diff --git a/src/asm.cpp b/src/asm.cpp
index 1c57d93b..533bb0b1 100644
--- a/src/asm.cpp
+++ b/src/asm.cpp
@@ -3,6 +3,7 @@
 
 #include "types.h"
 #include "utils/xstring.h"
+#include "utils/StringBuilder.h"
 #include "debug.h"
 #include "asm.h"
 #include "x6502.h"
@@ -256,8 +257,11 @@ int Assemble(unsigned char *output, int addr, char *str) {
 
 ///disassembles the opcodes in the buffer assuming the provided address. Uses GetMem() and 6502 current registers to query referenced values. returns a static string buffer.
 char *Disassemble(int addr, uint8 *opcode) {
-	static char str[64]={0},chr[5]={0};
+	static char str[64]={0};
+	const char *chr;
+	char indReg;
 	uint16 tmp,tmp2;
+	StringBuilder sb(str);
 
 	//these may be replaced later with passed-in values to make a lighter-weight disassembly mode that may not query the referenced values
 	#define RX (X.X)
@@ -286,7 +290,7 @@ char *Disassemble(int addr, uint8 *opcode) {
 
 		#ifdef BRK_3BYTE_HACK
 			case 0x00:
-			snprintf(str, sizeof(str), "BRK %02X %02X", opcode[1], opcode[2]);
+			sb << "BRK " << sb_hex(opcode[1], 2) << ' ' << sb_hex(opcode[2], 2);
 			break;
 		#else
 			case 0x00: strcpy(str,"BRK"); break;
@@ -323,207 +327,228 @@ char *Disassemble(int addr, uint8 *opcode) {
 		case 0xF8: strcpy(str,"SED"); break;
 
 		//(Indirect,X)
-		case 0x01: strcpy(chr,"ORA"); goto _indirectx;
-		case 0x21: strcpy(chr,"AND"); goto _indirectx;
-		case 0x41: strcpy(chr,"EOR"); goto _indirectx;
-		case 0x61: strcpy(chr,"ADC"); goto _indirectx;
-		case 0x81: strcpy(chr,"STA"); goto _indirectx;
-		case 0xA1: strcpy(chr,"LDA"); goto _indirectx;
-		case 0xC1: strcpy(chr,"CMP"); goto _indirectx;
-		case 0xE1: strcpy(chr,"SBC"); goto _indirectx;
+		case 0x01: chr = "ORA"; goto _indirectx;
+		case 0x21: chr = "AND"; goto _indirectx;
+		case 0x41: chr = "EOR"; goto _indirectx;
+		case 0x61: chr = "ADC"; goto _indirectx;
+		case 0x81: chr = "STA"; goto _indirectx;
+		case 0xA1: chr = "LDA"; goto _indirectx;
+		case 0xC1: chr = "CMP"; goto _indirectx;
+		case 0xE1: chr = "SBC"; goto _indirectx;
 		_indirectx:
 			indirectX(tmp);
-			snprintf(str, sizeof(str), "%s ($%02X,X) @ $%04X = #$%02X", chr,opcode[1],tmp,GetMem(tmp));
+			indReg = 'X';
+
+		_indirect:
+			sb << chr << " (" << sb_addr(opcode[1], 2) << ',' << indReg << ") @ " << sb_addr(tmp) << " = " << sb_lit(GetMem(tmp));
 			break;
 
 		//Zero Page
-		case 0x05: strcpy(chr,"ORA"); goto _zeropage;
-		case 0x06: strcpy(chr,"ASL"); goto _zeropage;
-		case 0x24: strcpy(chr,"BIT"); goto _zeropage;
-		case 0x25: strcpy(chr,"AND"); goto _zeropage;
-		case 0x26: strcpy(chr,"ROL"); goto _zeropage;
-		case 0x45: strcpy(chr,"EOR"); goto _zeropage;
-		case 0x46: strcpy(chr,"LSR"); goto _zeropage;
-		case 0x65: strcpy(chr,"ADC"); goto _zeropage;
-		case 0x66: strcpy(chr,"ROR"); goto _zeropage;
-		case 0x84: strcpy(chr,"STY"); goto _zeropage;
-		case 0x85: strcpy(chr,"STA"); goto _zeropage;
-		case 0x86: strcpy(chr,"STX"); goto _zeropage;
-		case 0xA4: strcpy(chr,"LDY"); goto _zeropage;
-		case 0xA5: strcpy(chr,"LDA"); goto _zeropage;
-		case 0xA6: strcpy(chr,"LDX"); goto _zeropage;
-		case 0xC4: strcpy(chr,"CPY"); goto _zeropage;
-		case 0xC5: strcpy(chr,"CMP"); goto _zeropage;
-		case 0xC6: strcpy(chr,"DEC"); goto _zeropage;
-		case 0xE4: strcpy(chr,"CPX"); goto _zeropage;
-		case 0xE5: strcpy(chr,"SBC"); goto _zeropage;
-		case 0xE6: strcpy(chr,"INC"); goto _zeropage;
+		case 0x05: chr = "ORA"; goto _zeropage;
+		case 0x06: chr = "ASL"; goto _zeropage;
+		case 0x24: chr = "BIT"; goto _zeropage;
+		case 0x25: chr = "AND"; goto _zeropage;
+		case 0x26: chr = "ROL"; goto _zeropage;
+		case 0x45: chr = "EOR"; goto _zeropage;
+		case 0x46: chr = "LSR"; goto _zeropage;
+		case 0x65: chr = "ADC"; goto _zeropage;
+		case 0x66: chr = "ROR"; goto _zeropage;
+		case 0x84: chr = "STY"; goto _zeropage;
+		case 0x85: chr = "STA"; goto _zeropage;
+		case 0x86: chr = "STX"; goto _zeropage;
+		case 0xA4: chr = "LDY"; goto _zeropage;
+		case 0xA5: chr = "LDA"; goto _zeropage;
+		case 0xA6: chr = "LDX"; goto _zeropage;
+		case 0xC4: chr = "CPY"; goto _zeropage;
+		case 0xC5: chr = "CMP"; goto _zeropage;
+		case 0xC6: chr = "DEC"; goto _zeropage;
+		case 0xE4: chr = "CPX"; goto _zeropage;
+		case 0xE5: chr = "SBC"; goto _zeropage;
+		case 0xE6: chr = "INC"; goto _zeropage;
 		_zeropage:
 		// ################################## Start of SP CODE ###########################
 		// Change width to %04X // don't!
-			snprintf(str, sizeof(str), "%s $%02X = #$%02X", chr,opcode[1],GetMem(opcode[1]));
+			sb << chr << ' ' << sb_addr(opcode[1], 2) << " = " << sb_lit(GetMem(opcode[1]));
 		// ################################## End of SP CODE ###########################
 			break;
 
 		//#Immediate
-		case 0x09: strcpy(chr,"ORA"); goto _immediate;
-		case 0x29: strcpy(chr,"AND"); goto _immediate;
-		case 0x49: strcpy(chr,"EOR"); goto _immediate;
-		case 0x69: strcpy(chr,"ADC"); goto _immediate;
-		//case 0x89: strcpy(chr,"STA"); goto _immediate;  //baka, no STA #imm!!
-		case 0xA0: strcpy(chr,"LDY"); goto _immediate;
-		case 0xA2: strcpy(chr,"LDX"); goto _immediate;
-		case 0xA9: strcpy(chr,"LDA"); goto _immediate;
-		case 0xC0: strcpy(chr,"CPY"); goto _immediate;
-		case 0xC9: strcpy(chr,"CMP"); goto _immediate;
-		case 0xE0: strcpy(chr,"CPX"); goto _immediate;
-		case 0xE9: strcpy(chr,"SBC"); goto _immediate;
+		case 0x09: chr = "ORA"; goto _immediate;
+		case 0x29: chr = "AND"; goto _immediate;
+		case 0x49: chr = "EOR"; goto _immediate;
+		case 0x69: chr = "ADC"; goto _immediate;
+		//case 0x89: chr = "STA"; goto _immediate;  //baka, no STA #imm!!
+		case 0xA0: chr = "LDY"; goto _immediate;
+		case 0xA2: chr = "LDX"; goto _immediate;
+		case 0xA9: chr = "LDA"; goto _immediate;
+		case 0xC0: chr = "CPY"; goto _immediate;
+		case 0xC9: chr = "CMP"; goto _immediate;
+		case 0xE0: chr = "CPX"; goto _immediate;
+		case 0xE9: chr = "SBC"; goto _immediate;
 		_immediate:
-			snprintf(str, sizeof(str), "%s #$%02X", chr,opcode[1]);
+			sb << chr << ' ' << sb_lit(opcode[1]);
 			break;
 
 		//Absolute
-		case 0x0D: strcpy(chr,"ORA"); goto _absolute;
-		case 0x0E: strcpy(chr,"ASL"); goto _absolute;
-		case 0x2C: strcpy(chr,"BIT"); goto _absolute;
-		case 0x2D: strcpy(chr,"AND"); goto _absolute;
-		case 0x2E: strcpy(chr,"ROL"); goto _absolute;
-		case 0x4D: strcpy(chr,"EOR"); goto _absolute;
-		case 0x4E: strcpy(chr,"LSR"); goto _absolute;
-		case 0x6D: strcpy(chr,"ADC"); goto _absolute;
-		case 0x6E: strcpy(chr,"ROR"); goto _absolute;
-		case 0x8C: strcpy(chr,"STY"); goto _absolute;
-		case 0x8D: strcpy(chr,"STA"); goto _absolute;
-		case 0x8E: strcpy(chr,"STX"); goto _absolute;
-		case 0xAC: strcpy(chr,"LDY"); goto _absolute;
-		case 0xAD: strcpy(chr,"LDA"); goto _absolute;
-		case 0xAE: strcpy(chr,"LDX"); goto _absolute;
-		case 0xCC: strcpy(chr,"CPY"); goto _absolute;
-		case 0xCD: strcpy(chr,"CMP"); goto _absolute;
-		case 0xCE: strcpy(chr,"DEC"); goto _absolute;
-		case 0xEC: strcpy(chr,"CPX"); goto _absolute;
-		case 0xED: strcpy(chr,"SBC"); goto _absolute;
-		case 0xEE: strcpy(chr,"INC"); goto _absolute;
+		case 0x0D: chr = "ORA"; goto _absolute;
+		case 0x0E: chr = "ASL"; goto _absolute;
+		case 0x2C: chr = "BIT"; goto _absolute;
+		case 0x2D: chr = "AND"; goto _absolute;
+		case 0x2E: chr = "ROL"; goto _absolute;
+		case 0x4D: chr = "EOR"; goto _absolute;
+		case 0x4E: chr = "LSR"; goto _absolute;
+		case 0x6D: chr = "ADC"; goto _absolute;
+		case 0x6E: chr = "ROR"; goto _absolute;
+		case 0x8C: chr = "STY"; goto _absolute;
+		case 0x8D: chr = "STA"; goto _absolute;
+		case 0x8E: chr = "STX"; goto _absolute;
+		case 0xAC: chr = "LDY"; goto _absolute;
+		case 0xAD: chr = "LDA"; goto _absolute;
+		case 0xAE: chr = "LDX"; goto _absolute;
+		case 0xCC: chr = "CPY"; goto _absolute;
+		case 0xCD: chr = "CMP"; goto _absolute;
+		case 0xCE: chr = "DEC"; goto _absolute;
+		case 0xEC: chr = "CPX"; goto _absolute;
+		case 0xED: chr = "SBC"; goto _absolute;
+		case 0xEE: chr = "INC"; goto _absolute;
 		_absolute:
 			absolute(tmp);
-			snprintf(str, sizeof(str), "%s $%04X = #$%02X", chr,tmp,GetMem(tmp));
+
+			sb << chr << ' ' << sb_addr(tmp) << " = " << sb_lit(GetMem(tmp));
+
 			break;
 
 		//branches
-		case 0x10: strcpy(chr,"BPL"); goto _branch;
-		case 0x30: strcpy(chr,"BMI"); goto _branch;
-		case 0x50: strcpy(chr,"BVC"); goto _branch;
-		case 0x70: strcpy(chr,"BVS"); goto _branch;
-		case 0x90: strcpy(chr,"BCC"); goto _branch;
-		case 0xB0: strcpy(chr,"BCS"); goto _branch;
-		case 0xD0: strcpy(chr,"BNE"); goto _branch;
-		case 0xF0: strcpy(chr,"BEQ"); goto _branch;
+		case 0x10: chr = "BPL"; goto _branch;
+		case 0x30: chr = "BMI"; goto _branch;
+		case 0x50: chr = "BVC"; goto _branch;
+		case 0x70: chr = "BVS"; goto _branch;
+		case 0x90: chr = "BCC"; goto _branch;
+		case 0xB0: chr = "BCS"; goto _branch;
+		case 0xD0: chr = "BNE"; goto _branch;
+		case 0xF0: chr = "BEQ"; goto _branch;
 		_branch:
 			relative(tmp);
-			snprintf(str, sizeof(str), "%s $%04X", chr,tmp);
+
+			sb << chr << ' ' << sb_addr(tmp);
+
 			break;
 
 		//(Indirect),Y
-		case 0x11: strcpy(chr,"ORA"); goto _indirecty;
-		case 0x31: strcpy(chr,"AND"); goto _indirecty;
-		case 0x51: strcpy(chr,"EOR"); goto _indirecty;
-		case 0x71: strcpy(chr,"ADC"); goto _indirecty;
-		case 0x91: strcpy(chr,"STA"); goto _indirecty;
-		case 0xB1: strcpy(chr,"LDA"); goto _indirecty;
-		case 0xD1: strcpy(chr,"CMP"); goto _indirecty;
-		case 0xF1: strcpy(chr,"SBC"); goto _indirecty;
+		case 0x11: chr = "ORA"; goto _indirecty;
+		case 0x31: chr = "AND"; goto _indirecty;
+		case 0x51: chr = "EOR"; goto _indirecty;
+		case 0x71: chr = "ADC"; goto _indirecty;
+		case 0x91: chr = "STA"; goto _indirecty;
+		case 0xB1: chr = "LDA"; goto _indirecty;
+		case 0xD1: chr = "CMP"; goto _indirecty;
+		case 0xF1: chr = "SBC"; goto _indirecty;
 		_indirecty:
 			indirectY(tmp);
-			snprintf(str, sizeof(str), "%s ($%02X),Y @ $%04X = #$%02X", chr,opcode[1],tmp,GetMem(tmp));
-			break;
+			indReg = 'Y';
+
+			goto _indirect;
 
 		//Zero Page,X
-		case 0x15: strcpy(chr,"ORA"); goto _zeropagex;
-		case 0x16: strcpy(chr,"ASL"); goto _zeropagex;
-		case 0x35: strcpy(chr,"AND"); goto _zeropagex;
-		case 0x36: strcpy(chr,"ROL"); goto _zeropagex;
-		case 0x55: strcpy(chr,"EOR"); goto _zeropagex;
-		case 0x56: strcpy(chr,"LSR"); goto _zeropagex;
-		case 0x75: strcpy(chr,"ADC"); goto _zeropagex;
-		case 0x76: strcpy(chr,"ROR"); goto _zeropagex;
-		case 0x94: strcpy(chr,"STY"); goto _zeropagex;
-		case 0x95: strcpy(chr,"STA"); goto _zeropagex;
-		case 0xB4: strcpy(chr,"LDY"); goto _zeropagex;
-		case 0xB5: strcpy(chr,"LDA"); goto _zeropagex;
-		case 0xD5: strcpy(chr,"CMP"); goto _zeropagex;
-		case 0xD6: strcpy(chr,"DEC"); goto _zeropagex;
-		case 0xF5: strcpy(chr,"SBC"); goto _zeropagex;
-		case 0xF6: strcpy(chr,"INC"); goto _zeropagex;
+		case 0x15: chr = "ORA"; goto _zeropagex;
+		case 0x16: chr = "ASL"; goto _zeropagex;
+		case 0x35: chr = "AND"; goto _zeropagex;
+		case 0x36: chr = "ROL"; goto _zeropagex;
+		case 0x55: chr = "EOR"; goto _zeropagex;
+		case 0x56: chr = "LSR"; goto _zeropagex;
+		case 0x75: chr = "ADC"; goto _zeropagex;
+		case 0x76: chr = "ROR"; goto _zeropagex;
+		case 0x94: chr = "STY"; goto _zeropagex;
+		case 0x95: chr = "STA"; goto _zeropagex;
+		case 0xB4: chr = "LDY"; goto _zeropagex;
+		case 0xB5: chr = "LDA"; goto _zeropagex;
+		case 0xD5: chr = "CMP"; goto _zeropagex;
+		case 0xD6: chr = "DEC"; goto _zeropagex;
+		case 0xF5: chr = "SBC"; goto _zeropagex;
+		case 0xF6: chr = "INC"; goto _zeropagex;
 		_zeropagex:
-			zpIndex(tmp,RX);
+			zpIndex(tmp, RX);
+			indReg = 'X';
+
+		_indexed:
 		// ################################## Start of SP CODE ###########################
 		// Change width to %04X // don't!
-			snprintf(str, sizeof(str), "%s $%02X,X @ $%04X = #$%02X", chr,opcode[1],tmp,GetMem(tmp));
+			sb << chr << ' ' << sb_addr(opcode[1], 2) << ',' << indReg << " @ " << sb_addr(tmp) << " = " << sb_lit(GetMem(tmp));
 		// ################################## End of SP CODE ###########################
 			break;
 
 		//Absolute,Y
-		case 0x19: strcpy(chr,"ORA"); goto _absolutey;
-		case 0x39: strcpy(chr,"AND"); goto _absolutey;
-		case 0x59: strcpy(chr,"EOR"); goto _absolutey;
-		case 0x79: strcpy(chr,"ADC"); goto _absolutey;
-		case 0x99: strcpy(chr,"STA"); goto _absolutey;
-		case 0xB9: strcpy(chr,"LDA"); goto _absolutey;
-		case 0xBE: strcpy(chr,"LDX"); goto _absolutey;
-		case 0xD9: strcpy(chr,"CMP"); goto _absolutey;
-		case 0xF9: strcpy(chr,"SBC"); goto _absolutey;
+		case 0x19: chr = "ORA"; goto _absolutey;
+		case 0x39: chr = "AND"; goto _absolutey;
+		case 0x59: chr = "EOR"; goto _absolutey;
+		case 0x79: chr = "ADC"; goto _absolutey;
+		case 0x99: chr = "STA"; goto _absolutey;
+		case 0xB9: chr = "LDA"; goto _absolutey;
+		case 0xBE: chr = "LDX"; goto _absolutey;
+		case 0xD9: chr = "CMP"; goto _absolutey;
+		case 0xF9: chr = "SBC"; goto _absolutey;
 		_absolutey:
 			absolute(tmp);
-			tmp2=(tmp+RY);
-			snprintf(str, sizeof(str), "%s $%04X,Y @ $%04X = #$%02X", chr,tmp,tmp2,GetMem(tmp2));
+			tmp2 = (tmp + RY);
+			indReg = 'Y';
+
+		_absindexed:
+			sb << chr << ' ' << sb_addr(tmp) << ',' << indReg << " @ " << sb_addr(tmp2) << " = " << sb_lit(GetMem(tmp2));
+
 			break;
 
 		//Absolute,X
-		case 0x1D: strcpy(chr,"ORA"); goto _absolutex;
-		case 0x1E: strcpy(chr,"ASL"); goto _absolutex;
-		case 0x3D: strcpy(chr,"AND"); goto _absolutex;
-		case 0x3E: strcpy(chr,"ROL"); goto _absolutex;
-		case 0x5D: strcpy(chr,"EOR"); goto _absolutex;
-		case 0x5E: strcpy(chr,"LSR"); goto _absolutex;
-		case 0x7D: strcpy(chr,"ADC"); goto _absolutex;
-		case 0x7E: strcpy(chr,"ROR"); goto _absolutex;
-		case 0x9D: strcpy(chr,"STA"); goto _absolutex;
-		case 0xBC: strcpy(chr,"LDY"); goto _absolutex;
-		case 0xBD: strcpy(chr,"LDA"); goto _absolutex;
-		case 0xDD: strcpy(chr,"CMP"); goto _absolutex;
-		case 0xDE: strcpy(chr,"DEC"); goto _absolutex;
-		case 0xFD: strcpy(chr,"SBC"); goto _absolutex;
-		case 0xFE: strcpy(chr,"INC"); goto _absolutex;
+		case 0x1D: chr = "ORA"; goto _absolutex;
+		case 0x1E: chr = "ASL"; goto _absolutex;
+		case 0x3D: chr = "AND"; goto _absolutex;
+		case 0x3E: chr = "ROL"; goto _absolutex;
+		case 0x5D: chr = "EOR"; goto _absolutex;
+		case 0x5E: chr = "LSR"; goto _absolutex;
+		case 0x7D: chr = "ADC"; goto _absolutex;
+		case 0x7E: chr = "ROR"; goto _absolutex;
+		case 0x9D: chr = "STA"; goto _absolutex;
+		case 0xBC: chr = "LDY"; goto _absolutex;
+		case 0xBD: chr = "LDA"; goto _absolutex;
+		case 0xDD: chr = "CMP"; goto _absolutex;
+		case 0xDE: chr = "DEC"; goto _absolutex;
+		case 0xFD: chr = "SBC"; goto _absolutex;
+		case 0xFE: chr = "INC"; goto _absolutex;
 		_absolutex:
 			absolute(tmp);
-			tmp2=(tmp+RX);
-			snprintf(str, sizeof(str), "%s $%04X,X @ $%04X = #$%02X", chr,tmp,tmp2,GetMem(tmp2));
-			break;
+			tmp2 = (tmp + RX);
+			indReg = 'X';
+
+			goto _absindexed;
 
 		//jumps
-		case 0x20: strcpy(chr,"JSR"); goto _jump;
-		case 0x4C: strcpy(chr,"JMP"); goto _jump;
-		case 0x6C: absolute(tmp); snprintf(str, sizeof(str), "JMP ($%04X) = $%04X", tmp,GetMem(tmp)|GetMem(tmp+1)<<8); break;
+		case 0x20: chr = "JSR"; goto _jump;
+		case 0x4C: chr = "JMP"; goto _jump;
 		_jump:
 			absolute(tmp);
-			snprintf(str, sizeof(str), "%s $%04X", chr,tmp);
+
+			sb << chr << ' ' << sb_addr(tmp);
+
+			break;
+
+		case 0x6C:
+			absolute(tmp);
+
+			sb << "JMP (" << sb_addr(tmp);
+			sb << ") = " << sb_addr(GetMem(tmp) | GetMem(tmp + 1) << 8);
+
 			break;
 
 		//Zero Page,Y
-		case 0x96: strcpy(chr,"STX"); goto _zeropagey;
-		case 0xB6: strcpy(chr,"LDX"); goto _zeropagey;
+		case 0x96: chr = "STX"; goto _zeropagey;
+		case 0xB6: chr = "LDX"; goto _zeropagey;
 		_zeropagey:
-			zpIndex(tmp,RY);
-		// ################################## Start of SP CODE ###########################
-		// Change width to %04X // don't!
-			snprintf(str, sizeof(str), "%s $%02X,Y @ $%04X = #$%02X", chr,opcode[1],tmp,GetMem(tmp));
-		// ################################## End of SP CODE ###########################
-			break;
+			zpIndex(tmp, RY);
+			indReg = 'Y';
+
+			goto _indexed;
 
 		//UNDEFINED
-		default: strcpy(str,"ERROR"); break;
-
+		default: strcpy(str, "ERROR"); break;
 	}
-
 	return str;
 }
diff --git a/src/drivers/Qt/TraceLogger.cpp b/src/drivers/Qt/TraceLogger.cpp
index 6eabb3c4..4e886413 100644
--- a/src/drivers/Qt/TraceLogger.cpp
+++ b/src/drivers/Qt/TraceLogger.cpp
@@ -25,7 +25,7 @@
 
 #ifdef WIN32
 #include <windows.h>
-#include <Qt/TraceFileWriter.h>
+#include "../win/TraceFileWriter.h"
 #else
 #include <unistd.h>
 #include <sys/types.h>
diff --git a/src/drivers/Qt/TraceFileWriter.h b/src/drivers/win/TraceFileWriter.h
similarity index 97%
rename from src/drivers/Qt/TraceFileWriter.h
rename to src/drivers/win/TraceFileWriter.h
index df249d6c..7877f715 100644
--- a/src/drivers/Qt/TraceFileWriter.h
+++ b/src/drivers/win/TraceFileWriter.h
@@ -125,7 +125,7 @@ public:
 
 	// Add a line to the buffer and write it out when the buffer is filled
 	// Under most failure cirumstances the line is added to the buffer
-	bool writeLine(const char *line)
+	bool writeLine(const char *line, bool addEol = true)
 	{
 		if (!isOpen)
 		{
@@ -138,6 +138,7 @@ public:
 		size_t eolSize = strlen(eol);
 		char *buff = buffers[buffIdx];
 		size_t lineLen = strlen(line);
+		size_t copyLen = lineLen + (addEol ? eolSize : 0);
 		if (buffOffs + lineLen + eolSize > BuffSize)
 		{
 			// Buffer is full. This shouldn't ever happen.
@@ -146,7 +147,8 @@ public:
 		}
 
 		memcpy(buff + buffOffs, line, lineLen);
-		memcpy(buff + buffOffs + lineLen, eol, eolSize);
+		if (addEol)
+			memcpy(buff + buffOffs + lineLen, eol, eolSize);
 		buffOffs += lineLen + eolSize;
 
 		// Check if the previous write is done, to detect it as early as possible
@@ -202,7 +204,7 @@ public:
 	}
 
 protected:
-	typedef BOOL (*SetFileInformationByHandlePtr)(
+	typedef BOOL (WINAPI *SetFileInformationByHandlePtr)(
 		HANDLE                    hFile,
 		FILE_INFO_BY_HANDLE_CLASS FileInformationClass,
 		LPVOID                    lpFileInformation,
diff --git a/src/drivers/win/debuggersp.cpp b/src/drivers/win/debuggersp.cpp
index d40b5d06..eecfe493 100644
--- a/src/drivers/win/debuggersp.cpp
+++ b/src/drivers/win/debuggersp.cpp
@@ -27,10 +27,12 @@
 #include "../../debug.h"
 #include "../../debugsymboltable.h"
 #include "../../conddebug.h"
+#include "utils/StringBuilder.h"
 
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
+#include <cstdlib>
 
 int GetNesFileAddress(int A);
 
@@ -62,7 +64,7 @@ bool symbRegNames = true;
 int debuggerWasActive = 0;
 char temp_chr[40] = {0};
 char delimiterChar[2] = "#";
-
+
 
 INT_PTR CALLBACK nameDebuggerBookmarkCallB(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);
 extern WNDPROC DefaultEditCtrlProc;
@@ -103,8 +105,14 @@ MemoryMappedRegister RegNames[] = {
 	{"$4017", "JOY2_FRAME"}
 };
 
+const char minRegFirstDigit = '2', maxRegFirstDigit = '4';
+
 int RegNameCount = sizeof(RegNames)/sizeof(MemoryMappedRegister);
 
+auto cmpRegNames = [](const void *a, const void *b) { 
+	return std::strncmp(((const MemoryMappedRegister *)a)->offset + 1, ((const MemoryMappedRegister *)b)->offset + 1, 4);
+};
+
 /**
 * Parses a line from a NL file.
 * @param line The line to parse
@@ -603,20 +611,39 @@ void replaceNames(Name* list, char* str, std::vector<uint16>* addressesLog)
 		list = list->next;
 	}
 
-	for (int i = 0; i < RegNameCount; i++) {
-		if (!symbRegNames) break;
-		// copypaste, because Name* is too complex to abstract
-		*buff = 0;
-		src = str;
+	if (symbRegNames) {
+		StringBuilder sb(buff);
 
-		while (pos = strstr(src, RegNames[i].offset)) {
-			*pos = 0;
-			strcat(buff, src);
-			strcat(buff, RegNames[i].name);
-			src = pos + 5;
+		pos = src = str;
+		while (pos = std::strchr(pos, '$'))
+		{
+			char first = pos[1];
+			if (first < minRegFirstDigit || first > maxRegFirstDigit)
+			{
+				pos += 1;
+				continue;
+			}
+
+			MemoryMappedRegister key = { pos, "" };
+			const MemoryMappedRegister *reg = (const MemoryMappedRegister *)std::bsearch(&key, RegNames, RegNameCount, sizeof(MemoryMappedRegister), cmpRegNames);
+			if (reg != nullptr)
+			{
+				*pos = '\0';
+				sb << src << reg->name;
+				
+				pos += 5;
+				src = pos;
+			}
+			else
+				pos += 1;
 		}
-		if (*buff) {
-			strcat(buff, src);
+
+		// If no registers were found then the string is unmodified and no copies are necessary
+		if (src != str)
+		{
+			if (*src)
+				sb << src;
+
 			strcpy(str, buff);
 		}
 	}
diff --git a/src/drivers/win/tracer.cpp b/src/drivers/win/tracer.cpp
index 35f97eda..3ce622f1 100644
--- a/src/drivers/win/tracer.cpp
+++ b/src/drivers/win/tracer.cpp
@@ -32,8 +32,10 @@
 #include "cdlogger.h"
 #include "tracer.h"
 #include "memview.h"
+#include "TraceFileWriter.h"
 #include "main.h" //for GetRomName()
 #include "utils/xstring.h"
+#include "utils/StringBuilder.h"
 
 //Used to determine the current hotkey mapping for the pause key in order to display on the dialog
 #include "mapinput.h"
@@ -132,7 +134,7 @@ bool log_old_emu_paused = true;		// thanks to this flag the window only updates
 extern bool JustFrameAdvanced;
 extern int currFrameCounter;
 
-FILE *LOG_FP;
+TraceFileWriter fileWriter;
 
 char trace_str[35000] = {0};
 WNDPROC IDC_TRACER_LOG_oldWndProc = 0;
@@ -686,14 +688,13 @@ void BeginLoggingSequence(void)
 	{
 		if(logfilename == NULL) ShowLogDirDialog();
 		if (!logfilename) return;
-		LOG_FP = fopen(logfilename,"w");
-		if (LOG_FP == NULL)
+		if (!fileWriter.open(logfilename, false))
 		{
 			sprintf(trace_str, "Error Opening File %s", logfilename);
 			MessageBox(hTracer, trace_str, "File Error", MB_OK);
 			return;
 		}
-		fprintf(LOG_FP,FCEU_NAME_AND_VERSION" - Trace Log File\n"); //mbg merge 7/19/06 changed string
+		fileWriter.writeLine(FCEU_NAME_AND_VERSION" - Trace Log File");
 	} else
 	{
 		ClearTraceLogBuf();
@@ -734,8 +735,8 @@ void BeginLoggingSequence(void)
 
 void FCEUD_FlushTrace()
 {
-	if(LOG_FP)
-		fflush(LOG_FP);
+	if(fileWriter.getOpen())
+		fileWriter.flush();
 }
 
 //todo: really speed this up
@@ -745,8 +746,8 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 		return;
 
 	unsigned int addr = X.PC;
-	uint8 tmp;
 	static int unloggedlines;
+	StringBuilder dataSb(str_data), dasmSb(str_disassembly), resSb(str_result);
 
 	// if instruction executed from the RAM, skip this, log all instead
 	// TODO: loops folding mame-lyke style
@@ -760,7 +761,7 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 			olddatacount = datacount;
 			if(unloggedlines > 0)
 			{
-				sprintf(str_result, "(%d lines skipped)", unloggedlines);
+				resSb << '(' << sb_dec(unloggedlines) << " lines skipped)";
 				OutputLogLine(str_result);
 				unloggedlines = 0;
 			}
@@ -778,20 +779,22 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 
 	if ((addr + size) > 0xFFFF)
 	{
-		sprintf(str_data, "%02X        ", opcode[0]);
-		sprintf(str_disassembly, "OVERFLOW");
+		dataSb << sb_hex(opcode[0], 2) << "        ";
+		dasmSb << "OVERFLOW";
 	} else
 	{
 		char* a = 0;
 		switch (size)
 		{
 			case 0:
-				sprintf(str_data, "%02X        ", opcode[0]);
-				sprintf(str_disassembly,"UNDEFINED");
+				dataSb << sb_hex(opcode[0], 2) << "        ";
+				dasmSb << "UNDEFINED";
 				break;
 			case 1:
 			{
-				sprintf(str_data, "%02X        ", opcode[0]);
+				StringBuilder decSb(str_decoration);
+
+				dataSb << sb_hex(opcode[0], 2) << "        ";
 				a = Disassemble(addr + 1, opcode);
 				// special case: an RTS opcode
 				if (opcode[0] == 0x60)
@@ -802,18 +805,18 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 					{
 						// this was a JSR instruction - take the subroutine address from it
 						unsigned int call_addr = GetMem(caller_addr + 1) + (GetMem(caller_addr + 2) << 8);
-						sprintf(str_decoration, " (from $%04X)", call_addr);
+						decSb << " (from " << sb_addr(call_addr) << ')';
 						strcat(a, str_decoration);
 					}
 				}
 				break;
 			}
 			case 2:
-				sprintf(str_data, "%02X %02X     ", opcode[0],opcode[1]);
+				dataSb << sb_hex(opcode[0], 2) << ' ' << sb_hex(opcode[1], 2) << "     ";
 				a = Disassemble(addr + 2, opcode);
 				break;
 			case 3:
-				sprintf(str_data, "%02X %02X %02X  ", opcode[0],opcode[1],opcode[2]);
+				dataSb << sb_hex(opcode[0], 2) << ' ' << sb_hex(opcode[1], 2) << ' ' << sb_hex(opcode[2], 2) << "  ";
 				a = Disassemble(addr + 3, opcode);
 				break;
 		}
@@ -822,6 +825,8 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 		{
 			if (logging_options & LOG_SYMBOLIC)
 			{
+				StringBuilder decSb(str_decoration);
+
 				loadNameFiles();
 				tempAddressesLog.resize(0);
 				// Insert Name and Comment lines if needed
@@ -830,24 +835,22 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 				{
 					if (node->name)
 					{
-						strcpy(str_decoration, node->name);
-						strcat(str_decoration, ":");
+						decSb << node->name << ':';
 						tempAddressesLog.push_back(addr);
 						OutputLogLine(str_decoration, &tempAddressesLog);
 					}
 					if (node->comment)
 					{
 						// make a copy
-						strcpy(str_decoration_comment, node->comment);
-						strcat(str_decoration_comment, "\r\n");
+						StringBuilder cmtSb(str_decoration_comment);
+						cmtSb << node->comment << "\r\n";
 						tracer_decoration_comment = str_decoration_comment;
 						// divide the str_decoration_comment into strings (Comment1, Comment2, ...)
 						char* tracer_decoration_comment_end_pos = strstr(tracer_decoration_comment, "\r\n");
 						while (tracer_decoration_comment_end_pos)
 						{
 							tracer_decoration_comment_end_pos[0] = 0;		// set \0 instead of \r
-							strcpy(str_decoration, "; ");
-							strcat(str_decoration, tracer_decoration_comment);
+							decSb << "; " << tracer_decoration_comment;
 							OutputLogLine(str_decoration, &tempAddressesLog);
 							tracer_decoration_comment_end_pos += 2;
 							tracer_decoration_comment = tracer_decoration_comment_end_pos;
@@ -860,8 +863,7 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 				for(int i=0;i<ARRAY_SIZE(pageNames);i++)
 					replaceNames(pageNames[i], a, &tempAddressesLog);
 			}
-			strncpy(str_disassembly, a, LOG_DISASSEMBLY_MAX_LEN);
-			str_disassembly[LOG_DISASSEMBLY_MAX_LEN - 1] = 0;
+			dasmSb.appendStr(a, LOG_DISASSEMBLY_MAX_LEN);
 		}
 	}
 
@@ -870,23 +872,19 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 		// special case: an RTS opcode
 		// add "----------" to emphasize the end of subroutine
 		static const char* emphasize = " -------------------------------------------------------------------------------------------------------------------------";
-		strncat(str_disassembly, emphasize, LOG_DISASSEMBLY_MAX_LEN - strlen(str_disassembly) - 1);
+		dasmSb.appendStr(emphasize, LOG_DISASSEMBLY_MAX_LEN);
 	}
 	// stretch the disassembly string out if we have to output other stuff.
 	if ((logging_options & (LOG_REGISTERS|LOG_PROCESSOR_STATUS)) && !(logging_options & LOG_TO_THE_LEFT))
 	{
-		for (int i = strlen(str_disassembly); i < (LOG_DISASSEMBLY_MAX_LEN - 1); ++i)
-			str_disassembly[i] = ' ';
-		str_disassembly[LOG_DISASSEMBLY_MAX_LEN - 1] = 0;
+		for (int i = dasmSb.size(); i < (LOG_DISASSEMBLY_MAX_LEN - 1); ++i)
+			dasmSb << ' ';
 	}
 
 	// Start filling the str_temp line: Frame count, Cycles count, Instructions count, AXYS state, Processor status, Tabs, Address, Data, Disassembly
 	if (logging_options & LOG_FRAMES_COUNT)
 	{
-		sprintf(str_result, "f%-6u ", currFrameCounter);
-	} else
-	{
-		str_result[0] = 0;
+		resSb << 'f' << sb_dec((unsigned)currFrameCounter, -6) << ' ';
 	}
 	if (logging_options & LOG_CYCLES_COUNT)
 	{
@@ -896,77 +894,74 @@ void FCEUD_TraceInstruction(uint8 *opcode, int size)
 			ResetDebugStatisticsCounters();
 			counter_value = 0;
 		}
-		sprintf(str_temp, "c%-11llu ", counter_value);
-		strcat(str_result, str_temp);
+		resSb << 'c' << sb_dec((uint64_t)counter_value, -11) << ' ';
 	}
 	if (logging_options & LOG_INSTRUCTIONS_COUNT)
 	{
-		sprintf(str_temp, "i%-11llu ", total_instructions);
-		strcat(str_result, str_temp);
+		resSb << 'i' << sb_dec(total_instructions, -11) << ' ';
 	}
 	
 	if (logging_options & LOG_REGISTERS)
 	{
-		sprintf(str_axystate,"A:%02X X:%02X Y:%02X S:%02X ",(X.A),(X.X),(X.Y),(X.S));
+		StringBuilder sb(str_axystate);
+		sb << "A:" << sb_hex(X.A, 2) << " X:" << sb_hex(X.X, 2) << " Y:" << sb_hex(X.Y, 2) << " S:" << sb_hex(X.S, 2) << ' ';
 	}
 	
 	if (logging_options & LOG_PROCESSOR_STATUS)
 	{
-		tmp = X.P^0xFF;
-		sprintf(str_procstatus,"P:%c%c%c%c%c%c%c%c ",
-			'N'|(tmp&0x80)>>2,
-			'V'|(tmp&0x40)>>1,
-			'U'|(tmp&0x20),
-			'B'|(tmp&0x10)<<1,
-			'D'|(tmp&0x08)<<2,
-			'I'|(tmp&0x04)<<3,
-			'Z'|(tmp&0x02)<<4,
-			'C'|(tmp&0x01)<<5
-			);
+		char *s = str_procstatus;
+		*(s++) = X.P & 0x80 ? 'N' : 'n';
+		*(s++) = X.P & 0x40 ? 'V' : 'v';
+		*(s++) = X.P & 0x20 ? 'U' : 'u';
+		*(s++) = X.P & 0x10 ? 'B' : 'b';
+		*(s++) = X.P & 0x08 ? 'D' : 'd';
+		*(s++) = X.P & 0x04 ? 'I' : 'i';
+		*(s++) = X.P & 0x02 ? 'Z' : 'z';
+		*(s++) = X.P & 0x01 ? 'C' : 'c';
+		*(s++) = ' ';
+		*(s++) = '\0';
 	}
 
 	if (logging_options & LOG_TO_THE_LEFT)
 	{
 		if (logging_options & LOG_REGISTERS)
-			strcat(str_result, str_axystate);
+			resSb << str_axystate;
 		if (logging_options & LOG_PROCESSOR_STATUS)
-			strcat(str_result, str_procstatus);
+			resSb << str_procstatus;
 	}
 
 	if (logging_options & LOG_CODE_TABBING)
 	{
 		// add spaces at the beginning of the line according to stack pointer
 		int spaces = (0xFF - X.S) & LOG_TABS_MASK;
-		for (int i = 0; i < spaces; i++)
-			str_tabs[i] = ' ';
+		std::memset(str_tabs, ' ', spaces);
 		str_tabs[spaces] = 0;
-		strcat(str_result, str_tabs);
+		resSb << str_tabs;
 	} else if (logging_options & LOG_TO_THE_LEFT)
 	{
-		strcat(str_result, " ");
+		resSb << ' ';
 	}
 
 	if (logging_options & LOG_BANK_NUMBER)
 	{
 		if (addr >= 0x8000)
-			sprintf(str_address, "$%02X:%04X: ", getBank(addr), addr);
+			resSb << sb_addr(getBank(addr), 2) << ':' << sb_hex(addr, 4);
 		else
-			sprintf(str_address, "  $%04X: ", addr);
+			resSb << "  " << sb_addr(addr);
 	} else
 	{
-		sprintf(str_address, "$%04X: ", addr);
+		resSb << sb_addr(addr);
 	}
-
-	strcat(str_result, str_address);
-	strcat(str_result, str_data);
-	strcat(str_result, str_disassembly);
+	
+	resSb << ": " << str_data;
+	resSb << str_disassembly;
 
 	if (!(logging_options & LOG_TO_THE_LEFT))
 	{
 		if (logging_options & LOG_REGISTERS)
-			strcat(str_result, str_axystate);
+			resSb << str_axystate;
 		if (logging_options & LOG_PROCESSOR_STATUS)
-			strcat(str_result, str_procstatus);
+			resSb << str_procstatus;
 	}
 
 	OutputLogLine(str_result, &tempAddressesLog);
@@ -978,9 +973,7 @@ void OutputLogLine(const char *str, std::vector<uint16>* addressesLog, bool add_
 {
 	if (logtofile)
 	{
-		fputs(str, LOG_FP);
-		if (add_newline)
-			fputs("\n", LOG_FP);
+		fileWriter.writeLine(str, add_newline);
 	} else
 	{
 		if (add_newline)
@@ -1025,7 +1018,7 @@ void EndLoggingSequence()
 {
 	if (logtofile)
 	{
-		fclose(LOG_FP);
+		fileWriter.close();
 	} else
 	{
 		strcpy(str_result, "Logging finished.");
diff --git a/src/utils/StringBuilder.h b/src/utils/StringBuilder.h
index 2c95e992..12fac0d0 100644
--- a/src/utils/StringBuilder.h
+++ b/src/utils/StringBuilder.h
@@ -59,6 +59,57 @@ public:
 		return appendInt<Radix>(intInfo.x, intInfo.minLen, intInfo.leadChar, intInfo.upperCase);
 	}
 
+	// Append an array of characters that may or may not be null-terminated
+	StringBuilder &appendSubstr(const char *str, size_t maxLen)
+	{
+		size_t len = std::strlen(str),
+			copyLen = len <= maxLen ? len : maxLen;
+
+		std::memcpy(end, str, copyLen);
+		end += len;
+		*end = '\0';
+
+		return *this;
+	}
+
+	// Substitute for strncpy/strncat
+	// maxLen is the TOTAL size, including what's already built
+	// If alwaysAppendNull the last character will always be null
+	StringBuilder &appendStr(const char *str, size_t maxLen, bool alwaysAddNull = true)
+	{
+		size_t len = std::strlen(str),
+			curLen = size(),
+			lenLeft = maxLen - curLen;
+
+		if (len < lenLeft)
+		{
+			std::memcpy(end, str, len + 1);
+			end += len;
+		}
+		else if (!alwaysAddNull)
+		{
+			// strncpy/strncat case: no terminating null
+			std::memcpy(end, str, lenLeft);
+			end += lenLeft;
+		}
+		else
+		{
+			// strncpy_s/strncat_s case: always null-terminate
+			if (lenLeft != 0)
+			{
+				size_t copyLen = lenLeft - 1;
+				std::memcpy(end, str, copyLen);
+
+				end += copyLen;
+				*end = '\0';
+			}
+			else
+				end[-1] = '\0';
+		}
+
+		return *this;
+	}
+
 protected:
 	inline StringBuilder &operator <<(nullptr_t)
 	{