diff --git a/makefile.burn_rules b/makefile.burn_rules
index 25060d090..d9a7e716d 100644
--- a/makefile.burn_rules
+++ b/makefile.burn_rules
@@ -146,6 +146,10 @@ ifdef	BUILD_X86_ASM
 endif
 
 ifdef	INCLUDE_KILLER_INSTINCT
-	alldir += burn/drv/midway cpu/adsp2100 cpu/mips3 cpu/mips3/x64
+	alldir += burn/drv/midway cpu/adsp2100 cpu/mips3
 	depobj += dcs2k.o ide.o adsp2100.o cop0.o cop1.o mips3.o adsp2100_intf.o mips3_intf.o
+ifdef	BUILD_X64_EXE
+	alldir += cpu/mips3/x64
+	depobj += mips3_x64.o
+endif
 endif
\ No newline at end of file
diff --git a/makefile.mingw b/makefile.mingw
index dedb11f6b..9008b19a7 100644
--- a/makefile.mingw
+++ b/makefile.mingw
@@ -300,6 +300,9 @@ endif
 
 ifdef BUILD_X64_EXE
 	DEF := $(DEF) -DBUILD_X64_EXE
+ifdef INCLUDE_KILLER_INSTINCT
+	DEF := $(DEF) -DXBYAK_NO_OP_NAMES -DMIPS3_X64_DRC
+endif
 endif
 
 ifdef	SYMBOL
diff --git a/src/cpu/mips3/x64/mips3_x64.cpp b/src/cpu/mips3/x64/mips3_x64.cpp
index 8ce373432..bbf43bae9 100644
--- a/src/cpu/mips3/x64/mips3_x64.cpp
+++ b/src/cpu/mips3/x64/mips3_x64.cpp
@@ -97,6 +97,10 @@ void mips3_x64::prolog()
     // RBX = cpu_state base
     push(rbp);
     push(rbx);
+#ifdef _WIN32
+    push(rsi);
+    push(rdi);
+#endif
     push(r15);
     mov(rbp, rsp);
     sub(rsp, 16);
@@ -113,6 +117,10 @@ void mips3_x64::epilog(bool do_ret)
     mov(rax, ADR(m_icounter));
     mov(ptr[rax], r15);
     pop(r15);
+#if _WIN32
+    pop(rdi);
+    pop(rsi);
+#endif
     pop(rbx);
     pop(rbp);
     if (do_ret)
@@ -452,9 +460,15 @@ void mips3_x64::set_next_pc(addr_t addr)
 
 void mips3_x64::fallback(uint32_t opcode, void (mips3::*f)(uint32_t))
 {
+#ifdef _WIN32
+    // WIN64 ABI - MICROSOFT
+    mov(rcx, (size_t) m_core);
+    mov(edx, opcode);
+#else
     // SysV AMD64 ABI - GNU
     mov(rdi, (size_t) m_core);
     mov(esi, opcode);
+#endif
     mov(rax, (size_t) (void*)f);
     call(rax);
 }