Allow sending messages to registered process with !

Enables sending messages to registered processes using the shorhand `!`
operator. If a message is sent to an atom name that is not registered using the
`!` operator a `badarg` run-time error occurs, matching OTP behaviour.

closes atomvm#1011
closes atomvm#98

Signed-off-by: Winford <winford@object.stream>

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - ESP32: fix i2c_driver_acquire and i2c_driver_release functions, that were working only once.
+- Sending messages to registered processes using the `!` operator now works.
 
 ## [0.6.0-beta.0] - 2024-02-08
 

src/libAtomVM/opcodesswitch.h

@@ -2213,7 +2213,16 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                 #endif
 
                 #ifdef IMPL_EXECUTE_LOOP
-                    int local_process_id = term_to_local_process_id(x_regs[0]);
+                    term process_term = x_regs[0];
+                    int local_process_id;
+                    if (term_is_atom(process_term)) {
+                        local_process_id = globalcontext_get_registered_process(ctx->global, term_to_atom_index(process_term));
+                        if (UNLIKELY(local_process_id == 0 )){
+                            RAISE_ERROR(BADARG_ATOM);
+                        }
+                    } else {
+                        local_process_id = term_to_local_process_id(process_term);
+                    }
                     TRACE("send/0 target_pid=%i\n", local_process_id);
                     TRACE_SEND(ctx, x_regs[0], x_regs[1]);
                     globalcontext_send_message(ctx->global, local_process_id, x_regs[1]);