From 37acae846c4679f604965d17cb8c171cebaf62f6 Mon Sep 17 00:00:00 2001
From: Sergio Martin <eienburuu@gmail.com>
Date: Sun, 14 Jan 2024 09:17:06 +0100
Subject: [PATCH] Ensuring CPU run function starts at the beggining of a page

---
 meson.build             | 6 +++++-
 source/core/Nes_Cpu.cpp | 9 ++-------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/meson.build b/meson.build
index b8fcaa9..b3772bc 100644
--- a/meson.build
+++ b/meson.build
@@ -4,6 +4,10 @@ project('quickerNES','c','cpp',
   default_options : ['cpp_std=c++20', 'default_library=shared', 'buildtype=release']
 )
 
+# Getting page alignment
+getConfCommand = run_command('getconf', 'PAGESIZE', check: true)
+pageSize = getConfCommand.stdout().strip()
+
 # quickerNES Core sources
 
 quickerNESCoreSrc = [
@@ -41,7 +45,7 @@ quickerNESCoreSrc = [
 # quickerNES Core Configuration
 
  quickerNESCoreDependency = declare_dependency(
-  compile_args        : [ '-Wfatal-errors', '-Wall', '-Werror', '-Wno-multichar' ],
+  compile_args        : [ '-Wfatal-errors', '-Wall', '-Werror', '-Wno-multichar', '-D_PAGE_SIZE="' + pageSize + '"'],
   include_directories : include_directories(['source', 'source/core', 'extern']),
   sources             : [ quickerNESCoreSrc, 'extern/metrohash128/metrohash128.cpp' ]
  )
diff --git a/source/core/Nes_Cpu.cpp b/source/core/Nes_Cpu.cpp
index 242bd89..4149d37 100644
--- a/source/core/Nes_Cpu.cpp
+++ b/source/core/Nes_Cpu.cpp
@@ -231,11 +231,8 @@ constexpr uint8_t clock_table [256] = {
  3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7 // F
 };
 
-#pragma GCC push_options
-#pragma GCC optimize ("align-functions=1024")
-
-
-Nes_Cpu::result_t Nes_Cpu::run ( nes_time_t end ) 
+__attribute__((optimize("align-functions=" _PAGE_SIZE)))
+ Nes_Cpu::result_t Nes_Cpu::run ( nes_time_t end ) 
 {
  set_end_time_( end );
  clock_count = 0;
@@ -1180,5 +1177,3 @@ end:
 
  return result;
 }
-
- #pragma GCC pop_options
\ No newline at end of file