public AsmContext Assemble(string content, string fileName = null)
{
var symbols = new AsmSymbols();
IList<Token> tokens = new List<Token>();
LoadRecursive(content, tokens, fileName);
tokens = ProcessSymbolConstants(tokens, symbols);
AsmContext last = null;
for (var i = 1; i < 10; i++) {
var context = new AsmContext {
Queue = new TokensQueue(tokens),
Symbols = symbols,
Pass = i
};
var parser = new AsmParser(context);
AssemblePass(context, parser);
if (TheSame(last, context)) break;
last = context;
}
return last;
}
private static void ProcessReserveWords(AsmParser parser, AsmSection output)
{
var cnt = parser.CalculateExpression();
output.ReserveBytes((int)cnt * 2);
}
private static void ProcessOrg(AsmParser parser, AsmSection output)
{
var val = parser.CalculateExpression();
output.Offset = (int)val;
}
private static void ProcessDataWords(AsmParser parser, AsmSection output)
{
do {
if (parser.IsEndOfLine) {
throw new TokenException("expected data words", parser.LastReadToken);
}
var token = parser.PeekToken();
if (token.Type == TokenType.String) {
token = parser.ReadToken(TokenType.String);
foreach (var ch in token.StringValue) {
output.EmitWord(ch);
}
} else {
var val = parser.ReadUshort();
output.EmitWord(val);
}
if (parser.IsEndOfLine) break;
var commaPreview = parser.PeekToken();
if (commaPreview.Type != TokenType.Comma) break;
parser.ReadToken(TokenType.Comma);
} while (true);
}
private static void ProcessDataDirective(Token token, AsmParser parser, AsmSection output)
{
switch (token.StringValue.ToLower()) {
case "db":
ProcessDataBytes(parser, output);
break;
case "dw":
ProcessDataWords(parser, output);
break;
case "rb":
ProcessReserveBytes(parser, output);
break;
case "rw":
ProcessReserveWords(parser, output);
break;
default:
throw new TokenException("invalid directive " + token.StringValue, token);
}
}
private static void ProcessDataBytes(AsmParser parser, AsmSection output)
{
do {
if (parser.IsEndOfLine) {
throw new TokenException("expected data bytes", parser.LastReadToken);
}
var token = parser.PeekToken();
if (token.Type == TokenType.String) {
token = parser.ReadToken(TokenType.String);
foreach (var ch in token.StringValue) {
if (ch > 255) {
throw new TokenException("unicode character cannot be translated to byte", token);
}
output.EmitByte((byte)ch);
}
} else {
var val = parser.ReadByte();
output.EmitByte(val);
}
if (parser.IsEndOfLine) break;
var commaPreview = parser.PeekToken();
if (commaPreview.Type != TokenType.Comma) break;
parser.ReadToken(TokenType.Comma);
} while (true);
}
private static bool CheckData(Token token, AsmContext context, AsmParser parser)
{
if (IsDataDirective(token)) {
ProcessDataDirective(token, parser, context.CurrentSection);
return true;
}
if (!context.Queue.IsEndOfLine) {
var preview = context.Queue.Peek();
if (IsDataDirective(preview)) {
context.Queue.Read(TokenType.Literal);
context.DefineLabel(token);
ProcessDataDirective(preview, parser, context.CurrentSection);
return true;
}
}
return false;
}
private static void AssemblePass(AsmContext context, AsmParser parser)
{
while (context.Queue.Count > 0) {
SkipEmptyLines(context);
if (context.Queue.Count == 0) break;
AssembleLine(context, parser);
}
}
private static void AssembleLine(AsmContext context, AsmParser parser)
{
var token = context.Queue.Read(TokenType.Literal);
try {
if (CheckLabel(token, context)) {
return;
}
if (CheckData(token, context, parser)) {
return;
}
switch (token.StringValue.ToLower()) {
case "section":
ProcessSection(context);
break;
case "org":
ProcessOrg(parser, context.CurrentSection);
break;
default:
var opcode = AvrOpcodes.Get(token.StringValue);
if (opcode != null) {
opcode.Compile(parser, context.CurrentSection);
} else {
throw new TokenException("Illegal instruction " + token.StringValue, token);
}
break;
}
if (context.Queue.Count > 0) {
var nl = context.Queue.Peek();
if (nl.Type != TokenType.NewLine) {
throw new TokenException("Extra characters on line", nl);
}
}
} catch (PureSectionDataException exc) {
throw new PureSectionDataException(exc.Message, token);
}
}