tree 043a8449c3dc1c7ecb4b2599db4a5dfe8d257131
parent dab5817bcf2b0f9db645bbba5cc6f9c71e9c0e38
author Johnathan Van Why <jrvanwhy@google.com> 1612573352 -0800
committer Johnathan Van Why <jrvanwhy@google.com> 1612575728 -0800

Add `libtock_runtime` startup code.

This includes:

1. `rust_start`: The first Rust code to run in a process
1. `set_main!`: Used to specify `main` in a process binary
1. `stack_size!`: Used to specify the stack size in a process binary
1. Documentation of the startup sequence, including the 3 above steps.

The documentation refers to a two things that haven't been implemented yet:
1. Debug syscalls performed by `rust_start` -- unimplemented because `memop` is
   still unimplemented.
1. The `exit` system call.