 8 mantissa bits */
static float rsqrt_exptab[DUMTAB1SIZE], rsqrt_mantissatab[DUMTAB2SIZE];
static void init_rsqrt(void)
{
int i;
for (i = 0; i < DUMTAB1SIZE; i++)
{
#ifdef ROCKBOX
union f2i f2i;
f2i.i = (i ? (i == DUMTAB1SIZE-1 ? DUMTAB1SIZE-2 : i) : 1)<< 23;
rsqrt_exptab[i] = 1./sqrt(f2i.f);
#else /* ROCKBOX */
float f;
long l = (i ? (i == DUMTAB1SIZE-1 ? DUMTAB1SIZE-2 : i) : 1)<< 23;
*(long *)(&f) = l;
rsqrt_exptab[i] = 1./sqrt(f);
#endif /* ROCKBOX */
}
for (i = 0; i < DUMTAB2SIZE; i++)
{
float f = 1 + (1./DUMTAB2SIZE) * i;
rsqrt_mantissatab[i] = 1./sqrt(f);
}
}
typedef struct sigsqrt
{
t_object x_obj;
float x_f;
} t_sigsqrt;
static t_class *sigsqrt_class;
static void *sigsqrt_new(void)
{
t_sigsqrt *x = (t_sigsqrt *)pd_new(sigsqrt_class);
outlet_new(&x->x_obj, gensym("signal"));
x->x_f = 0;
return (x);
}
t_int *sigsqrt_perform(t_int *w) /* not static; also used in d_fft.c */
{
float *in = *(t_float **)(w+1), *out = *(t_float **)(w+2);
t_int n = *(t_int *)(w+3);
while (n--)
{
float f = *in;
long l = *(long *)(in++);
if (f < 0) *out++ = 0;
else
{
float g = rsqrt_exptab[(l >> 23) & 0xff] *
rsqrt_mantissatab[(l >> 13) & 0x3ff];
*out++ = f * (1.5 * g - 0.5 * g * g * g * f);
}
}
return (w + 4);
}
static void sigsqrt_dsp(t_sigsqrt *x, t_signal **sp)
{
#ifdef ROCKBOX
(void) x;
#endif
dsp_add(sigsqrt_perform, 3, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
}
void sqrt_tilde_setup(void)
{
init_rsqrt();
sigsqrt_class = class_new(gensym("sqrt~"), (t_newmethod)sigsqrt_new, 0,
sizeof(t_sigsqrt), 0, 0);
class_addcreator(sigsqrt_new, gensym("q8_sqrt~"), 0); /* old name */
CLASS_MAINSIGNALIN(sigsqrt_class, t_sigsqrt, x_f);
class_addmethod(sigsqrt_class, (t_method)sigsqrt_dsp, gensym("dsp"), 0);
}
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