--- configure.in	2006-01-16 20:04:58.268962424 +0300
+++ configure.in	2006-01-16 20:07:43.681815848 +0300
@@ -155,6 +155,9 @@
               XF_CFLAGS="$XF_CFLAGS -DBENCHMARK"
             fi
           ;;
+	  x86_64-*-*)
+	    autodetect=no
+	    ARCH_DEFINES="-DARCH_X86_64 -march=k8"
         esac  
       ;;
       *)
--- src/iir.c	2006-01-16 20:01:23.000000000 +0300
+++ src/iir.c	2006-01-16 20:09:50.580524312 +0300
@@ -60,7 +60,7 @@
   clean_history();
 }
 
-#ifdef ARCH_X86
+#if defined(ARCH_X86) || defined(ARCH_X86_64)
 /* Round function provided by Frank Klemm which saves around 100K
  * CPU cycles in my PIII for each call to the IIR function with 4K samples
  */
--- src/iir_fpu.c	2006-01-15 03:26:32.000000000 +0300
+++ src/iir_fpu.c	2006-01-16 20:10:22.492672928 +0300
@@ -163,7 +163,7 @@
 #ifdef ARCH_PPC
       tempgint = round_ppc(out[channel]);
 #else
-#ifdef ARCH_X86
+#if defined(ARCH_X86) || defined(ARCH_X86_64)
       tempgint = round_trick(out[channel]);
 #else
       tempgint = (int)out[channel];
--- src/iir.h	2006-01-15 03:26:32.000000000 +0300
+++ src/iir.h	2006-01-16 20:15:35.987014544 +0300
@@ -58,7 +58,7 @@
 
 __inline__ int iir(gpointer * d, gint length, gint srate, gint nch);
 
-#ifdef ARCH_X86
+#if defined(ARCH_X86) || defined(ARCH_X86_64)
 __inline__ int round_trick(float floatvalue_to_round);
 #endif
 #ifdef ARCH_PPC