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| -rw-r--r-- | users/wpcarro/scratch/compiler/register_vm.py | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/compiler/register_vm.py b/users/wpcarro/scratch/compiler/register_vm.py new file mode 100644 index 000000000000..302bce5a0ecb --- /dev/null +++ b/users/wpcarro/scratch/compiler/register_vm.py @@ -0,0 +1,161 @@ +# Silly proof-of-concept register VM. + +def compile_binary_op(op, ast): + result = [] + for x in compile(ast[1]): + result.append(x) + result.append(PUSH_REG) + result.append(RES) + for x in compile(ast[2]): + result.append(x) + result.append(ASSIGN_REG_REG) + result.append(Y) + result.append(RES) + result.append(POP) + result.append(X) + result.append(op) + return result + +def compile(ast): + result = [] + + if ast[0] == 'CONST': + result.append(ASSIGN_REG_LIT) + result.append(RES) + result.append(ast[1]) + elif ast[0] == 'ADD': + result += compile_binary_op(ADD, ast) + elif ast[0] == 'SUB': + result += compile_binary_op(SUB, ast) + elif ast[0] == 'MUL': + result += compile_binary_op(MUL, ast) + elif ast[0] == 'DIV': + result += compile_binary_op(DIV, ast) + elif ast[0] == 'RETURN': + result.append(RETURN) + else: + raise Exception('Cannot compile unknown AST node: {}'.format(ast[0])) + + return result + +# opcodes +ASSIGN_REG_LIT = 0x0 +ASSIGN_REG_REG = 0x1 +ADD = 0x2 +SUB = 0x3 +MUL = 0x4 +DIV = 0x5 +SWAP = 0x6 +RETURN = 0x7 +PUSH_REG = 0x8 +POP = 0x9 + +# register indices +X = 0x0 +Y = 0x1 +RES = 0x2 + +registers = [0x0] * 8 +stack = [] + +def reg_name(i): + if i == X: return 'x' + if i == Y: return 'x' + if i == RES: return 'res' + +def print_instructions(xs): + i = 0 + + while i < len(xs): + if xs[i] == ASSIGN_REG_LIT: + # print('ASSIGN_REG_LIT {} {}'.format(reg_name(xs[i + 1]), xs[i + 2])) + print('{} <- {}'.format(reg_name(xs[i + 1]), xs[i + 2])) + i += 3 + elif xs[i] == ASSIGN_REG_REG: + # print('ASSIGN_REG_REG {} {}'.format(reg_name(xs[i + 1]), reg_name(xs[i + 2]))) + print('{} <- ${}'.format(reg_name(xs[i + 1]), reg_name(xs[i + 2]))) + i += 3 + elif xs[i] == ADD: + print('add') + i += 1 + elif xs[i] == SUB: + print('sub') + i += 1 + elif xs[i] == MUL: + print('mul') + i += 1 + elif xs[i] == DIV: + print('div') + i += 1 + elif xs[i] == PUSH_REG: + print('push ${}'.format(reg_name(xs[i + 1]))) + i += 2 + elif xs[i] == POP: + print('{} <- pop'.format(reg_name(xs[i + 1]))) + i += 2 + else: + raise Exception('Cannot print instruction: {}'.format(xs[i])) + +def eval(instructions): + print_instructions(instructions) + ip = 0 + cont = True + while ip < len(instructions): + if instructions[ip] == ASSIGN_REG_LIT: + r = instructions[ip + 1] + x = instructions[ip + 2] + registers[r] = x + ip += 3 + elif instructions[ip] == ASSIGN_REG_REG: + r_dst = instructions[ip + 1] + r_src = instructions[ip + 2] + registers[r_dst] = registers[r_src] + ip += 3 + elif instructions[ip] == ADD: + registers[RES] = registers[X] + registers[Y] + ip += 1 + elif instructions[ip] == MUL: + registers[RES] = registers[X] * registers[Y] + ip += 1 + elif instructions[ip] == SUB: + registers[RES] = registers[X] - registers[Y] + ip += 1 + elif instructions[ip] == MUL: + registers[RES] = registers[X] * registers[Y] + ip += 1 + elif instructions[ip] == DIV: + registers[RES] = registers[X] / registers[Y] + ip += 1 + elif instructions[ip] == SWAP: + r1 = instructions[ip + 1] + r2 = instructions[ip + 2] + registers[r1], registers[r2] = registers[r2], registers[r1] + ip += 3 + elif instructions[ip] == RETURN: + ip += 1 + cont = False + return registers[RES] + elif instructions[ip] == PUSH_REG: + src = instructions[ip + 1] + stack.append(registers[src]) + ip += 2 + elif instructions[ip] == POP: + dst = instructions[ip + 1] + registers[dst] = stack.pop() + ip += 2 + else: + raise Exception('Cannot eval instruction: {}'.format(instructions[ip])) + return registers[RES] + +def main(): + ast = ['ADD', + ['MUL', + ['MUL', ['CONST', 2], ['CONST', 3]], + ['DIV', ['CONST', 5], ['CONST', 5]]], + ['ADD', + ['SUB', ['CONST', 10], ['CONST', 1]], + ['MUL', ['CONST', 2], ['CONST', 2]]]] + + print('result: {}'.format(eval(compile(ast)))) + +main() |