From f8cfb71c629ba02682612415513bf557fccd6592 Mon Sep 17 00:00:00 2001
From: unknown <alfred.krohmer@ENTMCNODE3.ifn.et.tu-dresden.de>
Date: Wed, 4 Mar 2015 18:52:18 +0100
Subject: [PATCH] Inneren Schleifenheader und Scaling als TIE Instruktionen
 implementiert

---
 fft.c        | 29 +++++++++++++++--------------
 fft_inst.tie | 24 ++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/fft.c b/fft.c
index 9d1550f..c4754c7 100644
--- a/fft.c
+++ b/fft.c
@@ -61,6 +61,7 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
     scale = 0;
     
     int mm = m;
+    xtbool t;
 
     /* decimation in time - re-order data */
     for(m=1; m<=nn; ++m) {
@@ -87,19 +88,14 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
             shift = 0;
             for(i=0; i<n; ++i)
             {
-                j = fr[i];
-                if(j < 0) j = -j;
-
-                m = fi[i];
-                if(m < 0) m = -m;
-
-                if(j > 16383 || m > 16383)
-                {
-                    shift = 1;
-                    break;
-                }
+            	xtbool sshift;
+            	FFT_scale(fr[i], fi[i], sshift, scale);
+            	if(sshift)
+            	{
+            		shift = (int) sshift;
+            		break;
+            	}
             }
-            if(shift) ++scale;
         }
         else
         {
@@ -122,9 +118,14 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
             FFT_reg reg;
             fixed *reg_s = ((fixed*) &reg);
             
-            for(i=m; i<n; i+=istep)
+            WUR_FFT_loop(m);
+            while(1)
             {
-                j = i + l;
+            	i = RUR_FFT_loop();
+            	
+            	FFT_loop_check(n, istep, t, j);
+            	if(!t)
+            		break;
                 
                 reg_s[3] = fr[i];
                 reg_s[2] = fr[j];
diff --git a/fft_inst.tie b/fft_inst.tie
index 05ce3a6..34d71ab 100644
--- a/fft_inst.tie
+++ b/fft_inst.tie
@@ -132,6 +132,30 @@ table SIN_wave 16 1024 {
 
 regfile FFT_reg 64 2 fftv
 
+state FFT_loop 32 add_read_write
+
+operation FFT_scale {in AR fr, in AR fi, out BR shift, inout AR scale} {}
+{
+	wire [4:0] jc1 = TIEcmp(fr[15:0], 16'd16383, 1'b1);
+	wire [4:0] mc1 = TIEcmp(fi[15:0], 16'd16383, 1'b1);
+	wire [4:0] jc2 = TIEcmp(fr[15:0], 16'd49153, 1'b1);
+	wire [4:0] mc2 = TIEcmp(fi[15:0], 16'd49153, 1'b1);
+	
+	wire x = jc1[0] | mc1[0] | jc2[4] | mc2[4];
+	assign shift = x;
+	
+	wire [15:0] scaleInc = TIEadd(scale, 16'b0, 1'b1);
+	assign scale = TIEmux(x, scale, scaleInc);
+} 
+
+operation FFT_loop_check {in AR n, in AR istep, out BR t, out AR j} {inout FFT_loop}
+{
+	wire [4:0] cmpres = TIEcmp(FFT_loop, n, 1'b0);
+	assign t = cmpres[4];
+	assign FFT_loop = TIEadd(FFT_loop, istep, 1'b0);
+	assign j = TIEadd(FFT_loop, {1'b0, istep[15:1]}, 1'b0);
+}
+
 operation FFT_bit_reverse {in AR b, out AR o, in AR m} {}
 {
 	assign o = {