sim/mips/mdmx.c

/* Simulation code for the MIPS MDMX ASE.
   Copyright (C) 2002 Free Software Foundation, Inc.
   Contributed by Broadcom Corporation (SiByte).

This file is part of GDB, the GNU debugger.

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, 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 <stdio.h>

#include "sim-main.h"

/* Within mdmx.c we refer to the sim_cpu directly. */
#define CPU cpu
#define SD  (CPU_STATE(CPU))

/* XXX FIXME: temporary hack while the impact of making unpredictable()
   a "normal" (non-igen) function is evaluated.  */
#undef Unpredictable
#define Unpredictable() unpredictable_action (cpu, cia)

/* MDMX Representations

   An 8-bit packed byte element (OB) is always unsigned.
   The 24-bit accumulators are signed and are represented as 32-bit
   signed values, which are reduced to 24-bit signed values prior to
   Round and Clamp operations.
  
   A 16-bit packed halfword element (QH) is always signed.
   The 48-bit accumulators are signed and are represented as 64-bit
   signed values, which are reduced to 48-bit signed values prior to
   Round and Clamp operations.
  
   The code below assumes a 2's-complement representation of signed
   quantities.  Care is required to clear extended sign bits when
   repacking fields.
  
   The code (and the code for arithmetic shifts in mips.igen) also makes
   the (not guaranteed portable) assumption that right shifts of signed
   quantities in C do sign extension.  */

typedef unsigned64 unsigned48;
#define MASK48 (UNSIGNED64 (0xffffffffffff))

typedef unsigned32 unsigned24;
#define MASK24 (UNSIGNED32 (0xffffff))

typedef enum {
  mdmx_ob,          /* OB (octal byte) */
  mdmx_qh           /* QH (quad half-word) */
} MX_fmt;

typedef enum {
  sel_elem,         /* element select */
  sel_vect,         /* vector select */
  sel_imm           /* immediate select */
} VT_select;

#define OB_MAX  ((unsigned8)0xFF)
#define QH_MIN  ((signed16)0x8000)
#define QH_MAX  ((signed16)0x7FFF)

#define OB_CLAMP(x)  ((unsigned8)((x) > OB_MAX ? OB_MAX : (x)))
#define QH_CLAMP(x)  ((signed16)((x) < QH_MIN ? QH_MIN : \
                                ((x) > QH_MAX ? QH_MAX : (x))))

#define MX_FMT(fmtsel) (((fmtsel) & 0x1) == 0 ? mdmx_ob : mdmx_qh)
#define MX_VT(fmtsel)  (((fmtsel) & 0x10) == 0 ?    sel_elem : \
                       (((fmtsel) & 0x18) == 0x10 ? sel_vect : sel_imm))

#define QH_ELEM(v,fmtsel) \
        ((signed16)(((v) >> (((fmtsel) & 0xC) << 2)) & 0xFFFF))
#define OB_ELEM(v,fmtsel) \
        ((unsigned8)(((v) >> (((fmtsel) & 0xE) << 2)) & 0xFF))


typedef signed16 (*QH_FUNC)(signed16, signed16);
typedef unsigned8 (*OB_FUNC)(unsigned8, unsigned8);

/* vectorized logical operators */

static signed16
AndQH(signed16 ts, signed16 tt)
{
  return (signed16)((unsigned16)ts & (unsigned16)tt);
}

static unsigned8
AndOB(unsigned8 ts, unsigned8 tt)
{
  return ts & tt;
}

static signed16
NorQH(signed16 ts, signed16 tt)
{
  return (signed16)(((unsigned16)ts | (unsigned16)tt) ^ 0xFFFF);
}

static unsigned8
NorOB(unsigned8 ts, unsigned8 tt)
{
  return (ts | tt) ^ 0xFF;
}

static signed16
OrQH(signed16 ts, signed16 tt)
{
  return (signed16)((unsigned16)ts | (unsigned16)tt);
}

static unsigned8
OrOB(unsigned8 ts, unsigned8 tt)
{
  return ts | tt;
}

static signed16
XorQH(signed16 ts, signed16 tt)
{
  return (signed16)((unsigned16)ts ^ (unsigned16)tt);
}

static unsigned8
XorOB(unsigned8 ts, unsigned8 tt)
{
  return ts ^ tt;
}

static signed16
SLLQH(signed16 ts, signed16 tt)
{
  unsigned32 s = (unsigned32)tt & 0xF;
  return (signed16)(((unsigned32)ts << s) & 0xFFFF);
}

static unsigned8
SLLOB(unsigned8 ts, unsigned8 tt)
{
  unsigned32 s = tt & 0x7;
  return (ts << s) & 0xFF;
}

static signed16
SRLQH(signed16 ts, signed16 tt)
{
  unsigned32 s = (unsigned32)tt & 0xF;
  return (signed16)((unsigned16)ts >> s);
}

static unsigned8
SRLOB(unsigned8 ts, unsigned8 tt)
{
  unsigned32 s = tt & 0x7;
  return ts >> s;
}


/* Vectorized arithmetic operators.  */

static signed16
AddQH(signed16 ts, signed16 tt)
{
  signed32 t = (signed32)ts + (signed32)tt;
  return QH_CLAMP(t);
}

static unsigned8
AddOB(unsigned8 ts, unsigned8 tt)
{
  unsigned32 t = (unsigned32)ts + (unsigned32)tt;
  return OB_CLAMP(t);
}

static signed16
SubQH(signed16 ts, signed16 tt)
{
  signed32 t = (signed32)ts - (signed32)tt;
  return QH_CLAMP(t);
}

static unsigned8
SubOB(unsigned8 ts, unsigned8 tt)
{
  signed32 t;
  t = (signed32)ts - (signed32)tt;
  if (t < 0)
    t = 0;
  return (unsigned8)t;
}

static signed16
MinQH(signed16 ts, signed16 tt)
{
  return (ts < tt ? ts : tt);
}

static unsigned8
MinOB(unsigned8 ts, unsigned8 tt)
{
  return (ts < tt ? ts : tt);
}

static signed16
MaxQH(signed16 ts, signed16 tt)
{
  return (ts > tt ? ts : tt);
}

static unsigned8
MaxOB(unsigned8 ts, unsigned8 tt)
{
  return (ts > tt ? ts : tt);
}

static signed16
MulQH(signed16 ts, signed16 tt)
{
  signed32 t = (signed32)ts * (signed32)tt;
  return QH_CLAMP(t);
}

static unsigned8
MulOB(unsigned8 ts, unsigned8 tt)
{
  unsigned32 t = (unsigned32)ts * (unsigned32)tt;
  return OB_CLAMP(t);
}

/* "msgn" and "sra" are defined only for QH format.  */

static signed16
MsgnQH(signed16 ts, signed16 tt)
{
  signed16 t;
  if (ts < 0)
    t = (tt == QH_MIN ? QH_MAX : -tt);
  else if (ts == 0)
    t = 0;
  else
    t = tt;
  return t;
}

static signed16
SRAQH(signed16 ts, signed16 tt)
{
  unsigned32 s = (unsigned32)tt & 0xF;
  return (signed16)((signed32)ts >> s);
}


/* "pabsdiff" and "pavg" are defined only for OB format.  */

static unsigned8
AbsDiffOB(unsigned8 ts, unsigned8 tt)
{
  return (ts >= tt ? ts - tt : tt - ts);
}

static unsigned8
AvgOB(unsigned8 ts, unsigned8 tt)
{
  return ((unsigned32)ts + (unsigned32)tt + 1) >> 1;
}


/* Dispatch tables for operations that update a CPR.  */

static const QH_FUNC qh_func[] = {
  AndQH,  NorQH,  OrQH,   XorQH, SLLQH, SRLQH,
  AddQH,  SubQH,  MinQH,  MaxQH,
  MulQH,  MsgnQH, SRAQH,  NULL,  NULL
};

static const OB_FUNC ob_func[] = {
  AndOB,  NorOB,  OrOB,   XorOB, SLLOB, SRLOB,
  AddOB,  SubOB,  MinOB,  MaxOB,
  MulOB,  NULL,   NULL,   AbsDiffOB, AvgOB
};

/* Auxiliary functions for CPR updates.  */

/* Vector mapping for QH format.  */
static unsigned64
qh_vector_op(unsigned64 v1, unsigned64 v2, QH_FUNC func)
{
  unsigned64 result = 0;
  int  i;
  signed16 h, h1, h2;

  for (i = 0; i < 64; i += 16)
    {
      h1 = (signed16)(v1 & 0xFFFF);  v1 >>= 16;
      h2 = (signed16)(v2 & 0xFFFF);  v2 >>= 16;
      h = (*func)(h1, h2);
      result |= ((unsigned64)((unsigned16)h) << i);
    }
  return result;
}

static unsigned64
qh_map_op(unsigned64 v1, signed16 h2, QH_FUNC func)
{
  unsigned64 result = 0;
  int  i;
  signed16 h, h1;

  for (i = 0; i < 64; i += 16)
    {
      h1 = (signed16)(v1 & 0xFFFF);  v1 >>= 16;
      h = (*func)(h1, h2);
      result |= ((unsigned64)((unsigned16)h) << i);
    }
  return result;
}


/* Vector operations for OB format.  */

static unsigned64
ob_vector_op(unsigned64 v1, unsigned64 v2, OB_FUNC func)
{
  unsigned64 result = 0;
  int  i;
  unsigned8 b, b1, b2;

  for (i = 0; i < 64; i += 8)
    {
      b1 = v1 & 0xFF;  v1 >>= 8;
      b2 = v2 & 0xFF;  v2 >>= 8;
      b = (*func)(b1, b2);
      result |= ((unsigned64)b << i);
    }
  return result;
}

static unsigned64
ob_map_op(unsigned64 v1, unsigned8 b2, OB_FUNC func)
{
  unsigned64 result = 0;
  int  i;
  unsigned8 b, b1;

  for (i = 0; i < 64; i += 8)
    {
      b1 = v1 & 0xFF;  v1 >>= 8;
      b = (*func)(b1, b2);
      result |= ((unsigned64)b << i);
    }
  return result;
}


/* Primary entry for operations that update CPRs.  */
unsigned64
mdmx_cpr_op(sim_cpu *cpu,
	    address_word cia,
	    int op,
	    unsigned64 op1,
	    int vt,
	    MX_fmtsel fmtsel) 
{
  unsigned64 op2;
  unsigned64 result = 0;

  switch (MX_FMT (fmtsel))
    {
    case mdmx_qh:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = qh_map_op(op1, QH_ELEM(op2, fmtsel), qh_func[op]);
	  break;
	case sel_vect:
	  result = qh_vector_op(op1, ValueFPR(vt, fmt_mdmx), qh_func[op]);
	  break;
	case sel_imm:
	  result = qh_map_op(op1, vt, qh_func[op]);
	  break;
	}
      break;
    case mdmx_ob:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = ob_map_op(op1, OB_ELEM(op2, fmtsel), ob_func[op]);
	  break;
	case sel_vect:
	  result = ob_vector_op(op1, ValueFPR(vt, fmt_mdmx), ob_func[op]);
	  break;
	case sel_imm:
	  result = ob_map_op(op1, vt, ob_func[op]);
	  break;
	}
      break;
    default:
      Unpredictable ();
    }

  return result;
}


/* Operations that update CCs */

static void
qh_vector_test(sim_cpu *cpu, unsigned64 v1, unsigned64 v2, int cond)
{
  int  i;
  signed16 h1, h2;
  int  boolean;

  for (i = 0; i < 4; i++)
    {
      h1 = (signed16)(v1 & 0xFFFF);  v1 >>= 16;
      h2 = (signed16)(v2 & 0xFFFF);  v2 >>= 16;
      boolean = ((cond & MX_C_EQ) && (h1 == h2)) ||
	((cond & MX_C_LT) && (h1 < h2));
      SETFCC(i, boolean);
    }
}

static void
qh_map_test(sim_cpu *cpu, unsigned64 v1, signed16 h2, int cond)
{
  int  i;
  signed16 h1;
  int  boolean;

  for (i = 0; i < 4; i++)
    {
      h1 = (signed16)(v1 & 0xFFFF);  v1 >>= 16;
      boolean = ((cond & MX_C_EQ) && (h1 == h2)) ||
	((cond & MX_C_LT) && (h1 < h2));
      SETFCC(i, boolean);
    }
}

static void
ob_vector_test(sim_cpu *cpu, unsigned64 v1, unsigned64 v2, int cond)
{
  int  i;
  unsigned8 b1, b2;
  int  boolean;

  for (i = 0; i < 8; i++)
    {
      b1 = v1 & 0xFF;  v1 >>= 8;
      b2 = v2 & 0xFF;  v2 >>= 8;
      boolean = ((cond & MX_C_EQ) && (b1 == b2)) ||
	((cond & MX_C_LT) && (b1 < b2));
      SETFCC(i, boolean);
    }
}

static void
ob_map_test(sim_cpu *cpu, unsigned64 v1, unsigned8 b2, int cond)
{
  int  i;
  unsigned8 b1;
  int  boolean;

  for (i = 0; i < 8; i++)
    {
      b1 = (unsigned8)(v1 & 0xFF);  v1 >>= 8;
      boolean = ((cond & MX_C_EQ) && (b1 == b2)) ||
	((cond & MX_C_LT) && (b1 < b2));
      SETFCC(i, boolean);
    }
}


void
mdmx_cc_op(sim_cpu *cpu,
	   address_word cia,
	   int cond,
	   unsigned64 v1,
	   int vt,
	   MX_fmtsel fmtsel)
{
  unsigned64 op2;

  switch (MX_FMT (fmtsel))
    {
    case mdmx_qh:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  qh_map_test(cpu, v1, QH_ELEM(op2, fmtsel), cond);
	  break;
	case sel_vect:
	  qh_vector_test(cpu, v1, ValueFPR(vt, fmt_mdmx), cond);
	  break;
	case sel_imm:
	  qh_map_test(cpu, v1, vt, cond);
	  break;
	}
      break;
    case mdmx_ob:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  ob_map_test(cpu, v1, OB_ELEM(op2, fmtsel), cond);
	  break;
	case sel_vect:
	  ob_vector_test(cpu, v1, ValueFPR(vt, fmt_mdmx), cond);
	  break;
	case sel_imm:
	  ob_map_test(cpu, v1, vt, cond);
	  break;
	}
      break;
    default:
      Unpredictable ();
    }
}


/* Pick operations.  */

static unsigned64
qh_vector_pick(sim_cpu *cpu, unsigned64 v1, unsigned64 v2, int tf)
{
  unsigned64 result = 0;
  int  i, s;
  unsigned16 h;

  s = 0;
  for (i = 0; i < 4; i++)
    {
      h = ((GETFCC(i) == tf) ? (v1 & 0xFFFF) : (v2 & 0xFFFF));
      v1 >>= 16;  v2 >>= 16;
      result |= ((unsigned64)h << s);
      s += 16;
    }
  return result;
}

static unsigned64
qh_map_pick(sim_cpu *cpu, unsigned64 v1, signed16 h2, int tf)
{
  unsigned64 result = 0;
  int  i, s;
  unsigned16 h;

  s = 0;
  for (i = 0; i < 4; i++)
    {
      h = (GETFCC(i) == tf) ? (v1 & 0xFFFF) : (unsigned16)h2;
      v1 >>= 16;
      result |= ((unsigned64)h << s);
      s += 16;
    }
  return result;
}

static unsigned64
ob_vector_pick(sim_cpu *cpu, unsigned64 v1, unsigned64 v2, int tf)
{
  unsigned64 result = 0;
  int  i, s;
  unsigned8 b;

  s = 0;
  for (i = 0; i < 8; i++)
    {
      b = (GETFCC(i) == tf) ? (v1 & 0xFF) : (v2 & 0xFF);
      v1 >>= 8;  v2 >>= 8;
      result |= ((unsigned64)b << s);
      s += 8;
    }
  return result;
}

static unsigned64
ob_map_pick(sim_cpu *cpu, unsigned64 v1, unsigned8 b2, int tf)
{
  unsigned64 result = 0;
  int  i, s;
  unsigned8 b;

  s = 0;
  for (i = 0; i < 8; i++)
    {
      b = (GETFCC(i) == tf) ? (v1 & 0xFF) : b2;
      v1 >>= 8;
      result |= ((unsigned64)b << s);
      s += 8;
    }
  return result;
}


unsigned64
mdmx_pick_op(sim_cpu *cpu,
	     address_word cia,
	     int tf,
	     unsigned64 v1,
	     int vt,
	     MX_fmtsel fmtsel)
{
  unsigned64 result = 0;
  unsigned64 op2;

  switch (MX_FMT (fmtsel))
    {
    case mdmx_qh:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = qh_map_pick(cpu, v1, QH_ELEM(op2, fmtsel), tf);
	  break;
	case sel_vect:
	  result = qh_vector_pick(cpu, v1, ValueFPR(vt, fmt_mdmx), tf);
	  break;
	case sel_imm:
	  result = qh_map_pick(cpu, v1, vt, tf);
	  break;
	}
      break;
    case mdmx_ob:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = ob_map_pick(cpu, v1, OB_ELEM(op2, fmtsel), tf);
	  break;
	case sel_vect:
	  result = ob_vector_pick(cpu, v1, ValueFPR(vt, fmt_mdmx), tf);
	  break;
	case sel_imm:
	  result = ob_map_pick(cpu, v1, vt, tf);
	  break;
	}
      break;
    default:
      Unpredictable ();
    }
  return result;
}


/* Accumulators.  */

typedef void (*QH_ACC)(signed48 *a, signed16 ts, signed16 tt);

static void
AccAddAQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a += (signed48)ts + (signed48)tt;
}

static void
AccAddLQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a = (signed48)ts + (signed48)tt;
}

static void
AccMulAQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a += (signed48)ts * (signed48)tt;
}

static void
AccMulLQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a = (signed48)ts * (signed48)tt;
}

static void
SubMulAQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a -= (signed48)ts * (signed48)tt;
}

static void
SubMulLQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a = -((signed48)ts * (signed48)tt);
}

static void
AccSubAQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a += (signed48)ts - (signed48)tt;
}

static void
AccSubLQH(signed48 *a, signed16 ts, signed16 tt)
{
  *a =  (signed48)ts - (signed48)tt;
}


typedef void (*OB_ACC)(signed24 *acc, unsigned8 ts, unsigned8 tt);

static void
AccAddAOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a += (signed24)ts + (signed24)tt;
}

static void
AccAddLOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a = (signed24)ts + (signed24)tt;
}

static void
AccMulAOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a += (signed24)ts * (signed24)tt;
}

static void
AccMulLOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a = (signed24)ts * (signed24)tt;
}

static void
SubMulAOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a -= (signed24)ts * (signed24)tt;
}

static void
SubMulLOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a = -((signed24)ts * (signed24)tt);
}

static void
AccSubAOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a += (signed24)ts - (signed24)tt;
}

static void
AccSubLOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  *a = (signed24)ts - (signed24)tt;
}

static void
AccAbsDiffOB(signed24 *a, unsigned8 ts, unsigned8 tt)
{
  unsigned8 t = (ts >= tt ? ts - tt : tt - ts);
  *a += (signed24)t;
}


/* Dispatch tables for operations that update a CPR.  */

static const QH_ACC qh_acc[] = {
  AccAddAQH, AccAddAQH, AccMulAQH, AccMulLQH,
  SubMulAQH, SubMulLQH, AccSubAQH, AccSubLQH,
  NULL
};

static const OB_ACC ob_acc[] = {
  AccAddAOB, AccAddLOB, AccMulAOB, AccMulLOB,
  SubMulAOB, SubMulLOB, AccSubAOB, AccSubLOB,
  AccAbsDiffOB
};


static void
qh_vector_acc(signed48 a[], unsigned64 v1, unsigned64 v2, QH_ACC acc)
{
  int  i;
  signed16 h1, h2;

  for (i = 0; i < 4; i++)
    {
      h1 = (signed16)(v1 & 0xFFFF);  v1 >>= 16;
      h2 = (signed16)(v2 & 0xFFFF);  v2 >>= 16;
      (*acc)(&a[i], h1, h2);
    }
}

static void
qh_map_acc(signed48 a[], unsigned64 v1, signed16 h2, QH_ACC acc)
{
  int  i;
  signed16 h1;

  for (i = 0; i < 4; i++)
    {
      h1 = (signed16)(v1 & 0xFFFF);  v1 >>= 16;
      (*acc)(&a[i], h1, h2);
    }
}

static void
ob_vector_acc(signed24 a[], unsigned64 v1, unsigned64 v2, OB_ACC acc)
{
  int  i;
  unsigned8  b1, b2;

  for (i = 0; i < 8; i++)
    {
      b1 = v1 & 0xFF;  v1 >>= 8;
      b2 = v2 & 0xFF;  v2 >>= 8;
      (*acc)(&a[i], b1, b2);
    }
}

static void
ob_map_acc(signed24 a[], unsigned64 v1, unsigned8 b2, OB_ACC acc)
{
  int  i;
  unsigned8 b1;

  for (i = 0; i < 8; i++)
    {
      b1 = v1 & 0xFF;  v1 >>= 8;
      (*acc)(&a[i], b1, b2);
    }
}


/* Primary entry for operations that accumulate */
void
mdmx_acc_op(sim_cpu *cpu,
	    address_word cia,
	    int op,
	    unsigned64 op1,
	    int vt,
	    MX_fmtsel fmtsel) 
{
  unsigned64 op2;

  switch (MX_FMT (fmtsel))
    {
    case mdmx_qh:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  qh_map_acc(ACC.qh, op1, QH_ELEM(op2, fmtsel), qh_acc[op]);
	  break;
	case sel_vect:
	  qh_vector_acc(ACC.qh, op1, ValueFPR(vt, fmt_mdmx), qh_acc[op]);
	  break;
	case sel_imm:
	  qh_map_acc(ACC.qh, op1, vt, qh_acc[op]);
	  break;
	}
      break;
    case mdmx_ob:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  ob_map_acc(ACC.ob, op1, OB_ELEM(op2, fmtsel), ob_acc[op]);
	  break;
	case sel_vect:
	  ob_vector_acc(ACC.ob, op1, ValueFPR(vt, fmt_mdmx), ob_acc[op]);
	  break;
	case sel_imm:
	  ob_map_acc(ACC.ob, op1, vt, ob_acc[op]);
	  break;
	}
      break;
    default:
      Unpredictable ();
    }
}


/* Reading and writing accumulator (no conversion).  */

unsigned64
mdmx_rac_op(sim_cpu *cpu,
	    address_word cia,
	    int op,
	    int fmt) 
{
  unsigned64    result;
  unsigned int  shift;
  int           i;

  shift = op;          /* L = 00, M = 01, H = 10.  */
  result = 0;

  switch (fmt)
    {
    case MX_FMT_QH:
      shift <<= 4;              /* 16 bits per element.  */
      for (i = 3; i >= 0; --i)
	{
	  result <<= 16;
	  result |= ((ACC.qh[i] >> shift) & 0xFFFF);
	}
      break;
    case MX_FMT_OB:
      shift <<= 3;              /*  8 bits per element.  */
      for (i = 7; i >= 0; --i)
	{
	  result <<= 8;
	  result |= ((ACC.ob[i] >> shift) & 0xFF);
	}
      break;
    default:
      Unpredictable ();
    }
  return result;
}

void
mdmx_wacl(sim_cpu *cpu,
	  address_word cia,
	  int fmt,
	  unsigned64 vs,
	  unsigned64 vt) 
{
  int           i;

  switch (fmt)
    {
    case MX_FMT_QH:
      for (i = 0; i < 4; i++)
	{
	  signed32  s = (signed16)(vs & 0xFFFF);
	  ACC.qh[i] = ((signed48)s << 16) | (vt & 0xFFFF);
	  vs >>= 16;  vt >>= 16;
	}
      break;
    case MX_FMT_OB:
      for (i = 0; i < 8; i++)
	{
	  signed16  s = (signed8)(vs & 0xFF);
	  ACC.ob[i] = ((signed24)s << 8) | (vt & 0xFF);
	  vs >>= 8;   vt >>= 8;
	}
      break;
    default:
      Unpredictable ();
    }
}

void
mdmx_wach(sim_cpu *cpu,
	  address_word cia,
	  int fmt,
	  unsigned64 vs)
{
  int           i;

  switch (fmt)
    {
    case MX_FMT_QH:
      for (i = 0; i < 4; i++)
	{
	  signed32  s = (signed16)(vs & 0xFFFF);
	  ACC.qh[i] &= ~((signed48)0xFFFF << 32);
	  ACC.qh[i] |=  ((signed48)s << 32);
	  vs >>= 16;
	}
      break;
    case MX_FMT_OB:
      for (i = 0; i < 8; i++)
	{
	  ACC.ob[i] &= ~((signed24)0xFF << 16);
	  ACC.ob[i] |=  ((signed24)(vs & 0xFF) << 16);
	  vs >>= 8;
	}
      break;
    default:
      Unpredictable ();
    }
}


/* Reading and writing accumulator (rounding conversions).
   Enumerating function guarantees s >= 0 for QH ops.  */

typedef signed16 (*QH_ROUND)(signed48 a, signed16 s);

#define QH_BIT(n)  ((unsigned48)1 << (n))
#define QH_ONES(n) (((unsigned48)1 << (n))-1)

static signed16
RNASQH(signed48 a, signed16 s)
{
  signed48 t;
  signed16 result = 0;

  if (s > 48)
    result = 0;
  else
    {
      t = (a >> s);
      if ((a & QH_BIT(47)) == 0)
	{
	  if (s > 0 && ((a >> (s-1)) & 1) == 1)
	    t++;
	  if (t > QH_MAX)
	    t = QH_MAX;
	}
      else
	{
	  if (s > 0 && ((a >> (s-1)) & 1) == 1)
	    {
	      if (s > 1 && ((unsigned48)a & QH_ONES(s-1)) != 0)
		t++;
	    }
	  if (t < QH_MIN)
	    t = QH_MIN;
	}
      result = (signed16)t;
    }
  return result;
}

static signed16
RNAUQH(signed48 a, signed16 s)
{
  unsigned48 t;
  signed16 result;

  if (s > 48)
    result = 0;
  else if (s == 48)
    result = ((unsigned48)a & MASK48) >> 47;
  else
    {
      t = ((unsigned48)a & MASK48) >> s;
      if (s > 0 && ((a >> (s-1)) & 1) == 1)
	t++;
      if (t > 0xFFFF)
	t = 0xFFFF;
      result = (signed16)t;
    }
  return result;
}

static signed16
RNESQH(signed48 a, signed16 s)
{
  signed48 t;
  signed16 result = 0;

  if (s > 47)
    result = 0;
  else
    {
      t = (a >> s);
      if (s > 0 && ((a >> (s-1)) & 1) == 1)
	{
	  if (s == 1 || (a & QH_ONES(s-1)) == 0)
	    t += t & 1;
	  else
	    t += 1;
	}
      if ((a & QH_BIT(47)) == 0)
	{
	  if (t > QH_MAX)
	    t = QH_MAX;
	}
      else
	{
	  if (t < QH_MIN)
	    t = QH_MIN;
	}
      result = (signed16)t;
    }
  return result;
}

static signed16
RNEUQH(signed48 a, signed16 s)
{
  unsigned48 t;
  signed16 result;

  if (s > 48)
    result = 0;
  else if (s == 48)
    result = ((unsigned48)a > QH_BIT(47) ? 1 : 0);
  else
    {
      t = ((unsigned48)a & MASK48) >> s;
      if (s > 0 && ((a >> (s-1)) & 1) == 1)
	{
	  if (s > 1 && (a & QH_ONES(s-1)) != 0)
	    t++;
	  else
	    t += t & 1;
	}
      if (t > 0xFFFF)
	t = 0xFFFF;
      result = (signed16)t;
    }
  return result;
}

static signed16
RZSQH(signed48 a, signed16 s)
{
  signed48 t;
  signed16 result = 0;

  if (s > 47)
    result = 0;
  else
    {
      t = (a >> s);
      if ((a & QH_BIT(47)) == 0)
	{
	  if (t > QH_MAX)
	    t = QH_MAX;
	}
      else
	{
	  if (t < QH_MIN)
	    t = QH_MIN;
	}
      result = (signed16)t;
    }
  return result;
}

static signed16
RZUQH(signed48 a, signed16 s)
{
  unsigned48 t;
  signed16 result = 0;

  if (s > 48)
    result = 0;
  else if (s == 48)
    result = ((unsigned48)a > QH_BIT(47) ? 1 : 0);
  else
    {
      t = ((unsigned48)a & MASK48) >> s;
      if (t > 0xFFFF)
	t = 0xFFFF;
      result = (signed16)t;
    }
  return result;
}


typedef unsigned8 (*OB_ROUND)(signed24 a, unsigned8 s);

#define OB_BIT(n)  ((unsigned24)1 << (n))
#define OB_ONES(n) (((unsigned24)1 << (n))-1)

static unsigned8
RNAUOB(signed24 a, unsigned8 s)
{
  unsigned8 result;
  unsigned24 t;

  if (s > 24)
    result = 0;
  else if (s == 24)
    result = ((unsigned24)a & MASK24) >> 23;
  else
    {
      t = ((unsigned24)a & MASK24) >> s;
      if (s > 0 && ((a >> (s-1)) & 1) == 1)
	t ++;
      result = OB_CLAMP(t);
    }
  return result;
}

static unsigned8
RNEUOB(signed24 a, unsigned8 s)
{
  unsigned8 result;
  unsigned24 t;

  if (s > 24)
    result = 0;
  else if (s == 24)
    result = (((unsigned24)a & MASK24) > OB_BIT(23) ? 1 : 0);
  else
    {
      t = ((unsigned24)a & MASK24) >> s;
      if (s > 0 && ((a >> (s-1)) & 1) == 1)
	{
	  if (s > 1 && (a & OB_ONES(s-1)) != 0)
	    t++;
	  else
	    t += t & 1;
	}
      result = OB_CLAMP(t);
    }
  return result;
}

static unsigned8
RZUOB(signed24 a, unsigned8 s)
{
  unsigned8 result;
  unsigned24 t;

  if (s >= 24)
    result = 0;
  else
    {
      t = ((unsigned24)a & MASK24) >> s;
      result = OB_CLAMP(t);
    }
  return result;
}


static const QH_ROUND qh_round[] = {
  RNASQH, RNAUQH, RNESQH, RNEUQH, RZSQH,  RZUQH
};

static const OB_ROUND ob_round[] = {
  NULL,   RNAUOB, NULL,   RNEUOB, NULL,   RZUOB
};


static unsigned64
qh_vector_round(sim_cpu *cpu, address_word cia, unsigned64 v2, QH_ROUND round)
{
  unsigned64 result = 0;
  int  i, s;
  signed16 h, h2;

  s = 0;
  for (i = 0; i < 4; i++)
    {
      h2 = (signed16)(v2 & 0xFFFF);
      if (h2 >= 0)
	h = (*round)(ACC.qh[i], h2);
      else
	{
	  UnpredictableResult ();
	  h = 0xdead;
	}
      v2 >>= 16;
      result |= ((unsigned64)((unsigned16)h) << s);
      s += 16;
    }
  return result;
}

static unsigned64
qh_map_round(sim_cpu *cpu, address_word cia, signed16 h2, QH_ROUND round)
{
  unsigned64 result = 0;
  int  i, s;
  signed16  h;

  s = 0;
  for (i = 0; i < 4; i++)
    {
      if (h2 >= 0)
	h = (*round)(ACC.qh[i], h2);
      else
	{
	  UnpredictableResult ();
	  h = 0xdead;
	}
      result |= ((unsigned64)((unsigned16)h) << s);
      s += 16;
    }
  return result;
}

static unsigned64
ob_vector_round(sim_cpu *cpu, address_word cia, unsigned64 v2, OB_ROUND round)
{
  unsigned64 result = 0;
  int  i, s;
  unsigned8 b, b2;

  s = 0;
  for (i = 0; i < 8; i++)
    {
      b2 = v2 & 0xFF;  v2 >>= 8;
      b = (*round)(ACC.ob[i], b2);
      result |= ((unsigned64)b << s);
      s += 8;
    }
  return result;
}

static unsigned64
ob_map_round(sim_cpu *cpu, address_word cia, unsigned8 b2, OB_ROUND round)
{
  unsigned64 result = 0;
  int  i, s;
  unsigned8 b;

  s = 0;
  for (i = 0; i < 8; i++)
    {
      b = (*round)(ACC.ob[i], b2);
      result |= ((unsigned64)b << s);
      s += 8;
    }
  return result;
}


unsigned64
mdmx_round_op(sim_cpu *cpu,
	      address_word cia,
	      int rm,
	      int vt,
	      MX_fmtsel fmtsel) 
{
  unsigned64 op2;
  unsigned64 result = 0;

  switch (MX_FMT (fmtsel))
    {
    case mdmx_qh:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = qh_map_round(cpu, cia, QH_ELEM(op2, fmtsel), qh_round[rm]);
	  break;
	case sel_vect:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = qh_vector_round(cpu, cia, op2, qh_round[rm]);
	  break;
	case sel_imm:
	  result = qh_map_round(cpu, cia, vt, qh_round[rm]);
	  break;
	}
      break;
    case mdmx_ob:
      switch (MX_VT (fmtsel))
	{
	case sel_elem:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = ob_map_round(cpu, cia, OB_ELEM(op2, fmtsel), ob_round[rm]);
	  break;
	case sel_vect:
	  op2 = ValueFPR(vt, fmt_mdmx);
	  result = ob_vector_round(cpu, cia, op2, ob_round[rm]);
	  break;
	case sel_imm:
	  result = ob_map_round(cpu, cia, vt, ob_round[rm]);
	  break;
	}
      break;
    default:
      Unpredictable ();
    }

  return result;
}


/* Shuffle operation.  */

typedef struct {
  enum {vs, ss, vt} source;
  unsigned int      index;
} sh_map;

static const sh_map ob_shuffle[][8] = {
  /* MDMX 2.0 encodings (3-4, 6-7).  */
  /* vr5400   encoding  (5), otherwise.  */
  {                                                              }, /* RSVD */
  {{vt,4}, {vs,4}, {vt,5}, {vs,5}, {vt,6}, {vs,6}, {vt,7}, {vs,7}}, /* RSVD */
  {{vt,0}, {vs,0}, {vt,1}, {vs,1}, {vt,2}, {vs,2}, {vt,3}, {vs,3}}, /* RSVD */
  {{vs,0}, {ss,0}, {vs,1}, {ss,1}, {vs,2}, {ss,2}, {vs,3}, {ss,3}}, /* upsl */
  {{vt,1}, {vt,3}, {vt,5}, {vt,7}, {vs,1}, {vs,3}, {vs,5}, {vs,7}}, /* pach */
  {{vt,0}, {vt,2}, {vt,4}, {vt,6}, {vs,0}, {vs,2}, {vs,4}, {vs,6}}, /* pacl */
  {{vt,4}, {vs,4}, {vt,5}, {vs,5}, {vt,6}, {vs,6}, {vt,7}, {vs,7}}, /* mixh */
  {{vt,0}, {vs,0}, {vt,1}, {vs,1}, {vt,2}, {vs,2}, {vt,3}, {vs,3}}  /* mixl */
};

static const sh_map qh_shuffle[][4] = {
  {{vt,2}, {vs,2}, {vt,3}, {vs,3}},  /* mixh */
  {{vt,0}, {vs,0}, {vt,1}, {vs,1}},  /* mixl */
  {{vt,1}, {vt,3}, {vs,1}, {vs,3}},  /* pach */
  {                              },  /* RSVD */
  {{vt,1}, {vs,0}, {vt,3}, {vs,2}},  /* bfla */
  {                              },  /* RSVD */
  {{vt,2}, {vt,3}, {vs,2}, {vs,3}},  /* repa */
  {{vt,0}, {vt,1}, {vs,0}, {vs,1}}   /* repb */
};


unsigned64
mdmx_shuffle(sim_cpu *cpu,
	     address_word cia,
	     int shop,
	     unsigned64 op1,
	     unsigned64 op2)
{
  unsigned64 result = 0;
  int  i, s;
  int  op;

  if ((shop & 0x3) == 0x1)       /* QH format.  */
    {
      op = shop >> 2;
      s = 0;
      for (i = 0; i < 4; i++)
	{
	  unsigned64 v;

	  switch (qh_shuffle[op][i].source)
	    {
	    case vs:
	      v = op1;
	      break;
	    case vt:
	      v = op2;
	      break;
	    default:
	      Unpredictable ();
	      v = 0;
	    }
	  result |= (((v >> 16*qh_shuffle[op][i].index) & 0xFFFF) << s);
	  s += 16;
	}
    }
  else if ((shop & 0x1) == 0x0)  /* OB format.  */
    {
      op = shop >> 1;
      s = 0;
      for (i = 0; i < 8; i++)
	{
	  unsigned8 b;
	  unsigned int ishift = 8*ob_shuffle[op][i].index;

	  switch (ob_shuffle[op][i].source)
	    {
	    case vs:
	      b = (op1 >> ishift) & 0xFF;
	      break;
	    case ss:
	      b = ((op1 >> ishift) & 0x80) ? 0xFF : 0;
	      break;
	    case vt:
	      b = (op2 >> ishift) & 0xFF;
	      break;
	    default:
	      Unpredictable ();
	      b = 0;
	    }
	  result |= ((unsigned64)b << s);
	  s += 8;
	}
    }
  else
    Unpredictable ();

  return result;
}