1 files changed, 56 insertions, 0 deletions
diff --git a/externals/vanilla/sqrt~.c b/externals/vanilla/sqrt~.c
new file mode 100644
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);
+}