Example #1
0
def cgen_while(node):
    emit_comment('cgen_while')
    expr = node.ref_child[0]
    stmt = node.ref_child[1]
    top = ut.disFp
    l1 = create_label()
    l2 = create_label()
    node.attribute[AttName.exit_label] = l2
    emit_label(l1)
    t = cgen_expr(expr)
    if t.attribute[AttName.type] != Type.bool:
        raise TypeError("error in node " + str(node) +
                        "\n type of the decision statement must be bool!")
    t.attribute[AttName.address].load_address()
    emit_load("$t0", "$s0")
    align_stack(top)
    emit("beqz $t0, " + l2)
    cgen_stmt(stmt)
    align_stack(top)
    emit_jump(l1)
    emit_label(l2)

    emit_li("$t6", top)
    ut.emit_add("$t6", "$t6", "$fp")
    emit_move("$sp", "$t6")
    return
Example #2
0
def cgen_if2(expr, stmt):
    emit_comment('cgen_if2')
    l1 = create_label()
    top = ut.disFp
    t1 = cgen_expr(expr)
    if t1.attribute[AttName.type] != Type.bool:
        raise TypeError("error in node " + str(expr) +
                        "\n type of the decision statement must be bool!")
    t1.attribute[AttName.address].load_address()
    emit_load("$t0", "$s0")
    align_stack(top)
    emit("beqz $t0, " + l1)
    cgen_stmt(stmt)
    align_stack(top)
    emit_label(l1)
    return
Example #3
0
def cgen_stmt_block(node):
    emit_comment('cgen_stmt_block')
    ut.symbolTable.add_scope()
    top = ut.disFp
    node.attribute[AttName.has_return] = False

    for child_node in node.ref_child:
        if child_node.data == "variabledecl":
            cgen_variable_decl(child_node)
        else:
            ret = cgen_stmt(child_node)
            if ret.attribute[AttName.has_return]:
                node.attribute[AttName.has_return] = True

    align_stack(top)

    ut.symbolTable.remove_scope()
    return node
Example #4
0
def cgen_print_stmt(node):
    emit_comment('cgen_print_stmt')
    top = ut.disFp

    for child in node.ref_child:
        expr = cgen_expr(child)
        address = expr.attribute[AttName.address]
        type = expr.attribute[AttName.type]
        address.load_address()
        if type == Type.double:
            emit_load_double("$f12", "$s0")
            emit_li("$v0", 2)
            emit_syscall()
            #print_double()
        elif type == "string":
            emit_load("$a0", "$s0")
            emit_li("$v0", 4)
            emit_syscall()
        elif type == Type.bool:
            l1 = create_label()
            l2 = create_label()
            emit_load('$s0', '$s0')
            emit('beqz $s0, ' + l1)
            emit('la $a0, __true')
            emit_jump(l2)
            emit_label(l1)
            emit('la $a0, __false')
            emit_label(l2)
            emit_li("$v0", 4)
            emit_syscall()
        else:
            emit_load("$a0", "$s0")
            emit_li("$v0", 1)
            emit_syscall()

        align_stack(top)

    emit('la $a0, __newLine')
    emit_li("$v0", 4)
    emit_syscall()
Example #5
0
def cgen_if1(expr, stmt1, stmt2):
    emit_comment('cgen_if1')
    l1 = create_label()
    l2 = create_label()
    top = ut.disFp
    t1 = cgen_expr(expr)
    if t1.attribute[AttName.type] != Type.bool:
        raise TypeError("error in node " + str(expr) +
                        "\n type of the decision statement must be bool!")
    t1.attribute[AttName.address].load_address()
    emit_load("$t0", "$s0")
    align_stack(top)
    emit("beqz $t0, " + l1)
    st1 = cgen_stmt(stmt1)
    ret = 0
    if st1.attribute[AttName.has_return]:
        ret += 1
    align_stack(top)
    emit_jump(l2)
    emit_label(l1)
    st2 = cgen_stmt(stmt2)
    if st2.attribute[AttName.has_return]:
        ret += 1
    align_stack(top)
    emit_label(l2)
    return ret
Example #6
0
def cgen_stmt(node):
    emit_comment('cgen_stmt')

    child = node.ref_child[0]
    top = ut.disFp

    if child.data == "stmt":
        ret = cgen_stmt(child)
        node.attribute[AttName.has_return] = ret.attribute[AttName.has_return]
    elif child.data == "forstmt":
        cgen_for(child)
        node.attribute[AttName.has_return] = False
    elif child.data == "whilestmt":
        cgen_while(child)
        node.attribute[AttName.has_return] = False
    elif child.data == "ifstmt":
        ret = cgen_if(child)
        node.attribute[AttName.has_return] = ret.attribute[AttName.has_return]
    elif child.data == "stmtblock":
        ret = cgen_stmt_block(child)
        node.attribute[AttName.has_return] = ret.attribute[AttName.has_return]
    elif child.data == "expr":
        cgen_expr(child)
        align_stack(top)
        node.attribute[AttName.has_return] = False
    elif child.data == "breakstmt":
        cgen_break(child)
        node.attribute[AttName.has_return] = False
    elif child.data == "printstmt":
        cgen_print_stmt(child)
        node.attribute[AttName.has_return] = False
    elif child.data == "returnstmt":
        ret = cgen_return_stmt(child)
        node.attribute[AttName.has_return] = ret

    return node