It’s a new day, it’s a new advent of code puzzle.

In that one, we have to apparently cosplay as an IBM mainframe and just.. crunch them numbers. This doesn’t look fun, and I can’t think of a clever twist to make it fun, so let’s try to make it short and sweet.

Parsing

Our input looks like this:

Monkey 0: Starting items: 79, 98 Operation: new = old * 19 Test: divisible by 23 If true: throw to monkey 2 If false: throw to monkey 3 Monkey 1: Starting items: 54, 65, 75, 74 Operation: new = old + 6 Test: divisible by 19 If true: throw to monkey 2 If false: throw to monkey 0 (etc)

Part 1

The day 5 challenge actually looks fun!

Our input looks like this:

[D] [N] [C] [Z] [M] [P] 1 2 3 move 1 from 2 to 1 move 3 from 1 to 3 move 2 from 2 to 1 move 1 from 1 to 2

Which is a visual representation of stacks, and so, for once, we have some serious parsing to do, and that means I finally have a good reason to bust out the nom crate.

In the last article, we cleaned up our dynamic linker a little. We even implemented the Dynamic relocation.

But it’s still pretty far away from running real-world applications.

Let’s try running a simple C application with it:

// in `samples/puts.c` #include <stdio.h> int main() { puts("Hello from C"); return 0; }

$ cd samples/ $ gcc puts.c -o puts $ ../target/debug/elk ./puts Loading "/home/amos/ftl/elk/samples/puts" Loading "/usr/lib/libc-2.32.so" Fatal error: Could not read symbols from ELF object: Parsing error: String("Unknown SymType 10 (0xa)"): input: 1a 00 10 00 a0 bf 0b 00 00 00 00 00 c1 00 00 00 00 00 00 00