/* Print SPARC instructions.
   Copyright (C) 1989, 91-93, 1995, 1996 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of 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.

This program 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 a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "ansidecl.h"
#include "opcode/sparc.h"
#include "dis-asm.h"

#include <string.h>

/* Bitmask of v9 architectures.  */
#define MASK_V9 ((1 << SPARC_OPCODE_ARCH_V9) \
		 | (1 << SPARC_OPCODE_ARCH_V9A))
/* 1 if INSN is for v9 only.  */
#define V9_ONLY_P(insn) (! ((insn)->architecture & ~MASK_V9))
/* 1 if INSN is for v9.  */
#define V9_P(insn) (((insn)->architecture & MASK_V9) != 0)

/* For faster lookup, after insns are sorted they are hashed.  */
/* ??? I think there is room for even more improvement.  */

#define HASH_SIZE 256
/* It is important that we only look at insn code bits as that is how the
   opcode table is hashed.  OPCODE_BITS is a table of valid bits for each
   of the main types (0,1,2,3).  */
static int opcode_bits[4] = { 0x01c00000, 0x0, 0x01f80000, 0x01f80000 };
#define HASH_INSN(INSN) \
  ((((INSN) >> 24) & 0xc0) | (((INSN) & opcode_bits[((INSN) >> 30) & 3]) >> 19))
struct opcode_hash {
  struct opcode_hash *next;
  struct sparc_opcode *opcode;
};
static struct opcode_hash *opcode_hash_table[HASH_SIZE];
static void build_hash_table ();

/* Sign-extend a value which is N bits long.  */
#define	SEX(value, bits) \
	((((int)(value)) << ((8 * sizeof (int)) - bits))	\
			 >> ((8 * sizeof (int)) - bits) )

static  char *reg_names[] =
{ "g0", "g1", "g2", "g3", "g4", "g5", "g6", "g7",	
  "o0", "o1", "o2", "o3", "o4", "o5", "sp", "o7",	
  "l0", "l1", "l2", "l3", "l4", "l5", "l6", "l7",	
  "i0", "i1", "i2", "i3", "i4", "i5", "fp", "i7",	
  "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",	
  "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15",	
  "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",
  "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31",
  "f32", "f33", "f34", "f35", "f36", "f37", "f38", "f39",	
  "f40", "f41", "f42", "f43", "f44", "f45", "f46", "f47",	
  "f48", "f49", "f50", "f51", "f52", "f53", "f54", "f55",
  "f56", "f57", "f58", "f59", "f60", "f61", "f62", "f63",
/* psr, wim, tbr, fpsr, cpsr are v8 only.  */
  "y", "psr", "wim", "tbr", "pc", "npc", "fpsr", "cpsr"
};

#define	freg_names	(&reg_names[4 * 8])

/* These are ordered according to there register number in
   rdpr and wrpr insns.  */
static char *v9_priv_reg_names[] =
{
  "tpc", "tnpc", "tstate", "tt", "tick", "tba", "pstate", "tl",
  "pil", "cwp", "cansave", "canrestore", "cleanwin", "otherwin",
  "wstate", "fq"
  /* "ver" - special cased */
};

/* Macros used to extract instruction fields.  Not all fields have
   macros defined here, only those which are actually used.  */

#define X_RD(i) (((i) >> 25) & 0x1f)
#define X_RS1(i) (((i) >> 14) & 0x1f)
#define X_LDST_I(i) (((i) >> 13) & 1)
#define X_ASI(i) (((i) >> 5) & 0xff)
#define X_RS2(i) (((i) >> 0) & 0x1f)
#define X_IMM13(i) (((i) >> 0) & 0x1fff)
#define X_DISP22(i) (((i) >> 0) & 0x3fffff)
#define X_IMM22(i) X_DISP22 (i)
#define X_DISP30(i) (((i) >> 0) & 0x3fffffff)

/* These are for v9.  */
#define X_DISP16(i) (((((i) >> 20) & 3) << 14) | (((i) >> 0) & 0x3fff))
#define X_DISP19(i) (((i) >> 0) & 0x7ffff)
#define X_MEMBAR(i) ((i) & 0x7f)

/* Here is the union which was used to extract instruction fields
   before the shift and mask macros were written.

   union sparc_insn
     {
       unsigned long int code;
       struct
	 {
	   unsigned int anop:2;
	   #define	op	ldst.anop
	   unsigned int anrd:5;
	   #define	rd	ldst.anrd
	   unsigned int op3:6;
	   unsigned int anrs1:5;
	   #define	rs1	ldst.anrs1
	   unsigned int i:1;
	   unsigned int anasi:8;
	   #define	asi	ldst.anasi
	   unsigned int anrs2:5;
	   #define	rs2	ldst.anrs2
	   #define	shcnt	rs2
	 } ldst;
       struct
	 {
	   unsigned int anop:2, anrd:5, op3:6, anrs1:5, i:1;
	   unsigned int IMM13:13;
	   #define	imm13	IMM13.IMM13
	 } IMM13;
       struct
	 {
	   unsigned int anop:2;
	   unsigned int a:1;
	   unsigned int cond:4;
	   unsigned int op2:3;
	   unsigned int DISP22:22;
	   #define	disp22	branch.DISP22
	   #define	imm22	disp22
	 } branch;
       struct
	 {
	   unsigned int anop:2;
	   unsigned int a:1;
	   unsigned int z:1;
	   unsigned int rcond:3;
	   unsigned int op2:3;
	   unsigned int DISP16HI:2;
	   unsigned int p:1;
	   unsigned int _rs1:5;
	   unsigned int DISP16LO:14;
	 } branch16;
       struct
	 {
	   unsigned int anop:2;
	   unsigned int adisp30:30;
	   #define	disp30	call.adisp30
	 } call;
     };

   */

/* Nonzero if INSN is the opcode for a delayed branch.  */
static int
is_delayed_branch (insn)
     unsigned long insn;
{
  struct opcode_hash *op;

  for (op = opcode_hash_table[HASH_INSN (insn)]; op; op = op->next)
    {
      const struct sparc_opcode *opcode = op->opcode;
      if ((opcode->match & insn) == opcode->match
	  && (opcode->lose & insn) == 0)
	return (opcode->flags & F_DELAYED);
    }
  return 0;
}

/* Nonzero of opcode table has been initialized.  */
static int opcodes_initialized = 0;

/* extern void qsort (); */
static int compare_opcodes ();

/* Print one instruction from MEMADDR on INFO->STREAM.

   We suffix the instruction with a comment that gives the absolute
   address involved, as well as its symbolic form, if the instruction
   is preceded by a findable `sethi' and it either adds an immediate
   displacement to that register, or it is an `add' or `or' instruction
   on that register.  */

int
print_insn_sparc (memaddr, info)
     bfd_vma memaddr;
     disassemble_info *info;
{
  FILE *stream = info->stream;
  bfd_byte buffer[4];
  unsigned long insn;
  register unsigned int i;
  register struct opcode_hash *op;
  int sparc_v9_p = bfd_mach_sparc_v9_p (info->mach);

  if (!opcodes_initialized)
    {
      qsort ((char *) sparc_opcodes, sparc_num_opcodes,
	     sizeof (sparc_opcodes[0]), compare_opcodes);
      build_hash_table (sparc_opcodes, opcode_hash_table, sparc_num_opcodes);
      opcodes_initialized = 1;
    }

  {
    int status =
      (*info->read_memory_func) (memaddr, buffer, sizeof (buffer), info);
    if (status != 0)
      {
	(*info->memory_error_func) (status, memaddr, info);
	return -1;
      }
  }

  insn = bfd_getb32 (buffer);

  info->insn_info_valid = 1;			/* We do return this info */
  info->insn_type = dis_nonbranch;		/* Assume non branch insn */
  info->branch_delay_insns = 0;			/* Assume no delay */
  info->target = 0;				/* Assume no target known */

  for (op = opcode_hash_table[HASH_INSN (insn)]; op; op = op->next)
    {
      const struct sparc_opcode *opcode = op->opcode;

      /* ??? These architecture tests need to be more selective.  */

      /* If the current architecture isn't sparc64, skip sparc64 insns.  */
      if (!sparc_v9_p
	  && V9_ONLY_P (opcode))
	continue;

      /* If the current architecture is sparc64, skip sparc32 only insns.  */
      if (sparc_v9_p
	  && ! V9_P (opcode))
	continue;

      if ((opcode->match & insn) == opcode->match
	  && (opcode->lose & insn) == 0)
	{
	  /* Nonzero means that we have found an instruction which has
	     the effect of adding or or'ing the imm13 field to rs1.  */
	  int imm_added_to_rs1 = 0;

	  /* Nonzero means that we have found a plus sign in the args
	     field of the opcode table.  */
	  int found_plus = 0;
	  
	  /* Nonzero means we have an annulled branch.  */
	  int is_annulled = 0;

	  /* Do we have an `add' or `or' instruction where rs1 is the same
	     as rsd, and which has the i bit set?  */
	  if ((opcode->match == 0x80102000 || opcode->match == 0x80002000)
	  /*			  (or)				 (add)  */
	      && X_RS1 (insn) == X_RD (insn))
	    imm_added_to_rs1 = 1;

	  if (X_RS1 (insn) != X_RD (insn)
	      && strchr (opcode->args, 'r') != 0)
	      /* Can't do simple format if source and dest are different.  */
	      continue;
	  if (X_RS2 (insn) != X_RD (insn)
	      && strchr (opcode->args, 'O') != 0)
	      /* Can't do simple format if source and dest are different.  */
	      continue;

	  (*info->fprintf_func) (stream, opcode->name);

	  {
	    register const char *s;

	    if (opcode->args[0] != ',')
	      (*info->fprintf_func) (stream, " ");
	    for (s = opcode->args; *s != '\0'; ++s)
	      {
		while (*s == ',')
		  {
		    (*info->fprintf_func) (stream, ",");
		    ++s;
		    switch (*s) {
		    case 'a':
		      (*info->fprintf_func) (stream, "a");
		      is_annulled = 1;
		      ++s;
		      continue;
		    case 'N':
		      (*info->fprintf_func) (stream, "pn");
		      ++s;
		      continue;

		    case 'T':
		      (*info->fprintf_func) (stream, "pt");
		      ++s;
		      continue;

		    default:
		      break;
		    }		/* switch on arg */
		  }		/* while there are comma started args */

		(*info->fprintf_func) (stream, " ");
			
		switch (*s)
		  {
		  case '+':
		    found_plus = 1;

		    /* note fall-through */
		  default:
		    (*info->fprintf_func) (stream, "%c", *s);
		    break;

		  case '#':
		    (*info->fprintf_func) (stream, "0");
		    break;

#define	reg(n)	(*info->fprintf_func) (stream, "%%%s", reg_names[n])
		  case '1':
		  case 'r':
		    reg (X_RS1 (insn));
		    break;

		  case '2':
		  case 'O':
		    reg (X_RS2 (insn));
		    break;

		  case 'd':
		    reg (X_RD (insn));
		    break;
#undef	reg

#define	freg(n)		(*info->fprintf_func) (stream, "%%%s", freg_names[n])
#define	fregx(n)	(*info->fprintf_func) (stream, "%%%s", freg_names[((n) & ~1) | (((n) & 1) << 5)])
		  case 'e':
		    freg (X_RS1 (insn));
		    break;
		  case 'v':	/* double/even */
		  case 'V':	/* quad/multiple of 4 */
		    fregx (X_RS1 (insn));
		    break;

		  case 'f':
		    freg (X_RS2 (insn));
		    break;
		  case 'B':	/* double/even */
		  case 'R':	/* quad/multiple of 4 */
		    fregx (X_RS2 (insn));
		    break;

		  case 'g':
		    freg (X_RD (insn));
		    break;
		  case 'H':	/* double/even */
		  case 'J':	/* quad/multiple of 4 */
		    fregx (X_RD (insn));
		    break;
#undef	freg
#undef	fregx

#define	creg(n)	(*info->fprintf_func) (stream, "%%c%u", (unsigned int) (n))
		  case 'b':
		    creg (X_RS1 (insn));
		    break;

		  case 'c':
		    creg (X_RS2 (insn));
		    break;

		  case 'D':
		    creg (X_RD (insn));
		    break;
#undef	creg

		  case 'h':
		    (*info->fprintf_func) (stream, "%%hi(%#x)",
					   (0xFFFFFFFF
					    & ((int) X_IMM22 (insn) << 10)));
		    break;

		  case 'i':
		    {
		      int imm = SEX (X_IMM13 (insn), 13);

		      /* Check to see whether we have a 1+i, and take
			 note of that fact.

			 Note: because of the way we sort the table,
			 we will be matching 1+i rather than i+1,
			 so it is OK to assume that i is after +,
			 not before it.  */
		      if (found_plus)
			imm_added_to_rs1 = 1;
		      
		      if (imm <= 9)
			(*info->fprintf_func) (stream, "%d", imm);
		      else
			(*info->fprintf_func) (stream, "%#x", imm);
		    }
		    break;

		  case 'I':	/* 11 bit immediate.  */
		  case 'j':	/* 10 bit immediate.  */
		    {
		      int imm;

		      if (*s == 'I')
			imm = SEX (X_IMM13 (insn), 11);
		      else
			imm = SEX (X_IMM13 (insn), 10);

		      /* Check to see whether we have a 1+i, and take
			 note of that fact.
			 
			 Note: because of the way we sort the table,
			 we will be matching 1+i rather than i+1,
			 so it is OK to assume that i is after +,
			 not before it.  */
		      if (found_plus)
			imm_added_to_rs1 = 1;
		      
		      if (imm <= 9)
			(info->fprintf_func) (stream, "%d", imm);
		      else
			(info->fprintf_func) (stream, "%#x", (unsigned) imm);
		    }
		    break;

		  case 'K':
		    {
		      int mask = X_MEMBAR (insn);
		      int bit = 0x40, printed_one = 0;
		      char *name;

		      if (mask == 0)
			(info->fprintf_func) (stream, "0");
		      else
			while (bit)
			  {
			    if (mask & bit)
			      {
				if (printed_one)
				  (info->fprintf_func) (stream, "|");
				name = sparc_decode_membar (bit);
				(info->fprintf_func) (stream, "%s", name);
				printed_one = 1;
			      }
			    bit >>= 1;
			  }
		      break;
		    }

		  case 'k':
		    info->target = memaddr + SEX (X_DISP16 (insn), 16) * 4;
		    (*info->print_address_func) (info->target, info);
		    break;

		  case 'G':
		    info->target = memaddr + SEX (X_DISP19 (insn), 19) * 4;
		    (*info->print_address_func) (info->target, info);
		    break;

		  case '6':
		  case '7':
		  case '8':
		  case '9':
		    (*info->fprintf_func) (stream, "%%fcc%c", *s - '6' + '0');
		    break;

		  case 'z':
		    (*info->fprintf_func) (stream, "%%icc");
		    break;

		  case 'Z':
		    (*info->fprintf_func) (stream, "%%xcc");
		    break;

		  case 'E':
		    (*info->fprintf_func) (stream, "%%ccr");
		    break;

		  case 's':
		    (*info->fprintf_func) (stream, "%%fprs");
		    break;

		  case 'o':
		    (*info->fprintf_func) (stream, "%%asi");
		    break;

		  case 'W':
		    (*info->fprintf_func) (stream, "%%tick");
		    break;

		  case 'P':
		    (*info->fprintf_func) (stream, "%%pc");
		    break;

		  case '?':
		    if (X_RS1 (insn) == 31)
		      (*info->fprintf_func) (stream, "%%ver");
		    else if ((unsigned) X_RS1 (insn) < 16)
		      (*info->fprintf_func) (stream, "%%%s",
					     v9_priv_reg_names[X_RS1 (insn)]);
		    else
		      (*info->fprintf_func) (stream, "%%reserved");
		    break;

		  case '!':
		    if ((unsigned) X_RD (insn) < 15)
		      (*info->fprintf_func) (stream, "%%%s",
					     v9_priv_reg_names[X_RD (insn)]);
		    else
		      (*info->fprintf_func) (stream, "%%reserved");
		    break;

		  case '*':
		    {
		      char *name = sparc_decode_prefetch (X_RD (insn));

		      if (name)
			(*info->fprintf_func) (stream, "%s", name);
		      else
			(*info->fprintf_func) (stream, "%d", X_RD (insn));
		      break;
		    }

		  case 'M':
		    (*info->fprintf_func) (stream, "%%asr%d", X_RS1 (insn));
		    break;
		    
		  case 'm':
		    (*info->fprintf_func) (stream, "%%asr%d", X_RD (insn));
		    break;
		    
		  case 'L':
		    info->target = memaddr + SEX (X_DISP30 (insn), 30) * 4;
		    (*info->print_address_func) (info->target, info);
		    break;

		  case 'n':
		    (*info->fprintf_func)
		      (stream, "%#x", SEX (X_DISP22 (insn), 22));
		    break;

		  case 'l':
		    info->target = memaddr + SEX (X_DISP22 (insn), 22) * 4;
		    (*info->print_address_func) (info->target, info);
		    break;

		  case 'A':
		    {
		      char *name = sparc_decode_asi (X_ASI (insn));

		      if (name)
			(*info->fprintf_func) (stream, "%s", name);
		      else
			(*info->fprintf_func) (stream, "(%d)", X_ASI (insn));
		      break;
		    }

		  case 'C':
		    (*info->fprintf_func) (stream, "%%csr");
		    break;

		  case 'F':
		    (*info->fprintf_func) (stream, "%%fsr");
		    break;

		  case 'p':
		    (*info->fprintf_func) (stream, "%%psr");
		    break;

		  case 'q':
		    (*info->fprintf_func) (stream, "%%fq");
		    break;

		  case 'Q':
		    (*info->fprintf_func) (stream, "%%cq");
		    break;

		  case 't':
		    (*info->fprintf_func) (stream, "%%tbr");
		    break;

		  case 'w':
		    (*info->fprintf_func) (stream, "%%wim");
		    break;

		  case 'x':
		    (*info->fprintf_func) (stream, "%d",
					   ((X_LDST_I (insn) << 8)
					    + X_ASI (insn)));
		    break;

		  case 'y':
		    (*info->fprintf_func) (stream, "%%y");
		    break;

		  case 'u':
		  case 'U':
		    {
		      int val = *s == 'U' ? X_RS1 (insn) : X_RD (insn);
		      char *name = sparc_decode_sparclet_cpreg (val);

		      if (name)
			(*info->fprintf_func) (stream, "%s", name);
		      else
			(*info->fprintf_func) (stream, "%%cpreg(%d)", val);
		      break;
		    }
		  }
	      }
	  }

	  /* If we are adding or or'ing something to rs1, then
	     check to see whether the previous instruction was
	     a sethi to the same register as in the sethi.
	     If so, attempt to print the result of the add or
	     or (in this context add and or do the same thing)
	     and its symbolic value.  */
	  if (imm_added_to_rs1)
	    {
	      unsigned long prev_insn;
	      int errcode;

	      errcode =
		(*info->read_memory_func)
		  (memaddr - 4, buffer, sizeof (buffer), info);
	      prev_insn = bfd_getb32 (buffer);

	      if (errcode == 0)
		{
		  /* If it is a delayed branch, we need to look at the
		     instruction before the delayed branch.  This handles
		     sequences such as

		     sethi %o1, %hi(_foo), %o1
		     call _printf
		     or %o1, %lo(_foo), %o1
		     */

		  if (is_delayed_branch (prev_insn))
		    {
		      errcode = (*info->read_memory_func)
			(memaddr - 8, buffer, sizeof (buffer), info);
		      prev_insn = bfd_getb32 (buffer);
		    }
		}

	      /* If there was a problem reading memory, then assume
		 the previous instruction was not sethi.  */
	      if (errcode == 0)
		{
		  /* Is it sethi to the same register?  */
		  if ((prev_insn & 0xc1c00000) == 0x01000000
		      && X_RD (prev_insn) == X_RS1 (insn))
		    {
		      (*info->fprintf_func) (stream, "\t! ");
		      info->target = 
			(0xFFFFFFFF & (int) X_IMM22 (prev_insn) << 10)
			| SEX (X_IMM13 (insn), 13);
		      (*info->print_address_func) (info->target, info);
		      info->insn_type = dis_dref;
		      info->data_size = 4;  /* FIXME!!! */
		    }
		}
	    }

	  if (opcode->flags & (F_UNBR|F_CONDBR|F_JSR))
	    {
		/* FIXME -- check is_annulled flag */
	      if (opcode->flags & F_UNBR)
		info->insn_type = dis_branch;
	      if (opcode->flags & F_CONDBR)
		info->insn_type = dis_condbranch;
	      if (opcode->flags & F_JSR)
		info->insn_type = dis_jsr;
	      if (opcode->flags & F_DELAYED)
		info->branch_delay_insns = 1;
	    }

	  return sizeof (buffer);
	}
    }

  info->insn_type = dis_noninsn;	/* Mark as non-valid instruction */
  (*info->fprintf_func) (stream, "unknown");
  return sizeof (buffer);
}

/* Compare opcodes A and B.  */

static int
compare_opcodes (a, b)
     char *a, *b;
{
  struct sparc_opcode *op0 = (struct sparc_opcode *) a;
  struct sparc_opcode *op1 = (struct sparc_opcode *) b;
  unsigned long int match0 = op0->match, match1 = op1->match;
  unsigned long int lose0 = op0->lose, lose1 = op1->lose;
  register unsigned int i;

  /* If a bit is set in both match and lose, there is something
     wrong with the opcode table.  */
  if (match0 & lose0)
    {
      fprintf (stderr, "Internal error:  bad sparc-opcode.h: \"%s\", %#.8lx, %#.8lx\n",
	       op0->name, match0, lose0);
      op0->lose &= ~op0->match;
      lose0 = op0->lose;
    }

  if (match1 & lose1)
    {
      fprintf (stderr, "Internal error: bad sparc-opcode.h: \"%s\", %#.8lx, %#.8lx\n",
	       op1->name, match1, lose1);
      op1->lose &= ~op1->match;
      lose1 = op1->lose;
    }

  /* Because the bits that are variable in one opcode are constant in
     another, it is important to order the opcodes in the right order.  */
  for (i = 0; i < 32; ++i)
    {
      unsigned long int x = 1 << i;
      int x0 = (match0 & x) != 0;
      int x1 = (match1 & x) != 0;

      if (x0 != x1)
	return x1 - x0;
    }

  for (i = 0; i < 32; ++i)
    {
      unsigned long int x = 1 << i;
      int x0 = (lose0 & x) != 0;
      int x1 = (lose1 & x) != 0;

      if (x0 != x1)
	return x1 - x0;
    }

  /* Put non-sparc64 insns ahead of sparc64 ones.  */
  if (V9_ONLY_P (op0) != V9_ONLY_P (op1))
    return V9_ONLY_P (op0) - V9_ONLY_P (op1);

  /* They are functionally equal.  So as long as the opcode table is
     valid, we can put whichever one first we want, on aesthetic grounds.  */

  /* Our first aesthetic ground is that aliases defer to real insns.  */
  {
    int alias_diff = (op0->flags & F_ALIAS) - (op1->flags & F_ALIAS);
    if (alias_diff != 0)
      /* Put the one that isn't an alias first.  */
      return alias_diff;
  }

  /* Except for aliases, two "identical" instructions had
     better have the same opcode.  This is a sanity check on the table.  */
  i = strcmp (op0->name, op1->name);
  if (i)
      if (op0->flags & F_ALIAS) /* If they're both aliases, be arbitrary. */
	  return i;
      else
	  fprintf (stderr,
		   "Internal error: bad sparc-opcode.h: \"%s\" == \"%s\"\n",
		   op0->name, op1->name);

  /* Fewer arguments are preferred.  */
  {
    int length_diff = strlen (op0->args) - strlen (op1->args);
    if (length_diff != 0)
      /* Put the one with fewer arguments first.  */
      return length_diff;
  }

  /* Put 1+i before i+1.  */
  {
    char *p0 = (char *) strchr(op0->args, '+');
    char *p1 = (char *) strchr(op1->args, '+');

    if (p0 && p1)
      {
	/* There is a plus in both operands.  Note that a plus
	   sign cannot be the first character in args,
	   so the following [-1]'s are valid.  */
	if (p0[-1] == 'i' && p1[1] == 'i')
	  /* op0 is i+1 and op1 is 1+i, so op1 goes first.  */
	  return 1;
	if (p0[1] == 'i' && p1[-1] == 'i')
	  /* op0 is 1+i and op1 is i+1, so op0 goes first.  */
	  return -1;
      }
  }

  /* Put 1,i before i,1.  */
  {
    int i0 = strncmp (op0->args, "i,1", 3) == 0;
    int i1 = strncmp (op1->args, "i,1", 3) == 0;

    if (i0 ^ i1)
      return i0 - i1;
  }

  /* They are, as far as we can tell, identical.
     Since qsort may have rearranged the table partially, there is
     no way to tell which one was first in the opcode table as
     written, so just say there are equal.  */
  return 0;
}

/* Build a hash table from the opcode table.  */

static void
build_hash_table (table, hash_table, num_opcodes)
     struct sparc_opcode *table;
     struct opcode_hash **hash_table;
     int num_opcodes;
{
  register int i;
  int hash_count[HASH_SIZE];
  static struct opcode_hash *hash_buf = NULL;

  /* Start at the end of the table and work backwards so that each
     chain is sorted.  */

  memset (hash_table, 0, HASH_SIZE * sizeof (hash_table[0]));
  memset (hash_count, 0, HASH_SIZE * sizeof (hash_count[0]));
  if (hash_buf != NULL)
    free (hash_buf);
  hash_buf = (struct opcode_hash *) xmalloc (sizeof (struct opcode_hash) * num_opcodes);
  for (i = num_opcodes - 1; i >= 0; --i)
    {
      register int hash = HASH_INSN (sparc_opcodes[i].match);
      register struct opcode_hash *h = &hash_buf[i];
      h->next = hash_table[hash];
      h->opcode = &sparc_opcodes[i];
      hash_table[hash] = h;
      ++hash_count[hash];
    }

#if 0 /* for debugging */
  {
    int min_count = num_opcodes, max_count = 0;
    int total;

    for (i = 0; i < HASH_SIZE; ++i)
      {
        if (hash_count[i] < min_count)
	  min_count = hash_count[i];
	if (hash_count[i] > max_count)
	  max_count = hash_count[i];
	total += hash_count[i];
      }

    printf ("Opcode hash table stats: min %d, max %d, ave %f\n",
	    min_count, max_count, (double) total / HASH_SIZE);
  }
#endif
}