106 lines
2.3 KiB
C
106 lines
2.3 KiB
C
|
#include <m_pd.h>
|
||
|
|
#include <m_fixed.h>
|
||
|
|
|
||
|
|
/* sigrsqrt - reciprocal square root good to 8 mantissa bits */
|
||
|
|
|
||
|
|
#define DUMTAB1SIZE 256
|
||
|
|
#define DUMTAB2SIZE 1024
|
||
|
|
|
||
|
|
static float rsqrt_exptab[DUMTAB1SIZE], rsqrt_mantissatab[DUMTAB2SIZE];
|
||
|
|
|
||
|
|
static void init_rsqrt(void)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
for (i = 0; i < DUMTAB1SIZE; i++)
|
||
|
|
{
|
||
|
|
float f;
|
||
|
|
long l = (i ? (i == DUMTAB1SIZE-1 ? DUMTAB1SIZE-2 : i) : 1)<< 23;
|
||
|
|
*(long *)(&f) = l;
|
||
|
|
rsqrt_exptab[i] = 1./sqrt(f);
|
||
|
|
}
|
||
|
|
for (i = 0; i < DUMTAB2SIZE; i++)
|
||
|
|
{
|
||
|
|
float f = 1 + (1./DUMTAB2SIZE) * i;
|
||
|
|
rsqrt_mantissatab[i] = 1./sqrt(f);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* these are used in externs like "bonk" */
|
||
|
|
|
||
|
|
float q8_rsqrt(float f)
|
||
|
|
{
|
||
|
|
long l = *(long *)(&f);
|
||
|
|
if (f < 0) return (0);
|
||
|
|
else return (rsqrt_exptab[(l >> 23) & 0xff] *
|
||
|
|
rsqrt_mantissatab[(l >> 13) & 0x3ff]);
|
||
|
|
}
|
||
|
|
|
||
|
|
float q8_sqrt(float f)
|
||
|
|
{
|
||
|
|
long l = *(long *)(&f);
|
||
|
|
if (f < 0) return (0);
|
||
|
|
else return (f * rsqrt_exptab[(l >> 23) & 0xff] *
|
||
|
|
rsqrt_mantissatab[(l >> 13) & 0x3ff]);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* the old names are OK unless we're in IRIX N32 */
|
||
|
|
|
||
|
|
#ifndef N32
|
||
|
|
float qsqrt(float f) {return (q8_sqrt(f)); }
|
||
|
|
float qrsqrt(float f) {return (q8_rsqrt(f)); }
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
typedef struct sigrsqrt
|
||
|
|
{
|
||
|
|
t_object x_obj;
|
||
|
|
float x_f;
|
||
|
|
} t_sigrsqrt;
|
||
|
|
|
||
|
|
static t_class *sigrsqrt_class;
|
||
|
|
|
||
|
|
static void *sigrsqrt_new(void)
|
||
|
|
{
|
||
|
|
t_sigrsqrt *x = (t_sigrsqrt *)pd_new(sigrsqrt_class);
|
||
|
|
outlet_new(&x->x_obj, gensym("signal"));
|
||
|
|
x->x_f = 0;
|
||
|
|
return (x);
|
||
|
|
}
|
||
|
|
|
||
|
|
static t_int *sigrsqrt_perform(t_int *w)
|
||
|
|
{
|
||
|
|
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++ = 1.5 * g - 0.5 * g * g * g * f;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return (w + 4);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void sigrsqrt_dsp(t_sigrsqrt *x, t_signal **sp)
|
||
|
|
{
|
||
|
|
dsp_add(sigrsqrt_perform, 3, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
|
||
|
|
}
|
||
|
|
|
||
|
|
void rsqrt_tilde_setup(void)
|
||
|
|
{
|
||
|
|
init_rsqrt();
|
||
|
|
sigrsqrt_class = class_new(gensym("rsqrt~"), (t_newmethod)sigrsqrt_new, 0,
|
||
|
|
sizeof(t_sigrsqrt), 0, 0);
|
||
|
|
/* an old name for it: */
|
||
|
|
class_addcreator(sigrsqrt_new, gensym("q8_rsqrt~"), 0);
|
||
|
|
CLASS_MAINSIGNALIN(sigrsqrt_class, t_sigrsqrt, x_f);
|
||
|
|
class_addmethod(sigrsqrt_class, (t_method)sigrsqrt_dsp, gensym("dsp"), 0);
|
||
|
|
}
|
||
|
|
|