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/* Copyright (c) 2002-2003 krzYszcz and others.
* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt," in this distribution. */
/* When bit-shifting 32-bit values, gcc (intel?) bashes the second operand
modulo 32. In msp x << 32 gives 0, x >> 32 gives a propagated sign bit
(as expected). Mimicking that is clumsy. LATER consider making the calcs
more generic (use long long values?) */
#include "m_pd.h"
#include "sickle/sic.h"
//#define BITSHIFT_DEBUG
typedef struct _bitshift
{
t_sic x_sic;
int x_convert1;
int x_lshift;
int x_rshift;
int x_lover;
} t_bitshift;
static t_class *bitshift_class;
static t_int *bitshift_perform(t_int *w)
{
t_bitshift *x = (t_bitshift *)(w[1]);
int nblock = (int)(w[2]);
t_float *in = (t_float *)(w[3]);
t_float *out = (t_float *)(w[4]);
/* LATER think about performance */
if (x->x_lshift)
{
unsigned int shift = x->x_lshift;
if (x->x_convert1) while (nblock--)
{
/* CHECKED */
t_int i = ((t_int)*in++ << shift);
*out++ = (t_float)i;
}
else while (nblock--)
{
/* CHECKED */
t_int i = (*(t_int *)(t_float *)in++ << shift);
*out++ = *(t_float *)&i;
}
}
else if (x->x_rshift)
{
unsigned int shift = x->x_rshift;
if (x->x_convert1) while (nblock--)
{
/* CHECKME */
t_int i = ((t_int)*in++ >> shift);
*out++ = (t_float)i;
}
else while (nblock--)
{
/* CHECKME */
t_int i = (*(t_int *)(t_float *)in++ >> shift);
*out++ = *(t_float *)&i;
}
}
else if (x->x_lover)
while (nblock--) *out++ = 0; /* CHECKED both modes */
else
while (nblock--) *out++ = *in++; /* CHECKED both modes */
return (w + 5);
}
static void bitshift_dsp(t_bitshift *x, t_signal **sp)
{
dsp_add(bitshift_perform, 4, x, sp[0]->s_n, sp[0]->s_vec, sp[1]->s_vec);
}
static void bitshift_mode(t_bitshift *x, t_floatarg f)
{
int i = (int)f;
x->x_convert1 = (i > 0); /* CHECKED */
}
static void bitshift_shift(t_bitshift *x, t_floatarg f)
{
int i = (int)f;
int nbits = sizeof(t_int) * 8;
x->x_lshift = x->x_rshift = 0;
x->x_lover = 0;
if (i > 0)
{
#ifdef BITSHIFT_DEBUG
post("%.8x << %d == %.8x, %.8x << %d == %.8x",
1, i, 1 << i, -1, i, -1 << i);
#endif
if (i < nbits)
x->x_lshift = i;
else
x->x_lover = 1;
}
else if (i < 0)
{
#ifdef BITSHIFT_DEBUG
post("%.8x >> %d == %.8x, %.8x >> %d == %.8x",
0x7fffffff, -i, 0x7fffffff >> -i, -1, -i, -1 >> -i);
#endif
x->x_rshift = (i <= -nbits ? nbits - 1 : -i);
}
}
static void *bitshift_new(t_floatarg f1, t_floatarg f2)
{
t_bitshift *x = (t_bitshift *)pd_new(bitshift_class);
outlet_new((t_object *)x, &s_signal);
bitshift_shift(x, f1);
bitshift_mode(x, f2);
return (x);
}
void bitshift_tilde_setup(void)
{
bitshift_class = class_new(gensym("bitshift~"),
(t_newmethod)bitshift_new, 0,
sizeof(t_bitshift), 0,
A_DEFFLOAT, A_DEFFLOAT, 0);
sic_setup(bitshift_class, bitshift_dsp, SIC_FLOATTOSIGNAL);
class_addmethod(bitshift_class, (t_method)bitshift_mode,
gensym("mode"), A_FLOAT, 0);
class_addmethod(bitshift_class, (t_method)bitshift_shift,
gensym("shift"), A_FLOAT, 0);
}
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