From 4456e84bf00c91afb5f9aa2ed7d61c4b80d70b82 Mon Sep 17 00:00:00 2001
From: RetroEdit <30182911+RetroEdit@users.noreply.github.com>
Date: Sat, 29 Aug 2020 18:38:02 +0000
Subject: [PATCH] mGBA: Update SaveRAM mem domain to a hardcoded size.  (#2311)

* Revert "mgba - try resetting sram memdomain after frame advance, so sram autodetection can progress and feed into frontend. addresses #1620, maybe not in the best way"

This reverts commit 25327b510dce917566c8b4cb28125b19f12fd9f9. We decided exposing the whole buffer would be better than dealing with a variable size memory domain.

* mGBA: Update SaveRAM mem domain to a hardcoded size.
---
 .../Consoles/Nintendo/GBA/LibmGBA.cs            |  1 -
 .../Nintendo/GBA/MGBAHawk.IMemoryDomains.cs     | 17 ++++-------------
 .../Consoles/Nintendo/GBA/MGBAHawk.cs           |  4 ----
 3 files changed, 4 insertions(+), 18 deletions(-)

diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
index e32c533484..4e2bb265f4 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs
@@ -111,7 +111,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			public IntPtr oam;
 			public IntPtr rom;
 			public IntPtr sram;
-			public int sram_size;
 		}
 
 		[BizImport(cc, Compatibility = true)]
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs
index 3286646d78..2d646a45f9 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.IMemoryDomains.cs
@@ -31,7 +31,10 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			mm.Add(_vram = new MemoryDomainIntPtr("VRAM", le, IntPtr.Zero, 96 * 1024, true, 4));
 			mm.Add(_oam = new MemoryDomainIntPtr("OAM", le, IntPtr.Zero, 1024, true, 4));
 			mm.Add(_rom = new MemoryDomainIntPtr("ROM", le, IntPtr.Zero, romsize, true, 4));
-			mm.Add(_sram = new MemoryDomainIntPtr("SRAM", le, IntPtr.Zero, 0, true, 4)); // size will be fixed in wireup
+			// 128 KB is the max size for GBA savedata
+			// mGBA does not know a game's save type (and as a result actual savedata size) on startup.
+			// Instead, BizHawk's savedata buffer will be accessed directly for a consistent interface.
+			mm.Add(_sram = new MemoryDomainIntPtr("SRAM", le, IntPtr.Zero, 128 * 1024, true, 4));
 			mm.Add(_cwram = new MemoryDomainDelegate("Combined WRAM", (256 + 32) * 1024, le, null, null, 4));
 
 			mm.Add(new MemoryDomainDelegate("System Bus", 0x10000000, le,
@@ -60,16 +63,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			WireMemoryDomainPointers();
 		}
 
-		private void WireMemoryDomainPointers_SaveRam()
-		{
-			var s = new LibmGBA.MemoryAreas();
-			LibmGBA.BizGetMemoryAreas(Core, s);
-
-			_sram.Data = s.sram;
-			if (s.sram == IntPtr.Zero) s.sram_size = 0;
-			_sram.SetSize(s.sram_size);
-		}
-
 		private void WireMemoryDomainPointers()
 		{
 			var s = new LibmGBA.MemoryAreas();
@@ -83,8 +76,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			_oam.Data = s.oam;
 			_rom.Data = s.rom;
 			_sram.Data = s.sram;
-			if (s.sram == IntPtr.Zero) s.sram_size = 0;
-			_sram.SetSize(s.sram_size);
 
 			// special combined ram memory domain
 			_cwram.Peek =
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.cs
index d7dc7d2783..65ce72e702 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.cs
@@ -139,10 +139,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 				(short)controller.AxisValue("Tilt Z"),
 				(byte)(255 - controller.AxisValue("Light Sensor")));
 
-			//autodetection may have progressed.
-			//this isn't a great time to do it, but we have to do it some time. maybe it's the best time.
-			WireMemoryDomainPointers_SaveRam();
-
 			if (IsLagFrame)
 			{
 				LagCount++;