diff --git a/src/asm/x64util.h b/src/asm/x64util.h
index 654c8f4a..32669b97 100644
--- a/src/asm/x64util.h
+++ b/src/asm/x64util.h
@@ -1,5 +1,4 @@
 #pragma once
 
-extern "C" uint64 ATTR_MS_ABI udiv128(uint64 low, uint64 hi, uint64 divisor, uint64 *remainder);
 extern "C" void recompiler_fres();
 extern "C" void recompiler_frsqrte();
diff --git a/src/asm/x64util_masm.asm b/src/asm/x64util_masm.asm
index 14aa1ec0..2587c786 100644
--- a/src/asm/x64util_masm.asm
+++ b/src/asm/x64util_masm.asm
@@ -1,12 +1,5 @@
 .code
 
-udiv128 PROC
-	mov rax, rcx
-	div r8
-	mov [r9], rdx
-	ret
-udiv128 ENDP
-
 recompiler_fres	PROC
  ; store all modified registers
 push rdx