From 8c006a0d87d04f52e82b49d15b222850d278273e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Hru=C5=A1ka?= <ondra@ondrovo.com>
Date: Sat, 13 Nov 2021 20:22:24 +0100
Subject: [PATCH] implement exit

---
 exit.forth           |  3 +++
 include/fh_runtime.h |  1 +
 src/fh_builtins.c    | 16 +++++++++++++---
 src/fh_runtime.c     | 11 ++++++++++-
 4 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 exit.forth

diff --git a/exit.forth b/exit.forth
new file mode 100644
index 0000000..5ece9ac
--- /dev/null
+++ b/exit.forth
@@ -0,0 +1,3 @@
+: foo 1 . exit 2 . ;
+: bar foo foo ;
+bar
diff --git a/include/fh_runtime.h b/include/fh_runtime.h
index 0ded4e7..473064a 100644
--- a/include/fh_runtime.h
+++ b/include/fh_runtime.h
@@ -75,6 +75,7 @@ enum fh_substate {
   FH_SUBSTATE_DOTQUOTE,
   FH_SUBSTATE_PARENCOMMENT,
   FH_SUBSTATE_LINECOMMENT,
+  FH_SUBSTATE_EXIT,
   FH_SUBSTATE_MAX,
 };
 
diff --git a/src/fh_builtins.c b/src/fh_builtins.c
index 6148a59..f4a99bd 100644
--- a/src/fh_builtins.c
+++ b/src/fh_builtins.c
@@ -516,7 +516,7 @@ static enum fh_error w_abort(struct fh_thread_s *fh, const struct fh_word_s *w)
 
   fh->data_stack_top = 0;
   fh->return_stack_top = 0;
-  fh->state = FH_STATE_QUIT;
+  fh_setstate(fh, FH_STATE_QUIT, 0);
 
   return FH_OK;
 }
@@ -526,7 +526,16 @@ static enum fh_error w_quit(struct fh_thread_s *fh, const struct fh_word_s *w)
   (void) w;
 
   fh->return_stack_top = 0;
-  fh->state = FH_STATE_QUIT;
+  fh_setstate(fh, FH_STATE_QUIT, 0);
+
+  return FH_OK;
+}
+
+static enum fh_error w_exit(struct fh_thread_s *fh, const struct fh_word_s *w)
+{
+  (void) w;
+
+  fh_setsubstate(fh, FH_SUBSTATE_EXIT);
 
   return FH_OK;
 }
@@ -709,8 +718,9 @@ enum fh_error register_builtin_words(struct fh_thread_s *fh)
       {"space", w_space,           0, 0},
       {"dump",  w_dump,            0, 0},
       /* Control flow */
-      {"abort", w_abort,            0, 0},
+      {"abort", w_abort,           0, 0},
       {"quit",  w_quit,            0, 0},
+      {"exit",  w_exit,            0, 0},
       /* Syntax */
       {":",     w_colon,           0, 0},
       {";",     w_semicolon,       1, 0},
diff --git a/src/fh_runtime.c b/src/fh_runtime.c
index bd35291..4cdea08 100644
--- a/src/fh_runtime.c
+++ b/src/fh_runtime.c
@@ -27,6 +27,7 @@ static const char *substatenames[FH_SUBSTATE_MAX] = {
     [FH_SUBSTATE_DOTQUOTE] = "DOTQUOTE",
     [FH_SUBSTATE_PARENCOMMENT] = "PARENCOMMENT",
     [FH_SUBSTATE_LINECOMMENT] = "LINECOMMENT",
+    [FH_SUBSTATE_EXIT] = "EXIT",
 };
 
 /** Add a word to the dictionary. */
@@ -90,7 +91,7 @@ enum fh_error w_user_word(struct fh_thread_s *fh, const struct fh_word_s *w0)
   // make sure it's aligned
   fh->execptr = WORDALIGNED(fh->execptr);
   const struct fh_instruction_s *instr = (const struct fh_instruction_s *) &fh->compile[fh->execptr];
-  fh->execptr += sizeof(struct fh_instruction_s);
+  fh->execptr += INSTR_SIZE;
 
   uint32_t strl;
   uint32_t addr = 0;
@@ -134,6 +135,14 @@ enum fh_error w_user_word(struct fh_thread_s *fh, const struct fh_word_s *w0)
           if (w2->builtin) {
             LOG("Exec: builtin-word %s", w2->name);
             w2->handler(fh, w2);
+            if (fh->substate == FH_SUBSTATE_EXIT) {
+              fh_setsubstate(fh, 0);
+              LOG("Exec: early return");
+              TRY(rs_pop(fh, &fh->execptr));
+              if (fh->execptr == MAGICADDR_INTERACTIVE) {
+                goto end;
+              }
+            }
             goto instr;
           } else {
             LOG("Exec: user-word %s (CALL)", w2->name);