msp4th: disassembler user code

diff --git a/msp4th/dis.4th b/msp4th/dis.4th
new file mode 100644 (file)
index 0000000..bf1e006
--- /dev/null
+++ b/msp4th/dis.4th
@@ -0,0 +1,48 @@
+\ vim: ft=forth
+: ' ( -- opcode) gw lu not if push0 then ;  \ gets next word, leaves its opcode if found, else 0
+: colon 0x3a emit ;
+: semicolon 0x3b emit ;
+: space 0x20 emit ;
+: cmp-print-next
+    over == if drop 1 + dup p@ . push1 then ;
+: cmp-done
+    over == if drop push0 then ;
+: print-opcode ( n opcode -- n done? )
+    dup o2w
+    20022 cmp-print-next \ if
+    20032 cmp-print-next \ goto
+    20035 cmp-print-next \ pushn
+    20040 cmp-done       \ return
+    not
+    ;
+: get-opcode ( n -- n opcode )
+    dup p@ ;
+: dis ( opcode -- )
+    colon space dup o2w
+    o2p
+    dup if \ user defined
+        cr
+        push1 -
+        begin
+            push1 +
+            dup .
+            get-opcode
+            print-opcode
+            cr
+        until
+    else
+        semicolon
+    then
+    cr drop drop ;
+: prog-space ( -- ) \ printout program space
+    h@ 0 do
+        i dup .
+        p@ dup .
+        o2w cr
+    loop ;
+prog-space
+' dis o2p
+' dis dis
+' print-opcode dis
+20032 dis
+bye