diff --git a/asm/assemble.c b/asm/assemble.c
index d45fc329..cd58723b 100644
--- a/asm/assemble.c
+++ b/asm/assemble.c
@@ -1748,28 +1748,34 @@ static void gencode(struct out_data *data, insn *ins)
 
         case4(0274):
         {
-            int64_t uv;
+            uint64_t uv, um;
             int s;
 
-            if (absolute_op(opx)) {
-                if (ins->rex & REX_W)
-                    s = 64;
-                else if (ins->prefixes[PPS_OSIZE] == P_O16)
-                    s = 16;
-                else if (ins->prefixes[PPS_OSIZE] == P_O32)
-                    s = 32;
-                else
-                    s = bits;
+            if (ins->rex & REX_W)
+                s = 64;
+            else if (ins->prefixes[PPS_OSIZE] == P_O16)
+                s = 16;
+            else if (ins->prefixes[PPS_OSIZE] == P_O32)
+                s = 32;
+            else
+                s = bits;
 
-                /*
-                 * Forcibly discard bits irrelevant for our needs, to
-                 * prevent bogus warnings.
+            um = (uint64_t)2 << (s-1);
+            uv = opx->offset;
+
+            if (uv > 127 && uv < (uint64_t)-128 &&
+                (uv < um-128 || uv > um-1)) {
+                /* If this wasn't explicitly byte-sized, warn as though we
+                 * had fallen through to the imm16/32/64 case.
                  */
-                uv = opx->offset;
-                uv = (uv << (64-s)) >> (64-s);
-                opx->offset = uv;
+                nasm_error(ERR_WARNING | ERR_PASS2 | ERR_WARN_NOV,
+                        "%s value exceeds bounds",
+                        (opx->type & BITS8) ? "signed byte" :
+                        s == 16 ? "word" :
+                        s == 32 ? "dword" :
+                        "signed dword");
             }
-            out_imm(data, opx, 1, OUT_SIGNED);
+            out_imm(data, opx, 1, OUT_WRAP); /* XXX: OUT_SIGNED? */
             break;
         }