diff --git a/assemble.c b/assemble.c
index f06cee82..bdf9a10c 100644
--- a/assemble.c
+++ b/assemble.c
@@ -196,6 +196,7 @@ enum match_result {
     MERR_BADHLE,
     MERR_ENCMISMATCH,
     MERR_BADBND,
+    MERR_BADREPNE,
     /*
      * Matching success; the conditional ones first
      */
@@ -647,6 +648,7 @@ int64_t assemble(int32_t segment, int64_t offset, int bits, iflag_t cp,
                     case P_EVEX:
                     case P_VEX3:
                     case P_VEX2:
+                    case P_NOBND:
                     case P_none:
                         break;
                     default:
@@ -700,6 +702,11 @@ int64_t assemble(int32_t segment, int64_t offset, int bits, iflag_t cp,
         case MERR_BADBND:
             error(ERR_NONFATAL, "bnd prefix is not allowed");
             break;
+        case MERR_BADREPNE:
+            error(ERR_NONFATAL, "%s prefix is not allowed",
+                  (has_prefix(instruction, PPS_REP, P_REPNE) ?
+                   "repne" : "repnz"));
+            break;
         default:
             error(ERR_NONFATAL,
                   "invalid combination of opcode and operands");
@@ -814,6 +821,7 @@ int64_t insn_size(int32_t segment, int64_t offset, int bits, iflag_t cp,
             case P_EVEX:
             case P_VEX3:
             case P_VEX2:
+            case P_NOBND:
             case P_none:
                 break;
             default:
@@ -1351,6 +1359,15 @@ static int64_t calcsize(int32_t segment, int64_t offset, int bits,
 
     bad_hle_warn(ins, hleok);
 
+    /*
+     * when BND prefix is set by DEFAULT directive,
+     * BND prefix is added to every appropriate instruction line
+     * unless it is overridden by NOBND prefix.
+     */
+    if (globalbnd &&
+        (itemp_has(temp, IF_BND) && !has_prefix(ins, PPS_REP, P_NOBND)))
+            ins->prefixes[PPS_REP] = P_BND;
+
     return length;
 }
 
@@ -2328,11 +2345,17 @@ static enum match_result matches(const struct itemplate *itemp,
         return MOK_JUMP;
 
     /*
-     * Check if BND prefix is allowed
+     * Check if BND prefix is allowed.
+     * Other 0xF2 (REPNE/REPNZ) prefix is prohibited.
      */
     if (!itemp_has(itemp, IF_BND) &&
-        has_prefix(instruction, PPS_REP, P_BND))
+        (has_prefix(instruction, PPS_REP, P_BND) ||
+         has_prefix(instruction, PPS_REP, P_NOBND)))
         return MERR_BADBND;
+    else if (itemp_has(itemp, IF_BND) &&
+             (has_prefix(instruction, PPS_REP, P_REPNE) ||
+              has_prefix(instruction, PPS_REP, P_REPNZ)))
+        return MERR_BADREPNE;
 
     return MOK_GOOD;
 }
diff --git a/nasm.c b/nasm.c
index d10ddbcb..2bb30292 100644
--- a/nasm.c
+++ b/nasm.c
@@ -89,6 +89,7 @@ bool tasm_compatible_mode = false;
 int pass0, passn;
 int maxbits = 0;
 int globalrel = 0;
+int globalbnd = 0;
 
 static time_t official_compile_time;
 
@@ -1525,7 +1526,7 @@ static void assemble_file(char *fname, StrList **depend_ptr)
                     stdscan_reset();
                     stdscan_set(value);
                     tokval.t_type = TOKEN_INVALID;
-                    if (stdscan(NULL, &tokval) == TOKEN_SPECIAL) {
+                    if (stdscan(NULL, &tokval) != TOKEN_INVALID) {
                         switch ((int)tokval.t_integer) {
                         case S_REL:
                             globalrel = 1;
@@ -1533,6 +1534,12 @@ static void assemble_file(char *fname, StrList **depend_ptr)
                         case S_ABS:
                             globalrel = 0;
                             break;
+                        case P_BND:
+                            globalbnd = 1;
+                            break;
+                        case P_NOBND:
+                            globalbnd = 0;
+                            break;
                         default:
                             err = 1;
                             break;
diff --git a/nasm.h b/nasm.h
index f499c49a..736c290e 100644
--- a/nasm.h
+++ b/nasm.h
@@ -564,6 +564,7 @@ enum prefixes { /* instruction prefixes */
     P_XACQUIRE,
     P_XRELEASE,
     P_BND,
+    P_NOBND,
     P_EVEX,
     P_VEX3,
     P_VEX2,
@@ -1172,6 +1173,7 @@ extern bool tasm_compatible_mode;
 extern int optimizing;
 extern int globalbits;          /* 16, 32 or 64-bit mode */
 extern int globalrel;           /* default to relative addressing? */
+extern int globalbnd;           /* default to using bnd prefix? */
 extern int maxbits;             /* max bits supported by output */
 
 /*
diff --git a/parser.c b/parser.c
index 4f0898c2..2d8d4ff8 100644
--- a/parser.c
+++ b/parser.c
@@ -90,6 +90,7 @@ static int prefix_slot(int prefix)
     case P_XACQUIRE:
     case P_XRELEASE:
     case P_BND:
+    case P_NOBND:
         return PPS_REP;
     case P_O16:
     case P_O32:
diff --git a/standard.mac b/standard.mac
index b2dff8d6..60c0387c 100644
--- a/standard.mac
+++ b/standard.mac
@@ -205,6 +205,19 @@
     [default %1]
 %endmacro
 
+%imacro userel 0.nolist
+    [default rel]
+%endmacro
+%imacro useabs 0.nolist
+    [default abs]
+%endmacro
+%imacro usebnd 0.nolist
+    [default bnd]
+%endmacro
+%imacro usenobnd 0.nolist
+    [default nobnd]
+%endmacro
+
 %imacro incbin 1-2+.nolist 0
     %push
         %pathsearch %$dep %1
diff --git a/tokens.dat b/tokens.dat
index 09d4b9fb..0e446417 100644
--- a/tokens.dat
+++ b/tokens.dat
@@ -55,6 +55,7 @@ wait
 xacquire
 xrelease
 bnd
+nobnd
 
 % TOKEN_SPECIAL, 0, 0, S_*
 abs