/* reg.c --- register set model for M32C simulator.

Copyright (C) 2005-2021 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/>.  */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "cpu.h"

int verbose = 0;
int trace = 0;
int enable_counting = 0;
int in_gdb = 1;

regs_type regs;
int addr_mask = 0xffff;
int membus_mask = 0xfffff;
int m32c_cpu = 0;
int step_result;
unsigned int heapbottom = 0;
unsigned int heaptop = 0;

char *reg_names[] = {
  "mem",
  "r0", "r0h", "r0l",
  "r1", "r1h", "r1l",
  "r2", "r2r0",
  "r3", "r3r1",
  "r3r1r2r0",
  "r3r2r1r0",
  "a0",
  "a1", "a1a0",
  "sb", "fb",
  "intb", "intbl", "intbh",
  "sp", "usp", "isp", "pc", "flags"
};

int reg_bytes[] = {
  0,
  2, 1, 1,
  2, 1, 1,
  2, 4,
  2, 4,
  8,
  8,
  2,
  2, 4,
  2, 2,
  2, 1, 3,
  2, 2, 2, 3, 2
};


unsigned int b2mask[] = { 0, 0xff, 0xffff, 0xffffff, 0xffffffff };
unsigned int b2signbit[] = { 0, (1 << 7), (1 << 15), (1 << 24), (1 << 31) };
int b2maxsigned[] = { 0, 0x7f, 0x7fff, 0x7fffff, 0x7fffffff };
int b2minsigned[] = { 0, -128, -32768, -8388608, -2147483647 - 1 };

static regs_type oldregs;

int m32c_opcode_pc;

void
init_regs (void)
{
  memset (&regs, 0, sizeof (regs));
  memset (&oldregs, 0, sizeof (oldregs));
}

void
set_pointer_width (int bytes)
{
  if (bytes == 2)
    {
      addr_mask = 0xffff;
      membus_mask = 0x000fffff;
      reg_bytes[a0] = reg_bytes[a1] = reg_bytes[sb] = reg_bytes[fb] =
	reg_bytes[sp] = reg_bytes[usp] = reg_bytes[isp] = 2;
    }
  else
    {
      addr_mask = 0xffffff;
      membus_mask = 0x00ffffff;
      reg_bytes[a0] = reg_bytes[a1] = reg_bytes[sb] = reg_bytes[fb] =
	reg_bytes[sp] = reg_bytes[usp] = reg_bytes[isp] = 3;
    }
}

void
m32c_set_cpu (int cpu)
{
  switch (cpu)
    {
    case CPU_R8C:
    case CPU_M16C:
      set_pointer_width (2);
      decode_opcode = decode_r8c;
      break;
    case CPU_M32CM:
    case CPU_M32C:
      set_pointer_width (3);
      decode_opcode = decode_m32c;
      break;
    default:
      abort ();
    }
  m32c_cpu = cpu;
}

static unsigned int
get_reg_i (reg_id id)
{
  reg_bank_type *b = regs.r + (FLAG_B ? 1 : 0);

  switch (id)
    {
    case r0:
      return b->r_r0;
    case r0h:
      return b->r_r0 >> 8;
    case r0l:
      return b->r_r0 & 0xff;
    case r1:
      return b->r_r1;
    case r1h:
      return b->r_r1 >> 8;
    case r1l:
      return b->r_r1 & 0xff;
    case r2:
      return b->r_r2;
    case r2r0:
      return b->r_r2 * 65536 + b->r_r0;
    case r3:
      return b->r_r3;
    case r3r1:
      return b->r_r3 * 65536 + b->r_r1;

    case a0:
      return b->r_a0 & addr_mask;
    case a1:
      return b->r_a1 & addr_mask;
    case a1a0:
      return (b->r_a1 & 0xffff) * 65536 | (b->r_a0 & 0xffff);

    case sb:
      return b->r_sb & addr_mask;
    case fb:
      return b->r_fb & addr_mask;

    case intb:
      return regs.r_intbh * 65536 + regs.r_intbl;
    case intbl:
      return regs.r_intbl;
    case intbh:
      return regs.r_intbh;

    case sp:
      return ((regs.r_flags & FLAGBIT_U) ? regs.r_usp : regs.
	      r_isp) & addr_mask;
    case usp:
      return regs.r_usp & addr_mask;
    case isp:
      return regs.r_isp & addr_mask;

    case pc:
      return regs.r_pc & membus_mask;
    case flags:
      return regs.r_flags;
    default:
      abort ();
    }
}

unsigned int
get_reg (reg_id id)
{
  unsigned int rv = get_reg_i (id);
  if (trace > ((id != pc && id != fb && id != sp) ? 0 : 1))
    printf ("get_reg (%s) = %0*x\n", reg_names[id], reg_bytes[id] * 2, rv);
  return rv;
}

DI
get_reg_ll (reg_id id)
{
  reg_bank_type *b = regs.r + (FLAG_B ? 1 : 0);

  switch (id)
    {
    case r3r1r2r0:
      return ((DI) b->r_r3 << 48
	      | (DI) b->r_r1 << 32 | (DI) b->r_r2 << 16 | (DI) b->r_r0);
    case r3r2r1r0:
      return ((DI) b->r_r3 << 48
	      | (DI) b->r_r2 << 32 | (DI) b->r_r1 << 16 | (DI) b->r_r0);
    default:
      return get_reg (id);
    }
}

static int highest_sp = 0, lowest_sp = 0xffffff;

void
stack_heap_stats (void)
{
  printf ("heap:  %08x - %08x (%d bytes)\n", heapbottom, heaptop,
	  heaptop - heapbottom);
  printf ("stack: %08x - %08x (%d bytes)\n", lowest_sp, highest_sp,
	  highest_sp - lowest_sp);
}

void
put_reg (reg_id id, unsigned int v)
{
  reg_bank_type *b = regs.r + (FLAG_B ? 1 : 0);

  if (trace > ((id != pc) ? 0 : 1))
    printf ("put_reg (%s) = %0*x\n", reg_names[id], reg_bytes[id] * 2, v);

  switch (id)
    {
    case r0:
      b->r_r0 = v;
      break;
    case r0h:
      b->r_r0 = (b->r_r0 & 0xff) | (v << 8);
      break;
    case r0l:
      b->r_r0 = (b->r_r0 & 0xff00) | (v & 0xff);
      break;
    case r1:
      b->r_r1 = v;
      break;
    case r1h:
      b->r_r1 = (b->r_r1 & 0xff) | (v << 8);
      break;
    case r1l:
      b->r_r1 = (b->r_r1 & 0xff00) | (v & 0xff);
      break;
    case r2:
      b->r_r2 = v;
      break;
    case r2r0:
      b->r_r0 = v & 0xffff;
      b->r_r2 = v >> 16;
      break;
    case r3:
      b->r_r3 = v;
      break;
    case r3r1:
      b->r_r1 = v & 0xffff;
      b->r_r3 = v >> 16;
      break;

    case a0:
      b->r_a0 = v & addr_mask;
      break;
    case a1:
      b->r_a1 = v & addr_mask;
      break;
    case a1a0:
      b->r_a0 = v & 0xffff;
      b->r_a1 = v >> 16;
      break;

    case sb:
      b->r_sb = v & addr_mask;
      break;
    case fb:
      b->r_fb = v & addr_mask;
      break;

    case intb:
      regs.r_intbl = v & 0xffff;
      regs.r_intbh = v >> 16;
      break;
    case intbl:
      regs.r_intbl = v & 0xffff;
      break;
    case intbh:
      regs.r_intbh = v & 0xff;
      break;

    case sp:
      {
	SI *spp;
	if (regs.r_flags & FLAGBIT_U)
	  spp = &regs.r_usp;
	else
	  spp = &regs.r_isp;
	*spp = v & addr_mask;
	if (*spp < heaptop)
	  {
	    printf ("collision: pc %08lx heap %08x stack %08lx\n", regs.r_pc,
		    heaptop, *spp);
	    exit (1);
	  }
	if (*spp < lowest_sp)
	  lowest_sp = *spp;
	if (*spp > highest_sp)
	  highest_sp = *spp;
	break;
      }
    case usp:
      regs.r_usp = v & addr_mask;
      break;
    case isp:
      regs.r_isp = v & addr_mask;
      break;

    case pc:
      regs.r_pc = v & membus_mask;
      break;
    case flags:
      regs.r_flags = v;
      break;
    default:
      abort ();
    }
}

int
condition_true (int cond_id)
{
  int f;
  if (A16)
    {
      static const char *cond_name[] = {
	"C", "C&!Z", "Z", "S",
	"!C", "!(C&!Z)", "!Z", "!S",
	"(S^O)|Z", "O", "!(S^O)", "unk",
	"!((S^O)|Z)", "!O", "S^O", "unk"
      };
      switch (cond_id & 15)
	{
	case 0:
	  f = FLAG_C;
	  break;		/* GEU/C */
	case 1:
	  f = FLAG_C & !FLAG_Z;
	  break;		/* GTU */
	case 2:
	  f = FLAG_Z;
	  break;		/* EQ/Z */
	case 3:
	  f = FLAG_S;
	  break;		/* N */
	case 4:
	  f = !FLAG_C;
	  break;		/* LTU/NC */
	case 5:
	  f = !(FLAG_C & !FLAG_Z);
	  break;		/* LEU */
	case 6:
	  f = !FLAG_Z;
	  break;		/* NE/NZ */
	case 7:
	  f = !FLAG_S;
	  break;		/* PZ */

	case 8:
	  f = (FLAG_S ^ FLAG_O) | FLAG_Z;
	  break;		/* LE */
	case 9:
	  f = FLAG_O;
	  break;		/* O */
	case 10:
	  f = !(FLAG_S ^ FLAG_O);
	  break;		/* GE */
	case 12:
	  f = !((FLAG_S ^ FLAG_O) | FLAG_Z);
	  break;		/* GT */
	case 13:
	  f = !FLAG_O;
	  break;		/* NO */
	case 14:
	  f = FLAG_S ^ FLAG_O;
	  break;		/* LT */

	default:
	  f = 0;
	  break;
	}
      if (trace)
	printf ("cond[%d] %s = %s\n", cond_id, cond_name[cond_id & 15],
		f ? "true" : "false");
    }
  else
    {
      static const char *cond_name[] = {
	"!C", "LEU", "!Z", "PZ",
	"!O", "GT", "GE", "?",
	"C", "GTU", "Z", "N",
	"O", "LE", "LT", "!?"
      };
      switch (cond_id & 15)
	{
	case 0:
	  f = !FLAG_C;
	  break;		/* LTU/NC */
	case 1:
	  f = !(FLAG_C & !FLAG_Z);
	  break;		/* LEU */
	case 2:
	  f = !FLAG_Z;
	  break;		/* NE/NZ */
	case 3:
	  f = !FLAG_S;
	  break;		/* PZ */

	case 4:
	  f = !FLAG_O;
	  break;		/* NO */
	case 5:
	  f = !((FLAG_S ^ FLAG_O) | FLAG_Z);
	  break;		/* GT */
	case 6:
	  f = !(FLAG_S ^ FLAG_O);
	  break;		/* GE */

	case 8:
	  f = FLAG_C;
	  break;		/* GEU/C */
	case 9:
	  f = FLAG_C & !FLAG_Z;
	  break;		/* GTU */
	case 10:
	  f = FLAG_Z;
	  break;		/* EQ/Z */
	case 11:
	  f = FLAG_S;
	  break;		/* N */

	case 12:
	  f = FLAG_O;
	  break;		/* O */
	case 13:
	  f = (FLAG_S ^ FLAG_O) | FLAG_Z;
	  break;		/* LE */
	case 14:
	  f = FLAG_S ^ FLAG_O;
	  break;		/* LT */

	default:
	  f = 0;
	  break;
	}
      if (trace)
	printf ("cond[%d] %s = %s\n", cond_id, cond_name[cond_id & 15],
		f ? "true" : "false");
    }
  return f;
}

void
set_flags (int mask, int newbits)
{
  int i;
  regs.r_flags &= ~mask;
  regs.r_flags |= newbits & mask;
  if (trace)
    {
      printf ("flags now \033[32m %d", (regs.r_flags >> (A16 ? 8 : 12)) & 7);
      for (i = 7; i >= 0; i--)
	if (regs.r_flags & (1 << i))
	  putchar ("CDZSBOIU"[i]);
	else
	  putchar ('-');
      printf ("\033[0m\n");
    }
}

void
set_oszc (int value, int b, int c)
{
  int mask = b2mask[b];
  int f = 0;

  if (c)
    f |= FLAGBIT_C;
  if ((value & mask) == 0)
    f |= FLAGBIT_Z;
  if (value & b2signbit[b])
    f |= FLAGBIT_S;
  if ((value > b2maxsigned[b]) || (value < b2minsigned[b]))
    f |= FLAGBIT_O;
  set_flags (FLAGBIT_Z | FLAGBIT_S | FLAGBIT_O | FLAGBIT_C, f);
}

void
set_szc (int value, int b, int c)
{
  int mask = b2mask[b];
  int f = 0;

  if (c)
    f |= FLAGBIT_C;
  if ((value & mask) == 0)
    f |= FLAGBIT_Z;
  if (value & b2signbit[b])
    f |= FLAGBIT_S;
  set_flags (FLAGBIT_Z | FLAGBIT_S | FLAGBIT_C, f);
}

void
set_osz (int value, int b)
{
  int mask = b2mask[b];
  int f = 0;

  if ((value & mask) == 0)
    f |= FLAGBIT_Z;
  if (value & b2signbit[b])
    f |= FLAGBIT_S;
  if (value & ~mask && (value & ~mask) != ~mask)
    f |= FLAGBIT_O;
  set_flags (FLAGBIT_Z | FLAGBIT_S | FLAGBIT_O, f);
}

void
set_sz (int value, int b)
{
  int mask = b2mask[b];
  int f = 0;

  if ((value & mask) == 0)
    f |= FLAGBIT_Z;
  if (value & b2signbit[b])
    f |= FLAGBIT_S;
  set_flags (FLAGBIT_Z | FLAGBIT_S, f);
}

void
set_zc (int z, int c)
{
  set_flags (FLAGBIT_C | FLAGBIT_Z,
	     (c ? FLAGBIT_C : 0) | (z ? FLAGBIT_Z : 0));
}

void
set_c (int c)
{
  set_flags (FLAGBIT_C, c ? FLAGBIT_C : 0);
}

void
put_reg_ll (reg_id id, DI v)
{
  reg_bank_type *b = regs.r + (FLAG_B ? 1 : 0);

  switch (id)
    {
    case r3r1r2r0:
      b->r_r3 = v >> 48;
      b->r_r1 = v >> 32;
      b->r_r2 = v >> 16;
      b->r_r0 = v;
      break;
    case r3r2r1r0:
      b->r_r3 = v >> 48;
      b->r_r2 = v >> 32;
      b->r_r1 = v >> 16;
      b->r_r0 = v;
      break;
    default:
      put_reg (id, v);
    }
}

static void
print_flags (int f)
{
  int i;
  static char fn[] = "CDZSBOIU";
  printf ("%d.", (f >> 12) & 7);
  for (i = 7; i >= 0; i--)
    if (f & (1 << i))
      putchar (fn[i]);
}

#define TRC(f,n, id) \
  if (oldregs.f != regs.f) \
    { \
      printf("  %s %0*x:%0*x", n, \
	     reg_bytes[id]*2, (unsigned int)oldregs.f, \
	     reg_bytes[id]*2, (unsigned int)regs.f); \
      oldregs.f = regs.f; \
    }

void
trace_register_changes (void)
{
  if (!trace)
    return;
  printf ("\033[36mREGS:");
  TRC (r[0].r_r0, "r0", r0);
  TRC (r[0].r_r1, "r1", r1);
  TRC (r[0].r_r2, "r2", r2);
  TRC (r[0].r_r3, "r3", r3);
  TRC (r[0].r_a0, "a0", a0);
  TRC (r[0].r_a1, "a1", a1);
  TRC (r[0].r_sb, "sb", sb);
  TRC (r[0].r_fb, "fb", fb);
  TRC (r[1].r_r0, "r0'", r0);
  TRC (r[1].r_r1, "r1'", r1);
  TRC (r[1].r_r2, "r2'", r2);
  TRC (r[1].r_r3, "r3'", r3);
  TRC (r[1].r_a0, "a0'", a0);
  TRC (r[1].r_a1, "a1'", a1);
  TRC (r[1].r_sb, "sb'", sb);
  TRC (r[1].r_fb, "fb'", fb);
  TRC (r_intbh, "intbh", intbh);
  TRC (r_intbl, "intbl", intbl);
  TRC (r_usp, "usp", usp);
  TRC (r_isp, "isp", isp);
  TRC (r_pc, "pc", pc);
  if (oldregs.r_flags != regs.r_flags)
    {
      printf ("  flags ");
      print_flags (oldregs.r_flags);
      printf (":");
      print_flags (regs.r_flags);
    }
  printf ("\033[0m\n");
}

#define DRC(f, n, id) \
  printf("  %-3s %0*x", n,			       \
	 reg_bytes[id]*2, (unsigned int)regs.f);       \

void
m32c_dump_all_registers (void)
{
  printf ("\033[36mREGS:");
  DRC (r[0].r_r0, "r0", r0);
  DRC (r[0].r_r1, "r1", r1);
  DRC (r[0].r_r2, "r2", r2);
  DRC (r[0].r_r3, "r3", r3);
  DRC (r[0].r_a0, "a0", a0);
  DRC (r[0].r_a1, "a1", a1);
  DRC (r[0].r_sb, "sb", sb);
  DRC (r[0].r_fb, "fb", fb);
  printf ("\n     ");
  DRC (r[1].r_r0, "r0'", r0);
  DRC (r[1].r_r1, "r1'", r1);
  DRC (r[1].r_r2, "r2'", r2);
  DRC (r[1].r_r3, "r3'", r3);
  DRC (r[1].r_a0, "a0'", a0);
  DRC (r[1].r_a1, "a1'", a1);
  DRC (r[1].r_sb, "sb'", sb);
  DRC (r[1].r_fb, "fb'", fb);
  printf ("     \n");
  DRC (r_intbh, "intbh", intbh);
  DRC (r_intbl, "intbl", intbl);
  DRC (r_usp, "usp", usp);
  DRC (r_isp, "isp", isp);
  DRC (r_pc, "pc", pc);
  printf ("  flags ");
  print_flags (regs.r_flags);
  printf ("\033[0m\n");
  /*sim_disasm_one (); */
}