forth: SP@ / SP! (+4; Hayes 174/590)

2026-04-24 21:07:10 +00:00
parent acf9c273a2
commit 387a6e7f5d
5 changed files with 42 additions and 3 deletions
--- a/lib/forth/runtime.sx
+++ b/lib/forth/runtime.sx
@@ -393,6 +393,19 @@
        (s)
        (let ((a (forth-peek s))) (when (not (= a 0)) (forth-push s a)))))
    (forth-def-prim! state "DEPTH" (fn (s) (forth-push s (forth-depth s))))
+    (forth-def-prim! state "SP@" (fn (s) (forth-push s (forth-depth s))))
+    (forth-def-prim!
+      state
+      "SP!"
+      (fn
+        (s)
+        (let
+          ((n (forth-pop s)))
+          (let
+            ((cur (forth-depth s)))
+            (when
+              (> cur n)
+              (dict-set! s "dstack" (drop (get s "dstack") (- cur n))))))))
    (forth-def-prim!
      state
      "PICK"