From faada59567f8cb252f4a909116595ce309ff5828 Mon Sep 17 00:00:00 2001
From: "N.N." <krzyszcz@users.sourceforge.net>
Date: Fri, 23 May 2003 12:29:55 +0000
Subject: This commit was generated by cvs2svn to compensate for changes in
 r647, which included commits to RCS files with non-trunk default branches.

svn path=/trunk/externals/miXed/; revision=648
---
 cyclone/sickle/bitshift.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 cyclone/sickle/bitshift.c

(limited to 'cyclone/sickle/bitshift.c')

diff --git a/cyclone/sickle/bitshift.c b/cyclone/sickle/bitshift.c
new file mode 100644
index 0000000..db30fcd
--- /dev/null
+++ b/cyclone/sickle/bitshift.c
@@ -0,0 +1,130 @@
+/* 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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