diff --git a/editors/awk.c b/editors/awk.c
index 19f4840..72eca24 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -2039,28 +2039,30 @@
 		setvar_p(res, s);
 		break;
 
+	/* Bitwise ops must assume that operands are unsigned. GNU Awk 3.1.5:
+	 * awk '{ print or(-1,1) }' gives "4.29497e+09", not "-2.xxxe+09" */
 	case B_an:
-		setvar_i(res, (long)getvar_i(av[0]) & (long)getvar_i(av[1]));
+		setvar_i(res, (unsigned long)getvar_i(av[0]) & (unsigned long)getvar_i(av[1]));
 		break;
 
 	case B_co:
-		setvar_i(res, ~(long)getvar_i(av[0]));
+		setvar_i(res, ~(unsigned long)getvar_i(av[0]));
 		break;
 
 	case B_ls:
-		setvar_i(res, (long)getvar_i(av[0]) << (long)getvar_i(av[1]));
+		setvar_i(res, (unsigned long)getvar_i(av[0]) << (unsigned long)getvar_i(av[1]));
 		break;
 
 	case B_or:
-		setvar_i(res, (long)getvar_i(av[0]) | (long)getvar_i(av[1]));
+		setvar_i(res, (unsigned long)getvar_i(av[0]) | (unsigned long)getvar_i(av[1]));
 		break;
 
 	case B_rs:
-		setvar_i(res, (long)((unsigned long)getvar_i(av[0]) >> (unsigned long)getvar_i(av[1])));
+		setvar_i(res, (unsigned long)getvar_i(av[0]) >> (unsigned long)getvar_i(av[1]));
 		break;
 
 	case B_xo:
-		setvar_i(res, (long)getvar_i(av[0]) ^ (long)getvar_i(av[1]));
+		setvar_i(res, (unsigned long)getvar_i(av[0]) ^ (unsigned long)getvar_i(av[1]));
 		break;
 
 	case B_lo: