diff --git a/src/video_core/memory_manager.cpp b/src/video_core/memory_manager.cpp index 77a20bb84..47247f097 100644 --- a/src/video_core/memory_manager.cpp +++ b/src/video_core/memory_manager.cpp @@ -9,6 +9,13 @@ namespace Tegra { +MemoryManager::MemoryManager() { + // Mark the first page as reserved, so that 0 is not a valid GPUVAddr. Otherwise, games might + // try to use 0 as a valid address, which is also used to mean nullptr. This fixes a bug with + // Undertale using 0 for a render target. + PageSlot(0) = static_cast(PageStatus::Reserved); +} + GPUVAddr MemoryManager::AllocateSpace(u64 size, u64 align) { const std::optional gpu_addr{FindFreeBlock(0, size, align, PageStatus::Unmapped)}; diff --git a/src/video_core/memory_manager.h b/src/video_core/memory_manager.h index 4eb338aa2..fb03497ca 100644 --- a/src/video_core/memory_manager.h +++ b/src/video_core/memory_manager.h @@ -18,7 +18,7 @@ using GPUVAddr = u64; class MemoryManager final { public: - MemoryManager() = default; + MemoryManager(); GPUVAddr AllocateSpace(u64 size, u64 align); GPUVAddr AllocateSpace(GPUVAddr gpu_addr, u64 size, u64 align); @@ -37,6 +37,7 @@ private: enum class PageStatus : u64 { Unmapped = 0xFFFFFFFFFFFFFFFFULL, Allocated = 0xFFFFFFFFFFFFFFFEULL, + Reserved = 0xFFFFFFFFFFFFFFFDULL, }; std::optional FindFreeBlock(GPUVAddr region_start, u64 size, u64 align,