From 5b5ee5fdf0297c744927b5ce4db5a50979aca752 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@higgsboson.tk>
Date: Thu, 5 Mar 2015 16:24:22 +0100
Subject: [PATCH] =?UTF-8?q?Loopcounter=20in=20bit=5Freverse=20opcode=20ein?=
 =?UTF-8?q?gef=C3=BCgt?=
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---
 fft.c        | 12 +++++++-----
 fft_inst.tie | 20 +++++++++++---------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/fft.c b/fft.c
index 81f48ca..0db9e2f 100644
--- a/fft.c
+++ b/fft.c
@@ -61,13 +61,14 @@ 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) {
-        mr = FFT_bit_reverse(m, mm);
+    for(m=0;;) {
+        FFT_bit_reverse(m, mr, mm);
 
+        if(m >= nn) break;
         if(mr <= m) continue;
+        
         tr = fr[m];
         fr[m] = fr[mr];
         fr[mr] = tr;
@@ -97,10 +98,10 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
         	    if(FFT_shift_check(j,m))
         	    {
         	        shift = 1;
+        	        ++scale;
         	        break;
         	    }
-        	}
-        	if(shift) ++scale;        	
+        	}       	
         }
         else
         {
@@ -128,6 +129,7 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
             {
             	i = RUR_FFT_loop();
             	
+                xtbool t;
             	FFT_loop_check(n, istep, t, j);
             	if(!t)
             		break;
diff --git a/fft_inst.tie b/fft_inst.tie
index 5c2a075..b2ea686 100644
--- a/fft_inst.tie
+++ b/fft_inst.tie
@@ -150,17 +150,19 @@ operation FFT_loop_check {in AR n, in AR istep, out BR t, out AR j} {inout FFT_l
 	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} {}
+operation FFT_bit_reverse {inout AR m, out AR mr, in AR mm} {}
 {
-	assign o = {
-		TIEmux(m[2:0], 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, b[0]),
-		TIEmux(m[2:0], 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, b[0], b[1]),
-		TIEmux(m[2:0], 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, b[0], b[1], b[2]),
-		TIEmux(m[2:0], 1'b0, 1'b0, 1'b0, 1'b0, b[0], b[1], b[2], b[3]),
-		TIEmux(m[2:0], 1'b0, 1'b0, 1'b0, b[0], b[1], b[2], b[3], b[4]),
-		TIEmux(m[2:0], 1'b0, 1'b0, b[0], b[1], b[2], b[3], b[4], b[5]),
-		TIEmux(m[2:0], 1'b0, b[0], b[1], b[2], b[3], b[4], b[5], b[6])
+	wire [15:0] x = TIEadd(m, 0, 1'b1);
+	assign mr = {
+		TIEmux(mm[2:0], 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, x[0]),
+		TIEmux(mm[2:0], 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, x[0], x[1]),
+		TIEmux(mm[2:0], 1'b0, 1'b0, 1'b0, 1'b0, 1'b0, x[0], x[1], x[2]),
+		TIEmux(mm[2:0], 1'b0, 1'b0, 1'b0, 1'b0, x[0], x[1], x[2], x[3]),
+		TIEmux(mm[2:0], 1'b0, 1'b0, 1'b0, x[0], x[1], x[2], x[3], x[4]),
+		TIEmux(mm[2:0], 1'b0, 1'b0, x[0], x[1], x[2], x[3], x[4], x[5]),
+		TIEmux(mm[2:0], 1'b0, x[0], x[1], x[2], x[3], x[4], x[5], x[6])
 	};
+	assign m = x; 
 }
 
 operation FFT_twiddle {out AR wr, out AR wi, in AR j, in BR shift, in BR inverse} {}