From 08d9de69074ee289fc38a99fdf442727221a93fe Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Sun, 8 Mar 2020 16:54:32 -0700
Subject: [PATCH] ldr: optimize memory usage for tracking system programs

---
 .../loader/source/ldr_launch_record.cpp       | 32 +++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/stratosphere/loader/source/ldr_launch_record.cpp b/stratosphere/loader/source/ldr_launch_record.cpp
index aca54a1ea..4135d4f6e 100644
--- a/stratosphere/loader/source/ldr_launch_record.cpp
+++ b/stratosphere/loader/source/ldr_launch_record.cpp
@@ -22,15 +22,43 @@ namespace ams::ldr {
         /* Global cache. */
         std::set<u64> g_launched_programs;
 
+        constexpr size_t NumSystemProgramIds = ncm::SystemProgramId::End.value - ncm::SystemProgramId::Start.value + 1;
+        static_assert(util::IsPowerOfTwo(NumSystemProgramIds));
+        static_assert(util::IsAligned(NumSystemProgramIds, BITSIZEOF(u64)));
+
+        bool IsTrackableSystemProgramId(ncm::ProgramId program_id) {
+            return ncm::SystemProgramId::Start <= program_id && program_id <= ncm::SystemProgramId::End;
+        }
+
+        u64 g_system_launch_records[NumSystemProgramIds / BITSIZEOF(u64)];
+
+        void SetLaunchedSystemProgram(ncm::SystemProgramId program_id) {
+            const u64 val = program_id.value - ncm::SystemProgramId::Start.value;
+            g_system_launch_records[val / BITSIZEOF(u64)] |= (1ul << (val % BITSIZEOF(u64)));
+        }
+
+        bool HasLaunchedSystemProgram(ncm::SystemProgramId program_id) {
+            const u64 val = program_id.value - ncm::SystemProgramId::Start.value;
+            return (g_system_launch_records[val / BITSIZEOF(u64)] & (1ul << (val % BITSIZEOF(u64)))) != 0;
+        }
+
     }
 
     /* Launch Record API. */
     bool HasLaunchedProgram(ncm::ProgramId program_id) {
-        return g_launched_programs.find(static_cast<u64>(program_id)) != g_launched_programs.end();
+        if (IsTrackableSystemProgramId(program_id)) {
+            return HasLaunchedSystemProgram(ncm::SystemProgramId{program_id.value});
+        } else {
+            return g_launched_programs.find(static_cast<u64>(program_id)) != g_launched_programs.end();
+        }
     }
 
     void SetLaunchedProgram(ncm::ProgramId program_id) {
-        g_launched_programs.insert(static_cast<u64>(program_id));
+        if (IsTrackableSystemProgramId(program_id)) {
+            SetLaunchedSystemProgram(ncm::SystemProgramId{program_id.value});
+        } else {
+            g_launched_programs.insert(static_cast<u64>(program_id));
+        }
     }
 
 }