Qbasic Compiler Info

# Input: test.bas # 10 PRINT "Hello" # 20 END tokens = lexer("test.bas") ast = parser(tokens) ast.resolve_labels() # line 10 -> label_L10 ir = gen_ir(ast) asm = gen_x86(ir) write_exe(asm)

| Environment | Execution Time (ms) | File Size | | :--- | :--- | :--- | | QBASIC Interpreter (DOSBox) | 4850 ms | .BAS = 2 KB | | QB64 Compiler (C++ backend) | 210 ms | .EXE = 2.1 MB | | FreeBASIC (GCC backend) | 95 ms | .EXE = 280 KB | | Theoretical Native QBASIC Compiler | ~80 ms | ~120 KB | qbasic compiler

Observation: Compilation yields ~20-60x speedup. Overhead in QB64 results from graphics/compatibility layer. | Compiler | Backend | QBASIC Compatibility | Notable Feature | | :--- | :--- | :--- | :--- | | QB64 | C++ (GCC/LLVM) | High (syntax, graphics) | Emulates QBASIC’s _MEM and OpenGL | | FreeBASIC | GNU as / C | Partial (more QB 4.5) | Supports 64-bit and pointers | | QBASIC Compiler (QB71) | Custom ASM | Very high | Produces small .COM files for DOS | # Input: test

Design and Implementation Considerations for a QBASIC Compiler: Bridging Legacy Interpreters and Modern Execution Environments qbasic compiler