From ef84c70d222eb2b8ea56e67b793cc459b90cdd74 Mon Sep 17 00:00:00 2001
From: Annomatg <47226753+Annomatg@users.noreply.github.com>
Date: Wed, 27 Feb 2019 23:22:47 +0100
Subject: [PATCH] Speed up memory page mapping (#2141)

- Memory::MapPages total samplecount was reduced from 4.6% to 1.06%.
- From main menu into the game from 1.03% to 0.35%
---
 src/core/memory.cpp | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/core/memory.cpp b/src/core/memory.cpp
index e9166dbd9e..f809567b66 100644
--- a/src/core/memory.cpp
+++ b/src/core/memory.cpp
@@ -71,15 +71,20 @@ static void MapPages(PageTable& page_table, VAddr base, u64 size, u8* memory, Pa
                                  FlushMode::FlushAndInvalidate);
 
     VAddr end = base + size;
-    while (base != end) {
-        ASSERT_MSG(base < page_table.pointers.size(), "out of range mapping at {:016X}", base);
+    ASSERT_MSG(end <= page_table.pointers.size(), "out of range mapping at {:016X}",
+               base + page_table.pointers.size());
 
-        page_table.attributes[base] = type;
-        page_table.pointers[base] = memory;
+    std::fill(page_table.attributes.begin() + base, page_table.attributes.begin() + end, type);
 
-        base += 1;
-        if (memory != nullptr)
+    if (memory == nullptr) {
+        std::fill(page_table.pointers.begin() + base, page_table.pointers.begin() + end, memory);
+    } else {
+        while (base != end) {
+            page_table.pointers[base] = memory;
+
+            base += 1;
             memory += PAGE_SIZE;
+        }
     }
 }