diff --git a/asm/float.c b/asm/float.c
index ff3d9c8f..c90fb27c 100644
--- a/asm/float.c
+++ b/asm/float.c
@@ -556,7 +556,7 @@ static bool ieee_flconvert_bin(const char *string, int bits,
                         mp = &mult[MANT_LIMBS]; /* Guard slot */
                     ms += LIMB_BITS;
                 }
-                *mp |= v << ms;
+                *mp |= v << (ms % (sizeof(fp_limb) * CHAR_BIT));
                 ms -= bits;
 
                 if (!seendot)
diff --git a/asm/nasm.c b/asm/nasm.c
index 9e363140..c7d5e3c6 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -520,9 +520,14 @@ int main(int argc, char **argv)
      * is a preprocess mode, we're perfectly
      * fine to output into stdout.
      */
-    if (!outname) {
-        if (!(operating_mode & OP_PREPROCESS))
-            outname = filename_set_extension(inname, ofmt->extension);
+    if (!outname && !(operating_mode & OP_PREPROCESS)) {
+        outname = filename_set_extension(inname, ofmt->extension);
+        if (!strcmp(outname, inname)) {
+            outname = "nasm.out";
+            nasm_error(ERR_WARNING,
+                       "default output file same as input, using `%s' for output\n",
+                       inname, outname);
+        }
     }
 
     if (depend_file || (operating_mode & OP_DEPEND))