diff --git a/usr.bin/dc/bcode.c b/usr.bin/dc/bcode.c
index 85a778ec762..045d3294303 100644
--- a/usr.bin/dc/bcode.c
+++ b/usr.bin/dc/bcode.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bcode.c,v 1.64 2025/12/06 06:40:49 tb Exp $	*/
+/*	$OpenBSD: bcode.c,v 1.65 2025/12/15 12:10:46 tb Exp $	*/
 
 /*
  * Copyright (c) 2003, Otto Moerbeek <otto@drijf.net>
@@ -25,10 +25,6 @@
 
 #include "extern.h"
 
-#ifndef BN_MASK2
-#define BN_MASK2	(BN_ULONG)-1
-#endif
-
 /* #define	DEBUGGING */
 
 #define MAX_ARRAY_INDEX		2048
@@ -591,7 +587,7 @@ set_scale(void)
 			warnx("scale must be a nonnegative number");
 		else {
 			scale = get_ulong(n);
-			if (scale != BN_MASK2 && scale <= UINT_MAX)
+			if (scale != (BN_ULONG)-1 && scale <= UINT_MAX)
 				bmachine.scale = (u_int)scale;
 			else
 				warnx("scale too large");
@@ -619,7 +615,7 @@ set_obase(void)
 	n = pop_number();
 	if (n != NULL) {
 		base = get_ulong(n);
-		if (base != BN_MASK2 && base > 1 && base <= UINT_MAX)
+		if (base != (BN_ULONG)-1 && base > 1 && base <= UINT_MAX)
 			bmachine.obase = (u_int)base;
 		else
 			warnx("output base must be a number greater than 1");
@@ -646,7 +642,7 @@ set_ibase(void)
 	n = pop_number();
 	if (n != NULL) {
 		base = get_ulong(n);
-		if (base != BN_MASK2 && 2 <= base && base <= 16)
+		if (base != (BN_ULONG)-1 && 2 <= base && base <= 16)
 			bmachine.ibase = (u_int)base;
 		else
 			warnx("input base must be a number between 2 and 16 "
@@ -911,7 +907,7 @@ load_array(void)
 		idx = get_ulong(inumber);
 		if (BN_is_negative(inumber->number))
 			warnx("negative idx");
-		else if (idx == BN_MASK2 || idx > MAX_ARRAY_INDEX)
+		else if (idx == (BN_ULONG)-1 || idx > MAX_ARRAY_INDEX)
 			warnx("idx too big");
 		else {
 			stack = &bmachine.reg[reg];
@@ -950,7 +946,7 @@ store_array(void)
 		if (BN_is_negative(inumber->number)) {
 			warnx("negative idx");
 			stack_free_value(value);
-		} else if (idx == BN_MASK2 || idx > MAX_ARRAY_INDEX) {
+		} else if (idx == (BN_ULONG)-1 || idx > MAX_ARRAY_INDEX) {
 			warnx("idx too big");
 			stack_free_value(value);
 		} else {
@@ -1200,7 +1196,7 @@ bexp(void)
 		b = BN_get_word(p->number);
 		m = max(a->scale, bmachine.scale);
 		rscale = a->scale * (u_int)b;
-		if (rscale > m || (a->scale > 0 && (b == BN_MASK2 ||
+		if (rscale > m || (a->scale > 0 && (b == (BN_ULONG)-1 ||
 		    b > UINT_MAX)))
 			rscale = m;
 	}
@@ -1520,7 +1516,7 @@ quitN(void)
 		return;
 	i = get_ulong(n);
 	free_number(n);
-	if (i == BN_MASK2 || i == 0)
+	if (i == (BN_ULONG)-1 || i == 0)
 		warnx("Q command requires a number >= 1");
 	else if (bmachine.readsp < i)
 		warnx("Q command argument exceeded string execution depth");
@@ -1542,7 +1538,7 @@ skipN(void)
 	if (n == NULL)
 		return;
 	i = get_ulong(n);
-	if (i == BN_MASK2)
+	if (i == (BN_ULONG)-1)
 		warnx("J command requires a number >= 0");
 	else if (i > 0 && bmachine.readsp < i)
 		warnx("J command argument exceeded string execution depth");