forth: Phase 4 strings — S"/C"/."/TYPE/COUNT/CMOVE/FILL/BLANK (+16; Hayes 168/590)

lib/forth/runtime.sx

@@ -21,8 +21,97 @@
       (dict-set! s "base" 10)
       (dict-set! s "vars" (dict))
       (dict-set! s "cstack" (list))
+      (dict-set! s "mem" (dict))
+      (dict-set! s "here" 0)
       s)))
 
+(define
+  forth-mem-write!
+  (fn (state addr u) (dict-set! (get state "mem") (str addr) u)))
+
+(define
+  forth-mem-read
+  (fn
+    (state addr)
+    (or (get (get state "mem") (str addr)) 0)))
+
+(define
+  forth-alloc-bytes!
+  (fn
+    (state n)
+    (let
+      ((addr (get state "here")))
+      (dict-set! state "here" (+ addr n))
+      addr)))
+
+(define
+  forth-mem-write-string!
+  (fn
+    (state addr s)
+    (let
+      ((n (len s)))
+      (forth-mem-write-string-loop! state addr s 0 n))))
+
+(define
+  forth-mem-write-string-loop!
+  (fn
+    (state addr s i n)
+    (when
+      (< i n)
+      (begin
+        (forth-mem-write! state (+ addr i) (char-code (substr s i 1)))
+        (forth-mem-write-string-loop! state addr s (+ i 1) n)))))
+
+(define
+  forth-mem-read-string
+  (fn
+    (state addr n)
+    (forth-mem-read-string-loop state addr 0 n "")))
+
+(define
+  forth-mem-read-string-loop
+  (fn
+    (state addr i n acc)
+    (if
+      (>= i n)
+      acc
+      (forth-mem-read-string-loop
+        state
+        addr
+        (+ i 1)
+        n
+        (str acc (char-from-code (forth-mem-read state (+ addr i))))))))
+
+(define
+  forth-fill-loop
+  (fn
+    (state addr u char i)
+    (when
+      (< i u)
+      (begin
+        (forth-mem-write! state (+ addr i) char)
+        (forth-fill-loop state addr u char (+ i 1))))))
+
+(define
+  forth-cmove-loop
+  (fn
+    (state src dst u i)
+    (when
+      (< i u)
+      (begin
+        (forth-mem-write! state (+ dst i) (forth-mem-read state (+ src i)))
+        (forth-cmove-loop state src dst u (+ i 1))))))
+
+(define
+  forth-cmove-loop-desc
+  (fn
+    (state src dst u i)
+    (when
+      (>= i 0)
+      (begin
+        (forth-mem-write! state (+ dst i) (forth-mem-read state (+ src i)))
+        (forth-cmove-loop-desc state src dst u (- i 1))))))
+
 (define
   forth-cpush
   (fn (state v) (dict-set! state "cstack" (cons v (get state "cstack")))))
@@ -487,4 +576,82 @@
             (forth-error s "return stack underflow"))
           (forth-push s (nth rs 1))
           (forth-push s (nth rs 0)))))
+    (forth-def-prim!
+      state
+      "C@"
+      (fn
+        (s)
+        (let ((addr (forth-pop s))) (forth-push s (forth-mem-read s addr)))))
+    (forth-def-prim!
+      state
+      "C!"
+      (fn
+        (s)
+        (let
+          ((addr (forth-pop s)) (v (forth-pop s)))
+          (forth-mem-write! s addr v))))
+    (forth-def-prim! state "CHAR+" (fn (s) (forth-push s (+ (forth-pop s) 1))))
+    (forth-def-prim! state "CHARS" (fn (s) nil))
+    (forth-def-prim!
+      state
+      "TYPE"
+      (fn
+        (s)
+        (let
+          ((u (forth-pop s)) (addr (forth-pop s)))
+          (forth-emit-str s (forth-mem-read-string s addr u)))))
+    (forth-def-prim!
+      state
+      "COUNT"
+      (fn
+        (s)
+        (let
+          ((addr (forth-pop s)))
+          (let
+            ((u (forth-mem-read s addr)))
+            (forth-push s (+ addr 1))
+            (forth-push s u)))))
+    (forth-def-prim!
+      state
+      "FILL"
+      (fn
+        (s)
+        (let
+          ((char (forth-pop s)) (u (forth-pop s)) (addr (forth-pop s)))
+          (forth-fill-loop s addr u char 0))))
+    (forth-def-prim!
+      state
+      "BLANK"
+      (fn
+        (s)
+        (let
+          ((u (forth-pop s)) (addr (forth-pop s)))
+          (forth-fill-loop s addr u 32 0))))
+    (forth-def-prim!
+      state
+      "CMOVE"
+      (fn
+        (s)
+        (let
+          ((u (forth-pop s)) (dst (forth-pop s)) (src (forth-pop s)))
+          (forth-cmove-loop s src dst u 0))))
+    (forth-def-prim!
+      state
+      "CMOVE>"
+      (fn
+        (s)
+        (let
+          ((u (forth-pop s)) (dst (forth-pop s)) (src (forth-pop s)))
+          (forth-cmove-loop-desc s src dst u (- u 1)))))
+    (forth-def-prim!
+      state
+      "MOVE"
+      (fn
+        (s)
+        (let
+          ((u (forth-pop s)) (dst (forth-pop s)) (src (forth-pop s)))
+          (if
+            (or (<= dst src) (>= dst (+ src u)))
+            (forth-cmove-loop s src dst u 0)
+            (forth-cmove-loop-desc s src dst u (- u 1))))))
     state))