/* rx.c --- opcode semantics for stand-alone RX simulator.

Copyright (C) 2008-2021 Free Software Foundation, Inc.
Contributed by Red Hat, Inc.

This file is part of the GNU simulators.

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 3 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, see <http://www.gnu.org/licenses/>.  */

/* This must come before any other includes.  */
#include "defs.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include "libiberty.h"

#include "opcode/rx.h"
#include "cpu.h"
#include "mem.h"
#include "syscalls.h"
#include "fpu.h"
#include "err.h"
#include "misc.h"

#ifdef CYCLE_STATS
static const char * id_names[] = {
  "RXO_unknown",
  "RXO_mov",	/* d = s (signed) */
  "RXO_movbi",	/* d = [s,s2] (signed) */
  "RXO_movbir",	/* [s,s2] = d (signed) */
  "RXO_pushm",	/* s..s2 */
  "RXO_popm",	/* s..s2 */
  "RXO_xchg",	/* s <-> d */
  "RXO_stcc",	/* d = s if cond(s2) */
  "RXO_rtsd",	/* rtsd, 1=imm, 2-0 = reg if reg type */

  /* These are all either d OP= s or, if s2 is set, d = s OP s2.  Note
     that d may be "None".  */
  "RXO_and",
  "RXO_or",
  "RXO_xor",
  "RXO_add",
  "RXO_sub",
  "RXO_mul",
  "RXO_div",
  "RXO_divu",
  "RXO_shll",
  "RXO_shar",
  "RXO_shlr",

  "RXO_adc",	/* d = d + s + carry */
  "RXO_sbb",	/* d = d - s - ~carry */
  "RXO_abs",	/* d = |s| */
  "RXO_max",	/* d = max(d,s) */
  "RXO_min",	/* d = min(d,s) */
  "RXO_emul",	/* d:64 = d:32 * s */
  "RXO_emulu",	/* d:64 = d:32 * s (unsigned) */

  "RXO_rolc",	/* d <<= 1 through carry */
  "RXO_rorc",	/* d >>= 1 through carry*/
  "RXO_rotl",	/* d <<= #s without carry */
  "RXO_rotr",	/* d >>= #s without carry*/
  "RXO_revw",	/* d = revw(s) */
  "RXO_revl",	/* d = revl(s) */
  "RXO_branch",	/* pc = d if cond(s) */
  "RXO_branchrel",/* pc += d if cond(s) */
  "RXO_jsr",	/* pc = d */
  "RXO_jsrrel",	/* pc += d */
  "RXO_rts",
  "RXO_nop",
  "RXO_nop2",
  "RXO_nop3",
  "RXO_nop4",
  "RXO_nop5",
  "RXO_nop6",
  "RXO_nop7",

  "RXO_scmpu",
  "RXO_smovu",
  "RXO_smovb",
  "RXO_suntil",
  "RXO_swhile",
  "RXO_smovf",
  "RXO_sstr",

  "RXO_rmpa",
  "RXO_mulhi",
  "RXO_mullo",
  "RXO_machi",
  "RXO_maclo",
  "RXO_mvtachi",
  "RXO_mvtaclo",
  "RXO_mvfachi",
  "RXO_mvfacmi",
  "RXO_mvfaclo",
  "RXO_racw",

  "RXO_sat",	/* sat(d) */
  "RXO_satr",

  "RXO_fadd",	/* d op= s */
  "RXO_fcmp",
  "RXO_fsub",
  "RXO_ftoi",
  "RXO_fmul",
  "RXO_fdiv",
  "RXO_round",
  "RXO_itof",

  "RXO_bset",	/* d |= (1<<s) */
  "RXO_bclr",	/* d &= ~(1<<s) */
  "RXO_btst",	/* s & (1<<s2) */
  "RXO_bnot",	/* d ^= (1<<s) */
  "RXO_bmcc",	/* d<s> = cond(s2) */

  "RXO_clrpsw",	/* flag index in d */
  "RXO_setpsw",	/* flag index in d */
  "RXO_mvtipl",	/* new IPL in s */

  "RXO_rtfi",
  "RXO_rte",
  "RXO_rtd",	/* undocumented */
  "RXO_brk",
  "RXO_dbt",	/* undocumented */
  "RXO_int",	/* vector id in s */
  "RXO_stop",
  "RXO_wait",

  "RXO_sccnd",	/* d = cond(s) ? 1 : 0 */
};

static const char * optype_names[] = {
  " -  ",
  "#Imm",	/* #addend */
  " Rn ",	/* Rn */
  "[Rn]",	/* [Rn + addend] */
  "Ps++",	/* [Rn+] */
  "--Pr",	/* [-Rn] */
  " cc ",	/* eq, gtu, etc */
  "Flag",	/* [UIOSZC] */
  "RbRi"	/* [Rb + scale * Ri] */
};

#define N_RXO ARRAY_SIZE (id_names)
#define N_RXT ARRAY_SIZE (optype_names)
#define N_MAP 90

static unsigned long long benchmark_start_cycle;
static unsigned long long benchmark_end_cycle;

static int op_cache[N_RXT][N_RXT][N_RXT];
static int op_cache_rev[N_MAP];
static int op_cache_idx = 0;

static int
op_lookup (int a, int b, int c)
{
  if (op_cache[a][b][c])
    return op_cache[a][b][c];
  op_cache_idx ++;
  if (op_cache_idx >= N_MAP)
    {
      printf("op_cache_idx exceeds %d\n", N_MAP);
      exit(1);
    }
  op_cache[a][b][c] = op_cache_idx;
  op_cache_rev[op_cache_idx] = (a<<8) | (b<<4) | c;
  return op_cache_idx;
}

static char *
op_cache_string (int map)
{
  static int ci;
  static char cb[5][20];
  int a, b, c;

  map = op_cache_rev[map];
  a = (map >> 8) & 15;
  b = (map >> 4) & 15;
  c = (map >> 0) & 15;
  ci = (ci + 1) % 5;
  sprintf(cb[ci], "%s %s %s", optype_names[a], optype_names[b], optype_names[c]);
  return cb[ci];
}

static unsigned long long cycles_per_id[N_RXO][N_MAP];
static unsigned long long times_per_id[N_RXO][N_MAP];
static unsigned long long memory_stalls;
static unsigned long long register_stalls;
static unsigned long long branch_stalls;
static unsigned long long branch_alignment_stalls;
static unsigned long long fast_returns;

static unsigned long times_per_pair[N_RXO][N_MAP][N_RXO][N_MAP];
static int prev_opcode_id = RXO_unknown;
static int po0;

#define STATS(x) x

#else
#define STATS(x)
#endif /* CYCLE_STATS */


#ifdef CYCLE_ACCURATE

static int new_rt = -1;

/* Number of cycles to add if an insn spans an 8-byte boundary.  */
static int branch_alignment_penalty = 0;

#endif

static int running_benchmark = 1;

#define tprintf if (trace && running_benchmark) printf

jmp_buf decode_jmp_buf;
unsigned int rx_cycles = 0;

#ifdef CYCLE_ACCURATE
/* If nonzero, memory was read at some point and cycle latency might
   take effect.  */
static int memory_source = 0;
/* If nonzero, memory was written and extra cycles might be
   needed.  */
static int memory_dest = 0;

static void
cycles (int throughput)
{
  tprintf("%d cycles\n", throughput);
  regs.cycle_count += throughput;
}

/* Number of execution (E) cycles the op uses.  For memory sources, we
   include the load micro-op stall as two extra E cycles.  */
#define E(c) cycles (memory_source ? c + 2 : c)
#define E1 cycles (1)
#define E2 cycles (2)
#define EBIT cycles (memory_source ? 2 : 1)

/* Check to see if a read latency must be applied for a given register.  */
#define RL(r) \
  if (regs.rt == r )							\
    {									\
      tprintf("register %d load stall\n", r);				\
      regs.cycle_count ++;						\
      STATS(register_stalls ++);					\
      regs.rt = -1;							\
    }

#define RLD(r)					\
  if (memory_source)				\
    {						\
      tprintf ("Rt now %d\n", r);		\
      new_rt = r;				\
    }

static int
lsb_count (unsigned long v, int is_signed)
{
  int i, lsb;
  if (is_signed && (v & 0x80000000U))
    v = (unsigned long)(long)(-v);
  for (i=31; i>=0; i--)
    if (v & (1 << i))
      {
	/* v is 0..31, we want 1=1-2, 2=3-4, 3=5-6, etc. */
	lsb = (i + 2) / 2;
	return lsb;
      }
  return 0;
}

static int
divu_cycles(unsigned long num, unsigned long den)
{
  int nb = lsb_count (num, 0);
  int db = lsb_count (den, 0);
  int rv;

  if (nb < db)
    rv = 2;
  else
    rv = 3 + nb - db;
  E (rv);
  return rv;
}

static int
div_cycles(long num, long den)
{
  int nb = lsb_count ((unsigned long)num, 1);
  int db = lsb_count ((unsigned long)den, 1);
  int rv;

  if (nb < db)
    rv = 3;
  else
    rv = 5 + nb - db;
  E (rv);
  return rv;
}

#else /* !CYCLE_ACCURATE */

#define cycles(t)
#define E(c)
#define E1
#define E2
#define EBIT
#define RL(r)
#define RLD(r)

#define divu_cycles(n,d)
#define div_cycles(n,d)

#endif /* else CYCLE_ACCURATE */

static int size2bytes[] = {
  4, 1, 1, 1, 2, 2, 2, 3, 4
};

typedef struct {
  unsigned long dpc;
} RX_Data;

#define rx_abort() _rx_abort(__FILE__, __LINE__)
static void
_rx_abort (const char *file, int line)
{
  if (strrchr (file, '/'))
    file = strrchr (file, '/') + 1;
  fprintf(stderr, "abort at %s:%d\n", file, line);
  abort();
}

static unsigned char *get_byte_base;
static RX_Opcode_Decoded **decode_cache_base;
static SI get_byte_page;

void
reset_decoder (void)
{
  get_byte_base = 0;
  decode_cache_base = 0;
  get_byte_page = 0;
}

static inline void
maybe_get_mem_page (SI tpc)
{
  if (((tpc ^ get_byte_page) & NONPAGE_MASK) || enable_counting)
    {
      get_byte_page = tpc & NONPAGE_MASK;
      get_byte_base = rx_mem_ptr (get_byte_page, MPA_READING) - get_byte_page;
      decode_cache_base = rx_mem_decode_cache (get_byte_page) - get_byte_page;
    }
}

/* This gets called a *lot* so optimize it.  */
static int
rx_get_byte (void *vdata)
{
  RX_Data *rx_data = (RX_Data *)vdata;
  SI tpc = rx_data->dpc;

  /* See load.c for an explanation of this.  */
  if (rx_big_endian)
    tpc ^= 3;

  maybe_get_mem_page (tpc);

  rx_data->dpc ++;
  return get_byte_base [tpc];
}

static int
get_op (const RX_Opcode_Decoded *rd, int i)
{
  const RX_Opcode_Operand *o = rd->op + i;
  int addr, rv = 0;

  switch (o->type)
    {
    case RX_Operand_None:
      rx_abort ();

    case RX_Operand_Immediate:	/* #addend */
      return o->addend;

    case RX_Operand_Register:	/* Rn */
      RL (o->reg);
      rv = get_reg (o->reg);
      break;

    case RX_Operand_Predec:	/* [-Rn] */
      put_reg (o->reg, get_reg (o->reg) - size2bytes[o->size]);
      /* fall through */
    case RX_Operand_Postinc:	/* [Rn+] */
    case RX_Operand_Zero_Indirect:	/* [Rn + 0] */
    case RX_Operand_Indirect:	/* [Rn + addend] */
    case RX_Operand_TwoReg:	/* [Rn + scale * R2] */
#ifdef CYCLE_ACCURATE
      RL (o->reg);
      if (o->type == RX_Operand_TwoReg)
	RL (rd->op[2].reg);
      regs.rt = -1;
      if (regs.m2m == M2M_BOTH)
	{
	  tprintf("src memory stall\n");
#ifdef CYCLE_STATS
	  memory_stalls ++;
#endif
	  regs.cycle_count ++;
	  regs.m2m = 0;
	}

      memory_source = 1;
#endif

      if (o->type == RX_Operand_TwoReg)
	addr = get_reg (o->reg) * size2bytes[rd->size] + get_reg (rd->op[2].reg);
      else
	addr = get_reg (o->reg) + o->addend;

      switch (o->size)
	{
	default:
	case RX_AnySize:
	  rx_abort ();

	case RX_Byte: /* undefined extension */
	case RX_UByte:
	case RX_SByte:
	  rv = mem_get_qi (addr);
	  break;

	case RX_Word: /* undefined extension */
	case RX_UWord:
	case RX_SWord:
	  rv = mem_get_hi (addr);
	  break;

	case RX_3Byte:
	  rv = mem_get_psi (addr);
	  break;

	case RX_Long:
	  rv = mem_get_si (addr);
	  break;
	}

      if (o->type == RX_Operand_Postinc)
	put_reg (o->reg, get_reg (o->reg) + size2bytes[o->size]);

      break;

    case RX_Operand_Condition:	/* eq, gtu, etc */
      return condition_true (o->reg);

    case RX_Operand_Flag:	/* [UIOSZC] */
      return (regs.r_psw & (1 << o->reg)) ? 1 : 0;
    }

  /* if we've gotten here, we need to clip/extend the value according
     to the size.  */
  switch (o->size)
    {
    default:
    case RX_AnySize:
      rx_abort ();

    case RX_Byte: /* undefined extension */
      rv |= 0xdeadbe00; /* keep them honest */
      break;

    case RX_UByte:
      rv &= 0xff;
      break;

    case RX_SByte:
      rv = sign_ext (rv, 8);
      break;

    case RX_Word: /* undefined extension */
      rv |= 0xdead0000; /* keep them honest */
      break;

    case RX_UWord:
      rv &=  0xffff;
      break;

    case RX_SWord:
      rv = sign_ext (rv, 16);
      break;

    case RX_3Byte:
      rv &= 0xffffff;
      break;

    case RX_Long:
      break;
    }
  return rv;
}

static void
put_op (const RX_Opcode_Decoded *rd, int i, int v)
{
  const RX_Opcode_Operand *o = rd->op + i;
  int addr;

  switch (o->size)
    {
    default:
    case RX_AnySize:
      if (o->type != RX_Operand_Register)
	rx_abort ();
      break;

    case RX_Byte: /* undefined extension */
      v |= 0xdeadbe00; /* keep them honest */
      break;

    case RX_UByte:
      v &= 0xff;
      break;

    case RX_SByte:
      v = sign_ext (v, 8);
      break;

    case RX_Word: /* undefined extension */
      v |= 0xdead0000; /* keep them honest */
      break;

    case RX_UWord:
      v &=  0xffff;
      break;

    case RX_SWord:
      v = sign_ext (v, 16);
      break;

    case RX_3Byte:
      v &= 0xffffff;
      break;

    case RX_Long:
      break;
    }

  switch (o->type)
    {
    case RX_Operand_None:
      /* Opcodes like TST and CMP use this.  */
      break;

    case RX_Operand_Immediate:	/* #addend */
    case RX_Operand_Condition:	/* eq, gtu, etc */
      rx_abort ();

    case RX_Operand_Register:	/* Rn */
      put_reg (o->reg, v);
      RLD (o->reg);
      break;

    case RX_Operand_Predec:	/* [-Rn] */
      put_reg (o->reg, get_reg (o->reg) - size2bytes[o->size]);
      /* fall through */
    case RX_Operand_Postinc:	/* [Rn+] */
    case RX_Operand_Zero_Indirect:	/* [Rn + 0] */
    case RX_Operand_Indirect:	/* [Rn + addend] */
    case RX_Operand_TwoReg:	/* [Rn + scale * R2] */

#ifdef CYCLE_ACCURATE
      if (regs.m2m == M2M_BOTH)
	{
	  tprintf("dst memory stall\n");
	  regs.cycle_count ++;
#ifdef CYCLE_STATS
	  memory_stalls ++;
#endif
	  regs.m2m = 0;
	}
      memory_dest = 1;
#endif

      if (o->type == RX_Operand_TwoReg)
	addr = get_reg (o->reg) * size2bytes[rd->size] + get_reg (rd->op[2].reg);
      else
	addr = get_reg (o->reg) + o->addend;

      switch (o->size)
	{
	default:
	case RX_AnySize:
	  rx_abort ();

	case RX_Byte: /* undefined extension */
	case RX_UByte:
	case RX_SByte:
	  mem_put_qi (addr, v);
	  break;

	case RX_Word: /* undefined extension */
	case RX_UWord:
	case RX_SWord:
	  mem_put_hi (addr, v);
	  break;

	case RX_3Byte:
	  mem_put_psi (addr, v);
	  break;

	case RX_Long:
	  mem_put_si (addr, v);
	  break;
	}

      if (o->type == RX_Operand_Postinc)
	put_reg (o->reg, get_reg (o->reg) + size2bytes[o->size]);

      break;

    case RX_Operand_Flag:	/* [UIOSZC] */
      if (v)
	regs.r_psw |= (1 << o->reg);
      else
	regs.r_psw &= ~(1 << o->reg);
      break;
    }
}

#define PD(x) put_op (opcode, 0, x)
#define PS(x) put_op (opcode, 1, x)
#define PS2(x) put_op (opcode, 2, x)
#define GD() get_op (opcode, 0)
#define GS() get_op (opcode, 1)
#define GS2() get_op (opcode, 2)
#define DSZ() size2bytes[opcode->op[0].size]
#define SSZ() size2bytes[opcode->op[0].size]
#define S2SZ() size2bytes[opcode->op[0].size]

/* "Universal" sources.  */
#define US1() ((opcode->op[2].type == RX_Operand_None) ? GD() : GS())
#define US2() ((opcode->op[2].type == RX_Operand_None) ? GS() : GS2())

static void
push(int val)
{
  int rsp = get_reg (sp);
  rsp -= 4;
  put_reg (sp, rsp);
  mem_put_si (rsp, val);
}

/* Just like the above, but tag the memory as "pushed pc" so if anyone
   tries to write to it, it will cause an error.  */
static void
pushpc(int val)
{
  int rsp = get_reg (sp);
  rsp -= 4;
  put_reg (sp, rsp);
  mem_put_si (rsp, val);
  mem_set_content_range (rsp, rsp+3, MC_PUSHED_PC);
}

static int
pop (void)
{
  int rv;
  int rsp = get_reg (sp);
  rv = mem_get_si (rsp);
  rsp += 4;
  put_reg (sp, rsp);
  return rv;
}

static int
poppc (void)
{
  int rv;
  int rsp = get_reg (sp);
  if (mem_get_content_type (rsp) != MC_PUSHED_PC)
    execution_error (SIM_ERR_CORRUPT_STACK, rsp);
  rv = mem_get_si (rsp);
  mem_set_content_range (rsp, rsp+3, MC_UNINIT);
  rsp += 4;
  put_reg (sp, rsp);
  return rv;
}

#define MATH_OP(vop,c)				\
{ \
  umb = US2(); \
  uma = US1(); \
  ll = (unsigned long long) uma vop (unsigned long long) umb vop c; \
  tprintf ("0x%x " #vop " 0x%x " #vop " 0x%x = 0x%llx\n", uma, umb, c, ll); \
  ma = sign_ext (uma, DSZ() * 8);					\
  mb = sign_ext (umb, DSZ() * 8);					\
  sll = (long long) ma vop (long long) mb vop c; \
  tprintf ("%d " #vop " %d " #vop " %d = %lld\n", ma, mb, c, sll); \
  set_oszc (sll, DSZ(), (long long) ll > ((1 vop 1) ? (long long) b2mask[DSZ()] : (long long) -1)); \
  PD (sll); \
  E (1);    \
}

#define LOGIC_OP(vop) \
{ \
  mb = US2(); \
  ma = US1(); \
  v = ma vop mb; \
  tprintf("0x%x " #vop " 0x%x = 0x%x\n", ma, mb, v); \
  set_sz (v, DSZ()); \
  PD(v); \
  E (1); \
}

#define SHIFT_OP(val, type, count, OP, carry_mask)	\
{ \
  int i, c=0; \
  count = US2(); \
  val = (type)US1();				\
  tprintf("%lld " #OP " %d\n", val, count); \
  for (i = 0; i < count; i ++) \
    { \
      c = val & carry_mask; \
      val OP 1; \
    } \
  set_oszc (val, 4, c); \
  PD (val); \
}

typedef union {
  int i;
  float f;
} FloatInt;

static inline int
float2int (float f)
{
  FloatInt fi;
  fi.f = f;
  return fi.i;
}

static inline float
int2float (int i)
{
  FloatInt fi;
  fi.i = i;
  return fi.f;
}

static int
fop_fadd (fp_t s1, fp_t s2, fp_t *d)
{
  *d = rxfp_add (s1, s2);
  return 1;
}

static int
fop_fmul (fp_t s1, fp_t s2, fp_t *d)
{
  *d = rxfp_mul (s1, s2);
  return 1;
}

static int
fop_fdiv (fp_t s1, fp_t s2, fp_t *d)
{
  *d = rxfp_div (s1, s2);
  return 1;
}

static int
fop_fsub (fp_t s1, fp_t s2, fp_t *d)
{
  *d = rxfp_sub (s1, s2);
  return 1;
}

#define FPPENDING() (regs.r_fpsw & (FPSWBITS_CE | (FPSWBITS_FMASK & (regs.r_fpsw << FPSW_EFSH))))
#define FPCLEAR() regs.r_fpsw &= FPSWBITS_CLEAR
#define FPCHECK() \
  if (FPPENDING()) \
    return do_fp_exception (opcode_pc)

#define FLOAT_OP(func) \
{ \
  int do_store;   \
  fp_t fa, fb, fc; \
  FPCLEAR(); \
  fb = GS (); \
  fa = GD (); \
  do_store = fop_##func (fa, fb, &fc); \
  tprintf("%g " #func " %g = %g %08x\n", int2float(fa), int2float(fb), int2float(fc), fc); \
  FPCHECK(); \
  if (do_store) \
    PD (fc);	\
  mb = 0; \
  if ((fc & 0x80000000UL) != 0) \
    mb |= FLAGBIT_S; \
  if ((fc & 0x7fffffffUL) == 0)			\
    mb |= FLAGBIT_Z; \
  set_flags (FLAGBIT_S | FLAGBIT_Z, mb); \
}

#define carry (FLAG_C ? 1 : 0)

static struct {
  unsigned long vaddr;
  const char *str;
  int signal;
} exception_info[] = {
  { 0xFFFFFFD0UL, "priviledged opcode", SIGILL },
  { 0xFFFFFFD4UL, "access violation", SIGSEGV },
  { 0xFFFFFFDCUL, "undefined opcode", SIGILL },
  { 0xFFFFFFE4UL, "floating point", SIGFPE }
};
#define EX_PRIVILEDGED	0
#define EX_ACCESS	1
#define EX_UNDEFINED	2
#define EX_FLOATING	3
#define EXCEPTION(n)  \
  return generate_exception (n, opcode_pc)

#define PRIVILEDGED() \
  if (FLAG_PM) \
    EXCEPTION (EX_PRIVILEDGED)

static int
generate_exception (unsigned long type, SI opcode_pc)
{
  SI old_psw, old_pc, new_pc;

  new_pc = mem_get_si (exception_info[type].vaddr);
  /* 0x00020000 is the value used to initialise the known
     exception vectors (see rx.ld), but it is a reserved
     area of memory so do not try to access it, and if the
     value has not been changed by the program then the
     vector has not been installed.  */
  if (new_pc == 0 || new_pc == 0x00020000)
    {
      if (rx_in_gdb)
	return RX_MAKE_STOPPED (exception_info[type].signal);

      fprintf(stderr, "Unhandled %s exception at pc = %#lx\n",
	      exception_info[type].str, (unsigned long) opcode_pc);
      if (type == EX_FLOATING)
	{
	  int mask = FPPENDING ();
	  fprintf (stderr, "Pending FP exceptions:");
	  if (mask & FPSWBITS_FV)
	    fprintf(stderr, " Invalid");
	  if (mask & FPSWBITS_FO)
	    fprintf(stderr, " Overflow");
	  if (mask & FPSWBITS_FZ)
	    fprintf(stderr, " Division-by-zero");
	  if (mask & FPSWBITS_FU)
	    fprintf(stderr, " Underflow");
	  if (mask & FPSWBITS_FX)
	    fprintf(stderr, " Inexact");
	  if (mask & FPSWBITS_CE)
	    fprintf(stderr, " Unimplemented");
	  fprintf(stderr, "\n");
	}
      return RX_MAKE_EXITED (1);
    }

  tprintf ("Triggering %s exception\n", exception_info[type].str);

  old_psw = regs.r_psw;
  regs.r_psw &= ~ (FLAGBIT_I | FLAGBIT_U | FLAGBIT_PM);
  old_pc = opcode_pc;
  regs.r_pc = new_pc;
  pushpc (old_psw);
  pushpc (old_pc);
  return RX_MAKE_STEPPED ();
}

void
generate_access_exception (void)
{
  int rv;

  rv = generate_exception (EX_ACCESS, regs.r_pc);
  if (RX_EXITED (rv))
    longjmp (decode_jmp_buf, rv);
}

static int
do_fp_exception (unsigned long opcode_pc)
{
  while (FPPENDING())
    EXCEPTION (EX_FLOATING);
  return RX_MAKE_STEPPED ();
}

static int
op_is_memory (const RX_Opcode_Decoded *rd, int i)
{
  switch (rd->op[i].type)
    {
    case RX_Operand_Predec:
    case RX_Operand_Postinc:
    case RX_Operand_Indirect:
      return 1;
    default:
      return 0;
    }
}
#define OM(i) op_is_memory (opcode, i)

#define DO_RETURN(x) { longjmp (decode_jmp_buf, x); }

int
decode_opcode (void)
{
  unsigned int uma=0, umb=0;
  int ma=0, mb=0;
  int opcode_size, v;
  unsigned long long ll;
  long long sll;
  unsigned long opcode_pc;
  RX_Data rx_data;
  const RX_Opcode_Decoded *opcode;
#ifdef CYCLE_STATS
  unsigned long long prev_cycle_count;
#endif
#ifdef CYCLE_ACCURATE
  unsigned int tx;
#endif

#ifdef CYCLE_STATS
  prev_cycle_count = regs.cycle_count;
#endif

#ifdef CYCLE_ACCURATE
  memory_source = 0;
  memory_dest = 0;
#endif

  rx_cycles ++;

  maybe_get_mem_page (regs.r_pc);

  opcode_pc = regs.r_pc;

  /* Note that we don't word-swap this point, there's no point.  */
  if (decode_cache_base[opcode_pc] == NULL)
    {
      RX_Opcode_Decoded *opcode_w;
      rx_data.dpc = opcode_pc;
      opcode_w = decode_cache_base[opcode_pc] = calloc (1, sizeof (RX_Opcode_Decoded));
      opcode_size = rx_decode_opcode (opcode_pc, opcode_w,
				      rx_get_byte, &rx_data);
      opcode = opcode_w;
    }
  else
    {
      opcode = decode_cache_base[opcode_pc];
      opcode_size = opcode->n_bytes;
    }

#ifdef CYCLE_ACCURATE
  if (branch_alignment_penalty)
    {
      if ((regs.r_pc ^ (regs.r_pc + opcode_size - 1)) & ~7)
	{
	  tprintf("1 cycle branch alignment penalty\n");
	  cycles (branch_alignment_penalty);
#ifdef CYCLE_STATS
	  branch_alignment_stalls ++;
#endif
	}
      branch_alignment_penalty = 0;
    }
#endif

  regs.r_pc += opcode_size;

  rx_flagmask = opcode->flags_s;
  rx_flagand = ~(int)opcode->flags_0;
  rx_flagor = opcode->flags_1;

  switch (opcode->id)
    {
    case RXO_abs:
      sll = GS ();
      tprintf("|%lld| = ", sll);
      if (sll < 0)
	sll = -sll;
      tprintf("%lld\n", sll);
      PD (sll);
      set_osz (sll, 4);
      E (1);
      break;

    case RXO_adc:
      MATH_OP (+,carry);
      break;

    case RXO_add:
      MATH_OP (+,0);
      break;

    case RXO_and:
      LOGIC_OP (&);
      break;

    case RXO_bclr:
      ma = GD ();
      mb = GS ();
      if (opcode->op[0].type == RX_Operand_Register)
	mb &= 0x1f;
      else
	mb &= 0x07;
      ma &= ~(1 << mb);
      PD (ma);
      EBIT;
      break;

    case RXO_bmcc:
      ma = GD ();
      mb = GS ();
      if (opcode->op[0].type == RX_Operand_Register)
	mb &= 0x1f;
      else
	mb &= 0x07;
      if (GS2 ())
	ma |= (1 << mb);
      else
	ma &= ~(1 << mb);
      PD (ma);
      EBIT;
      break;

    case RXO_bnot:
      ma = GD ();
      mb = GS ();
      if (opcode->op[0].type == RX_Operand_Register)
	mb &= 0x1f;
      else
	mb &= 0x07;
      ma ^= (1 << mb);
      PD (ma);
      EBIT;
      break;

    case RXO_branch:
      if (opcode->op[1].type == RX_Operand_None || GS())
	{
#ifdef CYCLE_ACCURATE
	  SI old_pc = regs.r_pc;
	  int delta;
#endif
	  regs.r_pc = GD();
#ifdef CYCLE_ACCURATE
	  delta = regs.r_pc - old_pc;
	  if (delta >= 0 && delta < 16
	      && opcode_size > 1)
	    {
	      tprintf("near forward branch bonus\n");
	      cycles (2);
	    }
	  else
	    {
	      cycles (3);
	      branch_alignment_penalty = 1;
	    }
#ifdef CYCLE_STATS
	  branch_stalls ++;
#endif
#endif
	}
#ifdef CYCLE_ACCURATE
      else
	cycles (1);
#endif
      break;

    case RXO_branchrel:
      if (opcode->op[1].type == RX_Operand_None || GS())
	{
	  int delta = GD();
	  regs.r_pc = opcode_pc + delta;
#ifdef CYCLE_ACCURATE
	  /* Note: specs say 3, chip says 2.  */
	  if (delta >= 0 && delta < 16
	      && opcode_size > 1)
	    {
	      tprintf("near forward branch bonus\n");
	      cycles (2);
	    }
	  else
	    {
	      cycles (3);
	      branch_alignment_penalty = 1;
	    }
#ifdef CYCLE_STATS
	  branch_stalls ++;
#endif
#endif
	}
#ifdef CYCLE_ACCURATE
      else
	cycles (1);
#endif
      break;

    case RXO_brk:
      {
	int old_psw = regs.r_psw;
	if (rx_in_gdb)
	  DO_RETURN (RX_MAKE_HIT_BREAK ());
	if (regs.r_intb == 0)
	  {
	    tprintf("BREAK hit, no vector table.\n");
	    DO_RETURN (RX_MAKE_EXITED(1));
	  }
	regs.r_psw &= ~(FLAGBIT_I | FLAGBIT_U | FLAGBIT_PM);
	pushpc (old_psw);
	pushpc (regs.r_pc);
	regs.r_pc = mem_get_si (regs.r_intb);
	cycles(6);
      }
      break;

    case RXO_bset:
      ma = GD ();
      mb = GS ();
      if (opcode->op[0].type == RX_Operand_Register)
	mb &= 0x1f;
      else
	mb &= 0x07;
      ma |= (1 << mb);
      PD (ma);
      EBIT;
      break;

    case RXO_btst:
      ma = GS ();
      mb = GS2 ();
      if (opcode->op[1].type == RX_Operand_Register)
	mb &= 0x1f;
      else
	mb &= 0x07;
      umb = ma & (1 << mb);
      set_zc (! umb, umb);
      EBIT;
      break;

    case RXO_clrpsw:
      v = 1 << opcode->op[0].reg;
      if (FLAG_PM
	  && (v == FLAGBIT_I
	      || v == FLAGBIT_U))
	break;
      regs.r_psw &= ~v;
      cycles (1);
      break;

    case RXO_div: /* d = d / s */
      ma = GS();
      mb = GD();
      tprintf("%d / %d = ", mb, ma);
      if (ma == 0 || (ma == -1 && (unsigned int) mb == 0x80000000))
	{
	  tprintf("#NAN\n");
	  set_flags (FLAGBIT_O, FLAGBIT_O);
	  cycles (3);
	}
      else
	{
	  v = mb/ma;
	  tprintf("%d\n", v);
	  set_flags (FLAGBIT_O, 0);
	  PD (v);
	  div_cycles (mb, ma);
	}
      break;

    case RXO_divu: /* d = d / s */
      uma = GS();
      umb = GD();
      tprintf("%u / %u = ", umb, uma);
      if (uma == 0)
	{
	  tprintf("#NAN\n");
	  set_flags (FLAGBIT_O, FLAGBIT_O);
	  cycles (2);
	}
      else
	{
	  v = umb / uma;
	  tprintf("%u\n", v);
	  set_flags (FLAGBIT_O, 0);
	  PD (v);
	  divu_cycles (umb, uma);
	}
      break;

    case RXO_emul:
      ma = GD ();
      mb = GS ();
      sll = (long long)ma * (long long)mb;
      tprintf("%d * %d = %lld\n", ma, mb, sll);
      put_reg (opcode->op[0].reg, sll);
      put_reg (opcode->op[0].reg + 1, sll >> 32);
      E2;
      break;

    case RXO_emulu:
      uma = GD ();
      umb = GS ();
      ll = (long long)uma * (long long)umb;
      tprintf("%#x * %#x = %#llx\n", uma, umb, ll);
      put_reg (opcode->op[0].reg, ll);
      put_reg (opcode->op[0].reg + 1, ll >> 32);
      E2;
      break;

    case RXO_fadd:
      FLOAT_OP (fadd);
      E (4);
      break;

    case RXO_fcmp:
      ma = GD();
      mb = GS();
      FPCLEAR ();
      rxfp_cmp (ma, mb);
      FPCHECK ();
      E (1);
      break;

    case RXO_fdiv:
      FLOAT_OP (fdiv);
      E (16);
      break;

    case RXO_fmul:
      FLOAT_OP (fmul);
      E (3);
      break;

    case RXO_rtfi:
      PRIVILEDGED ();
      regs.r_psw = regs.r_bpsw;
      regs.r_pc = regs.r_bpc;
#ifdef CYCLE_ACCURATE
      regs.fast_return = 0;
      cycles(3);
#endif
      break;

    case RXO_fsub:
      FLOAT_OP (fsub);
      E (4);
      break;

    case RXO_ftoi:
      ma = GS ();
      FPCLEAR ();
      mb = rxfp_ftoi (ma, FPRM_ZERO);
      FPCHECK ();
      PD (mb);
      tprintf("(int) %g = %d\n", int2float(ma), mb);
      set_sz (mb, 4);
      E (2);
      break;

    case RXO_int:
      v = GS ();
      if (v == 255)
	{
	  int rc = rx_syscall (regs.r[5]);
	  if (! RX_STEPPED (rc))
	    DO_RETURN (rc);
	}
      else
	{
	  int old_psw = regs.r_psw;
	  regs.r_psw &= ~(FLAGBIT_I | FLAGBIT_U | FLAGBIT_PM);
	  pushpc (old_psw);
	  pushpc (regs.r_pc);
	  regs.r_pc = mem_get_si (regs.r_intb + 4 * v);
	}
      cycles (6);
      break;

    case RXO_itof:
      ma = GS ();
      FPCLEAR ();
      mb = rxfp_itof (ma, regs.r_fpsw);
      FPCHECK ();
      tprintf("(float) %d = %x\n", ma, mb);
      PD (mb);
      set_sz (ma, 4);
      E (2);
      break;

    case RXO_jsr:
    case RXO_jsrrel:
      {
#ifdef CYCLE_ACCURATE
	int delta;
	regs.m2m = 0;
#endif
	v = GD ();
#ifdef CYCLE_ACCURATE
	regs.link_register = regs.r_pc;
#endif
	pushpc (get_reg (pc));
	if (opcode->id == RXO_jsrrel)
	  v += regs.r_pc;
#ifdef CYCLE_ACCURATE
	delta = v - regs.r_pc;
#endif
	put_reg (pc, v);
#ifdef CYCLE_ACCURATE
	/* Note: docs say 3, chip says 2 */
	if (delta >= 0 && delta < 16)
	  {
	    tprintf ("near forward jsr bonus\n");
	    cycles (2);
	  }
	else
	  {
	    branch_alignment_penalty = 1;
	    cycles (3);
	  }
	regs.fast_return = 1;
#endif
      }
      break;

    case RXO_machi:
      ll = (long long)(signed short)(GS() >> 16) * (long long)(signed short)(GS2 () >> 16);
      ll <<= 16;
      put_reg64 (acc64, ll + regs.r_acc);
      E1;
      break;

    case RXO_maclo:
      ll = (long long)(signed short)(GS()) * (long long)(signed short)(GS2 ());
      ll <<= 16;
      put_reg64 (acc64, ll + regs.r_acc);
      E1;
      break;

    case RXO_max:
      mb = GS();
      ma = GD();
      if (ma > mb)
	PD (ma);
      else
	PD (mb);
      E (1);
      break;

    case RXO_min:
      mb = GS();
      ma = GD();
      if (ma < mb)
	PD (ma);
      else
	PD (mb);
      E (1);
      break;

    case RXO_mov:
      v = GS ();

      if (opcode->op[1].type == RX_Operand_Register
	  && opcode->op[1].reg == 17 /* PC */)
	{
	  /* Special case.  We want the address of the insn, not the
	     address of the next insn.  */
	  v = opcode_pc;
	}

      if (opcode->op[0].type == RX_Operand_Register
	  && opcode->op[0].reg == 16 /* PSW */)
	{
	  /* Special case, LDC and POPC can't ever modify PM.  */
	  int pm = regs.r_psw & FLAGBIT_PM;
	  v &= ~ FLAGBIT_PM;
	  v |= pm;
	  if (pm)
	    {
	      v &= ~ (FLAGBIT_I | FLAGBIT_U | FLAGBITS_IPL);
	      v |= pm;
	    }
	}
      if (FLAG_PM)
	{
	  /* various things can't be changed in user mode.  */
	  if (opcode->op[0].type == RX_Operand_Register)
	    if (opcode->op[0].reg == 32)
	      {
		v &= ~ (FLAGBIT_I | FLAGBIT_U | FLAGBITS_IPL);
		v |= regs.r_psw & (FLAGBIT_I | FLAGBIT_U | FLAGBITS_IPL);
	      }
	  if (opcode->op[0].reg == 34 /* ISP */
	      || opcode->op[0].reg == 37 /* BPSW */
	      || opcode->op[0].reg == 39 /* INTB */
	      || opcode->op[0].reg == 38 /* VCT */)
	    /* These are ignored.  */
	    break;
	}
      if (OM(0) && OM(1))
	cycles (2);
      else
	cycles (1);

      PD (v);

#ifdef CYCLE_ACCURATE
      if ((opcode->op[0].type == RX_Operand_Predec
	   && opcode->op[1].type == RX_Operand_Register)
	  || (opcode->op[0].type == RX_Operand_Postinc
	      && opcode->op[1].type == RX_Operand_Register))
	{
	  /* Special case: push reg doesn't cause a memory stall.  */
	  memory_dest = 0;
	  tprintf("push special case\n");
	}
#endif

      set_sz (v, DSZ());
      break;

    case RXO_movbi:
      PD (GS ());
      cycles (1);
      break;

    case RXO_movbir:
      PS (GD ());
      cycles (1);
      break;

    case RXO_mul:
      v = US2 ();
      ll = (unsigned long long) US1() * (unsigned long long) v;
      PD(ll);
      E (1);
      break;

    case RXO_mulhi:
      v = GS2 ();
      ll = (long long)(signed short)(GS() >> 16) * (long long)(signed short)(v >> 16);
      ll <<= 16;
      put_reg64 (acc64, ll);
      E1;
      break;

    case RXO_mullo:
      v = GS2 ();
      ll = (long long)(signed short)(GS()) * (long long)(signed short)(v);
      ll <<= 16;
      put_reg64 (acc64, ll);
      E1;
      break;

    case RXO_mvfachi:
      PD (get_reg (acchi));
      E1;
      break;

    case RXO_mvfaclo:
      PD (get_reg (acclo));
      E1;
      break;

    case RXO_mvfacmi:
      PD (get_reg (accmi));
      E1;
      break;

    case RXO_mvtachi:
      put_reg (acchi, GS ());
      E1;
      break;

    case RXO_mvtaclo:
      put_reg (acclo, GS ());
      E1;
      break;

    case RXO_mvtipl:
      regs.r_psw &= ~ FLAGBITS_IPL;
      regs.r_psw |= (GS () << FLAGSHIFT_IPL) & FLAGBITS_IPL;
      E1;
      break;

    case RXO_nop:
    case RXO_nop2:
    case RXO_nop3:
    case RXO_nop4:
    case RXO_nop5:
    case RXO_nop6:
    case RXO_nop7:
      E1;
      break;

    case RXO_or:
      LOGIC_OP (|);
      break;

    case RXO_popm:
      /* POPM cannot pop R0 (sp).  */
      if (opcode->op[1].reg == 0 || opcode->op[2].reg == 0)
	EXCEPTION (EX_UNDEFINED);
      if (opcode->op[1].reg >= opcode->op[2].reg)
	{
	  regs.r_pc = opcode_pc;
	  DO_RETURN (RX_MAKE_STOPPED (SIGILL));
	}
      for (v = opcode->op[1].reg; v <= opcode->op[2].reg; v++)
	{
	  cycles (1);
	  RLD (v);
	  put_reg (v, pop ());
	}
      break;

    case RXO_pushm:
      /* PUSHM cannot push R0 (sp).  */
      if (opcode->op[1].reg == 0 || opcode->op[2].reg == 0)
	EXCEPTION (EX_UNDEFINED);
      if (opcode->op[1].reg >= opcode->op[2].reg)
	{
	  regs.r_pc = opcode_pc;
	  return RX_MAKE_STOPPED (SIGILL);
	}
      for (v = opcode->op[2].reg; v >= opcode->op[1].reg; v--)
	{
	  RL (v);
	  push (get_reg (v));
	}
      cycles (opcode->op[2].reg - opcode->op[1].reg + 1);
      break;

    case RXO_racw:
      ll = get_reg64 (acc64) << GS ();
      ll += 0x80000000ULL;
      if ((signed long long)ll > (signed long long)0x00007fff00000000ULL)
	ll = 0x00007fff00000000ULL;
      else if ((signed long long)ll < (signed long long)0xffff800000000000ULL)
	ll = 0xffff800000000000ULL;
      else
	ll &= 0xffffffff00000000ULL;
      put_reg64 (acc64, ll);
      E1;
      break;

    case RXO_rte:
      PRIVILEDGED ();
      regs.r_pc = poppc ();
      regs.r_psw = poppc ();
      if (FLAG_PM)
	regs.r_psw |= FLAGBIT_U;
#ifdef CYCLE_ACCURATE
      regs.fast_return = 0;
      cycles (6);
#endif
      break;

    case RXO_revl:
      uma = GS ();
      umb = (((uma >> 24) & 0xff)
	     | ((uma >> 8) & 0xff00)
	     | ((uma << 8) & 0xff0000)
	     | ((uma << 24) & 0xff000000UL));
      PD (umb);
      E1;
      break;

    case RXO_revw:
      uma = GS ();
      umb = (((uma >> 8) & 0x00ff00ff)
	     | ((uma << 8) & 0xff00ff00UL));
      PD (umb);
      E1;
      break;

    case RXO_rmpa:
      RL(4);
      RL(5);
#ifdef CYCLE_ACCURATE
      tx = regs.r[3];
#endif

      while (regs.r[3] != 0)
	{
	  long long tmp;

	  switch (opcode->size)
	    {
	    case RX_Long:
	      ma = mem_get_si (regs.r[1]);
	      mb = mem_get_si (regs.r[2]);
	      regs.r[1] += 4;
	      regs.r[2] += 4;
	      break;
	    case RX_Word:
	      ma = sign_ext (mem_get_hi (regs.r[1]), 16);
	      mb = sign_ext (mem_get_hi (regs.r[2]), 16);
	      regs.r[1] += 2;
	      regs.r[2] += 2;
	      break;
	    case RX_Byte:
	      ma = sign_ext (mem_get_qi (regs.r[1]), 8);
	      mb = sign_ext (mem_get_qi (regs.r[2]), 8);
	      regs.r[1] += 1;
	      regs.r[2] += 1;
	      break;
	    default:
	      abort ();
	    }
	  /* We do the multiply as a signed value.  */
	  sll = (long long)ma * (long long)mb;
	  tprintf("        %016llx = %d * %d\n", sll, ma, mb);
	  /* but we do the sum as unsigned, while sign extending the operands.  */
	  tmp = regs.r[4] + (sll & 0xffffffffUL);
	  regs.r[4] = tmp & 0xffffffffUL;
	  tmp >>= 32;
	  sll >>= 32;
	  tmp += regs.r[5] + (sll & 0xffffffffUL);
	  regs.r[5] = tmp & 0xffffffffUL;
	  tmp >>= 32;
	  sll >>= 32;
	  tmp += regs.r[6] + (sll & 0xffffffffUL);
	  regs.r[6] = tmp & 0xffffffffUL;
	  tprintf("%08lx\033[36m%08lx\033[0m%08lx\n",
		  (unsigned long) regs.r[6],
		  (unsigned long) regs.r[5],
		  (unsigned long) regs.r[4]);

	  regs.r[3] --;
	}
      if (regs.r[6] & 0x00008000)
	regs.r[6] |= 0xffff0000UL;
      else
	regs.r[6] &= 0x0000ffff;
      ma = (regs.r[6] & 0x80000000UL) ? FLAGBIT_S : 0;
      if (regs.r[6] != 0 && regs.r[6] != 0xffffffffUL)
	set_flags (FLAGBIT_O|FLAGBIT_S, ma | FLAGBIT_O);
      else
	set_flags (FLAGBIT_O|FLAGBIT_S, ma);
#ifdef CYCLE_ACCURATE
      switch (opcode->size)
	{
	case RX_Long:
	  cycles (6 + 4 * tx);
	  break;
	case RX_Word:
	  cycles (6 + 5 * (tx / 2) + 4 * (tx % 2));
	  break;
	case RX_Byte:
	  cycles (6 + 7 * (tx / 4) + 4 * (tx % 4));
	  break;
	default:
	  abort ();
	}
#endif
      break;

    case RXO_rolc:
      v = GD ();
      ma = v & 0x80000000UL;
      v <<= 1;
      v |= carry;
      set_szc (v, 4, ma);
      PD (v);
      E1;
      break;

    case RXO_rorc:
      uma = GD ();
      mb = uma & 1;
      uma >>= 1;
      uma |= (carry ? 0x80000000UL : 0);
      set_szc (uma, 4, mb);
      PD (uma);
      E1;
      break;

    case RXO_rotl:
      mb = GS ();
      uma = GD ();
      if (mb)
	{
	  uma = (uma << mb) | (uma >> (32-mb));
	  mb = uma & 1;
	}
      set_szc (uma, 4, mb);
      PD (uma);
      E1;
      break;

    case RXO_rotr:
      mb = GS ();
      uma = GD ();
      if (mb)
	{
	  uma = (uma >> mb) | (uma << (32-mb));
	  mb = uma & 0x80000000;
	}
      set_szc (uma, 4, mb);
      PD (uma);
      E1;
      break;

    case RXO_round:
      ma = GS ();
      FPCLEAR ();
      mb = rxfp_ftoi (ma, regs.r_fpsw);
      FPCHECK ();
      PD (mb);
      tprintf("(int) %g = %d\n", int2float(ma), mb);
      set_sz (mb, 4);
      E (2);
      break;

    case RXO_rts:
      {
#ifdef CYCLE_ACCURATE
	int cyc = 5;
#endif
	regs.r_pc = poppc ();
#ifdef CYCLE_ACCURATE
	/* Note: specs say 5, chip says 3.  */
	if (regs.fast_return && regs.link_register == regs.r_pc)
	  {
#ifdef CYCLE_STATS
	    fast_returns ++;
#endif
	    tprintf("fast return bonus\n");
	    cyc -= 2;
	  }
	cycles (cyc);
	regs.fast_return = 0;
	branch_alignment_penalty = 1;
#endif
      }
      break;

    case RXO_rtsd:
      if (opcode->op[2].type == RX_Operand_Register)
	{
	  int i;
	  /* RTSD cannot pop R0 (sp).  */
	  put_reg (0, get_reg (0) + GS() - (opcode->op[0].reg-opcode->op[2].reg+1)*4);
	  if (opcode->op[2].reg == 0)
	    EXCEPTION (EX_UNDEFINED);
#ifdef CYCLE_ACCURATE
	  tx = opcode->op[0].reg - opcode->op[2].reg + 1;
#endif
	  for (i = opcode->op[2].reg; i <= opcode->op[0].reg; i ++)
	    {
	      RLD (i);
	      put_reg (i, pop ());
	    }
	}
      else
	{
#ifdef CYCLE_ACCURATE
	  tx = 0;
#endif
	  put_reg (0, get_reg (0) + GS());
	}
      put_reg (pc, poppc());
#ifdef CYCLE_ACCURATE
      if (regs.fast_return && regs.link_register == regs.r_pc)
	{
	  tprintf("fast return bonus\n");
#ifdef CYCLE_STATS
	  fast_returns ++;
#endif
	  cycles (tx < 3 ? 3 : tx + 1);
	}
      else
	{
	  cycles (tx < 5 ? 5 : tx + 1);
	}
      regs.fast_return = 0;
      branch_alignment_penalty = 1;
#endif
      break;

    case RXO_sat:
      if (FLAG_O && FLAG_S)
	PD (0x7fffffffUL);
      else if (FLAG_O && ! FLAG_S)
	PD (0x80000000UL);
      E1;
      break;

    case RXO_satr:
      if (FLAG_O && ! FLAG_S)
	{
	  put_reg (6, 0x0);
	  put_reg (5, 0x7fffffff);
	  put_reg (4, 0xffffffff);
	}
      else if (FLAG_O && FLAG_S)
	{
	  put_reg (6, 0xffffffff);
	  put_reg (5, 0x80000000);
	  put_reg (4, 0x0);
	}
      E1;
      break;
      
    case RXO_sbb:
      MATH_OP (-, ! carry);
      break;

    case RXO_sccnd:
      if (GS())
	PD (1);
      else
	PD (0);
      E1;
      break;

    case RXO_scmpu:
#ifdef CYCLE_ACCURATE
      tx = regs.r[3];
#endif
      while (regs.r[3] != 0)
	{
	  uma = mem_get_qi (regs.r[1] ++);
	  umb = mem_get_qi (regs.r[2] ++);
	  regs.r[3] --;
	  if (uma != umb || uma == 0)
	    break;
	}
      if (uma == umb)
	set_zc (1, 1);
      else
	set_zc (0, ((int)uma - (int)umb) >= 0);
      cycles (2 + 4 * (tx / 4) + 4 * (tx % 4));
      break;

    case RXO_setpsw:
      v = 1 << opcode->op[0].reg;
      if (FLAG_PM
	  && (v == FLAGBIT_I
	      || v == FLAGBIT_U))
	break;
      regs.r_psw |= v;
      cycles (1);
      break;

    case RXO_smovb:
      RL (3);
#ifdef CYCLE_ACCURATE
      tx = regs.r[3];
#endif
      while (regs.r[3])
	{
	  uma = mem_get_qi (regs.r[2] --);
	  mem_put_qi (regs.r[1]--, uma);
	  regs.r[3] --;
	}
#ifdef CYCLE_ACCURATE
      if (tx > 3)
	cycles (6 + 3 * (tx / 4) + 3 * (tx % 4));
      else
	cycles (2 + 3 * (tx % 4));
#endif
      break;

    case RXO_smovf:
      RL (3);
#ifdef CYCLE_ACCURATE
      tx = regs.r[3];
#endif
      while (regs.r[3])
	{
	  uma = mem_get_qi (regs.r[2] ++);
	  mem_put_qi (regs.r[1]++, uma);
	  regs.r[3] --;
	}
      cycles (2 + 3 * (int)(tx / 4) + 3 * (tx % 4));
      break;

    case RXO_smovu:
#ifdef CYCLE_ACCURATE
      tx = regs.r[3];
#endif
      while (regs.r[3] != 0)
	{
	  uma = mem_get_qi (regs.r[2] ++);
	  mem_put_qi (regs.r[1]++, uma);
	  regs.r[3] --;
	  if (uma == 0)
	    break;
	}
      cycles (2 + 3 * (int)(tx / 4) + 3 * (tx % 4));
      break;

    case RXO_shar: /* d = ma >> mb */
      SHIFT_OP (sll, int, mb, >>=, 1);
      E (1);
      break;

    case RXO_shll: /* d = ma << mb */
      SHIFT_OP (ll, int, mb, <<=, 0x80000000UL);
      E (1);
      break;

    case RXO_shlr: /* d = ma >> mb */
      SHIFT_OP (ll, unsigned int, mb, >>=, 1);
      E (1);
      break;

    case RXO_sstr:
      RL (3);
#ifdef CYCLE_ACCURATE
      tx = regs.r[3];
#endif
      switch (opcode->size)
	{
	case RX_Long:
	  while (regs.r[3] != 0)
	    {
	      mem_put_si (regs.r[1], regs.r[2]);
	      regs.r[1] += 4;
	      regs.r[3] --;
	    }
	  cycles (2 + tx);
	  break;
	case RX_Word:
	  while (regs.r[3] != 0)
	    {
	      mem_put_hi (regs.r[1], regs.r[2]);
	      regs.r[1] += 2;
	      regs.r[3] --;
	    }
	  cycles (2 + (int)(tx / 2) + tx % 2);
	  break;
	case RX_Byte:
	  while (regs.r[3] != 0)
	    {
	      mem_put_qi (regs.r[1], regs.r[2]);
	      regs.r[1] ++;
	      regs.r[3] --;
	    }
	  cycles (2 + (int)(tx / 4) + tx % 4);
	  break;
	default:
	  abort ();
	}
      break;

    case RXO_stcc:
      if (GS2())
	PD (GS ());
      E1;
      break;

    case RXO_stop:
      PRIVILEDGED ();
      regs.r_psw |= FLAGBIT_I;
      DO_RETURN (RX_MAKE_STOPPED(0));

    case RXO_sub:
      MATH_OP (-, 0);
      break;

    case RXO_suntil:
      RL(3);
#ifdef CYCLE_ACCURATE
      tx = 0;
#endif
      if (regs.r[3] == 0)
	{
	  cycles (3);
	  break;
	}
      switch (opcode->size)
	{
	case RX_Long:
	  uma = get_reg (2);
	  while (regs.r[3] != 0)
	    {
	      regs.r[3] --;
	      umb = mem_get_si (get_reg (1));
	      regs.r[1] += 4;
#ifdef CYCLE_ACCURATE
	      tx ++;
#endif
	      if (umb == uma)
		break;
	    }
#ifdef CYCLE_ACCURATE
	  cycles (3 + 3 * tx);
#endif
	  break;
	case RX_Word:
	  uma = get_reg (2) & 0xffff;
	  while (regs.r[3] != 0)
	    {
	      regs.r[3] --;
	      umb = mem_get_hi (get_reg (1));
	      regs.r[1] += 2;
#ifdef CYCLE_ACCURATE
	      tx ++;
#endif
	      if (umb == uma)
		break;
	    }
#ifdef CYCLE_ACCURATE
	  cycles (3 + 3 * (tx / 2) + 3 * (tx % 2));
#endif
	  break;
	case RX_Byte:
	  uma = get_reg (2) & 0xff;
	  while (regs.r[3] != 0)
	    {
	      regs.r[3] --;
	      umb = mem_get_qi (regs.r[1]);
	      regs.r[1] += 1;
#ifdef CYCLE_ACCURATE
	      tx ++;
#endif
	      if (umb == uma)
		break;
	    }
#ifdef CYCLE_ACCURATE
	  cycles (3 + 3 * (tx / 4) + 3 * (tx % 4));
#endif
	  break;
	default:
	  abort();
	}
      if (uma == umb)
	set_zc (1, 1);
      else
	set_zc (0, ((int)uma - (int)umb) >= 0);
      break;

    case RXO_swhile:
      RL(3);
#ifdef CYCLE_ACCURATE
      tx = 0;
#endif
      if (regs.r[3] == 0)
	break;
      switch (opcode->size)
	{
	case RX_Long:
	  uma = get_reg (2);
	  while (regs.r[3] != 0)
	    {
	      regs.r[3] --;
	      umb = mem_get_si (get_reg (1));
	      regs.r[1] += 4;
#ifdef CYCLE_ACCURATE
	      tx ++;
#endif
	      if (umb != uma)
		break;
	    }
#ifdef CYCLE_ACCURATE
	  cycles (3 + 3 * tx);
#endif
	  break;
	case RX_Word:
	  uma = get_reg (2) & 0xffff;
	  while (regs.r[3] != 0)
	    {
	      regs.r[3] --;
	      umb = mem_get_hi (get_reg (1));
	      regs.r[1] += 2;
#ifdef CYCLE_ACCURATE
	      tx ++;
#endif
	      if (umb != uma)
		break;
	    }
#ifdef CYCLE_ACCURATE
	  cycles (3 + 3 * (tx / 2) + 3 * (tx % 2));
#endif
	  break;
	case RX_Byte:
	  uma = get_reg (2) & 0xff;
	  while (regs.r[3] != 0)
	    {
	      regs.r[3] --;
	      umb = mem_get_qi (regs.r[1]);
	      regs.r[1] += 1;
#ifdef CYCLE_ACCURATE
	      tx ++;
#endif
	      if (umb != uma)
		break;
	    }
#ifdef CYCLE_ACCURATE
	  cycles (3 + 3 * (tx / 4) + 3 * (tx % 4));
#endif
	  break;
	default:
	  abort();
	}
      if (uma == umb)
	set_zc (1, 1);
      else
	set_zc (0, ((int)uma - (int)umb) >= 0);
      break;

    case RXO_wait:
      PRIVILEDGED ();
      regs.r_psw |= FLAGBIT_I;
      DO_RETURN (RX_MAKE_STOPPED(0));

    case RXO_xchg:
#ifdef CYCLE_ACCURATE
      regs.m2m = 0;
#endif
      v = GS (); /* This is the memory operand, if any.  */
      PS (GD ()); /* and this may change the address register.  */
      PD (v);
      E2;
#ifdef CYCLE_ACCURATE
      /* all M cycles happen during xchg's cycles.  */
      memory_dest = 0;
      memory_source = 0;
#endif
      break;

    case RXO_xor:
      LOGIC_OP (^);
      break;

    default:
      EXCEPTION (EX_UNDEFINED);
    }

#ifdef CYCLE_ACCURATE
  regs.m2m = 0;
  if (memory_source)
    regs.m2m |= M2M_SRC;
  if (memory_dest)
    regs.m2m |= M2M_DST;

  regs.rt = new_rt;
  new_rt = -1;
#endif

#ifdef CYCLE_STATS
  if (prev_cycle_count == regs.cycle_count)
    {
      printf("Cycle count not updated! id %s\n", id_names[opcode->id]);
      abort ();
    }
#endif

#ifdef CYCLE_STATS
  if (running_benchmark)
    {
      int omap = op_lookup (opcode->op[0].type, opcode->op[1].type, opcode->op[2].type);


      cycles_per_id[opcode->id][omap] += regs.cycle_count - prev_cycle_count;
      times_per_id[opcode->id][omap] ++;

      times_per_pair[prev_opcode_id][po0][opcode->id][omap] ++;

      prev_opcode_id = opcode->id;
      po0 = omap;
    }
#endif

  return RX_MAKE_STEPPED ();
}

#ifdef CYCLE_STATS
void
reset_pipeline_stats (void)
{
  memset (cycles_per_id, 0, sizeof(cycles_per_id));
  memset (times_per_id, 0, sizeof(times_per_id));
  memory_stalls = 0;
  register_stalls = 0;
  branch_stalls = 0;
  branch_alignment_stalls = 0;
  fast_returns = 0;
  memset (times_per_pair, 0, sizeof(times_per_pair));
  running_benchmark = 1;

  benchmark_start_cycle = regs.cycle_count;
}

void
halt_pipeline_stats (void)
{
  running_benchmark = 0;
  benchmark_end_cycle = regs.cycle_count;
}
#endif

void
pipeline_stats (void)
{
#ifdef CYCLE_STATS
  int i, o1;
  int p, p1;
#endif

#ifdef CYCLE_ACCURATE
  if (verbose == 1)
    {
      printf ("cycles: %llu\n", regs.cycle_count);
      return;
    }

  printf ("cycles: %13s\n", comma (regs.cycle_count));
#endif

#ifdef CYCLE_STATS
  if (benchmark_start_cycle)
    printf ("bmark:  %13s\n", comma (benchmark_end_cycle - benchmark_start_cycle));

  printf("\n");
  for (i = 0; i < N_RXO; i++)
    for (o1 = 0; o1 < N_MAP; o1 ++)
      if (times_per_id[i][o1])
	printf("%13s %13s %7.2f  %s %s\n",
	       comma (cycles_per_id[i][o1]),
	       comma (times_per_id[i][o1]),
	       (double)cycles_per_id[i][o1] / times_per_id[i][o1],
	       op_cache_string(o1),
	       id_names[i]+4);

  printf("\n");
  for (p = 0; p < N_RXO; p ++)
    for (p1 = 0; p1 < N_MAP; p1 ++)
      for (i = 0; i < N_RXO; i ++)
	for (o1 = 0; o1 < N_MAP; o1 ++)
	  if (times_per_pair[p][p1][i][o1])
	    {
	      printf("%13s   %s %-9s  ->  %s %s\n",
		     comma (times_per_pair[p][p1][i][o1]),
		     op_cache_string(p1),
		     id_names[p]+4,
		     op_cache_string(o1),
		     id_names[i]+4);
	    }

  printf("\n");
  printf("%13s memory stalls\n", comma (memory_stalls));
  printf("%13s register stalls\n", comma (register_stalls));
  printf("%13s branches taken (non-return)\n", comma (branch_stalls));
  printf("%13s branch alignment stalls\n", comma (branch_alignment_stalls));
  printf("%13s fast returns\n", comma (fast_returns));
#endif
}