From 795b0a5a5e0f65cbcb4006057772fc895e24508a Mon Sep 17 00:00:00 2001
From: PatrickvL <pvanlogchem@gmail.com>
Date: Thu, 27 Sep 2018 15:20:07 +0200
Subject: [PATCH] X86 : Log when starting instruction emulation, and log before
 assert(false), also insert missing newlines

---
 src/CxbxKrnl/CxbxKrnl.cpp |  4 ++--
 src/CxbxKrnl/EmuX86.cpp   | 24 ++++++++++++++++++++----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/CxbxKrnl/CxbxKrnl.cpp b/src/CxbxKrnl/CxbxKrnl.cpp
index e47d809be..b1139e7e3 100644
--- a/src/CxbxKrnl/CxbxKrnl.cpp
+++ b/src/CxbxKrnl/CxbxKrnl.cpp
@@ -1134,7 +1134,7 @@ void CxbxKrnlMain(int argc, char* argv[])
 			printf("[0x%X] INIT: Valid xbe signature. Xbe is legit\n", GetCurrentThreadId());
 		}
 		else {
-			printf("[0x%X] INIT: Invalid xbe signature. Homebrew, tampered or pirated xbe?", GetCurrentThreadId());
+			printf("[0x%X] INIT: Invalid xbe signature. Homebrew, tampered or pirated xbe?\n", GetCurrentThreadId());
 		}
 
 		// Check the integrity of the xbe sections
@@ -1147,7 +1147,7 @@ void CxbxKrnlMain(int argc, char* argv[])
 			CalcSHA1Hash(SHADigest, CxbxKrnl_Xbe->m_bzSection[sectionIndex], RawSize);
 
 			if (memcmp(SHADigest, (CxbxKrnl_Xbe->m_SectionHeader)[sectionIndex].bzSectionDigest, A_SHA_DIGEST_LEN) != 0) {
-				printf("[0x%X] INIT: SHA hash of section %s doesn't match, possible section corruption", GetCurrentThreadId(), CxbxKrnl_Xbe->m_szSectionName[sectionIndex]);
+				printf("[0x%X] INIT: SHA hash of section %s doesn't match, possible section corruption\n", GetCurrentThreadId(), CxbxKrnl_Xbe->m_szSectionName[sectionIndex]);
 			}
 			else {
 				printf("[0x%X] INIT: SHA hash check of section %s successful\n", GetCurrentThreadId(), CxbxKrnl_Xbe->m_szSectionName[sectionIndex]);
diff --git a/src/CxbxKrnl/EmuX86.cpp b/src/CxbxKrnl/EmuX86.cpp
index 134c7a1cc..25c2b5d94 100644
--- a/src/CxbxKrnl/EmuX86.cpp
+++ b/src/CxbxKrnl/EmuX86.cpp
@@ -131,6 +131,7 @@ uint32_t EmuX86_Mem_Read(xbaddr addr, int size)
 			return *(uint8_t*)addr;
 		default:
 			// UNREACHABLE(size);
+			assert(false);
 			return 0;
 		}
 	}
@@ -155,6 +156,7 @@ void EmuX86_Mem_Write(xbaddr addr, uint32_t value, int size)
 			break;
 		default:
 			// UNREACHABLE(size);
+			assert(false);
 			return;
 		}
 	}
@@ -398,6 +400,8 @@ inline uint32_t EmuX86_GetRegisterValue32(const LPEXCEPTION_POINTERS e, const ui
 		void* regptr = EmuX86_GetRegisterPointer(e, reg);
 		if (regptr != nullptr)
 			return *(uint32_t *)regptr;
+
+		assert(false);
 	}
 
 	return 0;
@@ -552,8 +556,8 @@ bool EmuX86_Operand_Addr_ForReadWrite(const LPEXCEPTION_POINTERS e, const _DInst
 	case O_IMM:
 	case O_IMM1:
 	case O_IMM2:
-		assert(false);
 		EmuLog(LOG_PREFIX, LOG_LEVEL::WARNING, "Refused operand write-access to immedate value address!");
+		assert(false);
 		return false;
 	}
 
@@ -1089,10 +1093,12 @@ bool EmuX86_Opcode_MOVZX(LPEXCEPTION_POINTERS e, _DInst& info)
 {
 	// MOVZX reads value from source :
 	uint32_t value = 0;
+
 	if (!EmuX86_Operand_Read(e, info, 1, &value))
 		return false;
 
-	// TODO : Implement MOVZX zero-extension!
+	// MOVZX zero-extension is implemented implicitly
+	assert(value <= 0xFFFF); // Assume input never exceeds a 16 bit value
 
 	// MOVZX writes value to destination :
 	if (!EmuX86_Operand_Write(e, info, 0, value))
@@ -2794,10 +2800,17 @@ bool EmuX86_DecodeException(LPEXCEPTION_POINTERS e)
 	// that case may be logged, but it shouldn't fail the opcode handler.
 	_DInst info;
 	DWORD StartingEip = e->ContextRecord->Eip;
+	LOG_CHECK_ENABLED(LOG_LEVEL::DEBUG) {
+			EmuLog(LOG_PREFIX, LOG_LEVEL::DEBUG, "Starting instruction emulation from 0x%08X", e->ContextRecord->Eip);
+	}
+
 	// Execute op-codes until we hit an unhandled instruction, or an error occurs
-	while (true) {
+	while (true)
+	//for (int x=0;x<1;x++)
+	{
 		if (!EmuX86_DecodeOpcode((uint8_t*)e->ContextRecord->Eip, info)) {
 			EmuLog(LOG_PREFIX, LOG_LEVEL::WARNING, "Error decoding opcode at 0x%08X", e->ContextRecord->Eip);
+			assert(false);
 			return false;
 		}
 
@@ -3132,8 +3145,11 @@ bool EmuX86_DecodeException(LPEXCEPTION_POINTERS e)
 		e->ContextRecord->Eip += info.size;
 	} // while true
 
+	return true;
+
 opcode_error:
-	EmuLog(LOG_PREFIX, LOG_LEVEL::WARNING, "0x%08X: Error while handling instruction %u", e->ContextRecord->Eip, info.opcode); // TODO : format decodedInstructions[0]
+	EmuLog(LOG_PREFIX, LOG_LEVEL::WARNING, "0x%08X: Error while handling instruction %s (%u)", e->ContextRecord->Eip, Distorm_OpcodeString(info.opcode), info.opcode);
+	assert(false);
 	return false;
 }