diff --git a/src/osd/osdcomm.h b/src/osd/osdcomm.h
index b102ba3deaa..d7f55d98d71 100644
--- a/src/osd/osdcomm.h
+++ b/src/osd/osdcomm.h
@@ -122,23 +122,12 @@ using unicode_char = std::uint32_t;
 
 
 /* Concatenate/extract 32-bit halves of 64-bit values */
-inline UINT64 concat_64(UINT32 hi, UINT32 lo) 
-{
-    return (UINT64(hi) << 32) | UINT32(lo);
-}
-
-inline UINT32 extract_64hi(UINT64 val) 
-{
-    return UINT32(val >> 32);
-}
-
-inline UINT32 extract_64lo(UINT64 val) 
-{
-    return UINT32(val);
-}
+constexpr UINT64 concat_64(UINT32 hi, UINT32 lo) { return (UINT64(hi) << 32) | UINT32(lo); }
+constexpr UINT32 extract_64hi(UINT64 val) { return UINT32(val >> 32); }
+constexpr UINT32 extract_64lo(UINT64 val) { return UINT32(val); }
 
 // Highly useful template for compile-time knowledge of an array size
-template <typename T, size_t N> constexpr inline size_t ARRAY_LENGTH(T (&)[N]) { return N;}
+template <typename T, size_t N> constexpr size_t ARRAY_LENGTH(T (&)[N]) { return N;}
 
 // For declaring an array of the same dimensions as another array (including multi-dimensional arrays)
 template <typename T, typename U> struct equivalent_array_or_type { typedef T type; };
@@ -150,28 +139,19 @@ template <typename T, typename U> using equivalent_array_t = typename equivalent
 #define EQUIVALENT_ARRAY(a, T) equivalent_array_t<T, std::remove_reference_t<decltype(a)> >
 
 /* Macros for normalizing data into big or little endian formats */
-inline UINT16 flipendian_int16( UINT16 val ) 
-{
-    return (val << 8) | (val >> 8 );
-}
+constexpr UINT16 flipendian_int16(UINT16 val) { return (val << 8) | (val >> 8); }
 
-inline UINT32 flipendian_int32( UINT32 val )
-{
-    val = ((val << 8) & 0xFF00FF00 ) | ((val >> 8) & 0xFF00FF ); 
-    return (val << 16) | (val >> 16);
-}
+constexpr UINT32 flipendian_int32_partial16(UINT32 val) { return ((val << 8) & 0xFF00FF00U) | ((val >> 8) & 0x00FF00FFU); }
+constexpr UINT32 flipendian_int32(UINT32 val) { return (flipendian_int32_partial16(val) << 16) | (flipendian_int32_partial16(val) >> 16); }
 
-inline UINT64 flipendian_int64( UINT64 val )
-{
-    val = ((val << 8) & U64(0xFF00FF00FF00FF00) ) | ((val >> 8) & U64(0x00FF00FF00FF00FF) );
-    val = ((val << 16) & U64(0xFFFF0000FFFF0000) ) | ((val >> 16) & U64(0x0000FFFF0000FFFF) );
-    return (val << 32) | (val >> 32);
-}	
+constexpr UINT64 flipendian_int64_partial16(UINT64 val) { return ((val << 8) & U64(0xFF00FF00FF00FF00)) | ((val >> 8) & U64(0x00FF00FF00FF00FF)); }
+constexpr UINT64 flipendian_int64_partial32(UINT64 val) { return ((flipendian_int64_partial16(val) << 16) & U64(0xFFFF0000FFFF0000)) | ((flipendian_int64_partial16(val) >> 16) & U64(0x0000FFFF0000FFFF)); }
+constexpr UINT64 flipendian_int64(UINT64 val) { return (flipendian_int64_partial32(val) << 32) | (flipendian_int64_partial32(val) >> 32); }
 
 #ifdef LSB_FIRST
-#define BIG_ENDIANIZE_INT16(x)      (flipendian_int16(x))
-#define BIG_ENDIANIZE_INT32(x)      (flipendian_int32(x))
-#define BIG_ENDIANIZE_INT64(x)      (flipendian_int64(x))
+constexpr UINT16 BIG_ENDIANIZE_INT16(UINT16 x) { return flipendian_int16(x); }
+constexpr UINT32 BIG_ENDIANIZE_INT32(UINT32 x) { return flipendian_int32(x); }
+constexpr UINT64 BIG_ENDIANIZE_INT64(UINT64 x) { return flipendian_int64(x); }
 #define LITTLE_ENDIANIZE_INT16(x)   (x)
 #define LITTLE_ENDIANIZE_INT32(x)   (x)
 #define LITTLE_ENDIANIZE_INT64(x)   (x)
@@ -179,14 +159,14 @@ inline UINT64 flipendian_int64( UINT64 val )
 #define BIG_ENDIANIZE_INT16(x)      (x)
 #define BIG_ENDIANIZE_INT32(x)      (x)
 #define BIG_ENDIANIZE_INT64(x)      (x)
-#define LITTLE_ENDIANIZE_INT16(x)   (flipendian_int16(x))
-#define LITTLE_ENDIANIZE_INT32(x)   (flipendian_int32(x))
-#define LITTLE_ENDIANIZE_INT64(x)   (flipendian_int64(x))
+constexpr UINT16 LITTLE_ENDIANIZE_INT16(UINT16 x) { return flipendian_int16(x); }
+constexpr UINT32 LITTLE_ENDIANIZE_INT32(UINT32 x) { return flipendian_int32(x); }
+constexpr UINT64 LITTLE_ENDIANIZE_INT64(UINT64 x) { return flipendian_int64(x); }
 #endif /* LSB_FIRST */
 
 #ifdef _MSC_VER
 #include <malloc.h>
-typedef ptrdiff_t ssize_t;
+using ssize_t = std::make_signed_t<size_t>;
 #if _MSC_VER == 1900 // VS2015
 #define __LINE__Var 0
 #endif // VS2015