diff --git a/vm/primitives.hpp b/vm/primitives.hpp
index f7291430b5..77c255afd5 100644
--- a/vm/primitives.hpp
+++ b/vm/primitives.hpp
@@ -138,11 +138,11 @@ namespace factor
 	_(unsigned_cell,cell,from_unsigned_cell,to_cell) \
 	_(signed_8,s64,from_signed_8,to_signed_8) \
 	_(unsigned_8,u64,from_unsigned_8,to_unsigned_8) \
-	_(signed_4,s32,from_unsigned_cell,to_fixnum) \
+	_(signed_4,s32,from_signed_cell,to_fixnum) \
 	_(unsigned_4,u32,from_unsigned_cell,to_cell) \
-	_(signed_2,s16,from_unsigned_cell,to_fixnum) \
+	_(signed_2,s16,from_signed_cell,to_fixnum) \
 	_(unsigned_2,u16,from_unsigned_cell,to_cell) \
-	_(signed_1,s8,from_unsigned_cell,to_fixnum) \
+	_(signed_1,s8,from_signed_cell,to_fixnum) \
 	_(unsigned_1,u8,from_unsigned_cell,to_cell) \
 	_(float,float,allot_float,to_float) \
 	_(double,double,allot_float,to_double) \