Fix issue #1009: sameboy: stack pointer saved in init state

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/Sameboy.cs

@@ -64,7 +64,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.Gameboy
 			{
 				Filename = "sameboy.wbx",
 				SbrkHeapSizeKB = 192,
-				InvisibleHeapSizeKB = 4,
+				InvisibleHeapSizeKB = 12,
 				SealedHeapSizeKB = 9 * 1024,
 				PlainHeapSizeKB = 4,
 				MmapHeapSizeKB = 1024

waterbox/sameboy/sgb.c

@@ -3,6 +3,7 @@
 #include <string.h>
 #include <stdio.h>
 #include "snes_spc/spc.h"
+#include "../emulibc/emulibc.h"
 
 #define utils_log printf
 
@@ -623,11 +624,14 @@ int sgb_init(const uint8_t *spc, int length)
 		return 0;
 	}
 
+	// make a scratch buffer in a predictable (not stack) place because spc stores multiple pointers to it
+	// which is kind of nasty...
+	int16_t *sound_buffer = alloc_invisible(4096 * sizeof(int16_t));
+
 	// the combination of the sameboy bootrom plus the built in SPC file we use means
 	// that the SPC doesn't finish its init fast enough for donkey kong, which starts poking
 	// data too early.  it's just a combination of various HLE concerns not meshing...
-	int16_t sound_buffer[4096];
-	spc_set_output(sgb.spc, sound_buffer, sizeof(sound_buffer) / sizeof(sound_buffer[0]));
+	spc_set_output(sgb.spc, sound_buffer, 4096);
 	for (int i = 0; i < 240; i++)
 	{
 		spc_end_frame(sgb.spc, 35104);