From 65a9afa3bf17ba83670acc3fee4f18ea8efb5402 Mon Sep 17 00:00:00 2001
From: musil <tmusil@users.sourceforge.net>
Date: Fri, 6 Mar 2015 17:47:38 +0000
Subject: update sqrt algo to millers exported q8_sqrt

svn path=/trunk/externals/iem/iem_spec2/; revision=17435
---
 src/spec2_sqrt~.c | 60 ++++++++++++-------------------------------------------
 1 file changed, 13 insertions(+), 47 deletions(-)

(limited to 'src/spec2_sqrt~.c')

diff --git a/src/spec2_sqrt~.c b/src/spec2_sqrt~.c
index 275b9b0..6f25ee1 100644
--- a/src/spec2_sqrt~.c
+++ b/src/spec2_sqrt~.c
@@ -11,34 +11,6 @@ iem_spec2 written by Thomas Musil, Copyright (c) IEM KUG Graz Austria 2000 - 200
 
 static t_class *spec2_sqrt_tilde_class;
 
-#define SPEC2DUMTAB1SIZE 256
-#define SPEC2DUMTAB2SIZE 1024
-
-static t_float spec2_rsqrt_exptab[SPEC2DUMTAB1SIZE], spec2_rsqrt_mantissatab[SPEC2DUMTAB2SIZE];
-
-static void init_spec2_rsqrt(void)
-{
-#ifndef __x86_64__
-  int i;
-  
-  for (i=0; i<SPEC2DUMTAB1SIZE; i++)
-  {
-    t_float f;
-    long l = (i ? (i == SPEC2DUMTAB1SIZE-1 ? SPEC2DUMTAB1SIZE-2 : i) : 1)<< 23;
-    
-    *(long *)(&f) = l;
-    spec2_rsqrt_exptab[i] = 1.0f/sqrt(f); 
-  }
-  
-  for (i=0; i<SPEC2DUMTAB2SIZE; i++)
-  {
-    t_float f = 1.0f + (1.0f / (t_float)SPEC2DUMTAB2SIZE) * (t_float)i;
-    
-    spec2_rsqrt_mantissatab[i] = 1.0f / sqrt(f);  
-  }
-#endif
-}
-
 typedef struct _spec2_sqrt_tilde
 {
   t_object  x_obj;
@@ -52,27 +24,23 @@ static t_int *spec2_sqrt_tilde_perform(t_int *w)
   int n = w[3]+1;
   
   while(n--)
-  { 
-#ifdef __x86_64__
+  {
     t_sample f = *in++;
-    if (f<0.f) {
-      *out++=0.f;
-    } else {
-      *out++=sqrtf(f);
+
+    if (f<0.0)
+	{
+      *out++=0.0;
     }
+	else
+	{
+#if ((defined PD_MAJOR_VERSION && defined PD_MINOR_VERSION) && (PD_MAJOR_VERSION > 0 || PD_MINOR_VERSION > 43))
+	  t_float g = q8_rsqrt(f);
+            
+      *out++ = f*g*(1.5 - 0.5 * g * g * f);
 #else
-    t_float f = *in;
-    long l = *(long *)(in++);
-    
-    if(f < 0.0f)
-      *out++ = 0.0f;
-    else
-    {
-      t_float g = spec2_rsqrt_exptab[(l >> 23) & 0xff] * spec2_rsqrt_mantissatab[(l >> 13) & 0x3ff];
-      
-      *out++ = f*g*(1.5f - 0.5f*g*g*f);
-    }
+	  *out++ = sqrt(f);
 #endif
+    }
   }
   return(w+4);
 }
@@ -95,10 +63,8 @@ static void *spec2_sqrt_tilde_new(void)
 
 void spec2_sqrt_tilde_setup(void)
 {
-  init_spec2_rsqrt();
   spec2_sqrt_tilde_class = class_new(gensym("spec2_sqrt~"), (t_newmethod)spec2_sqrt_tilde_new,
     0, sizeof(t_spec2_sqrt_tilde), 0, 0);
   CLASS_MAINSIGNALIN(spec2_sqrt_tilde_class, t_spec2_sqrt_tilde, x_msi);
   class_addmethod(spec2_sqrt_tilde_class, (t_method)spec2_sqrt_tilde_dsp, gensym("dsp"), 0);
-//  class_sethelpsymbol(spec2_sqrt_tilde_class, gensym("iemhelp2/spec2_sqrt~-help"));
 }
-- 
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