diff --git a/libcpu/i386_data.h b/libcpu/i386_data.h
new file mode 100644
index 0000000..b8a34c3
--- /dev/null
+++ b/libcpu/i386_data.h
@@ -0,0 +1,1418 @@
+/* Helper routines for disassembler for x86/x86-64.
+   Copyright (C) 2007, 2008 Red Hat, Inc.
+   This file is part of elfutils.
+   Written by Ulrich Drepper <drepper@redhat.com>, 2007.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#include <inttypes.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <libasm.h>
+
+struct instr_enc
+{
+  /* The mnemonic.  Especially encoded for the optimized table.  */
+  unsigned int mnemonic : MNEMONIC_BITS;
+
+  /* The rep/repe prefixes.  */
+  unsigned int rep : 1;
+  unsigned int repe : 1;
+
+  /* Mnemonic suffix.  */
+  unsigned int suffix : SUFFIX_BITS;
+
+  /* Nonzero if the instruction uses modr/m.  */
+  unsigned int modrm : 1;
+
+  /* 1st parameter.  */
+  unsigned int fct1 : FCT1_BITS;
+#ifdef STR1_BITS
+  unsigned int str1 : STR1_BITS;
+#endif
+  unsigned int off1_1 : OFF1_1_BITS;
+  unsigned int off1_2 : OFF1_2_BITS;
+  unsigned int off1_3 : OFF1_3_BITS;
+
+  /* 2nd parameter.  */
+  unsigned int fct2 : FCT2_BITS;
+#ifdef STR2_BITS
+  unsigned int str2 : STR2_BITS;
+#endif
+  unsigned int off2_1 : OFF2_1_BITS;
+  unsigned int off2_2 : OFF2_2_BITS;
+  unsigned int off2_3 : OFF2_3_BITS;
+
+  /* 3rd parameter.  */
+  unsigned int fct3 : FCT3_BITS;
+#ifdef STR3_BITS
+  unsigned int str3 : STR3_BITS;
+#endif
+  unsigned int off3_1 : OFF3_1_BITS;
+#ifdef OFF3_2_BITS
+  unsigned int off3_2 : OFF3_2_BITS;
+#endif
+#ifdef OFF3_3_BITS
+  unsigned int off3_3 : OFF3_3_BITS;
+#endif
+};
+
+
+typedef int (*opfct_t) (struct output_data *);
+
+
+static int
+data_prefix (struct output_data *d)
+{
+  char ch = '\0';
+  if (*d->prefixes & has_cs)
+    {
+      ch = 'c';
+      *d->prefixes &= ~has_cs;
+    }
+  else if (*d->prefixes & has_ds)
+    {
+      ch = 'd';
+      *d->prefixes &= ~has_ds;
+    }
+  else if (*d->prefixes & has_es)
+    {
+      ch = 'e';
+      *d->prefixes &= ~has_es;
+    }
+  else if (*d->prefixes & has_fs)
+    {
+      ch = 'f';
+      *d->prefixes &= ~has_fs;
+    }
+  else if (*d->prefixes & has_gs)
+    {
+      ch = 'g';
+      *d->prefixes &= ~has_gs;
+    }
+  else if (*d->prefixes & has_ss)
+    {
+      ch = 's';
+      *d->prefixes &= ~has_ss;
+    }
+  else
+    return 0;
+
+  if (*d->bufcntp + 4 > d->bufsize)
+    return *d->bufcntp + 4 - d->bufsize;
+
+  d->bufp[(*d->bufcntp)++] = '%';
+  d->bufp[(*d->bufcntp)++] = ch;
+  d->bufp[(*d->bufcntp)++] = 's';
+  d->bufp[(*d->bufcntp)++] = ':';
+
+  return 0;
+}
+
+#ifdef X86_64
+static const char hiregs[8][4] =
+  {
+    "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
+  };
+static const char aregs[8][4] =
+  {
+    "rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi"
+  };
+static const char dregs[8][4] =
+  {
+    "eax", "ecx", "edx", "ebx", "esp", "ebp", "esi", "edi"
+  };
+#else
+static const char aregs[8][4] =
+  {
+    "eax", "ecx", "edx", "ebx", "esp", "ebp", "esi", "edi"
+  };
+# define dregs aregs
+#endif
+
+static int
+general_mod$r_m (struct output_data *d)
+{
+  int r = data_prefix (d);
+  if (r != 0)
+    return r;
+
+  int prefixes = *d->prefixes;
+  const uint8_t *data = &d->data[d->opoff1 / 8];
+  char *bufp = d->bufp;
+  size_t *bufcntp = d->bufcntp;
+  size_t bufsize = d->bufsize;
+
+  uint_fast8_t modrm = data[0];
+#ifndef X86_64
+  if (unlikely ((prefixes & has_addr16) != 0))
+    {
+      int16_t disp = 0;
+      bool nodisp = false;
+
+      if ((modrm & 0xc7) == 6 || (modrm & 0xc0) == 0x80)
+	/* 16 bit displacement.  */
+	disp = read_2sbyte_unaligned (&data[1]);
+      else if ((modrm & 0xc0) == 0x40)
+	/* 8 bit displacement.  */
+	disp = *(const int8_t *) &data[1];
+      else if ((modrm & 0xc0) == 0)
+	nodisp = true;
+
+      char tmpbuf[sizeof ("-0x1234(%rr,%rr)")];
+      int n;
+      if ((modrm & 0xc7) == 6)
+	n = snprintf (tmpbuf, sizeof (tmpbuf), "0x%" PRIx16, disp);
+      else
+	{
+	  n = 0;
+	  if (!nodisp)
+	    n = snprintf (tmpbuf, sizeof (tmpbuf), "%s0x%" PRIx16,
+			  disp < 0 ? "-" : "", disp < 0 ? -disp : disp);
+
+	  if ((modrm & 0x4) == 0)
+	    n += snprintf (tmpbuf + n, sizeof (tmpbuf) - n, "(%%b%c,%%%ci)",
+			   "xp"[(modrm >> 1) & 1], "sd"[modrm & 1]);
+	  else
+	    n += snprintf (tmpbuf + n, sizeof (tmpbuf) - n, "(%%%s)",
+			   ((const char [4][3]) { "si", "di", "bp", "bx" })[modrm & 3]);
+	}
+
+      if (*bufcntp + n + 1 > bufsize)
+	return *bufcntp + n + 1 - bufsize;
+
+      memcpy (&bufp[*bufcntp], tmpbuf, n + 1);
+      *bufcntp += n;
+    }
+  else
+#endif
+    {
+      if ((modrm & 7) != 4)
+	{
+	  int32_t disp = 0;
+	  bool nodisp = false;
+
+	  if ((modrm & 0xc7) == 5 || (modrm & 0xc0) == 0x80)
+	    /* 32 bit displacement.  */
+	    disp = read_4sbyte_unaligned (&data[1]);
+	  else if ((modrm & 0xc0) == 0x40)
+	    /* 8 bit displacement.  */
+	    disp = *(const int8_t *) &data[1];
+	  else if ((modrm & 0xc0) == 0)
+	    nodisp = true;
+
+	  char tmpbuf[sizeof ("-0x12345678(%rrrr)")];
+	  int n;
+	  if (nodisp)
+	    {
+	      n = snprintf (tmpbuf, sizeof (tmpbuf), "(%%%s)",
+#ifdef X86_64
+			    (prefixes & has_rex_b) ? hiregs[modrm & 7] :
+#endif
+			    aregs[modrm & 7]);
+#ifdef X86_64
+	      if (prefixes & has_addr16)
+		{
+		  if (prefixes & has_rex_b)
+		    tmpbuf[n++] = 'd';
+		  else
+		    tmpbuf[2] = 'e';
+		}
+#endif
+	    }
+	  else if ((modrm & 0xc7) != 5)
+	    {
+	      int p;
+	      n = snprintf (tmpbuf, sizeof (tmpbuf), "%s0x%" PRIx32 "(%%%n%s)",
+			    disp < 0 ? "-" : "", disp < 0 ? -disp : disp, &p,
+#ifdef X86_64
+			    (prefixes & has_rex_b) ? hiregs[modrm & 7] :
+#endif
+			    aregs[modrm & 7]);
+#ifdef X86_64
+	      if (prefixes & has_addr16)
+		{
+		  if (prefixes & has_rex_b)
+		    tmpbuf[n++] = 'd';
+		  else
+		    tmpbuf[p] = 'e';
+		}
+#endif
+	    }
+	  else
+	    {
+#ifdef X86_64
+	      n = snprintf (tmpbuf, sizeof (tmpbuf), "%s0x%" PRIx32 "(%%rip)",
+			    disp < 0 ? "-" : "", disp < 0 ? -disp : disp);
+
+	      d->symaddr_use = addr_rel_always;
+	      d->symaddr = disp;
+#else
+	      n = snprintf (tmpbuf, sizeof (tmpbuf), "0x%" PRIx32, disp);
+#endif
+	    }
+
+	  if (*bufcntp + n + 1 > bufsize)
+	    return *bufcntp + n + 1 - bufsize;
+
+	  memcpy (&bufp[*bufcntp], tmpbuf, n + 1);
+	  *bufcntp += n;
+	}
+      else
+	{
+	  /* SIB */
+	  uint_fast8_t sib = data[1];
+	  int32_t disp = 0;
+	  bool nodisp = false;
+
+	  if ((modrm & 0xc7) == 5 || (modrm & 0xc0) == 0x80
+	      || ((modrm & 0xc7) == 0x4 && (sib & 0x7) == 0x5))
+	    /* 32 bit displacement.  */
+	    disp = read_4sbyte_unaligned (&data[2]);
+	  else if ((modrm & 0xc0) == 0x40)
+	    /* 8 bit displacement.  */
+	    disp = *(const int8_t *) &data[2];
+	  else
+	    nodisp = true;
+
+	  char tmpbuf[sizeof ("-0x12345678(%rrrr,%rrrr,N)")];
+	  char *cp = tmpbuf;
+	  int n;
+	  if ((modrm & 0xc0) != 0 || (sib & 0x3f) != 0x25
+#ifdef X86_64
+	      || (prefixes & has_rex_x) != 0
+#endif
+	      )
+	    {
+	      if (!nodisp)
+		{
+		  n = snprintf (cp, sizeof (tmpbuf), "%s0x%" PRIx32,
+				disp < 0 ? "-" : "", disp < 0 ? -disp : disp);
+		  cp += n;
+		}
+
+	      *cp++ = '(';
+
+	      if ((modrm & 0xc7) != 0x4 || (sib & 0x7) != 0x5)
+		{
+		  *cp++ = '%';
+		  cp = stpcpy (cp,
+#ifdef X86_64
+			       (prefixes & has_rex_b) ? hiregs[sib & 7] :
+			       (prefixes & has_addr16) ? dregs[sib & 7] :
+#endif
+			       aregs[sib & 7]);
+#ifdef X86_64
+		  if ((prefixes & (has_rex_b | has_addr16))
+		      == (has_rex_b | has_addr16))
+		    *cp++ = 'd';
+#endif
+		}
+
+	      if ((sib & 0x38) != 0x20
+#ifdef X86_64
+		  || (prefixes & has_rex_x) != 0
+#endif
+		  )
+		{
+		  *cp++ = ',';
+		  *cp++ = '%';
+		  cp = stpcpy (cp,
+#ifdef X86_64
+			       (prefixes & has_rex_x)
+			       ? hiregs[(sib >> 3) & 7] :
+			       (prefixes & has_addr16)
+			       ? dregs[(sib >> 3) & 7] :
+#endif
+			       aregs[(sib >> 3) & 7]);
+#ifdef X86_64
+		  if ((prefixes & (has_rex_b | has_addr16))
+		      == (has_rex_b | has_addr16))
+		    *cp++ = 'd';
+#endif
+
+		  *cp++ = ',';
+		  *cp++ = '0' + (1 << (sib >> 6));
+		}
+
+	      *cp++ = ')';
+	    }
+	  else
+	    {
+	      assert (! nodisp);
+#ifdef X86_64
+	      if ((prefixes & has_addr16) == 0)
+		n = snprintf (cp, sizeof (tmpbuf), "0x%" PRIx64,
+			      (int64_t) disp);
+	      else
+#endif
+		n = snprintf (cp, sizeof (tmpbuf), "0x%" PRIx32, disp);
+	      cp += n;
+	    }
+
+	  if (*bufcntp + (cp - tmpbuf) > bufsize)
+	    return *bufcntp + (cp - tmpbuf) - bufsize;
+
+	  memcpy (&bufp[*bufcntp], tmpbuf, cp - tmpbuf);
+	  *bufcntp += cp - tmpbuf;
+	}
+    }
+  return 0;
+}
+
+
+static int
+FCT_MOD$R_M (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      assert (d->opoff1 / 8 == d->opoff2 / 8);
+      assert (d->opoff2 % 8 == 5);
+      //uint_fast8_t byte = d->data[d->opoff2 / 8] & 7;
+      uint_fast8_t byte = modrm & 7;
+
+      size_t *bufcntp = d->bufcntp;
+      char *buf = d->bufp + *bufcntp;
+      size_t avail = d->bufsize - *bufcntp;
+      int needed;
+      if (*d->prefixes & (has_rep | has_repne))
+	needed = snprintf (buf, avail, "%%%s", dregs[byte]);
+      else
+	needed = snprintf (buf, avail, "%%mm%" PRIxFAST8, byte);
+      if ((size_t) needed > avail)
+	return needed - avail;
+      *bufcntp += needed;
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+
+
+static int
+FCT_Mod$R_m (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      assert (d->opoff1 / 8 == d->opoff2 / 8);
+      assert (d->opoff2 % 8 == 5);
+      //uint_fast8_t byte = data[opoff2 / 8] & 7;
+      uint_fast8_t byte = modrm & 7;
+
+      size_t *bufcntp = d->bufcntp;
+      size_t avail = d->bufsize - *bufcntp;
+      int needed = snprintf (&d->bufp[*bufcntp], avail, "%%xmm%" PRIxFAST8,
+			     byte);
+      if ((size_t) needed > avail)
+	return needed - avail;
+      *d->bufcntp += needed;
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+
+static int
+generic_abs (struct output_data *d, const char *absstring
+#ifdef X86_64
+	     , int abslen
+#else
+# define abslen 4
+#endif
+	     )
+{
+  int r = data_prefix (d);
+  if (r != 0)
+    return r;
+
+  assert (d->opoff1 % 8 == 0);
+  assert (d->opoff1 / 8 == 1);
+  if (*d->param_start + abslen > d->end)
+    return -1;
+  *d->param_start += abslen;
+#ifndef X86_64
+  uint32_t absval;
+# define ABSPRIFMT PRIx32
+#else
+  uint64_t absval;
+# define ABSPRIFMT PRIx64
+  if (abslen == 8)
+    absval = read_8ubyte_unaligned (&d->data[1]);
+  else
+#endif
+    absval = read_4ubyte_unaligned (&d->data[1]);
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "%s0x%" ABSPRIFMT,
+			 absstring, absval);
+  if ((size_t) needed > avail)
+    return needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_absval (struct output_data *d)
+{
+  return generic_abs (d, "$"
+#ifdef X86_64
+		      , 4
+#endif
+		      );
+}
+
+static int
+FCT_abs (struct output_data *d)
+{
+  return generic_abs (d, ""
+#ifdef X86_64
+		      , 8
+#endif
+		      );
+}
+
+static int
+FCT_ax (struct output_data *d)
+{
+  int is_16bit = (*d->prefixes & has_data16) != 0;
+
+  size_t *bufcntp = d->bufcntp;
+  char *bufp = d->bufp;
+  size_t bufsize = d->bufsize;
+
+  if (*bufcntp + 4 - is_16bit > bufsize)
+    return *bufcntp + 4 - is_16bit - bufsize;
+
+  bufp[(*bufcntp)++] = '%';
+  if (! is_16bit)
+    bufp[(*bufcntp)++] = (
+#ifdef X86_64
+			  (*d->prefixes & has_rex_w) ? 'r' :
+#endif
+			  'e');
+  bufp[(*bufcntp)++] = 'a';
+  bufp[(*bufcntp)++] = 'x';
+
+  return 0;
+}
+
+
+static int
+FCT_ax$w (struct output_data *d)
+{
+  if ((d->data[d->opoff2 / 8] & (1 << (7 - (d->opoff2 & 7)))) != 0)
+    return FCT_ax (d);
+
+  size_t *bufcntp = d->bufcntp;
+  char *bufp = d->bufp;
+  size_t bufsize = d->bufsize;
+
+  if (*bufcntp + 3 > bufsize)
+    return *bufcntp + 3 - bufsize;
+
+  bufp[(*bufcntp)++] = '%';
+  bufp[(*bufcntp)++] = 'a';
+  bufp[(*bufcntp)++] = 'l';
+
+  return 0;
+}
+
+
+static int
+__attribute__ ((noinline))
+FCT_crdb (struct output_data *d, const char *regstr)
+{
+  if (*d->prefixes & has_data16)
+    return -1;
+
+  size_t *bufcntp = d->bufcntp;
+
+  // XXX If this assert is true, use absolute offset below
+  assert (d->opoff1 / 8 == 2);
+  assert (d->opoff1 % 8 == 2);
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "%%%s%" PRIx32,
+			 regstr, (uint32_t) (d->data[d->opoff1 / 8] >> 3) & 7);
+  if ((size_t) needed > avail)
+    return needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_ccc (struct output_data *d)
+{
+  return FCT_crdb (d, "cr");
+}
+
+
+static int
+FCT_ddd (struct output_data *d)
+{
+  return FCT_crdb (d, "db");
+}
+
+
+static int
+FCT_disp8 (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  if (*d->param_start >= d->end)
+    return -1;
+  int32_t offset = *(const int8_t *) (*d->param_start)++;
+
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "0x%" PRIx32,
+			 (uint32_t) (d->addr + (*d->param_start - d->data)
+				     + offset));
+  if ((size_t) needed > avail)
+    return needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+__attribute__ ((noinline))
+FCT_ds_xx (struct output_data *d, const char *reg)
+{
+  int prefix = *d->prefixes & SEGMENT_PREFIXES;
+
+  if (prefix == 0)
+    *d->prefixes |= prefix = has_ds;
+  /* Make sure only one bit is set.  */
+  else if ((prefix - 1) & prefix)
+    return -1;
+
+  int r = data_prefix (d);
+
+  assert ((*d->prefixes & prefix) == 0);
+
+  if (r != 0)
+    return r;
+
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "(%%%s%s)",
+#ifdef X86_64
+			 *d->prefixes & idx_addr16 ? "e" : "r",
+#else
+			 *d->prefixes & idx_addr16 ? "" : "e",
+#endif
+			 reg);
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+
+  return 0;
+}
+
+
+static int
+FCT_ds_bx (struct output_data *d)
+{
+  return FCT_ds_xx (d, "bx");
+}
+
+
+static int
+FCT_ds_si (struct output_data *d)
+{
+  return FCT_ds_xx (d, "si");
+}
+
+
+static int
+FCT_dx (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+
+  if (*bufcntp + 7 > d->bufsize)
+    return *bufcntp + 7 - d->bufsize;
+
+  memcpy (&d->bufp[*bufcntp], "(%dx)", 5);
+  *bufcntp += 5;
+
+  return 0;
+}
+
+
+static int
+FCT_es_di (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "%%es:(%%%sdi)",
+#ifdef X86_64
+			 *d->prefixes & idx_addr16 ? "e" : "r"
+#else
+			 *d->prefixes & idx_addr16 ? "" : "e"
+#endif
+			 );
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+
+  return 0;
+}
+
+
+static int
+FCT_imm (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed;
+  if (*d->prefixes & has_data16)
+    {
+      if (*d->param_start + 2 > d->end)
+	return -1;
+      uint16_t word = read_2ubyte_unaligned_inc (*d->param_start);
+      needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx16, word);
+    }
+  else
+    {
+      if (*d->param_start + 4 > d->end)
+	return -1;
+      int32_t word = read_4sbyte_unaligned_inc (*d->param_start);
+#ifdef X86_64
+      if (*d->prefixes & has_rex_w)
+	needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx64,
+			   (int64_t) word);
+      else
+#endif
+	needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx32, word);
+    }
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_imm$w (struct output_data *d)
+{
+  if ((d->data[d->opoff2 / 8] & (1 << (7 - (d->opoff2 & 7)))) != 0)
+    return FCT_imm (d);
+
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  if (*d->param_start>= d->end)
+    return -1;
+  uint_fast8_t word = *(*d->param_start)++;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIxFAST8, word);
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+#ifdef X86_64
+static int
+FCT_imm64$w (struct output_data *d)
+{
+  if ((d->data[d->opoff2 / 8] & (1 << (7 - (d->opoff2 & 7)))) == 0
+      || (*d->prefixes & has_data16) != 0)
+    return FCT_imm$w (d);
+
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed;
+  if (*d->prefixes & has_rex_w)
+    {
+      if (*d->param_start + 8 > d->end)
+	return -1;
+      uint64_t word = read_8ubyte_unaligned_inc (*d->param_start);
+      needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx64, word);
+    }
+  else
+    {
+      if (*d->param_start + 4 > d->end)
+	return -1;
+      int32_t word = read_4sbyte_unaligned_inc (*d->param_start);
+      needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx32, word);
+    }
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+#endif
+
+
+static int
+FCT_imms (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  if (*d->param_start>= d->end)
+    return -1;
+  int8_t byte = *(*d->param_start)++;
+#ifdef X86_64
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx64,
+			 (int64_t) byte);
+#else
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx32,
+			 (int32_t) byte);
+#endif
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_imm$s (struct output_data *d)
+{
+  uint_fast8_t opcode = d->data[d->opoff2 / 8];
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  if ((opcode & 2) != 0)
+    return FCT_imms (d);
+
+  if ((*d->prefixes & has_data16) == 0)
+    {
+      if (*d->param_start + 4 > d->end)
+	return -1;
+      int32_t word = read_4sbyte_unaligned_inc (*d->param_start);
+#ifdef X86_64
+      int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx64,
+			     (int64_t) word);
+#else
+      int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx32, word);
+#endif
+      if ((size_t) needed > avail)
+	return (size_t) needed - avail;
+      *bufcntp += needed;
+    }
+  else
+    {
+      if (*d->param_start + 2 > d->end)
+	return -1;
+      uint16_t word = read_2ubyte_unaligned_inc (*d->param_start);
+      int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx16, word);
+      if ((size_t) needed > avail)
+	return (size_t) needed - avail;
+      *bufcntp += needed;
+    }
+  return 0;
+}
+
+
+static int
+FCT_imm16 (struct output_data *d)
+{
+  if (*d->param_start + 2 > d->end)
+    return -1;
+  uint16_t word = read_2ubyte_unaligned_inc (*d->param_start);
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx16, word);
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_imms8 (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  if (*d->param_start >= d->end)
+    return -1;
+  int_fast8_t byte = *(*d->param_start)++;
+  int needed;
+#ifdef X86_64
+  if (*d->prefixes & has_rex_w)
+    needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx64,
+		       (int64_t) byte);
+  else
+#endif
+    needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx32,
+		       (int32_t) byte);
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_imm8 (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  if (*d->param_start >= d->end)
+    return -1;
+  uint_fast8_t byte = *(*d->param_start)++;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx32,
+			 (uint32_t) byte);
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_rel (struct output_data *d)
+{
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  if (*d->param_start + 4 > d->end)
+    return -1;
+  int32_t rel = read_4sbyte_unaligned_inc (*d->param_start);
+#ifdef X86_64
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "0x%" PRIx64,
+			 (uint64_t) (d->addr + rel
+				     + (*d->param_start - d->data)));
+#else
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "0x%" PRIx32,
+			 (uint32_t) (d->addr + rel
+				     + (*d->param_start - d->data)));
+#endif
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_mmxreg (struct output_data *d)
+{
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 == 2 || d->opoff1 % 8 == 5);
+  byte = (byte >> (5 - d->opoff1 % 8)) & 7;
+  size_t *bufcntp =  d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "%%mm%" PRIxFAST8, byte);
+  if ((size_t) needed > avail)
+    return needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_mod$r_m (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      int prefixes = *d->prefixes;
+      if (prefixes & has_addr16)
+	return -1;
+
+      int is_16bit = (prefixes & has_data16) != 0;
+
+      size_t *bufcntp = d->bufcntp;
+      char *bufp = d->bufp;
+      if (*bufcntp + 5 - is_16bit > d->bufsize)
+	return *bufcntp + 5 - is_16bit - d->bufsize;
+      bufp[(*bufcntp)++] = '%';
+
+      char *cp;
+#ifdef X86_64
+      if ((prefixes & has_rex_b) != 0 && !is_16bit)
+	{
+	  cp = stpcpy (&bufp[*bufcntp], hiregs[modrm & 7]);
+	  if ((prefixes & has_rex_w) == 0)
+	    *cp++ = 'd';
+	}
+      else
+#endif
+	{
+	  cp = stpcpy (&bufp[*bufcntp], dregs[modrm & 7] + is_16bit);
+#ifdef X86_64
+	  if ((prefixes & has_rex_w) != 0)
+	    bufp[*bufcntp] = 'r';
+#endif
+	}
+      *bufcntp = cp - bufp;
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+
+
+#ifndef X86_64
+static int
+FCT_moda$r_m (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      if (*d->prefixes & has_addr16)
+	return -1;
+
+      size_t *bufcntp = d->bufcntp;
+      if (*bufcntp + 3 > d->bufsize)
+	return *bufcntp + 3 - d->bufsize;
+
+      memcpy (&d->bufp[*bufcntp], "???", 3);
+      *bufcntp += 3;
+
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+#endif
+
+
+#ifdef X86_64
+static const char rex_8bit[8][3] =
+  {
+    [0] = "a", [1] = "c", [2] = "d", [3] = "b",
+    [4] = "sp", [5] = "bp", [6] = "si", [7] = "di"
+  };
+#endif
+
+
+static int
+FCT_mod$r_m$w (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  const uint8_t *data = d->data;
+  uint_fast8_t modrm = data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      int prefixes = *d->prefixes;
+
+      if (prefixes & has_addr16)
+	return -1;
+
+      size_t *bufcntp = d->bufcntp;
+      char *bufp = d->bufp;
+      if (*bufcntp + 5 > d->bufsize)
+	return *bufcntp + 5 - d->bufsize;
+
+      if ((data[d->opoff3 / 8] & (1 << (7 - (d->opoff3 & 7)))) == 0)
+	{
+	  bufp[(*bufcntp)++] = '%';
+
+#ifdef X86_64
+	  if (prefixes & has_rex)
+	    {
+	      if (prefixes & has_rex_r)
+		*bufcntp += snprintf (bufp + *bufcntp, d->bufsize - *bufcntp,
+				      "r%db", 8 + (modrm & 7));
+	      else
+		{
+		  char *cp = stpcpy (bufp + *bufcntp, hiregs[modrm & 7]);
+		  *cp++ = 'l';
+		  *bufcntp = cp - bufp;
+		}
+	    }
+	  else
+#endif
+	    {
+	      bufp[(*bufcntp)++] = "acdb"[modrm & 3];
+	      bufp[(*bufcntp)++] = "lh"[(modrm & 4) >> 2];
+	    }
+	}
+      else
+	{
+	  int is_16bit = (prefixes & has_data16) != 0;
+
+	  bufp[(*bufcntp)++] = '%';
+
+	  char *cp;
+#ifdef X86_64
+	  if ((prefixes & has_rex_b) != 0 && !is_16bit)
+	    {
+	      cp = stpcpy (&bufp[*bufcntp], hiregs[modrm & 7]);
+	      if ((prefixes & has_rex_w) == 0)
+		*cp++ = 'd';
+	    }
+	  else
+#endif
+	    {
+	      cp = stpcpy (&bufp[*bufcntp], dregs[modrm & 7] + is_16bit);
+#ifdef X86_64
+	      if ((prefixes & has_rex_w) != 0)
+		bufp[*bufcntp] = 'r';
+#endif
+	    }
+	  *bufcntp = cp - bufp;
+	}
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+
+
+static int
+FCT_mod$8r_m (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      size_t *bufcntp = d->bufcntp;
+      char *bufp = d->bufp;
+      if (*bufcntp + 3 > d->bufsize)
+	return *bufcntp + 3 - d->bufsize;
+      bufp[(*bufcntp)++] = '%';
+      bufp[(*bufcntp)++] = "acdb"[modrm & 3];
+      bufp[(*bufcntp)++] = "lh"[(modrm & 4) >> 2];
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+
+
+static int
+FCT_mod$16r_m (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      assert (d->opoff1 / 8 == d->opoff2 / 8);
+      //uint_fast8_t byte = data[opoff2 / 8] & 7;
+      uint_fast8_t byte = modrm & 7;
+
+      size_t *bufcntp = d->bufcntp;
+      if (*bufcntp + 3 > d->bufsize)
+	return *bufcntp + 3 - d->bufsize;
+      d->bufp[(*bufcntp)++] = '%';
+      memcpy (&d->bufp[*bufcntp], dregs[byte] + 1, sizeof (dregs[0]) - 1);
+      *bufcntp += 2;
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+
+
+#ifdef X86_64
+static int
+FCT_mod$64r_m (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  uint_fast8_t modrm = d->data[d->opoff1 / 8];
+  if ((modrm & 0xc0) == 0xc0)
+    {
+      assert (d->opoff1 / 8 == d->opoff2 / 8);
+      //uint_fast8_t byte = data[opoff2 / 8] & 7;
+      uint_fast8_t byte = modrm & 7;
+
+      size_t *bufcntp = d->bufcntp;
+      if (*bufcntp + 4 > d->bufsize)
+	return *bufcntp + 4 - d->bufsize;
+      char *cp = &d->bufp[*bufcntp];
+      *cp++ = '%';
+      cp = stpcpy (cp,
+		   (*d->prefixes & has_rex_b) ? hiregs[byte] : aregs[byte]);
+      *bufcntp = cp - d->bufp;
+      return 0;
+    }
+
+  return general_mod$r_m (d);
+}
+#else
+static typeof (FCT_mod$r_m) FCT_mod$64r_m __attribute__ ((alias ("FCT_mod$r_m")));
+#endif
+
+
+static int
+FCT_reg (struct output_data *d)
+{
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 + 3 <= 8);
+  byte >>= 8 - (d->opoff1 % 8 + 3);
+  byte &= 7;
+  int is_16bit = (*d->prefixes & has_data16) != 0;
+  size_t *bufcntp = d->bufcntp;
+  if (*bufcntp + 5 > d->bufsize)
+    return *bufcntp + 5 - d->bufsize;
+  d->bufp[(*bufcntp)++] = '%';
+#ifdef X86_64
+  if ((*d->prefixes & has_rex_r) != 0 && !is_16bit)
+    {
+      *bufcntp += snprintf (&d->bufp[*bufcntp], d->bufsize - *bufcntp, "r%d",
+			    8 + byte);
+      if ((*d->prefixes & has_rex_w) == 0)
+	d->bufp[(*bufcntp)++] = 'd';
+    }
+  else
+#endif
+    {
+      memcpy (&d->bufp[*bufcntp], dregs[byte] + is_16bit, 3 - is_16bit);
+#ifdef X86_64
+      if ((*d->prefixes & has_rex_w) != 0 && !is_16bit)
+	d->bufp[*bufcntp] = 'r';
+#endif
+      *bufcntp += 3 - is_16bit;
+    }
+  return 0;
+}
+
+
+#ifdef X86_64
+static int
+FCT_oreg (struct output_data *d)
+{
+  /* Special form where register comes from opcode.  The rex.B bit is used,
+     rex.R and rex.X are ignored.  */
+  int save_prefixes = *d->prefixes;
+
+  *d->prefixes = ((save_prefixes & ~has_rex_r)
+		  | ((save_prefixes & has_rex_b) << (idx_rex_r - idx_rex_b)));
+
+  int r = FCT_reg (d);
+
+  *d->prefixes = save_prefixes;
+
+  return r;
+}
+#endif
+
+
+static int
+FCT_reg64 (struct output_data *d)
+{
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 + 3 <= 8);
+  byte >>= 8 - (d->opoff1 % 8 + 3);
+  byte &= 7;
+  if ((*d->prefixes & has_data16) != 0)
+    return -1;
+  size_t *bufcntp = d->bufcntp;
+  if (*bufcntp + 5 > d->bufsize)
+    return *bufcntp + 5 - d->bufsize;
+  d->bufp[(*bufcntp)++] = '%';
+#ifdef X86_64
+  if ((*d->prefixes & has_rex_r) != 0)
+    {
+      *bufcntp += snprintf (&d->bufp[*bufcntp], d->bufsize - *bufcntp, "r%d",
+			    8 + byte);
+      if ((*d->prefixes & has_rex_w) == 0)
+	d->bufp[(*bufcntp)++] = 'd';
+    }
+  else
+#endif
+    {
+      memcpy (&d->bufp[*bufcntp], aregs[byte], 3);
+      *bufcntp += 3;
+    }
+  return 0;
+}
+
+
+static int
+FCT_reg$w (struct output_data *d)
+{
+  if (d->data[d->opoff2 / 8] & (1 << (7 - (d->opoff2 & 7))))
+    return FCT_reg (d);
+
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 + 3 <= 8);
+  byte >>= 8 - (d->opoff1 % 8 + 3);
+  byte &= 7;
+
+  size_t *bufcntp = d->bufcntp;
+  if (*bufcntp + 4 > d->bufsize)
+    return *bufcntp + 4 - d->bufsize;
+
+  d->bufp[(*bufcntp)++] = '%';
+
+#ifdef X86_64
+  if (*d->prefixes & has_rex)
+    {
+      if (*d->prefixes & has_rex_r)
+	*bufcntp += snprintf (d->bufp + *bufcntp, d->bufsize - *bufcntp,
+			      "r%db", 8 + byte);
+      else
+	{
+	  char* cp = stpcpy (d->bufp + *bufcntp, rex_8bit[byte]);
+	  *cp++ = 'l';
+	  *bufcntp = cp - d->bufp;
+	}
+    }
+  else
+#endif
+    {
+      d->bufp[(*bufcntp)++] = "acdb"[byte & 3];
+      d->bufp[(*bufcntp)++] = "lh"[byte >> 2];
+    }
+  return 0;
+}
+
+
+#ifdef X86_64
+static int
+FCT_oreg$w (struct output_data *d)
+{
+  /* Special form where register comes from opcode.  The rex.B bit is used,
+     rex.R and rex.X are ignored.  */
+  int save_prefixes = *d->prefixes;
+
+  *d->prefixes = ((save_prefixes & ~has_rex_r)
+		  | ((save_prefixes & has_rex_b) << (idx_rex_r - idx_rex_b)));
+
+  int r = FCT_reg$w (d);
+
+  *d->prefixes = save_prefixes;
+
+  return r;
+}
+#endif
+
+
+static int
+FCT_freg (struct output_data *d)
+{
+  assert (d->opoff1 / 8 == 1);
+  assert (d->opoff1 % 8 == 5);
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "%%st(%" PRIx32 ")",
+			 (uint32_t) (d->data[1] & 7));
+  if ((size_t) needed > avail)
+    return (size_t) needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+#ifndef X86_64
+static int
+FCT_reg16 (struct output_data *d)
+{
+  if (*d->prefixes & has_data16)
+    return -1;
+
+  *d->prefixes |= has_data16;
+  return FCT_reg (d);
+}
+#endif
+
+
+static int
+FCT_sel (struct output_data *d)
+{
+  assert (d->opoff1 % 8 == 0);
+  assert (d->opoff1 / 8 == 5);
+  if (*d->param_start + 2 > d->end)
+    return -1;
+  *d->param_start += 2;
+  uint16_t absval = read_2ubyte_unaligned (&d->data[5]);
+
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "$0x%" PRIx16, absval);
+  if ((size_t) needed > avail)
+    return needed - avail;
+  *bufcntp += needed;
+  return 0;
+}
+
+
+static int
+FCT_sreg2 (struct output_data *d)
+{
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 + 3 <= 8);
+  byte >>= 8 - (d->opoff1 % 8 + 2);
+
+  size_t *bufcntp = d->bufcntp;
+  char *bufp = d->bufp;
+  if (*bufcntp + 3 > d->bufsize)
+    return *bufcntp + 3 - d->bufsize;
+
+  bufp[(*bufcntp)++] = '%';
+  bufp[(*bufcntp)++] = "ecsd"[byte & 3];
+  bufp[(*bufcntp)++] = 's';
+
+  return 0;
+}
+
+
+static int
+FCT_sreg3 (struct output_data *d)
+{
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 + 4 <= 8);
+  byte >>= 8 - (d->opoff1 % 8 + 3);
+
+  if ((byte & 7) >= 6)
+    return -1;
+
+  size_t *bufcntp = d->bufcntp;
+  char *bufp = d->bufp;
+  if (*bufcntp + 3 > d->bufsize)
+    return *bufcntp + 3 - d->bufsize;
+
+  bufp[(*bufcntp)++] = '%';
+  bufp[(*bufcntp)++] = "ecsdfg"[byte & 7];
+  bufp[(*bufcntp)++] = 's';
+
+  return 0;
+}
+
+
+static int
+FCT_string (struct output_data *d __attribute__ ((unused)))
+{
+  return 0;
+}
+
+
+static int
+FCT_xmmreg (struct output_data *d)
+{
+  uint_fast8_t byte = d->data[d->opoff1 / 8];
+  assert (d->opoff1 % 8 == 2 || d->opoff1 % 8 == 5);
+  byte = (byte >> (5 - d->opoff1 % 8)) & 7;
+
+  size_t *bufcntp = d->bufcntp;
+  size_t avail = d->bufsize - *bufcntp;
+  int needed = snprintf (&d->bufp[*bufcntp], avail, "%%xmm%" PRIxFAST8, byte);
+  if ((size_t) needed > avail)
+    return needed - avail;
+  *bufcntp += needed;
+  return 0;
+}