common_audio/signal_processing: Remove macro WEBRTC_SPL_SUB_SAT_W32

This macro is literally using the function WebRtcSpl_SubSatW32(), hence there is no need for a macro.

BUG=3348, 3353
TESTED=locally on Linux and trybots
R=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/14149004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@6899 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/common_audio/signal_processing/include/signal_processing_library.h b/common_audio/signal_processing/include/signal_processing_library.h
index 36ee34f..72a5388 100644
--- a/common_audio/signal_processing/include/signal_processing_library.h
+++ b/common_audio/signal_processing/include/signal_processing_library.h
@@ -103,7 +103,6 @@
 #define WEBRTC_SPL_SAT(a, b, c)         (b > a ? a : b < c ? c : b)
 #define WEBRTC_SPL_MUL_32_16(a, b)      ((a) * (b))
 
-#define WEBRTC_SPL_SUB_SAT_W32(a, b)    WebRtcSpl_SubSatW32(a, b)
 #define WEBRTC_SPL_ADD_SAT_W16(a, b)    WebRtcSpl_AddSatW16(a, b)
 
 // Shifting with negative numbers allowed
diff --git a/common_audio/signal_processing/signal_processing_unittest.cc b/common_audio/signal_processing/signal_processing_unittest.cc
index 2a34708..603294b 100644
--- a/common_audio/signal_processing/signal_processing_unittest.cc
+++ b/common_audio/signal_processing/signal_processing_unittest.cc
@@ -69,7 +69,6 @@
     EXPECT_EQ(21, WEBRTC_SPL_SAT(a, B, A));
     EXPECT_EQ(-49149, WEBRTC_SPL_MUL_32_16(a, b));
 
-    EXPECT_EQ(16386, WEBRTC_SPL_SUB_SAT_W32(a, b));
     EXPECT_EQ(16380, WEBRTC_SPL_ADD_SAT_W16(a, b));
 
     // Shifting with negative numbers allowed
diff --git a/common_audio/signal_processing/splitting_filter.c b/common_audio/signal_processing/splitting_filter.c
index dbda042..966eef7 100644
--- a/common_audio/signal_processing/splitting_filter.c
+++ b/common_audio/signal_processing/splitting_filter.c
@@ -74,14 +74,16 @@
 
     // First loop, use the states stored in memory.
     // "diff" should be safe from wrap around since max values are 2^25
-    diff = WEBRTC_SPL_SUB_SAT_W32(in_data[0], filter_state[1]); // = (x[0] - y_1[-1])
+    // diff = (x[0] - y_1[-1])
+    diff = WebRtcSpl_SubSatW32(in_data[0], filter_state[1]);
     // y_1[0] =  x[-1] + a_1 * (x[0] - y_1[-1])
     out_data[0] = WEBRTC_SPL_SCALEDIFF32(filter_coefficients[0], diff, filter_state[0]);
 
     // For the remaining loops, use previous values.
     for (k = 1; k < data_length; k++)
     {
-        diff = WEBRTC_SPL_SUB_SAT_W32(in_data[k], out_data[k - 1]); // = (x[n] - y_1[n-1])
+        // diff = (x[n] - y_1[n-1])
+        diff = WebRtcSpl_SubSatW32(in_data[k], out_data[k - 1]);
         // y_1[n] =  x[n-1] + a_1 * (x[n] - y_1[n-1])
         out_data[k] = WEBRTC_SPL_SCALEDIFF32(filter_coefficients[0], diff, in_data[k - 1]);
     }
@@ -91,12 +93,14 @@
     filter_state[1] = out_data[data_length - 1]; // y_1[N-1], becomes y_1[-1] next time
 
     // Second all-pass cascade; filter from out_data to in_data.
-    diff = WEBRTC_SPL_SUB_SAT_W32(out_data[0], filter_state[3]); // = (y_1[0] - y_2[-1])
+    // diff = (y_1[0] - y_2[-1])
+    diff = WebRtcSpl_SubSatW32(out_data[0], filter_state[3]);
     // y_2[0] =  y_1[-1] + a_2 * (y_1[0] - y_2[-1])
     in_data[0] = WEBRTC_SPL_SCALEDIFF32(filter_coefficients[1], diff, filter_state[2]);
     for (k = 1; k < data_length; k++)
     {
-        diff = WEBRTC_SPL_SUB_SAT_W32(out_data[k], in_data[k - 1]); // =(y_1[n] - y_2[n-1])
+        // diff = (y_1[n] - y_2[n-1])
+        diff = WebRtcSpl_SubSatW32(out_data[k], in_data[k - 1]);
         // y_2[0] =  y_1[-1] + a_2 * (y_1[0] - y_2[-1])
         in_data[k] = WEBRTC_SPL_SCALEDIFF32(filter_coefficients[1], diff, out_data[k-1]);
     }
@@ -105,12 +109,14 @@
     filter_state[3] = in_data[data_length - 1]; // y_2[N-1], becomes y_2[-1] next time
 
     // Third all-pass cascade; filter from in_data to out_data.
-    diff = WEBRTC_SPL_SUB_SAT_W32(in_data[0], filter_state[5]); // = (y_2[0] - y[-1])
+    // diff = (y_2[0] - y[-1])
+    diff = WebRtcSpl_SubSatW32(in_data[0], filter_state[5]);
     // y[0] =  y_2[-1] + a_3 * (y_2[0] - y[-1])
     out_data[0] = WEBRTC_SPL_SCALEDIFF32(filter_coefficients[2], diff, filter_state[4]);
     for (k = 1; k < data_length; k++)
     {
-        diff = WEBRTC_SPL_SUB_SAT_W32(in_data[k], out_data[k - 1]); // = (y_2[n] - y[n-1])
+        // diff = (y_2[n] - y[n-1])
+        diff = WebRtcSpl_SubSatW32(in_data[k], out_data[k - 1]);
         // y[n] =  y_2[n-1] + a_3 * (y_2[n] - y[n-1])
         out_data[k] = WEBRTC_SPL_SCALEDIFF32(filter_coefficients[2], diff, in_data[k-1]);
     }