Debugger, begin runtime stuff

asm/fib.scm

@@ -0,0 +1,36 @@
+  (variable result 0)
+  (push result)
+  (@)
+  (push fib)
+  (call)
+  (push cleanup)
+  (jmp)
+fib
+  (dup)
+  (push 0)
+  (=)
+  (over)
+  (push 1)
+  (=)
+  (or)
+  (push recur)
+  (branch)
+  (return)
+recur
+  (dup)
+  (push 1)
+  (-)
+  (push fib)
+  (call)
+  (over)
+  (push 2)
+  (-)
+  (push fib)
+  (call)
+  (+)
+  (nip)
+  (return)
+cleanup
+  (push result)
+  (!)
+  (bye)

asm/runtime.scm

@@ -0,0 +1,76 @@
+;; Note that this is scheme syntax wrapping asm for a stack machine
+(variable scan 0)
+(variable free 0)
+(variable eom 1024)
+;; These need to be initialized later
+(variable root 0)
+(variable the-cars 0) 
+(variable the-cdrs 0)
+(variable new-cars 0)
+(variable new-cdrs 0)
+
+
+(push main)
+(jmp)
+
+alloc
+;; Test if free will go beyond eom
+(push free)
+(@)
+(dup) ; ( -- free free)
+(push 8)
+(+)
+(dup) ; ( -- free free+8 free+8)
+(push eom)
+(@)
+(<) ; ( -- free free+8 (free+8 < eom))
+(branch alloc-do-gc)
+;; write free+8 to free
+(push free)
+(!)
+;; return the old free, it is memory the program can use
+(return)
+alloc-do-gc
+;; Empty the stack
+(drop)
+(drop)
+;; Run garbage collection
+(push gc-start)
+(call)
+;; Tail-call allocation
+(push alloc)
+(jmp)
+
+gc-start
+; Move scan & free back to 0
+(push 0)
+(push free)
+(!)
+(push 0)
+(push scan)
+(!)
+; Push the first cons to relocate (root)
+(push root)
+(@)
+; Call the relocation routine
+(push gc-loop)
+(call)
+; Swap new and old cars and cdrs
+(push new-cars)
+(@)
+(push the-cars)
+(@)
+(push new-cars)
+(!)
+(push the-cars)
+(!)
+(push new-cdrs)
+(@)
+(push the-cdrs)
+(@)
+(push new-cdrs)
+(!)
+(push the-cdrs)
+(!)
+; return to allocation
+(return)