From fa552f11ef1f96afab715c9653c705e3fbbe2a74 Mon Sep 17 00:00:00 2001
From: aroulin <andy.roulin@epfl.ch>
Date: Sun, 23 Aug 2015 15:13:36 +0200
Subject: Shader: RCP and RSQ computes only the 1st component

---
 src/video_core/shader/shader_interpreter.cpp | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

(limited to 'src/video_core/shader/shader_interpreter.cpp')

diff --git a/src/video_core/shader/shader_interpreter.cpp b/src/video_core/shader/shader_interpreter.cpp
index 063cc38f0..51fee6f97 100644
--- a/src/video_core/shader/shader_interpreter.cpp
+++ b/src/video_core/shader/shader_interpreter.cpp
@@ -221,13 +221,12 @@ void RunInterpreter(UnitState<Debug>& state) {
             {
                 Record<DebugDataRecord::SRC1>(state.debug, iteration, src1);
                 Record<DebugDataRecord::DEST_IN>(state.debug, iteration, dest);
+                float24 rcp_res = float24::FromFloat32(1.0f / src1[0].ToFloat32());
                 for (int i = 0; i < 4; ++i) {
                     if (!swizzle.DestComponentEnabled(i))
                         continue;
 
-                    // TODO: Be stable against division by zero!
-                    // TODO: I think this might be wrong... we should only use one component here
-                    dest[i] = float24::FromFloat32(1.0f / src1[i].ToFloat32());
+                    dest[i] = rcp_res;
                 }
                 Record<DebugDataRecord::DEST_OUT>(state.debug, iteration, dest);
                 break;
@@ -238,13 +237,12 @@ void RunInterpreter(UnitState<Debug>& state) {
             {
                 Record<DebugDataRecord::SRC1>(state.debug, iteration, src1);
                 Record<DebugDataRecord::DEST_IN>(state.debug, iteration, dest);
+                float24 rsq_res = float24::FromFloat32(1.0f / sqrt(src1[0].ToFloat32()));
                 for (int i = 0; i < 4; ++i) {
                     if (!swizzle.DestComponentEnabled(i))
                         continue;
 
-                    // TODO: Be stable against division by zero!
-                    // TODO: I think this might be wrong... we should only use one component here
-                    dest[i] = float24::FromFloat32(1.0f / sqrt(src1[i].ToFloat32()));
+                    dest[i] = rsq_res;
                 }
                 Record<DebugDataRecord::DEST_OUT>(state.debug, iteration, dest);
                 break;
-- 
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