From 23c844b2aa84a65e573dcc023d19b8f5294a8baf Mon Sep 17 00:00:00 2001
From: jhorv <38920027+jhorv@users.noreply.github.com>
Date: Sat, 11 Mar 2023 15:05:48 -0500
Subject: Misc performance tweaks (#4509)

* use Array.Empty() where instead of allocating new zero-length arrays

* structure for loops in a way that the JIT will elide array/Span bounds checking

* avoiding function calls in for loop condition tests

* avoid LINQ in a hot path

* conform with code style

* fix mistake in GetNextWaitingObject()

* fix GetNextWaitingObject() possibility of returning null if all list items have TimePoint == long.MaxValue

* make GetNextWaitingObject() behave FIFO behavior for multiple items with the same TimePoint
---
 ARMeilleure/Decoders/DecoderHelper.cs | 4 ++--
 ARMeilleure/Decoders/OpCodeTable.cs   | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

(limited to 'ARMeilleure/Decoders')

diff --git a/ARMeilleure/Decoders/DecoderHelper.cs b/ARMeilleure/Decoders/DecoderHelper.cs
index 38f98c39..5227e6a1 100644
--- a/ARMeilleure/Decoders/DecoderHelper.cs
+++ b/ARMeilleure/Decoders/DecoderHelper.cs
@@ -17,7 +17,7 @@ namespace ARMeilleure.Decoders
         {
             uint[] tbl = new uint[256];
 
-            for (int idx = 0; idx < 256; idx++)
+            for (int idx = 0; idx < tbl.Length; idx++)
             {
                 tbl[idx] = ExpandImm8ToFP32((uint)idx);
             }
@@ -29,7 +29,7 @@ namespace ARMeilleure.Decoders
         {
             ulong[] tbl = new ulong[256];
 
-            for (int idx = 0; idx < 256; idx++)
+            for (int idx = 0; idx < tbl.Length; idx++)
             {
                 tbl[idx] = ExpandImm8ToFP64((ulong)idx);
             }
diff --git a/ARMeilleure/Decoders/OpCodeTable.cs b/ARMeilleure/Decoders/OpCodeTable.cs
index 54abb141..8464ce55 100644
--- a/ARMeilleure/Decoders/OpCodeTable.cs
+++ b/ARMeilleure/Decoders/OpCodeTable.cs
@@ -1301,7 +1301,7 @@ namespace ARMeilleure.Decoders
         {
             List<InstInfo>[] temp = new List<InstInfo>[FastLookupSize];
 
-            for (int index = 0; index < FastLookupSize; index++)
+            for (int index = 0; index < temp.Length; index++)
             {
                 temp[index] = new List<InstInfo>();
             }
@@ -1311,7 +1311,7 @@ namespace ARMeilleure.Decoders
                 int mask  = ToFastLookupIndex(inst.Mask);
                 int value = ToFastLookupIndex(inst.Value);
 
-                for (int index = 0; index < FastLookupSize; index++)
+                for (int index = 0; index < temp.Length; index++)
                 {
                     if ((index & mask) == value)
                     {
@@ -1320,7 +1320,7 @@ namespace ARMeilleure.Decoders
                 }
             }
 
-            for (int index = 0; index < FastLookupSize; index++)
+            for (int index = 0; index < temp.Length; index++)
             {
                 table[index] = temp[index].ToArray();
             }
-- 
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