simple_chain/lib.rs
1//! Example JAR chain.
2//!
3//! The chain's endpoint receives an `args_len` (currently ignored)
4//! and returns a u64 — the sum of a fixed array. Exercises the
5//! transpiled-Image runtime end-to-end: stack frame, array on
6//! the stack, iterative sum, function return through the
7//! `#[subsoil::endpoint]` trampoline's halt wrapper.
8
9#![cfg_attr(target_os = "none", no_std)]
10
11/// Compute and return the sum of `[1, 2, 3, 4, 5]`.
12///
13/// Lives in the lib so the bench/test infrastructure can call it
14/// natively on the host as well.
15pub fn simple_chain_sum() -> u64 {
16 let xs = [1u64, 2, 3, 4, 5];
17 let mut acc = 0u64;
18 let mut i = 0;
19 while i < xs.len() {
20 acc = acc.wrapping_add(xs[i]);
21 i += 1;
22 }
23 acc
24}