diff --git a/src/fp.cpp b/src/fp.cpp
index 1e0198b..7454d70 100644
--- a/src/fp.cpp
+++ b/src/fp.cpp
@@ -282,6 +282,7 @@ struct OpeFunc {
 				fp_subNC = mcl_fp_subNC ## n; \
 			} \
 			fpDbl_mulPre = mcl_fpDbl_mulPre ## n; \
+			fp_mulIPre = mcl_fp_mulIPre ## n; \
 			if (n <= 256) { \
 				fpDbl_sqrPre = mcl_fpDbl_sqrPre ## n; \
 			} \
diff --git a/src/mul.txt b/src/mul.txt
index cbde576..e3b39de 100644
--- a/src/mul.txt
+++ b/src/mul.txt
@@ -18,6 +18,13 @@ noinline
 @endfor
   ret i$(bu) %t$(N-2)
 }
+define void @mcl_fp_mulIPre$(bit)(i$(bu)* %pz, i$(bit)* %px, i$(unit) %y)
+{
+  %x = load i$(bit)* %px
+  %z = call i$(bu) @mul$(bit)x$(unit)(i$(bit) %x, i$(unit) %y)
+  store i$(bu) %z, i$(bu)* %pz
+  ret void
+}
 define void @mcl_fpDbl_mulPre$(bit)(i$(unit)* %pz, i$(bit)* %px, i$(bit)* %py) {
   %x = load i$(bit)* %px
   %y = load i$(bit)* %py