diff --git a/libguile/bytevectors.c b/libguile/bytevectors.c
index fff5355..8574a36 100644
--- a/libguile/bytevectors.c
+++ b/libguile/bytevectors.c
@@ -103,7 +103,7 @@
                                                                 \
     memcpy (&c_result, &c_bv[c_index], (_len) / 8);             \
     if (!scm_is_eq (endianness, scm_i_native_endianness))       \
-      c_result = INT_SWAP (_len) (c_result);                    \
+      c_result = (INT_TYPE (_len, _sign)) INT_SWAP (_len) ((INT_TYPE (_len, unsigned)) c_result); \
                                                                 \
     result = SCM_I_MAKINUM (c_result);                          \
   }                                                             \
@@ -143,7 +143,7 @@
 								\
     c_value_short = (INT_TYPE (_len, _sign)) c_value;		\
     if (!scm_is_eq (endianness, scm_i_native_endianness))       \
-      c_value_short = INT_SWAP (_len) (c_value_short);		\
+      c_value_short = (INT_TYPE (_len, _sign)) INT_SWAP (_len) ((INT_TYPE (_len, unsigned)) c_value_short);  \
 								\
     memcpy (&c_bv[c_index], &c_value_short, (_len) / 8);	\
   }								\
@@ -918,7 +918,7 @@ bytevector_large_set (char *c_bv, size_t c_size, int signed_p,
 	    INT_TYPE (16, _sign)  c_value16;				\
 	    memcpy (&c_value16, c_bv, 2);				\
 	    if (swap)							\
-	      value = (INT_TYPE (16, _sign)) bswap_16 (c_value16);	\
+	      value = (INT_TYPE (16, _sign)) bswap_16 ((scm_t_uint16) c_value16); \
 	    else							\
 	      value = c_value16;					\
 	  }								\
@@ -981,7 +981,7 @@ bytevector_unsigned_ref (const char *c_bv, size_t c_size, SCM endianness)
 	      swap = !scm_is_eq (endianness, scm_i_native_endianness);	\
 									\
 	      if (swap)							\
-		c_value16 = (INT_TYPE (16, _sign)) bswap_16 (c_value);	\
+		c_value16 = (INT_TYPE (16, _sign)) bswap_16 ((scm_t_uint16) c_value); \
 	      else							\
 		c_value16 = c_value;					\
 									\