diff --git a/include/util.h b/include/util.h
index 9b3e472ff..2f469c8b8 100644
--- a/include/util.h
+++ b/include/util.h
@@ -95,45 +95,10 @@ int __builtin_clzl (unsigned long x);
 int __builtin_ctzl (unsigned long x);
 
 #ifdef CONFIG_ARCH_RISCV
-uint32_t __clzsi2(uint32_t x)
-{
-    uint32_t count = 0;
-    while ( !(x & 0x80000000U) && count < 34) {
-        x <<= 1;
-        count++;
-    }
-    return count;
-}
-
-uint32_t __ctzsi2(uint32_t x)
-{
-    uint32_t count = 0;
-    while ( !(x & 0x000000001) && count <= 32) {
-        x >>= 1;
-        count++;
-    }
-    return count;
-}
-
-uint32_t __clzdi2(uint64_t x)
-{
-    uint32_t count = 0;
-    while ( !(x & 0x8000000000000000U) && count < 65) {
-        x <<= 1;
-        count++;
-    }
-    return count;
-}
-
-uint32_t __ctzdi2(uint64_t x)
-{
-    uint32_t count = 0;
-    while ( !(x & 0x00000000000000001) && count <= 64) {
-        x >>= 1;
-        count++;
-    }
-    return count;
-}
+uint32_t __clzsi2(uint32_t x);
+uint32_t __ctzsi2(uint32_t x);
+uint32_t __clzdi2(uint64_t x);
+uint32_t __ctzdi2(uint64_t x);
 #endif
 /** MODIFIES: */
 /** DONT_TRANSLATE */
diff --git a/src/util.c b/src/util.c
index 552e736e8..d9af3e3fe 100644
--- a/src/util.c
+++ b/src/util.c
@@ -141,3 +141,45 @@ str_to_long(const char* str)
 
     return val;
 }
+
+#ifdef CONFIG_ARCH_RISCV
+uint32_t __clzsi2(uint32_t x)
+{
+    uint32_t count = 0;
+    while ( !(x & 0x80000000U) && count < 34) {
+        x <<= 1;
+        count++;
+    }
+    return count;
+}
+
+uint32_t __ctzsi2(uint32_t x)
+{
+    uint32_t count = 0;
+    while ( !(x & 0x000000001) && count <= 32) {
+        x >>= 1;
+        count++;
+    }
+    return count;
+}
+
+uint32_t __clzdi2(uint64_t x)
+{
+    uint32_t count = 0;
+    while ( !(x & 0x8000000000000000U) && count < 65) {
+        x <<= 1;
+        count++;
+    }
+    return count;
+}
+
+uint32_t __ctzdi2(uint64_t x)
+{
+    uint32_t count = 0;
+    while ( !(x & 0x00000000000000001) && count <= 64) {
+        x >>= 1;
+        count++;
+    }
+    return count;
+}
+#endif /* CONFIG_ARCH_RISCV */