From 5d28728e613c78409f089ba3a7f9690a557f2eee Mon Sep 17 00:00:00 2001
From: "Javier B. Torres" <lobo@quiltro.org>
Date: Wed, 3 Dec 2025 22:29:53 -0300
Subject: [PATCH] fix DUPk not working (use pop instead of peek)

---
 exe/uxnemu.ml   | 21 ++++++++++++++-------
 lib/Machine.ml  | 20 +++++---------------
 lib/Machine.mli |  1 -
 3 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/exe/uxnemu.ml b/exe/uxnemu.ml
index d57cffb..7008131 100644
--- a/exe/uxnemu.ml
+++ b/exe/uxnemu.ml
@@ -3,6 +3,11 @@ open Effect.Deep
 
 let debug = Option.is_some (Sys.getenv_opt "DBG")
 
+let print_stack ~name (Machine.Stack { data; sp }) =
+  Fmt.epr "%s: @[%a@]@." name
+    (Fmt.on_bytes (Fmt.octets ()))
+    (Bytes.sub data 0 sp)
+
 let rec run m pc =
   let dev = Machine.dev m in
   let console_vector = ref 0 in
@@ -13,7 +18,7 @@ let rec run m pc =
   in
   try Machine.dispatch ~trace:debug m pc with
   | effect Machine.Trace (pc, instr, args), k when debug ->
-      Fmt.epr "PC = %04x | %6s : %a\n" pc (Instr.to_string instr)
+      Fmt.epr "PC = %04x | %6s : %a@." pc (Instr.to_string instr)
         (Fmt.list ~sep:(Fmt.any " ") (Fmt.fmt "%02x"))
         args;
       Out_channel.flush stderr;
@@ -37,12 +42,8 @@ let rec run m pc =
   | effect Machine.DEO (port, value), k ->
       (match port with
       | 0x10 -> console_vector := value
-      | 0x18 ->
-          print_char (Char.chr value);
-          Out_channel.flush stdout
-      | 0x19 ->
-          prerr_char (Char.chr value);
-          Out_channel.flush stderr
+      | 0x18 -> print_char (Char.chr value)
+      | 0x19 -> prerr_char (Char.chr value)
       | _ -> ());
       continue k ()
 
@@ -54,11 +55,17 @@ let main () =
   let code =
     In_channel.with_open_bin Sys.argv.(1) (fun i -> In_channel.input_all i)
   in
+
   In_channel.set_binary_mode stdin true;
   Out_channel.set_binary_mode stdout true;
 
   let mach = Machine.create code in
+  Bytes.set (Machine.dev mach) 0 '\x00';
   run mach 0x100;
+  if debug then begin
+    print_stack ~name:"wst" (Machine.wst mach);
+    print_stack ~name:"rst" (Machine.rst mach)
+  end;
   exit (Bytes.get_uint8 (Machine.dev mach) 0x0f land 0x7f)
 
 let _ = main ()
diff --git a/lib/Machine.ml b/lib/Machine.ml
index 8ceb7e2..1ca17cf 100644
--- a/lib/Machine.ml
+++ b/lib/Machine.ml
@@ -84,9 +84,6 @@ let dev (Machine { dev; _ }) = dev
 let wst (Machine { stack; _ }) = stack
 let rst (Machine { callstack; _ }) = callstack
 
-let stack (Machine { stack; callstack; _ }) mode =
-  if mode then callstack else stack
-
 let create code =
   let data = Bytes.create 65536 in
   let dev = Bytes.create 256 in
@@ -178,8 +175,9 @@ let dispatch ?(trace = false) ?(breakpoints = []) (Machine m) (pc : int) =
             push mode stk c;
             push mode stk a
         | 0x06 (* DUP *) ->
-            let a = peek mode stk in
+            let a = pop mode stk in
             trace [ a ];
+            push mode stk a;
             push mode stk a
         | 0x07 (* OVR *) ->
             let b = pop mode stk in
@@ -203,7 +201,7 @@ let dispatch ?(trace = false) ?(breakpoints = []) (Machine m) (pc : int) =
             let a = pop mode stk in
             trace [ a; b ];
             pushbyte mode stk (if a > b then 1 else 0)
-        | 0x0b (* GTH *) ->
+        | 0x0b (* LTH *) ->
             let b = pop mode stk in
             let a = pop mode stk in
             trace [ a; b ];
@@ -223,18 +221,10 @@ let dispatch ?(trace = false) ?(breakpoints = []) (Machine m) (pc : int) =
             let addr = pop mode stk in
             trace [ addr ];
             if short then pc := addr else pc := !pc + Util.uint8_to_int8 addr
-        | 0x0f (* STH *) -> (
+        | 0x0f (* STH *) ->
             let a = pop mode stk in
             trace [ a ];
-            match mode with
-            | Mode mode ->
-                push
-                  (Mode
-                     {
-                       mode with
-                       temp = (match stk' with Stack { sp; _ } -> sp);
-                     })
-                  stk' a)
+            push mode stk' a
         | 0x10 (* LDZ *) ->
             let addr = popbyte mode stk in
             trace [ addr ];
diff --git a/lib/Machine.mli b/lib/Machine.mli
index d71b339..1d00709 100644
--- a/lib/Machine.mli
+++ b/lib/Machine.mli
@@ -16,7 +16,6 @@ val ram : machine -> bytes
 val dev : machine -> bytes
 val wst : machine -> stack
 val rst : machine -> stack
-val stack : machine -> bool -> stack
 
 type machine_state = Break | Next of int