19990502 sourceware importbinu_ss_19990502

1 files changed, 711 insertions, 0 deletions

diff --git a/opcodes/tic30-dis.c b/opcodes/tic30-dis.c
new file mode 100644
index 0000000..1051457
--- /dev/null
+++ b/opcodes/tic30-dis.c
@@ -0,0 +1,711 @@
+/* Disassembly routines for TMS320C30 architecture
+   Copyright (C) 1998 Free Software Foundation, Inc.
+   Contributed by Steven Haworth (steve@pm.cse.rmit.edu.au)
+
+   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 <errno.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include "dis-asm.h"
+#include "opcode/tic30.h"
+
+#define NORMAL_INSN   1
+#define PARALLEL_INSN 2
+
+/* Gets the type of instruction based on the top 2 or 3 bits of the
+   instruction word. */
+#define GET_TYPE(insn) (insn & 0x80000000 ? insn & 0xC0000000 : insn & 0xE0000000)
+
+/* Instruction types. */
+#define TWO_OPERAND_1 0x00000000
+#define TWO_OPERAND_2 0x40000000
+#define THREE_OPERAND 0x20000000
+#define PAR_STORE     0xC0000000
+#define MUL_ADDS      0x80000000
+#define BRANCHES      0x60000000
+
+/* Specific instruction id bits. */
+#define NORMAL_IDEN    0x1F800000
+#define PAR_STORE_IDEN 0x3E000000
+#define MUL_ADD_IDEN   0x2C000000
+#define BR_IMM_IDEN    0x1F000000
+#define BR_COND_IDEN   0x1C3F0000
+
+/* Addressing modes. */
+#define AM_REGISTER 0x00000000
+#define AM_DIRECT   0x00200000
+#define AM_INDIRECT 0x00400000
+#define AM_IMM      0x00600000
+
+#define P_FIELD 0x03000000
+
+#define REG_AR0 0x08
+#define LDP_INSN 0x08700000
+
+/* TMS320C30 program counter for current instruction. */
+static unsigned int _pc;
+
+struct instruction
+  {
+    int type;
+    template *tm;
+    partemplate *ptm;
+  };
+
+int get_tic30_instruction PARAMS ((unsigned long, struct instruction *));
+int print_two_operand
+  PARAMS ((disassemble_info *, unsigned long, struct instruction *));
+int print_three_operand
+  PARAMS ((disassemble_info *, unsigned long, struct instruction *));
+int print_par_insn
+  PARAMS ((disassemble_info *, unsigned long, struct instruction *));
+int print_branch
+  PARAMS ((disassemble_info *, unsigned long, struct instruction *));
+int get_indirect_operand PARAMS ((unsigned short, int, char *));
+int get_register_operand PARAMS ((unsigned char, char *));
+int cnvt_tmsfloat_ieee PARAMS ((unsigned long, int, float *));
+
+int
+print_insn_tic30 (pc, info)
+     bfd_vma pc;
+     disassemble_info *info;
+{
+  unsigned long insn_word;
+  struct instruction insn =
+  {0, NULL, NULL};
+  bfd_vma bufaddr = pc - info->buffer_vma;
+  /* Obtain the current instruction word from the buffer. */
+  insn_word = (*(info->buffer + bufaddr) << 24) | (*(info->buffer + bufaddr + 1) << 16) |
+    (*(info->buffer + bufaddr + 2) << 8) | *(info->buffer + bufaddr + 3);
+  _pc = pc / 4;
+  /* Get the instruction refered to by the current instruction word
+     and print it out based on its type. */
+  if (!get_tic30_instruction (insn_word, &insn))
+    return -1;
+  switch (GET_TYPE (insn_word))
+    {
+    case TWO_OPERAND_1:
+    case TWO_OPERAND_2:
+      if (!print_two_operand (info, insn_word, &insn))
+	return -1;
+      break;
+    case THREE_OPERAND:
+      if (!print_three_operand (info, insn_word, &insn))
+	return -1;
+      break;
+    case PAR_STORE:
+    case MUL_ADDS:
+      if (!print_par_insn (info, insn_word, &insn))
+	return -1;
+      break;
+    case BRANCHES:
+      if (!print_branch (info, insn_word, &insn))
+	return -1;
+      break;
+    }
+  return 4;
+}
+
+int
+get_tic30_instruction (insn_word, insn)
+     unsigned long insn_word;
+     struct instruction *insn;
+{
+  switch (GET_TYPE (insn_word))
+    {
+    case TWO_OPERAND_1:
+    case TWO_OPERAND_2:
+    case THREE_OPERAND:
+      insn->type = NORMAL_INSN;
+      {
+	template *current_optab = (template *) tic30_optab;
+	for (; current_optab < tic30_optab_end; current_optab++)
+	  {
+	    if (GET_TYPE (current_optab->base_opcode) == GET_TYPE (insn_word))
+	      {
+		if (current_optab->operands == 0)
+		  {
+		    if (current_optab->base_opcode == insn_word)
+		      {
+			insn->tm = current_optab;
+			break;
+		      }
+		  }
+		else if ((current_optab->base_opcode & NORMAL_IDEN) == (insn_word & NORMAL_IDEN))
+		  {
+		    insn->tm = current_optab;
+		    break;
+		  }
+	      }
+	  }
+      }
+      break;
+    case PAR_STORE:
+      insn->type = PARALLEL_INSN;
+      {
+	partemplate *current_optab = (partemplate *) tic30_paroptab;
+	for (; current_optab < tic30_paroptab_end; current_optab++)
+	  {
+	    if (GET_TYPE (current_optab->base_opcode) == GET_TYPE (insn_word))
+	      {
+		if ((current_optab->base_opcode & PAR_STORE_IDEN) == (insn_word & PAR_STORE_IDEN))
+		  {
+		    insn->ptm = current_optab;
+		    break;
+		  }
+	      }
+	  }
+      }
+      break;
+    case MUL_ADDS:
+      insn->type = PARALLEL_INSN;
+      {
+	partemplate *current_optab = (partemplate *) tic30_paroptab;
+	for (; current_optab < tic30_paroptab_end; current_optab++)
+	  {
+	    if (GET_TYPE (current_optab->base_opcode) == GET_TYPE (insn_word))
+	      {
+		if ((current_optab->base_opcode & MUL_ADD_IDEN) == (insn_word & MUL_ADD_IDEN))
+		  {
+		    insn->ptm = current_optab;
+		    break;
+		  }
+	      }
+	  }
+      }
+      break;
+    case BRANCHES:
+      insn->type = NORMAL_INSN;
+      {
+	template *current_optab = (template *) tic30_optab;
+	for (; current_optab < tic30_optab_end; current_optab++)
+	  {
+	    if (GET_TYPE (current_optab->base_opcode) == GET_TYPE (insn_word))
+	      {
+		if (current_optab->operand_types[0] & Imm24)
+		  {
+		    if ((current_optab->base_opcode & BR_IMM_IDEN) == (insn_word & BR_IMM_IDEN))
+		      {
+			insn->tm = current_optab;
+			break;
+		      }
+		  }
+		else if (current_optab->operands > 0)
+		  {
+		    if ((current_optab->base_opcode & BR_COND_IDEN) == (insn_word & BR_COND_IDEN))
+		      {
+			insn->tm = current_optab;
+			break;
+		      }
+		  }
+		else
+		  {
+		    if ((current_optab->base_opcode & (BR_COND_IDEN | 0x00800000)) == (insn_word & (BR_COND_IDEN | 0x00800000)))
+		      {
+			insn->tm = current_optab;
+			break;
+		      }
+		  }
+	      }
+	  }
+      }
+      break;
+    default:
+      return 0;
+    }
+  return 1;
+}
+
+int
+print_two_operand (info, insn_word, insn)
+     disassemble_info *info;
+     unsigned long insn_word;
+     struct instruction *insn;
+{
+  char name[12];
+  char operand[2][13] =
+  {
+    {0},
+    {0}};
+  float f_number;
+
+  if (insn->tm == NULL)
+    return 0;
+  strcpy (name, insn->tm->name);
+  if (insn->tm->opcode_modifier == AddressMode)
+    {
+      int src_op, dest_op;
+      /* Determine whether instruction is a store or a normal instruction. */
+      if ((insn->tm->operand_types[1] & (Direct | Indirect)) == (Direct | Indirect))
+	{
+	  src_op = 1;
+	  dest_op = 0;
+	}
+      else
+	{
+	  src_op = 0;
+	  dest_op = 1;
+	}
+      /* Get the destination register. */
+      if (insn->tm->operands == 2)
+	get_register_operand ((insn_word & 0x001F0000) >> 16, operand[dest_op]);
+      /* Get the source operand based on addressing mode. */
+      switch (insn_word & AddressMode)
+	{
+	case AM_REGISTER:
+	  /* Check for the NOP instruction before getting the operand. */
+	  if ((insn->tm->operand_types[0] & NotReq) == 0)
+	    get_register_operand ((insn_word & 0x0000001F), operand[src_op]);
+	  break;
+	case AM_DIRECT:
+	  sprintf (operand[src_op], "@0x%lX", (insn_word & 0x0000FFFF));
+	  break;
+	case AM_INDIRECT:
+	  get_indirect_operand ((insn_word & 0x0000FFFF), 2, operand[src_op]);
+	  break;
+	case AM_IMM:
+	  /* Get the value of the immediate operand based on variable type. */
+	  switch (insn->tm->imm_arg_type)
+	    {
+	    case Imm_Float:
+	      cnvt_tmsfloat_ieee ((insn_word & 0x0000FFFF), 2, &f_number);
+	      sprintf (operand[src_op], "%2.2f", f_number);
+	      break;
+	    case Imm_SInt:
+	      sprintf (operand[src_op], "%d", (short) (insn_word & 0x0000FFFF));
+	      break;
+	    case Imm_UInt:
+	      sprintf (operand[src_op], "%lu", (insn_word & 0x0000FFFF));
+	      break;
+	    default:
+	      return 0;
+	    }
+	  /* Handle special case for LDP instruction. */
+	  if ((insn_word & 0xFFFFFF00) == LDP_INSN)
+	    {
+	      strcpy (name, "ldp");
+	      sprintf (operand[0], "0x%06lX", (insn_word & 0x000000FF) << 16);
+	      operand[1][0] = '\0';
+	    }
+	}
+    }
+  /* Handle case for stack and rotate instructions. */
+  else if (insn->tm->operands == 1)
+    {
+      if (insn->tm->opcode_modifier == StackOp)
+	{
+	  get_register_operand ((insn_word & 0x001F0000) >> 16, operand[0]);
+	}
+    }
+  /* Output instruction to stream. */
+  info->fprintf_func (info->stream, "   %s %s%c%s", name,
+		      operand[0][0] ? operand[0] : "",
+		      operand[1][0] ? ',' : ' ',
+		      operand[1][0] ? operand[1] : "");
+  return 1;
+}
+
+int
+print_three_operand (info, insn_word, insn)
+     disassemble_info *info;
+     unsigned long insn_word;
+     struct instruction *insn;
+{
+  char operand[3][13] =
+  {
+    {0},
+    {0},
+    {0}};
+
+  if (insn->tm == NULL)
+    return 0;
+  switch (insn_word & AddressMode)
+    {
+    case AM_REGISTER:
+      get_register_operand ((insn_word & 0x000000FF), operand[0]);
+      get_register_operand ((insn_word & 0x0000FF00) >> 8, operand[1]);
+      break;
+    case AM_DIRECT:
+      get_register_operand ((insn_word & 0x000000FF), operand[0]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1]);
+      break;
+    case AM_INDIRECT:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0]);
+      get_register_operand ((insn_word & 0x0000FF00) >> 8, operand[1]);
+      break;
+    case AM_IMM:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1]);
+      break;
+    default:
+      return 0;
+    }
+  if (insn->tm->operands == 3)
+    get_register_operand ((insn_word & 0x001F0000) >> 16, operand[2]);
+  info->fprintf_func (info->stream, "   %s %s,%s%c%s", insn->tm->name,
+		      operand[0], operand[1],
+		      operand[2][0] ? ',' : ' ',
+		      operand[2][0] ? operand[2] : "");
+  return 1;
+}
+
+int
+print_par_insn (info, insn_word, insn)
+     disassemble_info *info;
+     unsigned long insn_word;
+     struct instruction *insn;
+{
+  size_t i, len;
+  char *name1, *name2;
+  char operand[2][3][13] =
+  {
+    {
+      {0},
+      {0},
+      {0}},
+    {
+      {0},
+      {0},
+      {0}}};
+
+  if (insn->ptm == NULL)
+    return 0;
+  /* Parse out the names of each of the parallel instructions from the
+     q_insn1_insn2 format. */
+  name1 = (char *) strdup (insn->ptm->name + 2);
+  name2 = "";
+  len = strlen (name1);
+  for (i = 0; i < len; i++)
+    {
+      if (name1[i] == '_')
+	{
+	  name2 = &name1[i + 1];
+	  name1[i] = '\0';
+	  break;
+	}
+    }
+  /* Get the operands of the instruction based on the operand order. */
+  switch (insn->ptm->oporder)
+    {
+    case OO_4op1:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0][0]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1][1]);
+      get_register_operand ((insn_word >> 16) & 0x07, operand[1][0]);
+      get_register_operand ((insn_word >> 22) & 0x07, operand[0][1]);
+      break;
+    case OO_4op2:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0][0]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1][0]);
+      get_register_operand ((insn_word >> 19) & 0x07, operand[1][1]);
+      get_register_operand ((insn_word >> 22) & 0x07, operand[0][1]);
+      break;
+    case OO_4op3:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0][1]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1][1]);
+      get_register_operand ((insn_word >> 16) & 0x07, operand[1][0]);
+      get_register_operand ((insn_word >> 22) & 0x07, operand[0][0]);
+      break;
+    case OO_5op1:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0][0]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1][1]);
+      get_register_operand ((insn_word >> 16) & 0x07, operand[1][0]);
+      get_register_operand ((insn_word >> 19) & 0x07, operand[0][1]);
+      get_register_operand ((insn_word >> 22) & 0x07, operand[0][2]);
+      break;
+    case OO_5op2:
+      get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0][1]);
+      get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1][1]);
+      get_register_operand ((insn_word >> 16) & 0x07, operand[1][0]);
+      get_register_operand ((insn_word >> 19) & 0x07, operand[0][0]);
+      get_register_operand ((insn_word >> 22) & 0x07, operand[0][2]);
+      break;
+    case OO_PField:
+      if (insn_word & 0x00800000)
+	get_register_operand (0x01, operand[0][2]);
+      else
+	get_register_operand (0x00, operand[0][2]);
+      if (insn_word & 0x00400000)
+	get_register_operand (0x03, operand[1][2]);
+      else
+	get_register_operand (0x02, operand[1][2]);
+      switch (insn_word & P_FIELD)
+	{
+	case 0x00000000:
+	  get_indirect_operand ((insn_word & 0x000000FF), 1, operand[0][1]);
+	  get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[0][0]);
+	  get_register_operand ((insn_word >> 16) & 0x07, operand[1][1]);
+	  get_register_operand ((insn_word >> 19) & 0x07, operand[1][0]);
+	  break;
+	case 0x01000000:
+	  get_indirect_operand ((insn_word & 0x000000FF), 1, operand[1][0]);
+	  get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[0][0]);
+	  get_register_operand ((insn_word >> 16) & 0x07, operand[1][1]);
+	  get_register_operand ((insn_word >> 19) & 0x07, operand[0][1]);
+	  break;
+	case 0x02000000:
+	  get_indirect_operand ((insn_word & 0x000000FF), 1, operand[1][1]);
+	  get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[1][0]);
+	  get_register_operand ((insn_word >> 16) & 0x07, operand[0][1]);
+	  get_register_operand ((insn_word >> 19) & 0x07, operand[0][0]);
+	  break;
+	case 0x03000000:
+	  get_indirect_operand ((insn_word & 0x000000FF), 1, operand[1][1]);
+	  get_indirect_operand ((insn_word & 0x0000FF00) >> 8, 1, operand[0][0]);
+	  get_register_operand ((insn_word >> 16) & 0x07, operand[1][0]);
+	  get_register_operand ((insn_word >> 19) & 0x07, operand[0][1]);
+	  break;
+	}
+      break;
+    default:
+      return 0;
+    }
+  info->fprintf_func (info->stream, "   %s %s,%s%c%s", name1,
+		      operand[0][0], operand[0][1],
+		      operand[0][2][0] ? ',' : ' ',
+		      operand[0][2][0] ? operand[0][2] : "");
+  info->fprintf_func (info->stream, "\n\t\t\t|| %s %s,%s%c%s", name2,
+		      operand[1][0], operand[1][1],
+		      operand[1][2][0] ? ',' : ' ',
+		      operand[1][2][0] ? operand[1][2] : "");
+  free (name1);
+  return 1;
+}
+
+int
+print_branch (info, insn_word, insn)
+     disassemble_info *info;
+     unsigned long insn_word;
+     struct instruction *insn;
+{
+  char operand[2][13] =
+  {
+    {0},
+    {0}};
+  unsigned long address;
+  int print_label = 0;
+
+  if (insn->tm == NULL)
+    return 0;
+  /* Get the operands for 24-bit immediate jumps. */
+  if (insn->tm->operand_types[0] & Imm24)
+    {
+      address = insn_word & 0x00FFFFFF;
+      sprintf (operand[0], "0x%lX", address);
+      print_label = 1;
+    }
+  /* Get the operand for the trap instruction. */
+  else if (insn->tm->operand_types[0] & IVector)
+    {
+      address = insn_word & 0x0000001F;
+      sprintf (operand[0], "0x%lX", address);
+    }
+  else
+    {
+      address = insn_word & 0x0000FFFF;
+      /* Get the operands for the DB instructions. */
+      if (insn->tm->operands == 2)
+	{
+	  get_register_operand (((insn_word & 0x01C00000) >> 22) + REG_AR0, operand[0]);
+	  if (insn_word & PCRel)
+	    {
+	      sprintf (operand[1], "%d", (short) address);
+	      print_label = 1;
+	    }
+	  else
+	    get_register_operand (insn_word & 0x0000001F, operand[1]);
+	}
+      /* Get the operands for the standard branches. */
+      else if (insn->tm->operands == 1)
+	{
+	  if (insn_word & PCRel)
+	    {
+	      address = (short) address;
+	      sprintf (operand[0], "%ld", address);
+	      print_label = 1;
+	    }
+	  else
+	    get_register_operand (insn_word & 0x0000001F, operand[0]);
+	}
+    }
+  info->fprintf_func (info->stream, "   %s %s%c%s", insn->tm->name,
+		      operand[0][0] ? operand[0] : "",
+		      operand[1][0] ? ',' : ' ',
+		      operand[1][0] ? operand[1] : "");
+  /* Print destination of branch in relation to current symbol. */
+  if (print_label && info->symbols)
+    {
+      asymbol *sym = *info->symbols;
+
+      if ((insn->tm->opcode_modifier == PCRel) && (insn_word & PCRel))
+	{
+	  address = (_pc + 1 + (short) address) - ((sym->section->vma + sym->value) / 4);
+	  /* Check for delayed instruction, if so adjust destination. */
+	  if (insn_word & 0x00200000)
+	    address += 2;
+	}
+      else
+	{
+	  address -= ((sym->section->vma + sym->value) / 4);
+	}
+      if (address == 0)
+	info->fprintf_func (info->stream, " <%s>", sym->name);
+      else
+	info->fprintf_func (info->stream, " <%s %c %d>", sym->name,
+			    ((short) address < 0) ? '-' : '+',
+			    abs (address));
+    }
+  return 1;
+}
+
+int
+get_indirect_operand (fragment, size, buffer)
+     unsigned short fragment;
+     int size;
+     char *buffer;
+{
+  unsigned char mod;
+  unsigned arnum;
+  unsigned char disp;
+
+  if (buffer == NULL)
+    return 0;
+  /* Determine which bits identify the sections of the indirect operand based on the
+     size in bytes. */
+  switch (size)
+    {
+    case 1:
+      mod = (fragment & 0x00F8) >> 3;
+      arnum = (fragment & 0x0007);
+      disp = 0;
+      break;
+    case 2:
+      mod = (fragment & 0xF800) >> 11;
+      arnum = (fragment & 0x0700) >> 8;
+      disp = (fragment & 0x00FF);
+      break;
+    default:
+      return 0;
+    }
+  {
+    const ind_addr_type *current_ind = tic30_indaddr_tab;
+    for (; current_ind < tic30_indaddrtab_end; current_ind++)
+      {
+	if (current_ind->modfield == mod)
+	  {
+	    if (current_ind->displacement == IMPLIED_DISP && size == 2)
+	      {
+		continue;
+	      }
+	    else
+	      {
+		size_t i, len;
+		int bufcnt;
+		
+		len = strlen (current_ind->syntax);
+		for (i = 0, bufcnt = 0; i < len; i++, bufcnt++)
+		  {
+		    buffer[bufcnt] = current_ind->syntax[i];
+		    if (buffer[bufcnt - 1] == 'a' && buffer[bufcnt] == 'r')
+		      buffer[++bufcnt] = arnum + '0';
+		    if (buffer[bufcnt] == '(' && current_ind->displacement == DISP_REQUIRED)
+		      {
+			sprintf (&buffer[bufcnt + 1], "%u", disp);
+			bufcnt += strlen (&buffer[bufcnt + 1]);
+		      }
+		  }
+		buffer[bufcnt + 1] = '\0';
+		break;
+	      }
+	  }
+      }
+  }
+  return 1;
+}
+
+int
+get_register_operand (fragment, buffer)
+     unsigned char fragment;
+     char *buffer;
+{
+  const reg *current_reg = tic30_regtab;
+
+  if (buffer == NULL)
+    return 0;
+  for (; current_reg < tic30_regtab_end; current_reg++)
+    {
+      if ((fragment & 0x1F) == current_reg->opcode)
+	{
+	  strcpy (buffer, current_reg->name);
+	  return 1;
+	}
+    }
+  return 0;
+}
+
+int
+cnvt_tmsfloat_ieee (tmsfloat, size, ieeefloat)
+     unsigned long tmsfloat;
+     int size;
+     float *ieeefloat;
+{
+  unsigned long exp, sign, mant;
+
+  if (size == 2)
+    {
+      if ((tmsfloat & 0x0000F000) == 0x00008000)
+	tmsfloat = 0x80000000;
+      else
+	{
+	  tmsfloat <<= 16;
+	  tmsfloat = (long) tmsfloat >> 4;
+	}
+    }
+  exp = tmsfloat & 0xFF000000;
+  if (exp == 0x80000000)
+    {
+      *ieeefloat = 0.0;
+      return 1;
+    }
+  exp += 0x7F000000;
+  sign = (tmsfloat & 0x00800000) << 8;
+  mant = tmsfloat & 0x007FFFFF;
+  if (exp == 0xFF000000)
+    {
+      if (mant == 0)
+	*ieeefloat = ERANGE;
+      if (sign == 0)
+	*ieeefloat = 1.0 / 0.0;
+      else
+	*ieeefloat = -1.0 / 0.0;
+      return 1;
+    }
+  exp >>= 1;
+  if (sign)
+    {
+      mant = (~mant) & 0x007FFFFF;
+      mant += 1;
+      exp += mant & 0x00800000;
+      exp &= 0x7F800000;
+      mant &= 0x007FFFFF;
+    }
+  if (tmsfloat == 0x80000000)
+    sign = mant = exp = 0;
+  tmsfloat = sign | exp | mant;
+  *ieeefloat = *((float *) &tmsfloat);
+  return 1;
+}