diff --git a/src/c/compiler.d b/src/c/compiler.d
index e4df7a143..045e49269 100644
--- a/src/c/compiler.d
+++ b/src/c/compiler.d
@@ -71,8 +71,6 @@ static int c_case(cl_object args, int flags);
 static int c_catch(cl_object args, int flags);
 static int c_compiler_let(cl_object args, int flags);
 static int c_cond(cl_object args, int flags);
-static int c_dolist(cl_object args, int flags);
-static int c_dotimes(cl_object args, int flags);
 static int c_eval_when(cl_object args, int flags);
 static int c_flet(cl_object args, int flags);
 static int c_funcall(cl_object args, int flags);
@@ -102,6 +100,7 @@ static int c_tagbody(cl_object args, int flags);
 static int c_throw(cl_object args, int flags);
 static int c_unwind_protect(cl_object args, int flags);
 static int c_while(cl_object args, int flags);
+static int c_until(cl_object args, int flags);
 static int compile_body(cl_object args, int flags);
 static int compile_form(cl_object args, int push);
 
@@ -232,8 +231,6 @@ static compiler_record database[] = {
   {@'catch', c_catch, 1},
   {@'ext::compiler-let', c_compiler_let, 0},
   {@'cond', c_cond, 1},
-  {@'dolist', c_dolist, 1},
-  {@'dotimes', c_dotimes, 1},
   {@'eval-when', c_eval_when, 0},
   {@'flet', c_flet, 1},
   {@'function', c_function, 1},
@@ -265,6 +262,7 @@ static compiler_record database[] = {
   {@'unwind-protect', c_unwind_protect, 1},
   {@'values', c_values, 1},
   {@'si::while', c_while, 0},
+  {@'si::until', c_until, 0},
   {NULL, NULL, 1}
 };
 
@@ -922,7 +920,7 @@ c_cond(cl_object args, int flags) {
 
 */
 static int
-c_while(cl_object body, int flags) {
+c_while_until(cl_object body, int flags, bool is_while) {
 	cl_object test = pop(&body);
 	cl_index labelt, labelb;
 
@@ -938,99 +936,20 @@ c_while(cl_object body, int flags) {
 	/* Compile test */
 	asm_complete(OP_JMP, labelt);
 	compile_form(test, FLAG_VALUES);
-	asm_op(OP_JNIL);
+	asm_op(is_while? OP_JT : OP_JNIL);
 	asm_arg(labelb - current_pc());
 
 	return flags;
 }
 
-/*
-	The OP_DOLIST & OP_DOTIMES operators save the lexical
-	environment and establishes a NIL block to execute the
-	enclosed forms, which iterate over the elements in a list or
-	over a range of integer numbers. At the exit of the block,
-	either by means of a OP_RETFROM jump or because of normal
-	termination, the lexical environment is restored, and all
-	bindings undone.
-
-		[OP_DOTIMES/OP_DOLIST + labelz + labelo]
-		...	; bindings
-		OP_EXIT
-		...	; body
-		...	; stepping forms
-		OP_EXIT
-	labelo:	...	; output form
-		OP_EXIT
-	labelz:
-
- */
-
 static int
-c_dolist_dotimes(int op, cl_object args, int flags) {
-	cl_object head = pop(&args);
-	cl_object var = pop(&head);
-	cl_object list = pop(&head);
-	cl_object specials, body;
-	cl_index labelz, labelo;
-	cl_object old_variables = ENV->variables;
-
-	body = c_process_declarations(args);
-	specials = VALUES(3);
-
-	if (!SYMBOLP(var))
-		FEillegal_variable_name(var);
-
-	/* Compute list and enter loop */
-	compile_form(list, FLAG_VALUES);
-	labelz = asm_jmp(op);
-	labelo = current_pc(); asm_arg(0);
-
-	/* Bind block */
-	c_register_block(Cnil);
-
-	/* Initialize the variable */
-	compile_form((op == OP_DOLIST)? Cnil : MAKE_FIXNUM(0), FLAG_REG0);
-	c_bind(var, specials);
-	asm_op(OP_EXIT);
-
-	/* From here on, declarations apply */
-	c_declare_specials(specials);
-
-	/* Variable assignment and iterated body */
-	compile_setq(OP_SETQ, var);
-	c_tagbody(body, 0);
-	asm_op(OP_EXIT);
-
-	/* Output */
-	asm_complete(0, labelo);
-	if (head != Cnil && CDR(head) != Cnil)
-		FEprogram_error("DOLIST: Too many output forms.", 0);
-	flags = maybe_values(flags);
-	if (Null(head)) {
-		compile_body(Cnil, flags);
-	} else {
-		compile_setq(OP_SETQ, var);
-		compile_form(pop(&head), flags);
-	}
-	asm_op(OP_EXIT);
-
-	/* Exit point for block */
-	asm_complete(op, labelz);
-
-	ENV->variables = old_variables;
-
-	return flags;
-}
-
-
-static int
-c_dolist(cl_object args, int flags) {
-	return c_dolist_dotimes(OP_DOLIST, args, flags);
+c_while(cl_object body, int flags) {
+	return c_while_until(body, flags, 1);
 }
 
 static int
-c_dotimes(cl_object args, int flags) {
-	return c_dolist_dotimes(OP_DOTIMES, args, flags);
+c_until(cl_object body, int flags) {
+	return c_while_until(body, flags, 0);
 }
 
 static int
@@ -1053,7 +972,7 @@ c_eval_when(cl_object args, int flags) {
 		...
 		fun2
 		...
-		OP_EXIT
+		OP_UNBIND n
 	labelz:
 */
 static cl_index
diff --git a/src/c/disassembler.d b/src/c/disassembler.d
index 705d79acf..eb4b5b04f 100644
--- a/src/c/disassembler.d
+++ b/src/c/disassembler.d
@@ -110,70 +110,6 @@ NO_ARGS:
 
 /* -------------------- DISASSEMBLER CORE -------------------- */
 
-/* OP_DOLIST	labelz, labelo
-   ...		; code to bind the local variable
-   OP_EXIT
-   ...		; code executed on each iteration
-   OP_EXIT
-   labelo:
-   ...		; code executed at the end
-   OP_EXIT
-   labelz:
-
-	High level construct for the DOLIST iterator. The list over which
-	we iterate is stored in VALUES(0).
-*/
-static cl_opcode *
-disassemble_dolist(cl_object bytecodes, cl_opcode *vector) {
-	cl_opcode *exit, *output;
-	cl_object lex_old = cl_env.lex_env;
-
-	GET_LABEL(exit, vector);
-	GET_LABEL(output, vector);
-	print_oparg("DOLIST\t", exit-base);
-	vector = disassemble(bytecodes, vector);
-	print_noarg("\t\t; dolist binding");
-	vector = disassemble(bytecodes, vector);
-	print_noarg("\t\t; dolist body");
-	vector = disassemble(bytecodes, vector);
-	print_noarg("\t\t; dolist");
-
-	cl_env.lex_env = lex_old;
-	return vector;
-}
-
-/* OP_TIMES	labelz, labelo
-   ...		; code to bind the local variable
-   OP_EXIT
-   ...		; code executed on each iteration
-   OP_EXIT
-   labelo:
-   ...		; code executed at the end
-   OP_EXIT
-   labelz:
-
-	High level construct for the DOTIMES iterator. The number of times
-	we iterate is stored in VALUES(0).
-*/
-static cl_opcode *
-disassemble_dotimes(cl_object bytecodes, cl_opcode *vector) {
-	cl_opcode *exit, *output;
-	cl_object lex_old = cl_env.lex_env;
-
-	GET_LABEL(exit, vector);
-	GET_LABEL(output, vector);
-	print_oparg("DOTIMES\t", exit-base);
-	vector = disassemble(bytecodes, vector);
-	print_noarg("\t\t; dotimes times");
-	vector = disassemble(bytecodes, vector);
-	print_noarg("\t\t; dotimes body");
-	vector = disassemble(bytecodes, vector);
-	print_noarg("\t\t; dotimes");
-
-	cl_env.lex_env = lex_old;
-	return vector;
-}
-
 /* OP_FLET	nfun{arg}
    fun1{object}
    ...
@@ -474,7 +410,7 @@ disassemble(cl_object bytecodes, cl_opcode *vector) {
 	case OP_CATCH:		string = "CATCH\t";
 				goto JMP;
 	/* OP_EXIT
-		Marks the end of a high level construct (DOLIST, DOTIMES...)
+		Marks the end of a high level construct
 	*/
 	case OP_EXIT:		print_noarg("EXIT");
 				return vector;
@@ -655,10 +591,6 @@ disassemble(cl_object bytecodes, cl_opcode *vector) {
 	*/
 	case OP_NTHVAL:		string = "NTHVAL\t";
 				goto NOARG;
-	case OP_DOLIST:		vector = disassemble_dolist(bytecodes, vector);
-				break;
-	case OP_DOTIMES:	vector = disassemble_dotimes(bytecodes, vector);
-				break;
 	/* OP_DO	label
 	     ...	; code executed within a NIL block
 	   OP_EXIT_FRAME
diff --git a/src/c/interpreter.d b/src/c/interpreter.d
index 57e66d6f0..d7929943a 100644
--- a/src/c/interpreter.d
+++ b/src/c/interpreter.d
@@ -446,116 +446,6 @@ interpret_funcall(cl_narg narg, cl_object fun) {
 
 /* -------------------- THE INTERPRETER -------------------- */
 
-/* OP_DOLIST	labelz, labelo
-   ...		; code to bind the local variable
-   OP_EXIT
-   ...		; code executed on each iteration
-   OP_EXIT
-   labelo:
-   ...		; code executed at the end
-   OP_EXIT
-   labelz:
-
-	High level construct for the DOLIST iterator. The list over which
-	we iterate is stored in VALUES(0).
-*/
-static cl_opcode *
-interpret_dolist(cl_object bytecodes, cl_opcode *vector) {
-	cl_opcode *volatile exit;
-	cl_opcode *output;
-
-	GET_LABEL(exit, vector);
-	GET_LABEL(output, vector);
-
-	/* 1) Set NIL block */
-	CL_BLOCK_BEGIN(id) {
-		cl_object list = VALUES(0);
-
-		bind_block(Cnil, id);
-
-		/* 2) Build list & bind variable*/
-		vector = interpret(bytecodes, vector);
-
-		/* 3) Repeat until list is exahusted */
-		while (!endp(list)) {
-			NVALUES = 1;
-			VALUES(0) = CAR(list);
-			interpret(bytecodes, vector);
-			list = CDR(list);
-		}
-		VALUES(0) = Cnil;
-		NVALUES = 1;
-		interpret(bytecodes, output);
-
-		/* 4) Restore environment */
-		cl_env.lex_env = cl_env.frs_top->frs_lex;
-		bds_unwind(cl_env.frs_top->frs_bds_top);
-	} CL_BLOCK_END;
-	return exit;
-}
-
-/* OP_TIMES	labelz, labelo
-   ...		; code to bind the local variable
-   OP_EXIT
-   ...		; code executed on each iteration
-   OP_EXIT
-   labelo:
-   ...		; code executed at the end
-   OP_EXIT
-   labelz:
-
-	High level construct for the DOTIMES iterator. The number of times
-	we iterate is stored in VALUES(0).
-*/
-static cl_opcode *
-interpret_dotimes(cl_object bytecodes, cl_opcode *vector) {
-	cl_opcode *volatile exit;
-	cl_opcode *output;
-
-	GET_LABEL(exit, vector);
-	GET_LABEL(output, vector);
-
-	CL_BLOCK_BEGIN(id) {
-		cl_object length = VALUES(0);
-
-		/* 1) Set up a nil block */
-		bind_block(Cnil, id);
-
-		/* 2) Retrieve number and bind variables */
-		vector = interpret(bytecodes, vector);
-
-		if (FIXNUMP(length)) {
-		    cl_fixnum i, l = fix(length);
-		    /* 3) Loop while needed */
-		    for (i = 0; i < l; i++) {
-			NVALUES = 1;
-			VALUES(0) = MAKE_FIXNUM(i);
-			interpret(bytecodes, vector);
-		    }
-		    length = MAKE_FIXNUM(i);
-		} else {
-		    cl_object i;
-		    for (i = MAKE_FIXNUM(0);
-			 number_compare(i, length) < 0;
-			 i = one_plus(i))
-		    {
-			NVALUES = 1;
-			VALUES(0) = i;
-			interpret(bytecodes, vector);
-		    }
-		    length = i;
-		}
-		NVALUES = 1;
-		VALUES(0) = length;
-		interpret(bytecodes, output);
-
-		/* 4) Restore environment */
-		cl_env.lex_env = cl_env.frs_top->frs_lex;
-		bds_unwind(cl_env.frs_top->frs_bds_top);
-	} CL_BLOCK_END;
-	return exit;
-}
-
 static cl_object
 close_around(cl_object fun, cl_object lex) {
 	cl_object v = cl_alloc_object(t_bytecodes);
@@ -569,7 +459,7 @@ close_around(cl_object fun, cl_object lex) {
    ...
    funn{object}
    ...
-   OP_EXIT
+   OP_UNBIND n
 
 	Executes the enclosed code in a lexical enviroment extended with
 	the functions "fun1" ... "funn".
@@ -591,12 +481,12 @@ interpret_flet(cl_object bytecodes, cl_opcode *vector) {
 	return vector;
 }
 
-/* OP_FLET	nfun{arg}
+/* OP_LABELS	nfun{arg}
    fun1{object}
    ...
    funn{object}
    ...
-   OP_EXIT
+   OP_UNBIND n
 
 	Executes the enclosed code in a lexical enviroment extended with
 	the functions "fun1" ... "funn".
@@ -1055,7 +945,7 @@ interpret(cl_object bytecodes, void *pc) {
 
 	/* OP_BLOCK	label{arg}
 	   ...
-	   OP_EXIT
+	   OP_EXIT_FRAME
 	 label:
 
 	   Executes the enclosed code in a named block.
@@ -1114,7 +1004,7 @@ interpret(cl_object bytecodes, void *pc) {
 	     ...
 	   labeln:
 	     ...
-	   OP_EXIT
+	   OP_EXIT_TAGBODY
 
 	   High level construct for the TAGBODY form.
 	*/
@@ -1159,14 +1049,6 @@ interpret(cl_object bytecodes, void *pc) {
 		VALUES(0) = reg0 = Cnil;
 		NVALUES = 0;
 		break;
-	case OP_DOLIST:
-		vector = interpret_dolist(bytecodes, vector);
-		reg0 = VALUES(0);
-		break;
-	case OP_DOTIMES:
-		vector = interpret_dotimes(bytecodes, vector);
-		reg0 = VALUES(0);
-		break;
 	case OP_MSETQ:
 		vector = interpret_msetq(bytecodes, vector);
 		reg0 = VALUES(0);
@@ -1246,10 +1128,10 @@ interpret(cl_object bytecodes, void *pc) {
 	}
 	/* OP_PROTECT	label
 	     ...	; code to be protected and whose value is output
-	   OP_EXIT
+	   OP_PROTECT_NORMAL
 	   label:
 	     ...	; code executed at exit
-	   OP_EXIT
+	   OP_PROTECT_EXIT
 
 	  High level construct for UNWIND-PROTECT. The first piece of code is
 	  executed and its output value is saved. Then the second piece of code
diff --git a/src/c/symbols_list.h b/src/c/symbols_list.h
index c1c8d6362..6bf58606b 100644
--- a/src/c/symbols_list.h
+++ b/src/c/symbols_list.h
@@ -1524,6 +1524,7 @@ cl_symbols[] = {
 #endif
 
 {SYS_ "WHILE", SI_ORDINARY, NULL, -1, OBJNULL},
+{SYS_ "UNTIL", SI_ORDINARY, NULL, -1, OBJNULL},
 {SYS_ "QUASIQUOTE", SI_ORDINARY, NULL, -1, OBJNULL},
 {SYS_ "*EXIT-HOOKS*", SI_SPECIAL, NULL, -1, Cnil},
 
diff --git a/src/c/symbols_list2.h b/src/c/symbols_list2.h
index ea72a32a2..84b152e39 100644
--- a/src/c/symbols_list2.h
+++ b/src/c/symbols_list2.h
@@ -1524,6 +1524,7 @@ cl_symbols[] = {
 #endif
 
 {SYS_ "WHILE",NULL},
+{SYS_ "UNTIL",NULL},
 {SYS_ "QUASIQUOTE",NULL},
 {SYS_ "*EXIT-HOOKS*",NULL},
 
diff --git a/src/h/bytecodes.h b/src/h/bytecodes.h
index 745101347..498c799ec 100644
--- a/src/h/bytecodes.h
+++ b/src/h/bytecodes.h
@@ -163,8 +163,6 @@ enum {
   OP_TAGBODY,
   OP_EXIT_TAGBODY,
   OP_EXIT_FRAME,
-  OP_DOLIST,
-  OP_DOTIMES,
   OP_PROTECT,
   OP_PROTECT_NORMAL,
   OP_PROTECT_EXIT,
diff --git a/src/lsp/evalmacros.lsp b/src/lsp/evalmacros.lsp
index 8e78cd932..d5d0bea21 100644
--- a/src/lsp/evalmacros.lsp
+++ b/src/lsp/evalmacros.lsp
@@ -247,7 +247,8 @@ SECOND-FORM."
 (defmacro multiple-value-bind (vars form &rest body)
   `(multiple-value-call #'(lambda (&optional ,@(mapcar #'list vars)) ,@body) ,form))
 
-(defmacro sys::while (test &body body)
+(defun while-until (test body jmp-op)
+  (declare (si::c-local))
   (let ((label (gensym))
 	(exit (gensym)))
     `(TAGBODY
@@ -255,7 +256,13 @@ SECOND-FORM."
       ,label
         ,@body
       ,exit
-	(UNLESS ,test (GO ,label)))))
+	(,jmp-op ,test (GO ,label)))))
+
+(defmacro sys::while (test &body body)
+  (while-until test body 'when))
+
+(defmacro sys::until (test &body body)
+  (while-until test body 'unless))
 
 (defmacro case (keyform &rest clauses &aux (form nil) (key (gensym)))
   (dolist (clause (reverse clauses)
@@ -276,25 +283,6 @@ SECOND-FORM."
 
 (defmacro return (&optional (val nil)) `(RETURN-FROM NIL ,val))
 
-(defmacro dolist ((var form &optional (val nil)) &rest body
-                                                 &aux (temp (gensym)) decl)
-  (multiple-value-setq (decl body)
-    (find-declarations body))
-    ;; Since ENDP did not complain, this is definitely a (CDR ,temp) is safe
-  `(DO* ((,temp ,form (CDR (THE CONS ,temp))) (,var))
-	((ENDP ,temp) ,val)
-    ,@decl
-    (SETQ ,var (CAR ,temp))
-    ,@body
-    ))
-
-(defmacro dotimes ((var form &optional (val nil)) &rest body
-                                                  &aux (temp (gensym)))
-  `(DO* ((,temp ,form) (,var 0 (1+ ,var)))
-        ((>= ,var ,temp) ,val)
-        (DECLARE (FIXNUM ,var)) ; Beppe  (:READ-ONLY ,temp)
-        ,@body))
-
 ;; Declarations
 (defmacro declaim (&rest decl-specs)
   (if (cdr decl-specs)
diff --git a/src/lsp/export.lsp b/src/lsp/export.lsp
index bc662eae6..a1230cb8c 100644
--- a/src/lsp/export.lsp
+++ b/src/lsp/export.lsp
@@ -41,6 +41,56 @@
 ;; This is also needed for booting ECL. In particular it is required in
 ;; defmacro.lsp.
 ;;
+(let ((f #'(ext::lambda-block dolist (whole env)
+	   (let (body pop finished control var expr exit)
+	     (setq body (rest whole))
+	     (when (endp body)
+	       (simple-program-error "Syntax error in ~A:~%~A" 'DOLIST whole))
+	     (setq control (first body) body (rest body))
+	     (when (endp control)
+	       (simple-program-error "Syntax error in ~A:~%~A" 'DOLIST whole))
+	     (setq var (first control) control (rest control))
+	     (if (<= 1 (length control) 2)
+		 (setq expr (first control) exit (rest control))
+		 (simple-program-error "Syntax error in ~A:~%~A" 'DOLIST whole))
+	     (multiple-value-bind (declarations body)
+		 (process-declarations body nil)
+	       `(block nil
+		 (let* ((%dolist-var ,expr)
+			,var)
+		   (declare ,@declarations)
+		   (si::while %dolist-var
+		      (setq ,var (first %dolist-var))
+		      ,@body
+		      (setq %dolist-var (rest %dolist-var)))
+		   ,(when exit `(setq ,var nil))
+		   ,@exit)))))))
+  (si::fset 'dolist f t))
+
+(let ((f #'(ext::lambda-block dotimes (whole env)
+	   (let (body pop finished control var expr exit)
+	     (setq body (rest whole))
+	     (when (endp body)
+	       (simple-program-error "Syntax error in ~A:~%~A" 'DOTIMES whole))
+	     (setq control (first body) body (rest body))
+	     (when (endp control)
+	       (simple-program-error "Syntax error in ~A:~%~A" 'DOTIMES whole))
+	     (setq var (first control) control (rest control))
+	     (if (<= 1 (length control) 2)
+		 (setq expr (first control) exit (rest control))
+		 (simple-program-error "Syntax error in ~A:~%~A" 'DOTIMES whole))
+	     (multiple-value-bind (declarations body)
+		 (process-declarations body nil)
+	       `(block nil
+		 (let* ((%dotimes-var ,expr)
+			(,var 0))
+		   (declare ,@declarations)
+		   (si::while (< ,var %dotimes-var)
+		     ,@body
+		     (setq ,var (1+ ,var)))
+		   ,@exit)))))))
+  (si::fset 'dotimes f t))
+
 (let ((f #'(ext::lambda-block do/do*-expand (whole env)
            (let (do/do* control test result vl step let psetq body)
 	     (setq do/do* (first whole) body (rest whole))
@@ -48,13 +98,13 @@
 		 (setq let 'LET psetq 'PSETQ)
 		 (setq let 'LET* psetq 'SETQ))
 	     (when (endp body)
-	       (simple-program-error "Syntax error in DO/DO* body:~%~A" whole))
+	       (simple-program-error "Syntax error in ~A:~%~A" do/do* whole))
 	     (setq control (first body) body (rest body))
 	     (when (endp body)
-	       (simple-program-error "Syntax error in DO/DO* body:~%~A" whole))
+	       (simple-program-error "Syntax error in ~A:~%~A" do/do* whole))
 	     (setq test (first body) body (rest body))
 	     (when (endp test)
-	       (simple-program-error "Syntax error in DO/DO* body:~%~A" whole))
+	       (simple-program-error "Syntax error in ~A:~%~A" do/do* whole))
 	     (setq result (rest test) test (first test))
 	     (dolist (c control)
 	       (when (symbolp c) (setq c (list c)))
@@ -65,15 +115,15 @@
 		  (setq vl (cons (butlast c) vl)
 			step (list* (third c) (first c) step)))
 		 (t
-		  (simple-program-error "Syntax error in DO/DO* body:~%~A" whole))))
-	     (multiple-value-bind (declarations real-body doc)
+		  (simple-program-error "Syntax error in ~A:~%~A" do/do* whole))))
+	     (multiple-value-bind (declarations real-body)
 		 (process-declarations body nil)
 	       `(BLOCK NIL
 		 (,let ,(nreverse vl)
 		   (declare ,@declarations)
-		   (sys::while ,test
-			       ,@real-body
-			       ,@(when step (list (cons psetq (nreverse step)))))
+		   (sys::until ,test
+		      ,@real-body
+		      ,@(when step (list (cons psetq (nreverse step)))))
 		   ,@(or result '(nil)))))))))
   (si::fset 'do f t)
   (si::fset 'do* f t))