From 95c3e58ff95605dc3db8b17ad39f7ffeebe181c0 Mon Sep 17 00:00:00 2001
From: Connor Olding <cloningdonor@gmail.com>
Date: Tue, 7 Apr 2015 11:33:11 -0700
Subject: [PATCH] split decimate, interpolate

---
 include/os2piir_stereo.h    | 58 ++++++++++++++++++++-----------------
 include/process_nonlinear.h | 10 +++----
 2 files changed, 36 insertions(+), 32 deletions(-)

diff --git a/include/os2piir_stereo.h b/include/os2piir_stereo.h
index 5710154..f2a70a6 100644
--- a/include/os2piir_stereo.h
+++ b/include/os2piir_stereo.h
@@ -14,7 +14,6 @@ typedef struct {
 	v2df ao[8], bo[8];
 	v2df at[8], bt[8];
 	v2df x1, x2, x3;
-	int i;
 } halfband_t;
 
 INNER void
@@ -60,39 +59,46 @@ halfband(halfband_t *h, v2df x0)
 }
 
 INNER v2df
-decimate(halfband_t *h, v2df x0)
+decimate_a(halfband_t *h, v2df x0)
 {
 	v2df c[8];
-	if ((h->i = !h->i)) {
-		halfband_b(c, h->bo, x0, h->x2);
-		copy(h->bo, c);
-		h->x2 = h->x1;
-		h->x1 = x0;
-		return V(0);
-	} else {
-		halfband_a(c, h->ao, x0, h->x2);
-		copy(h->ao, c);
-		h->x2 = h->x1;
-		h->x1 = x0;
-		return (c[7] + h->bo[7])*V(0.5);
-	}
+	halfband_b(c, h->bo, x0, h->x2);
+	copy(h->bo, c);
+	h->x2 = h->x1;
+	h->x1 = x0;
+	return V(0);
+}
+
+INNER v2df
+decimate_b(halfband_t *h, v2df x0)
+{
+	v2df c[8];
+	halfband_a(c, h->ao, x0, h->x2);
+	copy(h->ao, c);
+	h->x2 = h->x1;
+	h->x1 = x0;
+	return (c[7] + h->bo[7])*V(0.5);
 }
 
 // note: do not zero-stuff! send the input each time.
 INNER v2df
-interpolate(halfband_t *h, v2df x0)
+interpolate_a(halfband_t *h, v2df x0)
 {
 	v2df c[8];
-	if ((h->i = !h->i)) {
-		halfband_a(c, h->ao, x0, h->x1);
-		copy(h->ao, c);
-		return c[7];
-	} else {
-		halfband_b(c, h->bo, x0, h->x1);
-		copy(h->bo, c);
-		h->x1 = x0;
-		return c[7];
-	}
+	halfband_a(c, h->ao, x0, h->x1);
+	copy(h->ao, c);
+	return c[7];
+}
+
+// note: do not zero-stuff! send the input each time.
+INNER v2df
+interpolate_b(halfband_t *h, v2df x0)
+{
+	v2df c[8];
+	halfband_b(c, h->bo, x0, h->x1);
+	copy(h->bo, c);
+	h->x1 = x0;
+	return c[7];
 }
 
 #undef copy
diff --git a/include/process_nonlinear.h b/include/process_nonlinear.h
index 603e489..5146662 100644
--- a/include/process_nonlinear.h
+++ b/include/process_nonlinear.h
@@ -30,9 +30,8 @@
 		}
 
 		for (ulong i = 0; i < rem; i++) {
-			hb_up->i = 0; // so compiler can optimize
-			over[i*2+0] = interpolate(hb_up, buf[i]);
-			over[i*2+1] = interpolate(hb_up, buf[i]);
+			over[i*2+0] = interpolate_a(hb_up, buf[i]);
+			over[i*2+1] = interpolate_b(hb_up, buf[i]);
 		}
 
 		for (ulong i = 0; i < rem2; i++) {
@@ -40,9 +39,8 @@
 		}
 
 		for (ulong i = 0; i < rem; i++) {
-			hb_down->i = 0; // so compiler can optimize
-			         decimate(hb_down, over[i*2+0]);
-			buf[i] = decimate(hb_down, over[i*2+1]);
+			         decimate_a(hb_down, over[i*2+0]);
+			buf[i] = decimate_b(hb_down, over[i*2+1]);
 		}
 
 		for (ulong i = 0; i < rem; i++) {