func isodd(num) {
i = 0;
odd = 0;
while((i == num) == 0) {
if(odd == 0) {
odd = 1;
} else {
odd = 0;
}
i = i + 1;
}
return odd;
}
func print_even(num)
{
while(num) {
if(isodd(num)) {
print(num + " is odd");
} else {
print(num + " is even");
}
num = num - 1;
}
}
print_even(4);
func print_range(a, b) {
while(a <= b) {
print(a);
a = a + 1;
}
}
I only compile this on UNIX like systems. You need the standard build tools
such as autoconf, libtool, and flex and bison. Also there is a runtime
requirement : libobject which you can get at https://github.com/libobject/libobject
Please see the file LICENSE located in the root directory of the project.
The compiler generates instructions of the custom instruction set (como_opcode.h) The virtual machine is stack based and only a few instructions take operands. Most instructions pop there arguments from the stack. Here is the relevant source code and instruction output generated from the compiler. This was run with the following command: ./como --print-asm test/for_loop
for(i = 5; i >= 0; i--)
{
if(i % 2 == 0) {
print(i);
}
}
0 LABEL
1 LOAD_CONST 5
2 STORE_NAME i
3 LOAD_NAME i
4 LOAD_CONST 0
5 IS_GREATER_THAN_OR_EQUAL
6 JZ 25
7 LABEL
8 LOAD_NAME i
9 LOAD_CONST 2
10 IREM
11 LOAD_CONST 0
12 IS_EQUAL
13 JZ 17
14 LOAD_NAME i
15 IPRINT
16 JMP 18
17 LABEL
18 LABEL
19 POSTFIX_DEC
20 LOAD_NAME i
21 LOAD_CONST 0
22 IS_GREATER_THAN_OR_EQUAL
23 JZ 25
24 JMP 7
25 LABEL
26 HALT
- There is no
continue, orbreakstatements in loops at this time. The first idea that comes to mind to implement this is to have the executor keep track if the VM is in a loop and store the correct JMP address. This is on the roadmap for 2017