xasm/xasm.d

// xasm 3.1.0 by Piotr Fusik <fox@scene.pl>
// http://xasm.atari.org
// Can be compiled with DMD v2.087.1.

// Poetic License:
//
// This work 'as-is' we provide.
// No warranty express or implied.
// We've done our best,
// to debug and test.
// Liability for damages denied.
//
// Permission is granted hereby,
// to copy, share, and modify.
// Use as is fit,
// free or for profit.
// These rights, on this notice, rely.

import std.algorithm;
import std.array;
import std.conv;
import std.math;
import std.path;
import std.stdio;

version (Windows) {
	import core.sys.windows.windows;
}

int readByte(File *file) {
	char c;
	if (file.readf("%c", &c) != 1)
		return -1;
	return c;
}

const string TITLE = "xasm 3.1.0";

string sourceFilename = null;
bool[26] options;
string[26] optionParameters;
string[] commandLineDefinitions = null;
string makeTarget;
string[] makeSources = null;

int exitCode = 0;

int totalLines;

bool pass2 = false;

bool optionFill; // opt f
bool option5200; // opt g
bool optionHeaders; // opt h
bool optionListing; // opt l
bool optionObject; // opt o
bool optionUnusedLabels; // opt u

string currentFilename;
int lineNo;
int includeLevel = 0;
string line;
int column;

bool foundEnd;

class AssemblyError : Exception {
	this(string msg) {
		super(msg);
	}
}

class Label {
	int value;
	bool unused = true;
	bool unknownInPass1 = false;
	bool passed = false;

	this(int value) {
		this.value = value;
	}
}

Label[string] labelTable;
Label currentLabel;

alias int function(int a, int b) OperatorFunction;

bool inOpcode = false;

struct ValOp {
	int value;
	OperatorFunction func;
	int priority;
}

ValOp[] valOpStack;

int value;
bool unknownInPass1;

enum AddrMode {
	ACCUMULATOR = 0,
	IMMEDIATE = 1,
	ABSOLUTE = 2,
	ZEROPAGE = 3,
	ABSOLUTE_X = 4,
	ZEROPAGE_X = 5,
	ABSOLUTE_Y = 6,
	ZEROPAGE_Y = 7,
	INDIRECT_X = 8,
	INDIRECT_Y = 9,
	INDIRECT = 10,
	ABS_OR_ZP = 11, // temporarily used in readAddrMode
	STANDARD_MASK = 15,
	INCREMENT = 0x20,
	DECREMENT = 0x30,
	ZERO = 0x40
}

AddrMode addrMode;

enum OrgModifier {
	NONE,
	FORCE_HEADER,
	FORCE_FFFF,
	RELOCATE
}

int origin = -1;
int loadOrigin;
int loadingOrigin;
ushort[] blockEnds;
int blockIndex;

bool repeating; // line
int repeatCounter; // line

bool instructionBegin;
bool pairing;

bool willSkip;
bool skipping;
ushort[] skipOffsets;
int skipOffsetsIndex = 0;

int repeatOffset; // instruction repeat

bool wereManyInstructions;

alias void function(int move) MoveFunction;

int value1;
AddrMode addrMode1;
int value2;
AddrMode addrMode2;

struct IfContext {
	bool condition;
	bool wasElse;
	bool aConditionMatched;
}

IfContext[] ifContexts;

File listingStream;
char[32] listingLine;
int listingColumn;
string lastListedFilename = null;

File objectStream;

int objectBytes = 0;

bool getOption(char letter) {
	assert(letter >= 'a' && letter <= 'z');
	return options[letter - 'a'];
}

void warning(string msg, bool error = false) {
	stdout.flush();
	version (Windows) {
		HANDLE stderrHandle = GetStdHandle(STD_ERROR_HANDLE);
		CONSOLE_SCREEN_BUFFER_INFO csbi;
		GetConsoleScreenBufferInfo(stderrHandle, &csbi);
		SetConsoleTextAttribute(stderrHandle, (csbi.wAttributes & ~0xf) | (error ? 12 : 14));
		scope (exit) SetConsoleTextAttribute(stderrHandle, csbi.wAttributes);
	}
	if (line !is null)
		stderr.writeln(line);
	stderr.writefln("%s (%d) %s: %s", currentFilename, lineNo, error ? "ERROR" : "WARNING", msg);
	exitCode = 1;
}

void illegalCharacter() {
	throw new AssemblyError("Illegal character");
}

bool eol() {
	return column >= line.length;
}

char readChar() {
	if (eol())
		throw new AssemblyError("Unexpected end of line");
	return line[column++];
}

int readDigit(int base) {
	if (eol()) return -1;
	int r = line[column];
	if (r >= '0' && r <= '9') {
		r -= '0';
	} else {
		r &= 0xdf;
		if (r >= 'A' && r <= 'Z')
			r -= 'A' - 10;
		else
			return -1;
	}
	if (r < base) {
		column++;
		return r;
	}
	return -1;
}

int readNumber(int base) {
	long r = readDigit(base);
	if (r < 0)
		illegalCharacter();
	do {
		int d = readDigit(base);
		if (d < 0)
			return cast(int) r;
		r = r * base + d;
	} while (r <= 0x7fffffff);
	throw new AssemblyError("Number too big");
}

void readSpaces() {
	switch (readChar()) {
	case '\t':
	case ' ':
		break;
	default:
		throw new AssemblyError("Space expected");
	}
	while (!eol()) {
		switch (line[column]) {
		case '\t':
		case ' ':
			column++;
			break;
		default:
			return;
		}
	}
}

string readLabel() {
	string label;
	while (!eol()) {
		char c = line[column++];
		if (c >= '0' && c <= '9' || c == '_') {
			label ~= c;
			continue;
		}
		c &= 0xdf;
		if (c >= 'A' && c <= 'Z') {
			label ~= c;
			continue;
		}
		column--;
		break;
	}
	return label >= "A" ? label : null;
}

void readComma() {
	if (readChar() != ',')
		throw new AssemblyError("Bad or missing function parameter");
}

string readInstruction() {
	string r;
	for (int i = 0; i < 3; i++) {
		char c = readChar() & 0xdf;
		if (c < 'A' || c > 'Z')
			throw new AssemblyError("Illegal instruction");
		r ~= c;
	}
	return r;
}

string readFunction() {
	if (column + 5 >= line.length) return null;
	if (line[column + 3] != '(') return null;
	string r;
	for (int i = 0; i < 3; i++) {
		char c = line[column + i] & 0xdf;
		if (c < 'A' || c > 'Z') return null;
		r ~= c;
	}
	column += 4;
	return r;
}

string readFilename() {
	readSpaces();
	char delimiter = readChar();
	switch (delimiter) {
	case '"':
	case '\'':
		string filename;
		char c;
		while ((c = readChar()) != delimiter)
			filename ~= c;
		return filename;
	default:
		illegalCharacter();
	}
	assert(0);
}

void readStringChar(char c) {
	if (readChar() != c)
		throw new AssemblyError("String error");
}

ubyte[] readString() {
	if (eol()) return null;
	char delimiter = readChar();
	switch (delimiter) {
	case '"':
	case '\'':
		ubyte[] r;
		for (;;) {
			char c = readChar();
			if (c == delimiter) {
				if (eol()) return r;
				if (line[column] != delimiter) {
					if (line[column] == '*') {
						column++;
						foreach (ref ubyte b; r)
							b ^= 0x80;
					}
					return r;
				}
				column++;
			}
			r ~= cast(ubyte) c;
		}
	default:
		column--;
		return null;
	}
}

void checkNoExtraCharacters() {
	if (eol()) return;
	switch (line[column]) {
	case '\t':
	case ' ':
		return;
	default:
		throw new AssemblyError("Extra characters on line");
	}
}

void checkOriginDefined() {
	if (origin < 0)
		throw new AssemblyError("No ORG specified");
}

int operatorPlus(int a, int b) {
	return b;
}

int operatorMinus(int a, int b) {
	return -b;
}

int operatorLow(int a, int b) {
	return b & 0xff;
}

int operatorHigh(int a, int b) {
	return (b >> 8) & 0xff;
}

int operatorLogicalNot(int a, int b) {
	return !b;
}

int operatorBitwiseNot(int a, int b) {
	return ~b;
}

int operatorAdd(int a, int b) {
	long r = cast(long) a + b;
	if (r < -0x80000000L || r > 0x7fffffffL)
		throw new AssemblyError("Arithmetic overflow");
	return a + b;
}

int operatorSubtract(int a, int b) {
	long r = cast(long) a - b;
	if (r < -0x80000000L || r > 0x7fffffffL)
		throw new AssemblyError("Arithmetic overflow");
	return a - b;
}

int operatorMultiply(int a, int b) {
	long r = cast(long) a * b;
	if (r < -0x80000000L || r > 0x7fffffffL)
		throw new AssemblyError("Arithmetic overflow");
	return a * b;
}

int operatorDivide(int a, int b) {
	if (b == 0)
		throw new AssemblyError("Divide by zero");
	return a / b;
}

int operatorModulus(int a, int b) {
	if (b == 0)
		throw new AssemblyError("Divide by zero");
	return a % b;
}

int operatorAnd(int a, int b) {
	return a & b;
}

int operatorOr(int a, int b) {
	return a | b;
}

int operatorXor(int a, int b) {
	return a ^ b;
}

int operatorEqual(int a, int b) {
	return a == b;
}

int operatorNotEqual(int a, int b) {
	return a != b;
}

int operatorLess(int a, int b) {
	return a < b;
}

int operatorGreater(int a, int b) {
	return a > b;
}

int operatorLessEqual(int a, int b) {
	return a <= b;
}

int operatorGreaterEqual(int a, int b) {
	return a >= b;
}

int operatorShiftLeft(int a, int b) {
	if (b < 0)
		return operatorShiftRight(a, -b);
	if (a != 0 && b >= 32)
		throw new AssemblyError("Arithmetic overflow");
	long r = cast(long) a << b;
	if (r & 0xffffffff00000000L)
		throw new AssemblyError("Arithmetic overflow");
	return a << b;
}

int operatorShiftRight(int a, int b) {
	if (b < 0)
		return operatorShiftLeft(a, -b);
	if (b >= 32)
		b = 31;
	return a >> b;
}

int operatorLogicalAnd(int a, int b) {
	return a && b;
}

int operatorLogicalOr(int a, int b) {
	return a || b;
}

void pushValOp(int value, OperatorFunction func, int priority) {
	ValOp valOp;
	valOp.value = value;
	valOp.func = func;
	valOp.priority = priority;
	valOpStack ~= valOp;
}

void readValue() {
	assert(valOpStack.length == 0);
	unknownInPass1 = false;
	int priority = 0;
	do {
		int operand;
		char c = readChar();
		switch (c) {
		case '[':
			priority += 10;
			continue;
		case '+':
			pushValOp(0, &operatorPlus, priority + 8);
			continue;
		case '-':
			pushValOp(0, &operatorMinus, priority + 8);
			continue;
		case '<':
			pushValOp(0, &operatorLow, priority + 8);
			continue;
		case '>':
			pushValOp(0, &operatorHigh, priority + 8);
			continue;
		case '!':
			pushValOp(0, &operatorLogicalNot, priority + 4);
			continue;
		case '~':
			pushValOp(0, &operatorBitwiseNot, priority + 8);
			continue;
		case '(':
			throw new AssemblyError("Use square brackets instead");
		case '*':
			checkOriginDefined();
			operand = origin;
			break;
		case '#':
			if (!repeating)
				throw new AssemblyError("'#' is allowed only in repeated lines");
			operand = repeatCounter;
			break;
		case '\'':
		case '"':
			operand = readChar();
			if (operand == c)
				readStringChar(c);
			readStringChar(c);
			if (!eol() && line[column] == '*') {
				column++;
				operand ^= 0x80;
			}
			break;
		case '^':
			switch (readChar()) {
			case '0':
				operand = option5200 ? 0xc000 : 0xd000;
				break;
			case '1':
				operand = option5200 ? 0xc010 : 0xd010;
				break;
			case '2':
				operand = option5200 ? 0xe800 : 0xd200;
				break;
			case '3':
				if (option5200)
					throw new AssemblyError("There's no PIA chip in Atari 5200");
				operand = 0xd300;
				break;
			case '4':
				operand = 0xd400;
				break;
			default:
				illegalCharacter();
			}
			int d = readDigit(16);
			if (d < 0)
				illegalCharacter();
			operand += d;
			break;
		case '{':
			if (inOpcode)
				throw new AssemblyError("Nested opcodes not supported");
			ValOp[] savedValOpStack = valOpStack;
			AddrMode savedAddrMode = addrMode;
			bool savedUnknownInPass1 = unknownInPass1;
			bool savedInstructionBegin = instructionBegin;
			valOpStack.length = 0;
			inOpcode = true;
			assemblyInstruction(readInstruction());
			if (readChar() != '}')
				throw new AssemblyError("Missing '}'");
			assert(!instructionBegin);
			inOpcode = false;
			valOpStack = savedValOpStack;
			addrMode = savedAddrMode;
			unknownInPass1 = savedUnknownInPass1;
			instructionBegin = savedInstructionBegin;
			operand = value;
			break;
		case '$':
			operand = readNumber(16);
			break;
		case '%':
			operand = readNumber(2);
			break;
		default:
			column--;
			if (c >= '0' && c <= '9') {
				operand = readNumber(10);
				break;
			}
			string label = readLabel();
			if (label is null)
				illegalCharacter();
			if (label in labelTable) {
				Label l = labelTable[label];
				operand = l.value;
				l.unused = false;
				if (pass2) {
					if (l.passed) {
						if (l.unknownInPass1)
							unknownInPass1 = true;
					} else {
						if (l.unknownInPass1)
							throw new AssemblyError("Illegal forward reference");
						unknownInPass1 = true;
					}
				} else {
					if (l.unknownInPass1)
						unknownInPass1 = true;
				}
			} else {
				if (pass2)
					throw new AssemblyError("Undeclared label: " ~ label);
				unknownInPass1 = true;
			}
			break;
		}
		while (!eol() && line[column] == ']') {
			column++;
			priority -= 10;
			if (priority < 0)
				throw new AssemblyError("Unmatched bracket");
		}
		if (eol()) {
			if (priority != 0)
				throw new AssemblyError("Unmatched bracket");
			pushValOp(operand, &operatorPlus, 1);
		} else {
			switch (line[column++]) {
			case '+':
				pushValOp(operand, &operatorAdd, priority + 6);
				break;
			case '-':
				pushValOp(operand, &operatorSubtract, priority + 6);
				break;
			case '*':
				pushValOp(operand, &operatorMultiply, priority + 7);
				break;
			case '/':
				pushValOp(operand, &operatorDivide, priority + 7);
				break;
			case '%':
				pushValOp(operand, &operatorModulus, priority + 7);
				break;
			case '<':
				switch (readChar()) {
				case '<':
					pushValOp(operand, &operatorShiftLeft, priority + 7);
					break;
				case '=':
					pushValOp(operand, &operatorLessEqual, priority + 5);
					break;
				case '>':
					pushValOp(operand, &operatorNotEqual, priority + 5);
					break;
				default:
					column--;
					pushValOp(operand, &operatorLess, priority + 5);
					break;
				}
				break;
			case '=':
				switch (readChar()) {
				default:
					column--;
					goto case '=';
				case '=':
					pushValOp(operand, &operatorEqual, priority + 5);
					break;
				}
				break;
			case '>':
				switch (readChar()) {
				case '>':
					pushValOp(operand, &operatorShiftRight, priority + 7);
					break;
				case '=':
					pushValOp(operand, &operatorGreaterEqual, priority + 5);
					break;
				default:
					column--;
					pushValOp(operand, &operatorGreater, priority + 5);
					break;
				}
				break;
			case '!':
				switch (readChar()) {
				case '=':
					pushValOp(operand, &operatorNotEqual, priority + 5);
					break;
				default:
					illegalCharacter();
				}
				break;
			case '&':
				switch (readChar()) {
				case '&':
					pushValOp(operand, &operatorLogicalAnd, priority + 3);
					break;
				default:
					column--;
					pushValOp(operand, &operatorAnd, priority + 7);
					break;
				}
				break;
			case '|':
				switch (readChar()) {
				case '|':
					pushValOp(operand, &operatorLogicalOr, priority + 2);
					break;
				default:
					column--;
					pushValOp(operand, &operatorOr, priority + 6);
					break;
				}
				break;
			case '^':
				pushValOp(operand, &operatorXor, priority + 6);
				break;
			default:
				column--;
				if (priority != 0)
					throw new AssemblyError("Unmatched bracket");
				pushValOp(operand, &operatorPlus, 1);
				break;
			}
		}
		for (;;) {
			immutable sp = valOpStack.length - 1;
			if (sp <= 0 || valOpStack[sp].priority > valOpStack[sp - 1].priority)
				break;
			int operand1 = valOpStack[sp - 1].value;
			OperatorFunction func1 = valOpStack[sp - 1].func;
			valOpStack[sp - 1] = valOpStack[sp];
			valOpStack.length = sp;
			if (pass2 || !unknownInPass1) { // skip operations if unknown operands
				valOpStack[sp - 1].value = func1(operand1, valOpStack[sp - 1].value);
			}
		}
	} while (valOpStack.length != 1 || valOpStack[0].priority != 1);
	value = valOpStack[0].value;
	valOpStack.length = 0;
}

debug int testValue(string l) {
	line = l;
	column = 0;
	readValue();
	writefln("Value of %s is %x", l, value);
	return value;
}

unittest {
	assert(testValue("123") == 123);
	assert(testValue("$1234abCd") == 0x1234abcd);
	assert(testValue("%101") == 5);
	assert(testValue("^07") == 0xd007);
	assert(testValue("^1f") == 0xd01f);
	assert(testValue("^23") == 0xd203);
	assert(testValue("^31") == 0xd301);
	assert(testValue("^49") == 0xd409);
	assert(testValue("!0") == 1);
	assert(testValue("<$1234") == 0x34);
	assert(testValue(">$1234567") == 0x45);
	assert(testValue("1+2") == 3);
	assert(testValue("1+2*3") == 7);
	assert(testValue("[1+2]*3") == 9);
	assert(testValue("{nop}") == 0xea);
	assert(testValue("{CLC}+{sec}") == 0x50);
	assert(testValue("{Jsr}") == 0x20);
	assert(testValue("{bit a:}") == 0x2c);
	assert(testValue("{bIt $7d}") == 0x24);
}

void mustBeKnownInPass1() {
	if (unknownInPass1)
		throw new AssemblyError("Label not defined before");
}

void readWord() {
	readValue();
	if ((!unknownInPass1 || pass2) && (value < -0xffff || value > 0xffff))
		throw new AssemblyError("Value out of range");
}

void readUnsignedWord() {
	readWord();
	if ((!unknownInPass1 || pass2) && value < 0)
		throw new AssemblyError("Value out of range");
}

void readKnownPositive() {
	readValue();
	mustBeKnownInPass1();
	if (value <= 0)
		throw new AssemblyError("Value out of range");
}

void optionalIncDec() {
	if (eol()) return;
	switch (line[column]) {
	case '+':
		column++;
		addrMode += AddrMode.INCREMENT;
		return;
	case '-':
		column++;
		addrMode += AddrMode.DECREMENT;
		return;
	default:
		return;
	}
}

void readAddrMode() {
	readSpaces();
	char c = readChar();
	switch (c) {
	case '@':
		addrMode = AddrMode.ACCUMULATOR;
		return;
	case '#':
	case '<':
	case '>':
		addrMode = AddrMode.IMMEDIATE;
		if (inOpcode && line[column] == '}')
			return;
		readWord();
		final switch (c) {
		case '#':
			break;
		case '<':
			value &= 0xff;
			break;
		case '>':
			value = (value >> 8) & 0xff;
			break;
		}
		return;
	case '(':
		if (inOpcode) {
			switch (readChar()) {
			case ',':
				switch (readChar()) {
				case 'X':
				case 'x':
					break;
				default:
					illegalCharacter();
				}
				if (readChar() != ')')
					throw new AssemblyError("Need parenthesis");
				addrMode = AddrMode.INDIRECT_X;
				return;
			case ')':
				if (readChar() == ',') {
					switch (readChar()) {
					case 'Y':
					case 'y':
						break;
					default:
						illegalCharacter();
					}
					addrMode = AddrMode.INDIRECT_Y;
					return;
				} else {
					column--;
					addrMode = AddrMode.INDIRECT;
					return;
				}
			default:
				column--;
				break;
			}
		}
		readUnsignedWord();
		switch (readChar()) {
		case ',':
			switch (readChar()) {
			case 'X':
			case 'x':
				addrMode = AddrMode.INDIRECT_X;
				break;
			case '0':
				addrMode = cast(AddrMode) (AddrMode.INDIRECT_X + AddrMode.ZERO);
				break;
			default:
				illegalCharacter();
			}
			if (readChar() != ')')
				throw new AssemblyError("Need parenthesis");
			return;
		case ')':
			if (eol()) {
				addrMode = AddrMode.INDIRECT;
				return;
			}
			if (line[column] == ',') {
				column++;
				switch (readChar()) {
				case 'Y':
				case 'y':
					addrMode = AddrMode.INDIRECT_Y;
					break;
				case '0':
					addrMode = cast(AddrMode) (AddrMode.INDIRECT_Y + AddrMode.ZERO);
					break;
				default:
					illegalCharacter();
				}
				optionalIncDec();
				return;
			}
			addrMode = AddrMode.INDIRECT;
			return;
		default:
			illegalCharacter();
		}
		break;
	case 'A':
	case 'a':
		if (!eol() && line[column] == ':') {
			column++;
			addrMode = AddrMode.ABSOLUTE;
		} else {
			addrMode = AddrMode.ABS_OR_ZP;
			column--;
		}
		break;
	case 'Z':
	case 'z':
		if (!eol() && line[column] == ':') {
			column++;
			addrMode = AddrMode.ZEROPAGE;
		} else {
			addrMode = AddrMode.ABS_OR_ZP;
			column--;
		}
		break;
	default:
		addrMode = AddrMode.ABS_OR_ZP;
		column--;
		break;
	}
	// absolute or zeropage addressing, optionally indexed
	if (inOpcode && (addrMode == AddrMode.ABSOLUTE || addrMode == AddrMode.ZEROPAGE)) {
		switch (readChar()) {
		case '}':
			column--;
			return;
		case ',':
			switch (readChar()) {
			case 'X':
			case 'x':
				addrMode += cast(AddrMode) (AddrMode.ABSOLUTE_X - AddrMode.ABSOLUTE);
				return;
			case 'Y':
			case 'y':
				addrMode += cast(AddrMode) (AddrMode.ABSOLUTE_Y - AddrMode.ABSOLUTE);
				return;
			default:
				illegalCharacter();
			}
			return;
		default:
			column--;
			break;
		}
	}
	readUnsignedWord();
	if (addrMode == AddrMode.ABS_OR_ZP) {
		if (unknownInPass1 || value > 0xff)
			addrMode = AddrMode.ABSOLUTE;
		else
			addrMode = AddrMode.ZEROPAGE;
	}
	if (eol()) return;
	if (line[column] == ',') {
		column++;
		switch (readChar()) {
		case 'X':
		case 'x':
			addrMode += cast(AddrMode) (AddrMode.ABSOLUTE_X - AddrMode.ABSOLUTE);
			optionalIncDec();
			return;
		case 'Y':
		case 'y':
			addrMode += cast(AddrMode) (AddrMode.ABSOLUTE_Y - AddrMode.ABSOLUTE);
			optionalIncDec();
			return;
		default:
			illegalCharacter();
		}
	}
}

void readAbsoluteAddrMode() {
	if (inOpcode && readChar() == '}') {
		column--;
	} else {
		readAddrMode();
		switch (addrMode) {
		case AddrMode.ABSOLUTE:
		case AddrMode.ZEROPAGE:
			break;
		default:
			illegalAddrMode();
		}
	}
	addrMode = AddrMode.ABSOLUTE;
}

debug AddrMode testAddrMode(string l) {
	line = l;
	column = 0;
	readAddrMode();
	writefln("Addressing mode of \"%s\" is %x", l, addrMode);
	return addrMode;
}

unittest {
	assert(testAddrMode(" @") == AddrMode.ACCUMULATOR);
	assert(testAddrMode(" #0") == AddrMode.IMMEDIATE);
	assert(testAddrMode(" $abc,x-") == cast(AddrMode) (AddrMode.ABSOLUTE_X + AddrMode.DECREMENT));
	assert(testAddrMode(" $ab,Y+") == cast(AddrMode) (AddrMode.ZEROPAGE_Y + AddrMode.INCREMENT));
	assert(testAddrMode(" (0,x)") == AddrMode.INDIRECT_X);
	assert(testAddrMode(" ($ff),Y+") == cast(AddrMode) (AddrMode.INDIRECT_Y + AddrMode.INCREMENT));
	assert(testAddrMode(" ($abcd)") == AddrMode.INDIRECT);
	inOpcode = true;
	assert(testAddrMode(" a:}") == AddrMode.ABSOLUTE);
	assert(testAddrMode(" z:}") == AddrMode.ZEROPAGE);
	assert(testAddrMode(" a:,x}") == AddrMode.ABSOLUTE_X);
	assert(testAddrMode(" z:,y}") == AddrMode.ZEROPAGE_Y);
	assert(testAddrMode(" (,X)}") == AddrMode.INDIRECT_X);
	assert(testAddrMode(" (),y}") == AddrMode.INDIRECT_Y);
	assert(testAddrMode(" ()}") == AddrMode.INDIRECT);
	inOpcode = false;
}

bool inFalseCondition() {
	foreach (IfContext ic; ifContexts) {
		if (!ic.condition) return true;
	}
	return false;
}

string makeEscape(string s) {
	return s.replace("$", "$$");
}

File openInputFile(string filename) {
	if (find(makeSources, filename).empty)
		makeSources ~= filename;
	try {
		return File(filename);
	} catch (Exception e) {
		throw new AssemblyError(e.msg);
	}
}

File openOutputFile(char letter, string defaultExt) {
	string filename = optionParameters[letter - 'a'];
	if (filename is null)
		filename = sourceFilename.setExtension(defaultExt);
	if (letter == 'o')
		makeTarget = makeEscape(filename);
	try {
		return File(filename, "wb");
	} catch (Exception e) {
		throw new AssemblyError(e.msg);
	}
}

void ensureListingFileOpen(char letter, string msg) {
	if (!listingStream.isOpen) {
		listingStream = openOutputFile(letter, "lst");
		if (!getOption('q'))
			write(msg);
		listingStream.writeln(TITLE);
	}
}

void listNibble(int x) {
	listingLine[listingColumn++] = cast(char) (x <= 9 ? x + '0' : x + ('A' - 10));
}

void listByte(ubyte x) {
	listNibble(x >> 4);
	listNibble(x & 0xf);
}

void listWord(ushort x) {
	listByte(cast(ubyte) (x >> 8));
	listByte(cast(ubyte) x);
}

void listLine() {
	if (!optionListing || !getOption('l') || line is null)
		return;
	assert(pass2);
	if (inFalseCondition() && !getOption('c'))
		return;
	if (getOption('i') && includeLevel > 0)
		return;
	ensureListingFileOpen('l', "Writing listing file...\n");
	if (currentFilename != lastListedFilename) {
		listingStream.writeln("Source: ", currentFilename);
		lastListedFilename = currentFilename;
	}
	int i = 4;
	int x = lineNo;
	while (x > 0 && i >= 0) {
		listingLine[i--] = '0' + x % 10;
		x /= 10;
	}
	while (i >= 0)
		listingLine[i--] = ' ';
	listingLine[5] = ' ';
	while (listingColumn < 32)
		listingLine[listingColumn++] = ' ';
	listingStream.writefln("%.32s%s", listingLine, line);
}

void listCommentLine() {
	if (currentLabel is null)
		listingColumn = 6;
	else {
		assert(!inFalseCondition());
		checkOriginDefined();
	}
	listLine();
}

void listLabelTable() {