diff --git a/decode.c b/decode.c
index 29d5a21..38e12a9 100644
--- a/decode.c
+++ b/decode.c
@@ -277,6 +277,7 @@ struct InstrDesc
     uint8_t gp_fixed_operand_size : 3;
     uint8_t lock : 1;
     uint8_t vsib : 1;
+    uint16_t reg_types;
 } __attribute__((packed));
 
 #define DESC_HAS_MODRM(desc) (((desc)->operand_indices & (3 << 0)) != 0)
@@ -573,6 +574,17 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
     if ((prefixes & PREFIX_LOCK) && instr->operands[0].type != FD_OT_MEM)
         return -1;
 
+    for (int i = 0; i < 4; i++)
+    {
+        if (instr->operands[i].type != FD_OT_REG)
+            continue;
+        uint32_t reg_type = (desc->reg_types >> 4 * i) & 0xf;
+        if (reg_type == FD_RT_GPL && !(prefixes & PREFIX_REX) &&
+            instr->operands[i].size == 1 && instr->operands[i].reg >= 4)
+            reg_type = FD_RT_GPH;
+        instr->operands[i].misc = reg_type;
+    }
+
     instr->size = off;
 
     return off;
diff --git a/fadec.h b/fadec.h
index 1516f4b..49df189 100644
--- a/fadec.h
+++ b/fadec.h
@@ -48,10 +48,36 @@ typedef enum {
     FD_OT_MEM = 3,
 } FdOpType;
 
+typedef enum {
+    /** Register type is encoded in mnemonic **/
+    FD_RT_IMP = 0,
+    /** Low general purpose register **/
+    FD_RT_GPL = 1,
+    /** High-byte general purpose register **/
+    FD_RT_GPH = 2,
+    /** Segment register **/
+    FD_RT_SEG = 3,
+    /** FPU register ST(n) **/
+    FD_RT_FPU = 4,
+    /** MMX register MMn **/
+    FD_RT_MMX = 5,
+    /** Vector (SSE/AVX) register XMMn/YMMn/ZMMn **/
+    FD_RT_VEC = 6,
+    /** Vector mask (AVX-512) register Kn **/
+    FD_RT_MASK = 7,
+    /** Bound register BNDn **/
+    FD_RT_BND = 8,
+    /** Control Register CRn **/
+    FD_RT_CR = 9,
+    /** Debug Register DRn **/
+    FD_RT_DR = 10,
+} FdRegType;
+
 typedef struct {
     uint8_t type;
     uint8_t size;
     int8_t reg;
+    uint8_t misc;
 } FdOp;
 
 typedef struct {
@@ -137,22 +163,18 @@ void fd_format(const FdInstr* instr, char* buf, size_t len);
 #define FD_OP_SIZE(instr,idx) ((instr)->operands[idx].size)
 /** Gets the accessed register index of a register operand. Note that /only/ the
  * index is returned, no further interpretation of the index (which depends on
- * the instruction type) is done. When an instruction accesses an 8-bit general
- * purpose register with an index in the range 4-7, it needs to be determined
- * explicitly whether a high-byte register is accessed (using FD_OP_REG_HIGH).
- * If that is the case, the index needs to be decreased by 4.
+ * the instruction type) is done. The register type can be fetches using
+ * FD_OP_REG_TYPE, e.g. for distinguishing high-byte registers.
  * Only valid if  FD_OP_TYPE == FD_OT_REG  **/
 #define FD_OP_REG(instr,idx) ((FdReg) (instr)->operands[idx].reg)
-/** Returns whether the accessed register is a actually high-byte register when
- * used on a general purpose instruction. In that case, the register index has
- * to be decreased by 4.
- * Only valid if  FD_OP_TYPE == FD_OT_REG  and the operand refers to a general
- * purpose register (depends on the instruction type) **/
-#define FD_OP_REG_HIGH(instr,idx) ( \
-            (instr)->operands[idx].size == 1 && \
-            (instr)->operands[idx].reg >= 4 && \
-            ((instr)->flags & FD_FLAG_REX) == 0 \
-        )
+/** Gets the type of the accessed register.
+ * Only valid if  FD_OP_TYPE == FD_OT_REG  **/
+#define FD_OP_REG_TYPE(instr,idx) ((FdRegType) (instr)->operands[idx].misc)
+/** DEPRECATED: use FD_OP_REG_TYPE() == FD_RT_GPH instead.
+ * Returns whether the accessed register is a high-byte register. In that case,
+ * the register index has to be decreased by 4.
+ * Only valid if  FD_OP_TYPE == FD_OT_REG  **/
+#define FD_OP_REG_HIGH(instr,idx) (FD_OP_REG_TYPE(instr,idx) == FD_RT_GPH)
 /** Gets the index of the base register from a memory operand, or FD_REG_NONE,
  * if the memory operand has no base register. This is the only case where the
  * 64-bit register RIP can be returned, in which case the operand also has no
diff --git a/parseinstrs.py b/parseinstrs.py
index 631753c..ed5a203 100644
--- a/parseinstrs.py
+++ b/parseinstrs.py
@@ -40,6 +40,7 @@ InstrFlags = bitstruct("InstrFlags", [
     "gp_fixed_operand_size:3",
     "lock:1",
     "vsib:1",
+    "reg_types:16",
 ])
 
 ENCODINGS = {
@@ -72,26 +73,28 @@ ENCODINGS = {
 }
 
 OPKIND_LOOKUP = {
-    "-": (0, 0),
-    "IMM": (2, 0),
-    "IMM8": (1, 0),
-    "IMM16": (1, 1),
-    "IMM32": (1, 2),
-    "GP": (2, 0),
-    "GP8": (1, 0),
-    "GP16": (1, 1),
-    "GP32": (1, 2),
-    "GP64": (1, 3),
-    "XMM": (3, 0),
-    "XMM8": (1, 0),
-    "XMM16": (1, 1),
-    "XMM32": (1, 2),
-    "XMM64": (1, 3),
-    "XMM128": (1, 4),
-    "XMM256": (1, 5),
-    "SREG": (0, 0),
-    "FPU": (0, 0),
-    "MEMZ": (0, 0),
+    # sizeidx (0, fixedsz, opsz, vecsz), fixedsz (log2), regtype
+    "-": (0, 0, 0),
+    "IMM": (2, 0, 0),
+    "IMM8": (1, 0, 0),
+    "IMM16": (1, 1, 0),
+    "IMM32": (1, 2, 0),
+    "GP": (2, 0, 1),
+    "GP8": (1, 0, 1),
+    "GP16": (1, 1, 1),
+    "GP32": (1, 2, 1),
+    "GP64": (1, 3, 1),
+    "XMM": (3, 0, 6),
+    "XMM8": (1, 0, 6),
+    "XMM16": (1, 1, 6),
+    "XMM32": (1, 2, 6),
+    "XMM64": (1, 3, 6),
+    "XMM128": (1, 4, 6),
+    "XMM256": (1, 5, 6),
+    "SREG": (0, 0, 3),
+    "FPU": (0, 0, 4),
+    "MEMZ": (0, 0, 0),
+    "BND": (0, 0, 0),
 }
 
 class InstrDesc(namedtuple("InstrDesc", "mnemonic,flags,encoding")):
@@ -102,13 +105,16 @@ class InstrDesc(namedtuple("InstrDesc", "mnemonic,flags,encoding")):
 
         fixed_opsz = set()
         opsizes = 0
+        reg_types = 0
         for i, opkind in enumerate(desc[1:5]):
-            enc_size, fixed_size = OPKIND_LOOKUP[opkind]
+            enc_size, fixed_size, reg_type = OPKIND_LOOKUP[opkind]
             if enc_size == 1: fixed_opsz.add(fixed_size)
             opsizes |= enc_size << 2 * i
+            reg_types |= reg_type << 4 * i
 
         flags = copy(ENCODINGS[desc[0]])
         flags.operand_sizes = opsizes
+        flags.reg_types = reg_types
         if fixed_opsz: flags.gp_fixed_operand_size = next(iter(fixed_opsz))
 
         # Miscellaneous Flags