Merge pull request #303 from Tilka/movbe

Add remaining possible uses of MOVBE

1 files changed, 109 insertions, 113 deletions

diff --git a/Source/Core/Common/x64Analyzer.cpp b/Source/Core/Common/x64Analyzer.cpp
index 72ff1105a5..4878f9dea8 100644
--- a/Source/Core/Common/x64Analyzer.cpp
+++ b/Source/Core/Common/x64Analyzer.cpp
@@ -8,8 +8,8 @@ bool DisassembleMov(const unsigned char *codePtr, InstructionInfo *info)
 {
 	unsigned const char *startCodePtr = codePtr;
 	u8 rex = 0;
-	u8 codeByte = 0;
-	u8 codeByte2 = 0;
+	u32 opcode;
+	int opcode_length;
 
 	//Check for regular prefix
 	info->operandSize = 4;
@@ -17,6 +17,7 @@ bool DisassembleMov(const unsigned char *codePtr, InstructionInfo *info)
 	info->signExtend = false;
 	info->hasImmediate = false;
 	info->isMemoryWrite = false;
+	info->byteSwap = false;
 
 	u8 modRMbyte = 0;
 	u8 sibByte = 0;
@@ -45,41 +46,53 @@ bool DisassembleMov(const unsigned char *codePtr, InstructionInfo *info)
 		codePtr++;
 	}
 
-	codeByte = *codePtr++;
-
-	// Skip two-byte opcode byte
-	bool twoByte = false;
-	if (codeByte == 0x0F)
+	opcode = *codePtr++;
+	opcode_length = 1;
+	if (opcode == 0x0F)
 	{
-		twoByte = true;
-		codeByte2 = *codePtr++;
-	}
-
-	if (!twoByte)
-	{
-		if ((codeByte & 0xF0) == 0x80 ||
-			((codeByte & 0xF8) == 0xC0 && (codeByte & 0x0E) != 0x02))
+		opcode = (opcode << 8) | *codePtr++;
+		opcode_length = 2;
+		if ((opcode & 0xFB) == 0x38)
 		{
-			modRMbyte = *codePtr++;
-			hasModRM = true;
+			opcode = (opcode << 8) | *codePtr++;
+			opcode_length = 3;
 		}
 	}
-	else
+
+	switch (opcode_length)
 	{
-		if (((codeByte2 & 0xF0) == 0x00 && (codeByte2 & 0x0F) >= 0x04 && (codeByte2 & 0x0D) != 0x0D) ||
-			(codeByte2 & 0xF0) == 0x30 ||
-			codeByte2 == 0x77 ||
-			(codeByte2 & 0xF0) == 0x80 ||
-			((codeByte2 & 0xF0) == 0xA0 && (codeByte2 & 0x07) <= 0x02) ||
-			(codeByte2 & 0xF8) == 0xC8)
-		{
-			// No mod R/M byte
-		}
-		else
-		{
-			modRMbyte = *codePtr++;
-			hasModRM = true;
-		}
+		case 1:
+			if ((opcode & 0xF0) == 0x80 ||
+			    ((opcode & 0xF8) == 0xC0 && (opcode & 0x0E) != 0x02))
+			{
+				modRMbyte = *codePtr++;
+				hasModRM = true;
+			}
+			break;
+		case 2:
+			if (((opcode & 0xF0) == 0x00 && (opcode & 0x0F) >= 0x04 && (opcode & 0x0D) != 0x0D) ||
+			    ((opcode & 0xF0) == 0xA0 && (opcode & 0x07) <= 0x02) ||
+			    (opcode & 0xF0) == 0x30 ||
+			    (opcode & 0xFF) == 0x77 ||
+			    (opcode & 0xF0) == 0x80 ||
+			    (opcode & 0xF8) == 0xC8)
+			{
+				// No mod R/M byte
+			}
+			else
+			{
+				modRMbyte = *codePtr++;
+				hasModRM = true;
+			}
+			break;
+		case 3:
+			// TODO: support more 3-byte opcode instructions
+			if ((opcode & 0xFE) == 0xF0)
+			{
+				modRMbyte = *codePtr++;
+				hasModRM = true;
+			}
+			break;
 	}
 
 	if (hasModRM)
@@ -114,109 +127,92 @@ bool DisassembleMov(const unsigned char *codePtr, InstructionInfo *info)
 	if (displacementSize == 1)
 		info->displacement = (s32)(s8)*codePtr;
 	else
-		info->displacement = *((s32 *)codePtr);
+		info->displacement = *((s32*)codePtr);
 	codePtr += displacementSize;
 
-
-	switch (codeByte)
+	switch (opcode)
 	{
-	// writes
 	case 0xC6: // mem <- imm8
-		{
-			info->isMemoryWrite = true;
-			info->hasImmediate = true;
-			info->immediate = *codePtr;
-			codePtr++; //move past immediate
-		}
+		info->isMemoryWrite = true;
+		info->hasImmediate = true;
+		info->immediate = *codePtr;
+		codePtr++;
 		break;
 
 	case 0xC7: // mem <- imm16/32
+		info->isMemoryWrite = true;
+		switch (info->operandSize)
 		{
-			info->isMemoryWrite = true;
-			if (info->operandSize == 2)
-			{
-				info->hasImmediate = true;
-				info->immediate = *(u16*)codePtr;
-				codePtr += 2;
-			}
-			else if (info->operandSize == 4)
-			{
-				info->hasImmediate = true;
-				info->immediate = *(u32*)codePtr;
-				codePtr += 4;
-			}
-			else if (info->operandSize == 8)
-			{
-				info->zeroExtend = true;
-				info->immediate = *(u32*)codePtr;
-				codePtr += 4;
-			}
-		}
-
-	case 0x88: // mem <- r8
-		{
-			info->isMemoryWrite = true;
-			if (info->operandSize == 4)
-			{
-				info->operandSize = 1;
-				break;
-			}
-			else
-				return false;
+		case 2:
+			info->hasImmediate = true;
+			info->immediate = *(u16*)codePtr;
+			codePtr += 2;
 			break;
-		}
 
-	case 0x89: // mem <- r16/32/64
-		{
-			info->isMemoryWrite = true;
+		case 4:
+			info->hasImmediate = true;
+			info->immediate = *(u32*)codePtr;
+			codePtr += 4;
+			break;
+		case 8:
+			info->zeroExtend = true;
+			info->immediate = *(u32*)codePtr;
+			codePtr += 4;
 			break;
 		}
+		break;
 
-	case 0x0F: // two-byte escape
+	case 0x88: // mem <- r8
+		info->isMemoryWrite = true;
+		if (info->operandSize != 4)
 		{
-			info->isMemoryWrite = false;
-			switch (codeByte2)
-			{
-			case 0xB6: // movzx on byte
-				info->zeroExtend = true;
-				info->operandSize = 1;
-				break;
-			case 0xB7: // movzx on short
-				info->zeroExtend = true;
-				info->operandSize = 2;
-				break;
-			case 0xBE: // movsx on byte
-				info->signExtend = true;
-				info->operandSize = 1;
-				break;
-			case 0xBF: // movsx on short
-				info->signExtend = true;
-				info->operandSize = 2;
-				break;
-			default:
-				return false;
-			}
-			break;
+			return false;
 		}
+		info->operandSize = 1;
+		break;
+
+	case 0x89: // mem <- r16/32/64
+		info->isMemoryWrite = true;
+		break;
 
 	case 0x8A: // r8 <- mem
+		if (info->operandSize != 4)
 		{
-			info->isMemoryWrite = false;
-			if (info->operandSize == 4)
-			{
-				info->operandSize = 1;
-				break;
-			}
-			else
-				return false;
+			return false;
 		}
+		info->operandSize = 1;
+		break;
 
 	case 0x8B: // r16/32/64 <- mem
-		{
-			info->isMemoryWrite = false;
-			break;
-		}
+		break;
+
+	case 0x0FB6: // movzx on byte
+		info->zeroExtend = true;
+		info->operandSize = 1;
+		break;
+
+	case 0x0FB7: // movzx on short
+		info->zeroExtend = true;
+		info->operandSize = 2;
+		break;
+
+	case 0x0FBE: // movsx on byte
+		info->signExtend = true;
+		info->operandSize = 1;
+		break;
+
+	case 0x0FBF: // movsx on short
+		info->signExtend = true;
+		info->operandSize = 2;
+		break;
+
+	case 0x0F38F0: // movbe read
+		info->byteSwap = true;
+		break;
 
+	case 0x0F38F1: // movbe write
+		info->byteSwap = true;
+		info->isMemoryWrite = true;
 		break;
 
 	default: