diff --git a/opflags.h b/opflags.h
index 707452e5..ef2838c1 100644
--- a/opflags.h
+++ b/opflags.h
@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------- *
  *   
- *   Copyright 1996-2012 The NASM Authors - All Rights Reserved
+ *   Copyright 1996-2013 The NASM Authors - All Rights Reserved
  *   See the file AUTHORS included with the NASM distribution for
  *   the specific copyright holders.
  *
@@ -253,25 +253,19 @@
 #define UDWORD                  (GEN_SUBCLASS(4) | IMMEDIATE)   /* operand is in the range 0..0xFFFFFFFF */
 
 /*
- * split vector registers - low 16 and high 16.
- * avoid a conflict in subclass bitfield with any of special EA types.
+ * Subset of vector registers: register 0 only and registers 0-15.
+ * Avoid conflicts in subclass bitfield with any of special EA types!
  */
 #define RM_XMM_L16              (GEN_SUBCLASS(6) | RM_XMM)                                              /* XMM r/m operand  0 ~ 15 */
-#define RM_XMM_H16              (                  RM_XMM)                                              /* XMM r/m operand 16 ~ 31 */
 #define XMM0                    (GEN_SUBCLASS(1) | GEN_SUBCLASS(6) | XMMREG)                            /* XMM register   zero  */
 #define XMM_L16                 (                  GEN_SUBCLASS(6) | XMMREG)                            /* XMM register  0 ~ 15 */
-#define XMM_H16                 (                                    XMMREG)                            /* XMM register 16 ~ 31 */
 
 #define RM_YMM_L16              (GEN_SUBCLASS(6) | RM_YMM)                                              /* YMM r/m operand  0 ~ 15 */
-#define RM_YMM_H16              (                  RM_YMM)                                              /* YMM r/m operand 16 ~ 31 */
 #define YMM0                    (GEN_SUBCLASS(1) | GEN_SUBCLASS(6) | YMMREG)                            /* YMM register   zero  */
 #define YMM_L16                 (                  GEN_SUBCLASS(6) | YMMREG)                            /* YMM register  0 ~ 15 */
-#define YMM_H16                 (                                    YMMREG)                            /* YMM register 16 ~ 31 */
 
 #define RM_ZMM_L16              (GEN_SUBCLASS(6) | RM_ZMM)                                              /* ZMM r/m operand  0 ~ 15 */
-#define RM_ZMM_H16              (                  RM_ZMM)                                              /* ZMM r/m operand 16 ~ 31 */
 #define ZMM0                    (GEN_SUBCLASS(1) | GEN_SUBCLASS(6) | ZMMREG)                            /* ZMM register   zero  */
 #define ZMM_L16                 (                  GEN_SUBCLASS(6) | ZMMREG)                            /* ZMM register  0 ~ 15 */
-#define ZMM_H16                 (                                    ZMMREG)                            /* ZMM register 16 ~ 31 */
 
 #endif /* NASM_OPFLAGS_H */
diff --git a/regs.dat b/regs.dat
index 51682d68..723f6a44 100644
--- a/regs.dat
+++ b/regs.dat
@@ -118,17 +118,17 @@ mm0-7	MMXREG		mmxreg		0
 # SSE registers
 xmm0	XMM0		xmmreg		0
 xmm1-15	XMM_L16		xmmreg		1
-xmm16-31	XMM_H16		xmmreg		16
+xmm16-31	XMMREG		xmmreg		16
 
 # AVX registers
 ymm0	YMM0		ymmreg		0
 ymm1-15	YMM_L16		ymmreg		1
-ymm16-31	YMM_H16		ymmreg		16
+ymm16-31	YMMREG		ymmreg		16
 
 # AVX512 registers
 zmm0	ZMM0		zmmreg		0
 zmm1-15	ZMM_L16		zmmreg		1
-zmm16-31	ZMM_H16		zmmreg		16
+zmm16-31	ZMMREG		zmmreg		16
 
 # Opmask registers
 k0	OPMASK0		opmaskreg	0