diff --git a/src/emu/emucore.h b/src/emu/emucore.h
index 212bf31c849..1782ac8726d 100644
--- a/src/emu/emucore.h
+++ b/src/emu/emucore.h
@@ -263,9 +263,7 @@ template <unsigned B, typename T, typename... U> T bitswap(T val, U... b)
 }
 
 // explicit versions that check number of bit position arguments
-template <typename T, typename... U> constexpr T BITSWAP4(T val, U... b) {  return bitswap<4U>(val, b...); }
 template <typename T, typename... U> constexpr T BITSWAP8(T val, U... b) {  return bitswap<8U>(val, b...); }
-template <typename T, typename... U> constexpr T BITSWAP12(T val, U... b) {  return bitswap<12U>(val, b...); }
 template <typename T, typename... U> constexpr T BITSWAP16(T val, U... b) {  return bitswap<16U>(val, b...); }
 template <typename T, typename... U> constexpr T BITSWAP24(T val, U... b) {  return bitswap<24U>(val, b...); }
 template <typename T, typename... U> constexpr T BITSWAP32(T val, U... b) {  return bitswap<32U>(val, b...); }