NESHawk: DMC timing on multiple write ocodes

src/BizHawk.Emulation.Cores/CPUs/MOS 6502X/Execute.cs

@@ -511,13 +511,13 @@ namespace BizHawk.Emulation.Cores.Components.M6502
 		private const int VOP_NUM = 264;
 
 		//opcode bytes.. theoretically redundant with the temp variables? who knows.
-		private int opcode;
+		public int opcode;
 		private byte opcode2, opcode3;
 
 		private int ea, alu_temp; //cpu internal temp variables
 		private int mi; //microcode index
 		private bool iflag_pending; //iflag must be stored after it is checked in some cases (CLI and SEI).
-		private bool rdy_freeze; //true if the CPU must be frozen
+		public bool rdy_freeze; //true if the CPU must be frozen
 
 		//tracks whether an interrupt condition has popped up recently.
 		//not sure if this is real or not but it helps with the branch_irq_hack

src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs

@@ -491,7 +491,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				{
 					dmc_realign = true;
 				}
-
+				
+				// By this point the cpu should be frozen, if it is not, then we are in a multi-write opcode, add another cycle delay
+				if (!cpu.RDY && !cpu.rdy_freeze && ((cpu.TotalExecutedCycles & 1) == 1))
+				{
+					apu.dmc_dma_countdown+=2;
+				}
+				
 				cpu.RDY = false;
 				dmc_dma_exec = true;
 				apu.dmc_dma_countdown--;