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-rw-r--r--externals/vanilla/sqrt~.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/externals/vanilla/sqrt~.c b/externals/vanilla/sqrt~.c
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index 00000000..ea3da693
--- /dev/null
+++ b/externals/vanilla/sqrt~.c
@@ -0,0 +1,56 @@
+/* Copyright (c) 1997-2001 Miller Puckette and others.
+* For information on usage and redistribution, and for a DISCLAIMER OF ALL
+* WARRANTIES, see the file, "LICENSE.txt," in this distribution. */
+
+#include "d_math.h"
+
+static float rsqrt_exptab[DUMTAB1SIZE], rsqrt_mantissatab[DUMTAB2SIZE];
+
+typedef struct sigsqrt
+{
+ t_object x_obj;
+ t_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 */
+{
+ t_sample *in = *(t_sample **)(w+1), *out = *(t_sample **)(w+2);
+ t_int n = *(t_int *)(w+3);
+ while (n--)
+ {
+ t_sample f = *in;
+ long l = *(long *)(in++);
+ if (f < 0) *out++ = 0;
+ else
+ {
+ t_sample 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)
+{
+ dsp_add(sigsqrt_perform, 3, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);
+}
+
+void sqrt_tilde_setup(void)
+{
+ 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);
+}