Assembler (#6)

Co-authored-by: Andre Wagner <WagnerAndre@JohnDeere.com>
Reviewed-on: https://192.168.5.48/andre/tyche/pulls/6

src/assembler/assembler.cc

@@ -0,0 +1,98 @@
+#include "assembler.hh"
+
+#include <unordered_map>
+
+#include "as_exceptions.hh"
+#include "../bytecode/bytecode.hh"
+#include "../vm/instruction.hh"
+
+using namespace std::string_literals;
+
+namespace tyche::as {
+
+ByteArray Assembler::assemble()
+{
+    bc::BytecodePrototype bp;
+
+    lexer_.reset();
+
+    enum class Section { Const, Function } section;
+    uint32_t function_id = 0;
+
+    for (;;) {
+        Token t = lexer_.ingest();
+        if (t.type == TokenType::Enter)
+            continue;
+
+        if (t.type == TokenType::Directive) {
+            if (std::get<std::string>(t.token) == ".const") {
+                section = Section::Const;
+                expect_token(TokenType::Enter);
+            } else if (std::get<std::string>(t.token) == ".func") {
+                section = Section::Function;
+                function_id = std::get<int>(expect_token(TokenType::Integer));
+                if (function_id >= bp.functions.size())
+                    bp.functions.resize(function_id + 1, { 0, 0 });
+                expect_token(TokenType::Enter);
+            } else {
+                throw AssemblyError("Invalid directive " + std::get<std::string>(t.token), t.line, t.column);
+            }
+
+        } else if (section == Section::Const && t.type == TokenType::Integer) {
+            int index = std::get<int>(t.token);
+            if ((size_t) index >= bp.constants.size())
+                bp.constants.resize(index + 1);
+            expect_token(TokenType::Colon);
+            Token tt = lexer_.ingest();
+            if (tt.type == TokenType::Float)
+                bp.constants[index] = std::get<float>(tt.token);
+            else if (tt.type == TokenType::String)
+                bp.constants[index] = std::get<std::string>(tt.token);
+            else
+                throw AssemblyError("Expected float or string as constant", tt.line, tt.column);
+            expect_token(TokenType::Enter);
+
+        } else if (section == Section::Function && t.type == TokenType::Instruction) {
+            std::string instruction = std::get<std::string>(t.token);
+            std::optional<int> oper = {};
+            Token tt = lexer_.ingest();
+            if (tt.type == TokenType::Integer) {
+                oper = std::get<int>(tt.token);
+                tt = lexer_.ingest();
+            }
+
+            auto oinst = vm::translate_instruction(instruction, oper);
+            if (!oinst)
+                throw AssemblyError("Invalid or misused instruction '" + instruction + "'", tt.line, tt.column);
+
+            bp.functions.at(function_id).code.append_byte((uint8_t) *oinst);
+            switch (vm::instruction_operand_type(*oinst)) {
+                case vm::OperandType::Int8:  bp.functions.at(function_id).code.append_int8((int8_t) *oper); break;
+                case vm::OperandType::Int16: bp.functions.at(function_id).code.append_int16((int16_t) *oper); break;
+                case vm::OperandType::Int32: bp.functions.at(function_id).code.append_int32(*oper); break;
+                case vm::OperandType::NoOperand: default:
+            }
+
+            if (tt.type != TokenType::Enter)
+                throw AssemblyError("Expected enter", tt.line, tt.column);
+
+        } else if (t.type == TokenType::EOF_) {
+            break;
+
+        } else if (t.type != TokenType::Enter) {
+            throw AssemblyError("Unexpected token of type " + token_type_name(t.type) + ")", t.line, t.column);
+        }
+    }
+
+    return bc::Bytecode::generate(bp);
+}
+
+TokenValue Assembler::expect_token(TokenType type)
+{
+    Token t = lexer_.ingest();
+    if (t.type != type)
+        throw AssemblyError("Expected " + token_type_name(t.type), t.line, t.column);
+    return t.token;
+}
+
+} // tyche