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/*---------------------------------------------------------------------------+
 |  fpu_entry.c                                                              |
 |                                                                           |
 | The entry functions for wm-FPU-emu                                        |
 |                                                                           |
 | Copyright (C) 1992,1993,1994,1996                                         |
 |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
 |                  E-mail   billm@jacobi.maths.monash.edu.au                |
 |                                                                           |
 | See the files "README" and "COPYING" for further copyright and warranty   |
 | information.                                                              |
 |                                                                           |
 +---------------------------------------------------------------------------*/
 
/*---------------------------------------------------------------------------+
 | Note:                                                                     |
 |    The file contains code which accesses user memory.                     |
 |    Emulator static data may change when user memory is accessed, due to   |
 |    other processes using the emulator while swapping is in progress.      |
 +---------------------------------------------------------------------------*/
 
/*---------------------------------------------------------------------------+
 | math_emulate(), restore_i387_soft() and save_i387_soft() are the only     |
 | entry points for wm-FPU-emu.                                              |
 +---------------------------------------------------------------------------*/
 
#include <linux/signal.h>
 
#include <asm/segment.h>
 
#include "fpu_system.h"
#include "fpu_emu.h"
#include "exception.h"
#include "control_w.h"
#include "status_w.h"
 
#define __BAD__ FPU_illegal   /* Illegal on an 80486, causes SIGILL */
 
#ifndef NO_UNDOC_CODE    /* Un-documented FPU op-codes supported by default. */
 
/* WARNING: These codes are not documented by Intel in their 80486 manual
   and may not work on FPU clones or later Intel FPUs. */
 
/* Changes to support the un-doc codes provided by Linus Torvalds. */
 
#define _d9_d8_ fstp_i    /* unofficial code (19) */
#define _dc_d0_ fcom_st   /* unofficial code (14) */
#define _dc_d8_ fcompst   /* unofficial code (1c) */
#define _dd_c8_ fxch_i    /* unofficial code (0d) */
#define _de_d0_ fcompst   /* unofficial code (16) */
#define _df_c0_ ffreep    /* unofficial code (07) ffree + pop */
#define _df_c8_ fxch_i    /* unofficial code (0f) */
#define _df_d0_ fstp_i    /* unofficial code (17) */
#define _df_d8_ fstp_i    /* unofficial code (1f) */
 
static FUNC const st_instr_table[64] = {
  fadd__,   fld_i_,  __BAD__, __BAD__, fadd_i,  ffree_,  faddp_,  _df_c0_,
  fmul__,   fxch_i,  __BAD__, __BAD__, fmul_i,  _dd_c8_, fmulp_,  _df_c8_,
  fcom_st,  fp_nop,  __BAD__, __BAD__, _dc_d0_, fst_i_,  _de_d0_, _df_d0_,
  fcompst,  _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i,  fcompp,  _df_d8_,
  fsub__,   fp_etc,  __BAD__, finit_,  fsubri,  fucom_,  fsubrp,  fstsw_,
  fsubr_,   fconst,  fucompp, __BAD__, fsub_i,  fucomp,  fsubp_,  __BAD__,
  fdiv__,   trig_a,  __BAD__, __BAD__, fdivri,  __BAD__, fdivrp,  __BAD__,
  fdivr_,   trig_b,  __BAD__, __BAD__, fdiv_i,  __BAD__, fdivp_,  __BAD__,
};
 
#else     /* Support only documented FPU op-codes */
 
static FUNC const st_instr_table[64] = {
  fadd__,   fld_i_,  __BAD__, __BAD__, fadd_i,  ffree_,  faddp_,  __BAD__,
  fmul__,   fxch_i,  __BAD__, __BAD__, fmul_i,  __BAD__, fmulp_,  __BAD__,
  fcom_st,  fp_nop,  __BAD__, __BAD__, __BAD__, fst_i_,  __BAD__, __BAD__,
  fcompst,  __BAD__, __BAD__, __BAD__, __BAD__, fstp_i,  fcompp,  __BAD__,
  fsub__,   fp_etc,  __BAD__, finit_,  fsubri,  fucom_,  fsubrp,  fstsw_,
  fsubr_,   fconst,  fucompp, __BAD__, fsub_i,  fucomp,  fsubp_,  __BAD__,
  fdiv__,   trig_a,  __BAD__, __BAD__, fdivri,  __BAD__, fdivrp,  __BAD__,
  fdivr_,   trig_b,  __BAD__, __BAD__, fdiv_i,  __BAD__, fdivp_,  __BAD__,
};
 
#endif NO_UNDOC_CODE
 
 
#define _NONE_ 0   /* Take no special action */
#define _REG0_ 1   /* Need to check for not empty st(0) */
#define _REGI_ 2   /* Need to check for not empty st(0) and st(rm) */
#define _REGi_ 0   /* Uses st(rm) */
#define _PUSH_ 3   /* Need to check for space to push onto stack */
#define _null_ 4   /* Function illegal or not implemented */
#define _REGIi 5   /* Uses st(0) and st(rm), result to st(rm) */
#define _REGIp 6   /* Uses st(0) and st(rm), result to st(rm) then pop */
#define _REGIc 0   /* Compare st(0) and st(rm) */
#define _REGIn 0   /* Uses st(0) and st(rm), but handle checks later */
 
#ifndef NO_UNDOC_CODE
 
/* Un-documented FPU op-codes supported by default. (see above) */
 
static unsigned char const type_table[64] = {
  _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,
  _REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,
  _REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
  _REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
  _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
  _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
  _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
  _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
};
 
#else     /* Support only documented FPU op-codes */
 
static unsigned char const type_table[64] = {
  _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_,
  _REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
  _REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_,
  _REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_,
  _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
  _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
  _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
  _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
};
 
#endif NO_UNDOC_CODE
 
 
#ifdef RE_ENTRANT_CHECKING
char emulating=0;
#endif RE_ENTRANT_CHECKING
 
static int valid_prefix(unsigned char *Byte, unsigned char **fpu_eip,
                        overrides *override);
 
asmlinkage void math_emulate(long arg)
{
  unsigned char  FPU_modrm, byte1;
  unsigned short code;
  fpu_addr_modes addr_modes;
  int unmasked;
  FPU_REG loaded_data;
  void *data_address;
  struct address data_sel_off;
  struct address entry_sel_off;
  unsigned long code_base = 0;
  unsigned long code_limit = 0;  /* Initialized to stop compiler warnings */
  char         st0_tag;
  FPU_REG      *st0_ptr;
  struct desc_struct code_descriptor;
 
#ifdef RE_ENTRANT_CHECKING
  if ( emulating )
    {
      printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n");
    }
  RE_ENTRANT_CHECK_ON;
#endif RE_ENTRANT_CHECKING
 
  if (!current->used_math)
    {
      int i;
      for ( i = 0; i < 8; i++ )
        {
          /* Make sure that the registers are compatible
             with the assumptions of the emulator. */
          if ( !((regs[i].exp == EXP_UNDER) && (regs[i].sigh == 0)
                 && (regs[i].sigl == 0)) )
            regs[i].sigh |= 0x80000000;
        }
      finit();
      current->used_math = 1;
    }
 
  SETUP_DATA_AREA(arg);
 
  FPU_ORIG_EIP = FPU_EIP;
 
  if ( (FPU_EFLAGS & 0x00020000) != 0 )
    {
      /* Virtual 8086 mode */
      addr_modes.default_mode = VM86;
      FPU_EIP += code_base = FPU_CS << 4;
      code_limit = code_base + 0xffff;  /* Assumes code_base <= 0xffff0000 */
    }
  else if ( FPU_CS == USER_CS && FPU_DS == USER_DS )
    {
      addr_modes.default_mode = 0;
    }
  else if ( FPU_CS == KERNEL_CS )
    {
      printk("math_emulate: %04x:%08lx\n",FPU_CS,FPU_EIP);
      panic("Math emulation needed in kernel");
    }
  else
    {
 
      if ( (FPU_CS & 4) != 4 )   /* Must be in the LDT */
        {
          /* Can only handle segmented addressing via the LDT
             for now, and it must be 16 bit */
          printk("FPU emulator: Unsupported addressing mode\n");
          math_abort(FPU_info, SIGILL);
        }
 
      if ( SEG_D_SIZE(code_descriptor = LDT_DESCRIPTOR(FPU_CS)) )
        {
          /* The above test may be wrong, the book is not clear */
          /* Segmented 32 bit protected mode */
          addr_modes.default_mode = SEG32;
        }
      else
        {
          /* 16 bit protected mode */
          addr_modes.default_mode = PM16;
        }
      FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor);
      code_limit = code_base
        + (SEG_LIMIT(code_descriptor)+1) * SEG_GRANULARITY(code_descriptor)
          - 1;
      if ( code_limit < code_base ) code_limit = 0xffffffff;
    }
 
  FPU_lookahead = 1;
  if (current->flags & PF_PTRACED)
    FPU_lookahead = 0;
 
  if ( !valid_prefix(&byte1, (unsigned char **)&FPU_EIP,
                     &addr_modes.override) )
    {
      RE_ENTRANT_CHECK_OFF;
      printk("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n"
             "FPU emulator: self-modifying code! (emulation impossible)\n",
             byte1);
      RE_ENTRANT_CHECK_ON;
      EXCEPTION(EX_INTERNAL|0x126);
      math_abort(FPU_info,SIGILL);
    }
 
do_another_FPU_instruction:
 
  no_ip_update = 0;
 
  FPU_EIP++;  /* We have fetched the prefix and first code bytes. */
 
  if ( addr_modes.default_mode )
    {
      /* This checks for the minimum instruction bytes.
         We also need to check any extra (address mode) code access. */
      if ( FPU_EIP > code_limit )
        math_abort(FPU_info,SIGSEGV);
    }
 
  if ( (byte1 & 0xf8) != 0xd8 )
    {
      if ( byte1 == FWAIT_OPCODE )
        {
          if (partial_status & SW_Summary)
            goto do_the_FPU_interrupt;
          else
            goto FPU_fwait_done;
        }
#ifdef PARANOID
      EXCEPTION(EX_INTERNAL|0x128);
      math_abort(FPU_info,SIGILL);
#endif PARANOID
    }
 
  RE_ENTRANT_CHECK_OFF;
  FPU_code_verify_area(1);
  FPU_modrm = get_fs_byte((unsigned char *) FPU_EIP);
  RE_ENTRANT_CHECK_ON;
  FPU_EIP++;
 
  if (partial_status & SW_Summary)
    {
      /* Ignore the error for now if the current instruction is a no-wait
         control instruction */
      /* The 80486 manual contradicts itself on this topic,
         but a real 80486 uses the following instructions:
         fninit, fnstenv, fnsave, fnstsw, fnstenv, fnclex.
       */
      code = (FPU_modrm << 8) | byte1;
      if ( ! ( (((code & 0xf803) == 0xe003) ||    /* fnclex, fninit, fnstsw */
                (((code & 0x3003) == 0x3001) &&   /* fnsave, fnstcw, fnstenv,
                                                     fnstsw */
                 ((code & 0xc000) != 0xc000))) ) )
        {
          /*
           *  We need to simulate the action of the kernel to FPU
           *  interrupts here.
           */
        do_the_FPU_interrupt:
          FPU_EIP = FPU_ORIG_EIP;       /* Point to current FPU instruction. */
 
          RE_ENTRANT_CHECK_OFF;
          current->tss.trap_no = 16;
          current->tss.error_code = 0;
          send_sig(SIGFPE, current, 1);
          return;
        }
    }
 
  entry_sel_off.offset = FPU_ORIG_EIP;
  entry_sel_off.selector = FPU_CS;
  entry_sel_off.opcode = (byte1 << 8) | FPU_modrm;
 
  FPU_rm = FPU_modrm & 7;
 
  if ( FPU_modrm < 0300 )
    {
      /* All of these instructions use the mod/rm byte to get a data address */
 
      if ( (addr_modes.default_mode & SIXTEEN)
          ^ (addr_modes.override.address_size == ADDR_SIZE_PREFIX) )
        data_address = get_address_16(FPU_modrm, &FPU_EIP, &data_sel_off,
                                      addr_modes);
      else
        data_address = get_address(FPU_modrm, &FPU_EIP, &data_sel_off,
                                   addr_modes);
 
      if ( addr_modes.default_mode )
        {
          if ( FPU_EIP-1 > code_limit )
            math_abort(FPU_info,SIGSEGV);
        }
 
      if ( !(byte1 & 1) )
        {
          unsigned short status1 = partial_status;
 
          st0_ptr = &st(0);
          st0_tag = st0_ptr->tag;
 
          /* Stack underflow has priority */
          if ( NOT_EMPTY_ST0 )
            {
              if ( addr_modes.default_mode & PROTECTED )
                {
                  /* This table works for 16 and 32 bit protected mode */
                  if ( access_limit < data_sizes_16[(byte1 >> 1) & 3] )
                    math_abort(FPU_info,SIGSEGV);
                }
 
              unmasked = 0;  /* Do this here to stop compiler warnings. */
              switch ( (byte1 >> 1) & 3 )
                {
                case 0:
                  unmasked = reg_load_single((float *)data_address,
                                             &loaded_data);
                  break;
                case 1:
                  reg_load_int32((long *)data_address, &loaded_data);
                  break;
                case 2:
                  unmasked = reg_load_double((double *)data_address,
                                             &loaded_data);
                  break;
                case 3:
                  reg_load_int16((short *)data_address, &loaded_data);
                  break;
                }
 
              /* No more access to user memory, it is safe
                 to use static data now */
 
              /* NaN operands have the next priority. */
              /* We have to delay looking at st(0) until after
                 loading the data, because that data might contain an SNaN */
              if ( (st0_tag == TW_NaN) ||
                  (loaded_data.tag == TW_NaN) )
                {
                  /* Restore the status word; we might have loaded a
                     denormal. */
                  partial_status = status1;
                  if ( (FPU_modrm & 0x30) == 0x10 )
                    {
                      /* fcom or fcomp */
                      EXCEPTION(EX_Invalid);
                      setcc(SW_C3 | SW_C2 | SW_C0);
                      if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) )
                        pop();             /* fcomp, masked, so we pop. */
                    }
                  else
                    {
#ifdef PECULIAR_486
                      /* This is not really needed, but gives behaviour
                         identical to an 80486 */
                      if ( (FPU_modrm & 0x28) == 0x20 )
                        /* fdiv or fsub */
                        real_2op_NaN(&loaded_data, st0_ptr,
                                     st0_ptr);
                      else
#endif PECULIAR_486
                        /* fadd, fdivr, fmul, or fsubr */
                        real_2op_NaN(st0_ptr, &loaded_data,
                                     st0_ptr);
                    }
                  goto reg_mem_instr_done;
                }
 
              if ( unmasked && !((FPU_modrm & 0x30) == 0x10) )
                {
                  /* Is not a comparison instruction. */
                  if ( (FPU_modrm & 0x38) == 0x38 )
                    {
                      /* fdivr */
                      if ( (st0_tag == TW_Zero) &&
                          (loaded_data.tag == TW_Valid) )
                        {
                          if ( divide_by_zero(loaded_data.sign,
                                              st0_ptr) )
                            {
                              /* We use the fact here that the unmasked
                                 exception in the loaded data was for a
                                 denormal operand */
                              /* Restore the state of the denormal op bit */
                              partial_status &= ~SW_Denorm_Op;
                              partial_status |= status1 & SW_Denorm_Op;
                            }
                        }
                    }
                  goto reg_mem_instr_done;
                }
 
              switch ( (FPU_modrm >> 3) & 7 )
                {
                case 0:         /* fadd */
                  clear_C1();
                  reg_add(st0_ptr, &loaded_data, st0_ptr,
                          control_word);
                  break;
                case 1:         /* fmul */
                  clear_C1();
                  reg_mul(st0_ptr, &loaded_data, st0_ptr,
                          control_word);
                  break;
                case 2:         /* fcom */
                  compare_st_data(&loaded_data);
                  break;
                case 3:         /* fcomp */
                  if ( !compare_st_data(&loaded_data) && !unmasked )
                    pop();
                  break;
                case 4:         /* fsub */
                  clear_C1();
                  reg_sub(st0_ptr, &loaded_data, st0_ptr,
                          control_word);
                  break;
                case 5:         /* fsubr */
                  clear_C1();
                  reg_sub(&loaded_data, st0_ptr, st0_ptr,
                          control_word);
                  break;
                case 6:         /* fdiv */
                  clear_C1();
                  reg_div(st0_ptr, &loaded_data, st0_ptr,
                          control_word);
                  break;
                case 7:         /* fdivr */
                  clear_C1();
                  if ( st0_tag == TW_Zero )
                    partial_status = status1;  /* Undo any denorm tag,
                                               zero-divide has priority. */
                  reg_div(&loaded_data, st0_ptr, st0_ptr,
                          control_word);
                  break;
                }
            }
          else
            {
              if ( (FPU_modrm & 0x30) == 0x10 )
                {
                  /* The instruction is fcom or fcomp */
                  EXCEPTION(EX_StackUnder);
                  setcc(SW_C3 | SW_C2 | SW_C0);
                  if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) )
                    pop();             /* fcomp */
                }
              else
                stack_underflow();
            }
        reg_mem_instr_done:
          operand_address = data_sel_off;
        }
      else
        {
          if ( !(no_ip_update =
                 load_store_instr(((FPU_modrm & 0x38) | (byte1 & 6)) >> 1,
                                  addr_modes, data_address)) )
            {
              operand_address = data_sel_off;
            }
        }
 
    }
  else
    {
      /* None of these instructions access user memory */
      unsigned char instr_index = (FPU_modrm & 0x38) | (byte1 & 7);
 
#ifdef PECULIAR_486
      /* This is supposed to be undefined, but a real 80486 seems
         to do this: */
      operand_address.offset = 0;
      operand_address.selector = FPU_DS;
#endif PECULIAR_486
 
      st0_ptr = &st(0);
      st0_tag = st0_ptr->tag;
      switch ( type_table[(int) instr_index] )
        {
        case _NONE_:   /* also _REGIc: _REGIn */
          break;
        case _REG0_:
          if ( !NOT_EMPTY_ST0 )
            {
              stack_underflow();
              goto FPU_instruction_done;
            }
          break;
        case _REGIi:
          if ( !NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm) )
            {
              stack_underflow_i(FPU_rm);
              goto FPU_instruction_done;
            }
          break;
        case _REGIp:
          if ( !NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm) )
            {
              stack_underflow_pop(FPU_rm);
              goto FPU_instruction_done;
            }
          break;
        case _REGI_:
          if ( !NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm) )
            {
              stack_underflow();
              goto FPU_instruction_done;
            }
          break;
        case _PUSH_:     /* Only used by the fld st(i) instruction */
          break;
        case _null_:
          FPU_illegal();
          goto FPU_instruction_done;
        default:
          EXCEPTION(EX_INTERNAL|0x111);
          goto FPU_instruction_done;
        }
      (*st_instr_table[(int) instr_index])();
 
FPU_instruction_done:
      ;
    }
 
  if ( ! no_ip_update )
    instruction_address = entry_sel_off;
 
FPU_fwait_done:
 
#ifdef DEBUG
  RE_ENTRANT_CHECK_OFF;
  emu_printall();
  RE_ENTRANT_CHECK_ON;
#endif DEBUG
 
  if (FPU_lookahead && !need_resched)
    {
      FPU_ORIG_EIP = FPU_EIP - code_base;
      if ( valid_prefix(&byte1, (unsigned char **)&FPU_EIP,
                        &addr_modes.override) )
        goto do_another_FPU_instruction;
    }
 
  if ( addr_modes.default_mode )
    FPU_EIP -= code_base;
 
  RE_ENTRANT_CHECK_OFF;
}
 
 
/* Support for prefix bytes is not yet complete. To properly handle
   all prefix bytes, further changes are needed in the emulator code
   which accesses user address space. Access to separate segments is
   important for msdos emulation. */
static int valid_prefix(unsigned char *Byte, unsigned char **fpu_eip,
                        overrides *override)
{
  unsigned char byte;
  unsigned char *ip = *fpu_eip;
 
  *override = (overrides) { 0, 0, PREFIX_DEFAULT };       /* defaults */
 
  RE_ENTRANT_CHECK_OFF;
  FPU_code_verify_area(1);
  byte = get_fs_byte(ip);
  RE_ENTRANT_CHECK_ON;
 
  while ( 1 )
    {
      switch ( byte )
        {
        case ADDR_SIZE_PREFIX:
          override->address_size = ADDR_SIZE_PREFIX;
          goto do_next_byte;
 
        case OP_SIZE_PREFIX:
          override->operand_size = OP_SIZE_PREFIX;
          goto do_next_byte;
 
        case PREFIX_CS:
          override->segment = PREFIX_CS_;
          goto do_next_byte;
        case PREFIX_ES:
          override->segment = PREFIX_ES_;
          goto do_next_byte;
        case PREFIX_SS:
          override->segment = PREFIX_SS_;
          goto do_next_byte;
        case PREFIX_FS:
          override->segment = PREFIX_FS_;
          goto do_next_byte;
        case PREFIX_GS:
          override->segment = PREFIX_GS_;
          goto do_next_byte;
        case PREFIX_DS:
          override->segment = PREFIX_DS_;
          goto do_next_byte;
 
/* lock is not a valid prefix for FPU instructions,
   let the cpu handle it to generate a SIGILL. */
/*      case PREFIX_LOCK: */
 
          /* rep.. prefixes have no meaning for FPU instructions */
        case PREFIX_REPE:
        case PREFIX_REPNE:
 
        do_next_byte:
          ip++;
          RE_ENTRANT_CHECK_OFF;
          FPU_code_verify_area(1);
          byte = get_fs_byte(ip);
          RE_ENTRANT_CHECK_ON;
          break;
        case FWAIT_OPCODE:
          *Byte = byte;
          return 1;
        default:
          if ( (byte & 0xf8) == 0xd8 )
            {
              *Byte = byte;
              *fpu_eip = ip;
              return 1;
            }
          else
            {
              /* Not a valid sequence of prefix bytes followed by
                 an FPU instruction. */
              *Byte = byte;  /* Needed for error message. */
              return 0;
            }
        }
    }
}
 
 
void math_abort(struct info * info, unsigned int signal)
{
        FPU_EIP = FPU_ORIG_EIP;
        current->tss.trap_no = 16;
        current->tss.error_code = 0;
        send_sig(signal,current,1);
        RE_ENTRANT_CHECK_OFF;
        __asm__("movl %0,%%esp ; ret": :"g" (((long) info)-4));
#ifdef PARANOID
      printk("ERROR: wm-FPU-emu math_abort failed!\n");
#endif PARANOID
}
 
 
 
void restore_i387_soft(struct _fpstate *buf)
{
  fpu_addr_modes addr_modes = {{ 0, 0, PREFIX_DEFAULT }, 0};
 
  frstor(addr_modes, (char *)buf);
}
 
 
struct _fpstate * save_i387_soft(struct _fpstate * buf)
{
  fpu_addr_modes addr_modes = {{ 0, 0, PREFIX_DEFAULT }, 0};
 
  fsave(addr_modes, (char *)buf);
 
  return buf;
}

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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [i386/] [math-emu/] [fpu_entry.c] - Blame information for rev 1782

Line No.	Rev	Author	Line
1	1623	jcastillo	`/*---------------------------------------------------------------------------+`
2			`\| fpu_entry.c \|`
3			`\| \|`
4			`\| The entry functions for wm-FPU-emu \|`
5			`\| \|`
6			`\| Copyright (C) 1992,1993,1994,1996 \|`
7			`\| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia \|`
8			`\| E-mail billm@jacobi.maths.monash.edu.au \|`
9			`\| \|`
10			`\| See the files "README" and "COPYING" for further copyright and warranty \|`
11			`\| information. \|`
12			`\| \|`
13			`+---------------------------------------------------------------------------*/`
14
15			`/*---------------------------------------------------------------------------+`
16			`\| Note: \|`
17			`\| The file contains code which accesses user memory. \|`
18			`\| Emulator static data may change when user memory is accessed, due to \|`
19			`\| other processes using the emulator while swapping is in progress. \|`
20			`+---------------------------------------------------------------------------*/`
21
22			`/*---------------------------------------------------------------------------+`
23			`\| math_emulate(), restore_i387_soft() and save_i387_soft() are the only \|`
24			`\| entry points for wm-FPU-emu. \|`
25			`+---------------------------------------------------------------------------*/`
26
27			`#include <linux/signal.h>`
28
29			`#include <asm/segment.h>`
30
31			`#include "fpu_system.h"`
32			`#include "fpu_emu.h"`
33			`#include "exception.h"`
34			`#include "control_w.h"`
35			`#include "status_w.h"`
36
37			`#define __BAD__ FPU_illegal /* Illegal on an 80486, causes SIGILL */`
38
39			`#ifndef NO_UNDOC_CODE /* Un-documented FPU op-codes supported by default. */`
40
41			`/* WARNING: These codes are not documented by Intel in their 80486 manual`
42			`and may not work on FPU clones or later Intel FPUs. */`
43
44			`/* Changes to support the un-doc codes provided by Linus Torvalds. */`
45
46			`#define _d9_d8_ fstp_i /* unofficial code (19) */`
47			`#define _dc_d0_ fcom_st /* unofficial code (14) */`
48			`#define _dc_d8_ fcompst /* unofficial code (1c) */`
49			`#define _dd_c8_ fxch_i /* unofficial code (0d) */`
50			`#define _de_d0_ fcompst /* unofficial code (16) */`
51			`#define _df_c0_ ffreep /* unofficial code (07) ffree + pop */`
52			`#define _df_c8_ fxch_i /* unofficial code (0f) */`
53			`#define _df_d0_ fstp_i /* unofficial code (17) */`
54			`#define _df_d8_ fstp_i /* unofficial code (1f) */`
55
56			`static FUNC const st_instr_table[64] = {`
57			`fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, _df_c0_,`
58			`fmul__, fxch_i, __BAD__, __BAD__, fmul_i, _dd_c8_, fmulp_, _df_c8_,`
59			`fcom_st, fp_nop, __BAD__, __BAD__, _dc_d0_, fst_i_, _de_d0_, _df_d0_,`
60			`fcompst, _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i, fcompp, _df_d8_,`
61			`fsub__, fp_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,`
62			`fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,`
63			`fdiv__, trig_a, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,`
64			`fdivr_, trig_b, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,`
65			`};`
66
67			`#else /* Support only documented FPU op-codes */`
68
69			`static FUNC const st_instr_table[64] = {`
70			`fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__,`
71			`fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__,`
72			`fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__,`
73			`fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__,`
74			`fsub__, fp_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,`
75			`fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,`
76			`fdiv__, trig_a, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,`
77			`fdivr_, trig_b, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,`
78			`};`
79
80			`#endif NO_UNDOC_CODE`
81
82
83			`#define _NONE_ 0 /* Take no special action */`
84			`#define _REG0_ 1 /* Need to check for not empty st(0) */`
85			`#define _REGI_ 2 /* Need to check for not empty st(0) and st(rm) */`
86			`#define _REGi_ 0 /* Uses st(rm) */`
87			`#define _PUSH_ 3 /* Need to check for space to push onto stack */`
88			`#define _null_ 4 /* Function illegal or not implemented */`
89			`#define _REGIi 5 /* Uses st(0) and st(rm), result to st(rm) */`
90			`#define _REGIp 6 /* Uses st(0) and st(rm), result to st(rm) then pop */`
91			`#define _REGIc 0 /* Compare st(0) and st(rm) */`
92			`#define _REGIn 0 /* Uses st(0) and st(rm), but handle checks later */`
93
94			`#ifndef NO_UNDOC_CODE`
95
96			`/* Un-documented FPU op-codes supported by default. (see above) */`
97
98			`static unsigned char const type_table[64] = {`
99			`_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,`
100			`_REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,`
101			`_REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,`
102			`_REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,`
103			`_REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,`
104			`_REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,`
105			`_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,`
106			`_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_`
107			`};`
108
109			`#else /* Support only documented FPU op-codes */`
110
111			`static unsigned char const type_table[64] = {`
112			`_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_,`
113			`_REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_,`
114			`_REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_,`
115			`_REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_,`
116			`_REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,`
117			`_REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,`
118			`_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,`
119			`_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_`
120			`};`
121
122			`#endif NO_UNDOC_CODE`
123
124
125			`#ifdef RE_ENTRANT_CHECKING`
126			`char emulating=0;`
127			`#endif RE_ENTRANT_CHECKING`
128
129			`static int valid_prefix(unsigned char Byte, unsigned char *fpu_eip,`
130			`overrides *override);`
131
132			`asmlinkage void math_emulate(long arg)`
133			`{`
134			`unsigned char FPU_modrm, byte1;`
135			`unsigned short code;`
136			`fpu_addr_modes addr_modes;`
137			`int unmasked;`
138			`FPU_REG loaded_data;`
139			`void *data_address;`
140			`struct address data_sel_off;`
141			`struct address entry_sel_off;`
142			`unsigned long code_base = 0;`
143			`unsigned long code_limit = 0; /* Initialized to stop compiler warnings */`
144			`char st0_tag;`
145			`FPU_REG *st0_ptr;`
146			`struct desc_struct code_descriptor;`
147
148			`#ifdef RE_ENTRANT_CHECKING`
149			`if ( emulating )`
150			`{`
151			`printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n");`
152			`}`
153			`RE_ENTRANT_CHECK_ON;`
154			`#endif RE_ENTRANT_CHECKING`
155
156			`if (!current->used_math)`
157			`{`
158			`int i;`
159			`for ( i = 0; i < 8; i++ )`
160			`{`
161			`/* Make sure that the registers are compatible`
162			`with the assumptions of the emulator. */`
163			`if ( !((regs[i].exp == EXP_UNDER) && (regs[i].sigh == 0)`
164			`&& (regs[i].sigl == 0)) )`
165			`regs[i].sigh \|= 0x80000000;`
166			`}`
167			`finit();`
168			`current->used_math = 1;`
169			`}`
170
171			`SETUP_DATA_AREA(arg);`
172
173			`FPU_ORIG_EIP = FPU_EIP;`
174
175			`if ( (FPU_EFLAGS & 0x00020000) != 0 )`
176			`{`
177			`/* Virtual 8086 mode */`
178			`addr_modes.default_mode = VM86;`
179			`FPU_EIP += code_base = FPU_CS << 4;`
180			`code_limit = code_base + 0xffff; /* Assumes code_base <= 0xffff0000 */`
181			`}`
182			`else if ( FPU_CS == USER_CS && FPU_DS == USER_DS )`
183			`{`
184			`addr_modes.default_mode = 0;`
185			`}`
186			`else if ( FPU_CS == KERNEL_CS )`
187			`{`
188			`printk("math_emulate: %04x:%08lx\n",FPU_CS,FPU_EIP);`
189			`panic("Math emulation needed in kernel");`
190			`}`
191			`else`
192			`{`
193
194			`if ( (FPU_CS & 4) != 4 ) /* Must be in the LDT */`
195			`{`
196			`/* Can only handle segmented addressing via the LDT`
197			`for now, and it must be 16 bit */`
198			`printk("FPU emulator: Unsupported addressing mode\n");`
199			`math_abort(FPU_info, SIGILL);`
200			`}`
201
202			`if ( SEG_D_SIZE(code_descriptor = LDT_DESCRIPTOR(FPU_CS)) )`
203			`{`
204			`/* The above test may be wrong, the book is not clear */`
205			`/* Segmented 32 bit protected mode */`
206			`addr_modes.default_mode = SEG32;`
207			`}`
208			`else`
209			`{`
210			`/* 16 bit protected mode */`
211			`addr_modes.default_mode = PM16;`
212			`}`
213			`FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor);`
214			`code_limit = code_base`
215			`+ (SEG_LIMIT(code_descriptor)+1) * SEG_GRANULARITY(code_descriptor)`
216			`- 1;`
217			`if ( code_limit < code_base ) code_limit = 0xffffffff;`
218			`}`
219
220			`FPU_lookahead = 1;`
221			`if (current->flags & PF_PTRACED)`
222			`FPU_lookahead = 0;`
223
224			`if ( !valid_prefix(&byte1, (unsigned char **)&FPU_EIP,`
225			`&addr_modes.override) )`
226			`{`
227			`RE_ENTRANT_CHECK_OFF;`
228			`printk("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n"`
229			`"FPU emulator: self-modifying code! (emulation impossible)\n",`
230			`byte1);`
231			`RE_ENTRANT_CHECK_ON;`
232			`EXCEPTION(EX_INTERNAL\|0x126);`
233			`math_abort(FPU_info,SIGILL);`
234			`}`
235
236			`do_another_FPU_instruction:`
237
238			`no_ip_update = 0;`
239
240			`FPU_EIP++; /* We have fetched the prefix and first code bytes. */`
241
242			`if ( addr_modes.default_mode )`
243			`{`
244			`/* This checks for the minimum instruction bytes.`
245			`We also need to check any extra (address mode) code access. */`
246			`if ( FPU_EIP > code_limit )`
247			`math_abort(FPU_info,SIGSEGV);`
248			`}`
249
250			`if ( (byte1 & 0xf8) != 0xd8 )`
251			`{`
252			`if ( byte1 == FWAIT_OPCODE )`
253			`{`
254			`if (partial_status & SW_Summary)`
255			`goto do_the_FPU_interrupt;`
256			`else`
257			`goto FPU_fwait_done;`
258			`}`
259			`#ifdef PARANOID`
260			`EXCEPTION(EX_INTERNAL\|0x128);`
261			`math_abort(FPU_info,SIGILL);`
262			`#endif PARANOID`
263			`}`
264
265			`RE_ENTRANT_CHECK_OFF;`
266			`FPU_code_verify_area(1);`
267			`FPU_modrm = get_fs_byte((unsigned char *) FPU_EIP);`
268			`RE_ENTRANT_CHECK_ON;`
269			`FPU_EIP++;`
270
271			`if (partial_status & SW_Summary)`
272			`{`
273			`/* Ignore the error for now if the current instruction is a no-wait`
274			`control instruction */`
275			`/* The 80486 manual contradicts itself on this topic,`
276			`but a real 80486 uses the following instructions:`
277			`fninit, fnstenv, fnsave, fnstsw, fnstenv, fnclex.`
278			`*/`
279			`code = (FPU_modrm << 8) \| byte1;`
280			`if ( ! ( (((code & 0xf803) == 0xe003) \|\| /* fnclex, fninit, fnstsw */`
281			`(((code & 0x3003) == 0x3001) && /* fnsave, fnstcw, fnstenv,`
282			`fnstsw */`
283			`((code & 0xc000) != 0xc000))) ) )`
284			`{`
285			`/*`
286			`* We need to simulate the action of the kernel to FPU`
287			`* interrupts here.`
288			`*/`
289			`do_the_FPU_interrupt:`
290			`FPU_EIP = FPU_ORIG_EIP; /* Point to current FPU instruction. */`
291
292			`RE_ENTRANT_CHECK_OFF;`
293			`current->tss.trap_no = 16;`
294			`current->tss.error_code = 0;`
295			`send_sig(SIGFPE, current, 1);`
296			`return;`
297			`}`
298			`}`
299
300			`entry_sel_off.offset = FPU_ORIG_EIP;`
301			`entry_sel_off.selector = FPU_CS;`
302			`entry_sel_off.opcode = (byte1 << 8) \| FPU_modrm;`
303
304			`FPU_rm = FPU_modrm & 7;`
305
306			`if ( FPU_modrm < 0300 )`
307			`{`
308			`/* All of these instructions use the mod/rm byte to get a data address */`
309
310			`if ( (addr_modes.default_mode & SIXTEEN)`
311			`^ (addr_modes.override.address_size == ADDR_SIZE_PREFIX) )`
312			`data_address = get_address_16(FPU_modrm, &FPU_EIP, &data_sel_off,`
313			`addr_modes);`
314			`else`
315			`data_address = get_address(FPU_modrm, &FPU_EIP, &data_sel_off,`
316			`addr_modes);`
317
318			`if ( addr_modes.default_mode )`
319			`{`
320			`if ( FPU_EIP-1 > code_limit )`
321			`math_abort(FPU_info,SIGSEGV);`
322			`}`
323
324			`if ( !(byte1 & 1) )`
325			`{`
326			`unsigned short status1 = partial_status;`
327
328			`st0_ptr = &st(0);`
329			`st0_tag = st0_ptr->tag;`
330
331			`/* Stack underflow has priority */`
332			`if ( NOT_EMPTY_ST0 )`
333			`{`
334			`if ( addr_modes.default_mode & PROTECTED )`
335			`{`
336			`/* This table works for 16 and 32 bit protected mode */`
337			`if ( access_limit < data_sizes_16[(byte1 >> 1) & 3] )`
338			`math_abort(FPU_info,SIGSEGV);`
339			`}`
340
341			`unmasked = 0; /* Do this here to stop compiler warnings. */`
342			`switch ( (byte1 >> 1) & 3 )`
343			`{`
344			`case 0:`
345			`unmasked = reg_load_single((float *)data_address,`
346			`&loaded_data);`
347			`break;`
348			`case 1:`
349			`reg_load_int32((long *)data_address, &loaded_data);`
350			`break;`
351			`case 2:`
352			`unmasked = reg_load_double((double *)data_address,`
353			`&loaded_data);`
354			`break;`
355			`case 3:`
356			`reg_load_int16((short *)data_address, &loaded_data);`
357			`break;`
358			`}`
359
360			`/* No more access to user memory, it is safe`
361			`to use static data now */`
362
363			`/* NaN operands have the next priority. */`
364			`/* We have to delay looking at st(0) until after`
365			`loading the data, because that data might contain an SNaN */`
366			`if ( (st0_tag == TW_NaN) \|\|`
367			`(loaded_data.tag == TW_NaN) )`
368			`{`
369			`/* Restore the status word; we might have loaded a`
370			`denormal. */`
371			`partial_status = status1;`
372			`if ( (FPU_modrm & 0x30) == 0x10 )`
373			`{`
374			`/* fcom or fcomp */`
375			`EXCEPTION(EX_Invalid);`
376			`setcc(SW_C3 \| SW_C2 \| SW_C0);`
377			`if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) )`
378			`pop(); /* fcomp, masked, so we pop. */`
379			`}`
380			`else`
381			`{`
382			`#ifdef PECULIAR_486`
383			`/* This is not really needed, but gives behaviour`
384			`identical to an 80486 */`
385			`if ( (FPU_modrm & 0x28) == 0x20 )`
386			`/* fdiv or fsub */`
387			`real_2op_NaN(&loaded_data, st0_ptr,`
388			`st0_ptr);`
389			`else`
390			`#endif PECULIAR_486`
391			`/* fadd, fdivr, fmul, or fsubr */`
392			`real_2op_NaN(st0_ptr, &loaded_data,`
393			`st0_ptr);`
394			`}`
395			`goto reg_mem_instr_done;`
396			`}`
397
398			`if ( unmasked && !((FPU_modrm & 0x30) == 0x10) )`
399			`{`
400			`/* Is not a comparison instruction. */`
401			`if ( (FPU_modrm & 0x38) == 0x38 )`
402			`{`
403			`/* fdivr */`
404			`if ( (st0_tag == TW_Zero) &&`
405			`(loaded_data.tag == TW_Valid) )`
406			`{`
407			`if ( divide_by_zero(loaded_data.sign,`
408			`st0_ptr) )`
409			`{`
410			`/* We use the fact here that the unmasked`
411			`exception in the loaded data was for a`
412			`denormal operand */`
413			`/* Restore the state of the denormal op bit */`
414			`partial_status &= ~SW_Denorm_Op;`
415			`partial_status \|= status1 & SW_Denorm_Op;`
416			`}`
417			`}`
418			`}`
419			`goto reg_mem_instr_done;`
420			`}`
421
422			`switch ( (FPU_modrm >> 3) & 7 )`
423			`{`
424			`case 0: /* fadd */`
425			`clear_C1();`
426			`reg_add(st0_ptr, &loaded_data, st0_ptr,`
427			`control_word);`
428			`break;`
429			`case 1: /* fmul */`
430			`clear_C1();`
431			`reg_mul(st0_ptr, &loaded_data, st0_ptr,`
432			`control_word);`
433			`break;`
434			`case 2: /* fcom */`
435			`compare_st_data(&loaded_data);`
436			`break;`
437			`case 3: /* fcomp */`
438			`if ( !compare_st_data(&loaded_data) && !unmasked )`
439			`pop();`
440			`break;`
441			`case 4: /* fsub */`
442			`clear_C1();`
443			`reg_sub(st0_ptr, &loaded_data, st0_ptr,`
444			`control_word);`
445			`break;`
446			`case 5: /* fsubr */`
447			`clear_C1();`
448			`reg_sub(&loaded_data, st0_ptr, st0_ptr,`
449			`control_word);`
450			`break;`
451			`case 6: /* fdiv */`
452			`clear_C1();`
453			`reg_div(st0_ptr, &loaded_data, st0_ptr,`
454			`control_word);`
455			`break;`
456			`case 7: /* fdivr */`
457			`clear_C1();`
458			`if ( st0_tag == TW_Zero )`
459			`partial_status = status1; /* Undo any denorm tag,`
460			`zero-divide has priority. */`
461			`reg_div(&loaded_data, st0_ptr, st0_ptr,`
462			`control_word);`
463			`break;`
464			`}`
465			`}`
466			`else`
467			`{`
468			`if ( (FPU_modrm & 0x30) == 0x10 )`
469			`{`
470			`/* The instruction is fcom or fcomp */`
471			`EXCEPTION(EX_StackUnder);`
472			`setcc(SW_C3 \| SW_C2 \| SW_C0);`
473			`if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) )`
474			`pop(); /* fcomp */`
475			`}`
476			`else`
477			`stack_underflow();`
478			`}`
479			`reg_mem_instr_done:`
480			`operand_address = data_sel_off;`
481			`}`
482			`else`
483			`{`
484			`if ( !(no_ip_update =`
485			`load_store_instr(((FPU_modrm & 0x38) \| (byte1 & 6)) >> 1,`
486			`addr_modes, data_address)) )`
487			`{`
488			`operand_address = data_sel_off;`
489			`}`
490			`}`
491
492			`}`
493			`else`
494			`{`
495			`/* None of these instructions access user memory */`
496			`unsigned char instr_index = (FPU_modrm & 0x38) \| (byte1 & 7);`
497
498			`#ifdef PECULIAR_486`
499			`/* This is supposed to be undefined, but a real 80486 seems`
500			`to do this: */`
501			`operand_address.offset = 0;`
502			`operand_address.selector = FPU_DS;`
503			`#endif PECULIAR_486`
504
505			`st0_ptr = &st(0);`
506			`st0_tag = st0_ptr->tag;`
507			`switch ( type_table[(int) instr_index] )`
508			`{`
509			`case _NONE_: /* also _REGIc: _REGIn */`
510			`break;`
511			`case _REG0_:`
512			`if ( !NOT_EMPTY_ST0 )`
513			`{`
514			`stack_underflow();`
515			`goto FPU_instruction_done;`
516			`}`
517			`break;`
518			`case _REGIi:`
519			`if ( !NOT_EMPTY_ST0 \|\| !NOT_EMPTY(FPU_rm) )`
520			`{`
521			`stack_underflow_i(FPU_rm);`
522			`goto FPU_instruction_done;`
523			`}`
524			`break;`
525			`case _REGIp:`
526			`if ( !NOT_EMPTY_ST0 \|\| !NOT_EMPTY(FPU_rm) )`
527			`{`
528			`stack_underflow_pop(FPU_rm);`
529			`goto FPU_instruction_done;`
530			`}`
531			`break;`
532			`case _REGI_:`
533			`if ( !NOT_EMPTY_ST0 \|\| !NOT_EMPTY(FPU_rm) )`
534			`{`
535			`stack_underflow();`
536			`goto FPU_instruction_done;`
537			`}`
538			`break;`
539			`case _PUSH_: /* Only used by the fld st(i) instruction */`
540			`break;`
541			`case _null_:`
542			`FPU_illegal();`
543			`goto FPU_instruction_done;`
544			`default:`
545			`EXCEPTION(EX_INTERNAL\|0x111);`
546			`goto FPU_instruction_done;`
547			`}`
548			`(*st_instr_table[(int) instr_index])();`
549
550			`FPU_instruction_done:`
551			`;`
552			`}`
553
554			`if ( ! no_ip_update )`
555			`instruction_address = entry_sel_off;`
556
557			`FPU_fwait_done:`
558
559			`#ifdef DEBUG`
560			`RE_ENTRANT_CHECK_OFF;`
561			`emu_printall();`
562			`RE_ENTRANT_CHECK_ON;`
563			`#endif DEBUG`
564
565			`if (FPU_lookahead && !need_resched)`
566			`{`
567			`FPU_ORIG_EIP = FPU_EIP - code_base;`
568			`if ( valid_prefix(&byte1, (unsigned char **)&FPU_EIP,`
569			`&addr_modes.override) )`
570			`goto do_another_FPU_instruction;`
571			`}`
572
573			`if ( addr_modes.default_mode )`
574			`FPU_EIP -= code_base;`
575
576			`RE_ENTRANT_CHECK_OFF;`
577			`}`
578
579
580			`/* Support for prefix bytes is not yet complete. To properly handle`
581			`all prefix bytes, further changes are needed in the emulator code`
582			`which accesses user address space. Access to separate segments is`
583			`important for msdos emulation. */`
584			`static int valid_prefix(unsigned char Byte, unsigned char *fpu_eip,`
585			`overrides *override)`
586			`{`
587			`unsigned char byte;`
588			`unsigned char ip = fpu_eip;`
589
590			`override = (overrides) { 0, 0, PREFIX_DEFAULT }; / defaults */`
591
592			`RE_ENTRANT_CHECK_OFF;`
593			`FPU_code_verify_area(1);`
594			`byte = get_fs_byte(ip);`
595			`RE_ENTRANT_CHECK_ON;`
596
597			`while ( 1 )`
598			`{`
599			`switch ( byte )`
600			`{`
601			`case ADDR_SIZE_PREFIX:`
602			`override->address_size = ADDR_SIZE_PREFIX;`
603			`goto do_next_byte;`
604
605			`case OP_SIZE_PREFIX:`
606			`override->operand_size = OP_SIZE_PREFIX;`
607			`goto do_next_byte;`
608
609			`case PREFIX_CS:`
610			`override->segment = PREFIX_CS_;`
611			`goto do_next_byte;`
612			`case PREFIX_ES:`
613			`override->segment = PREFIX_ES_;`
614			`goto do_next_byte;`
615			`case PREFIX_SS:`
616			`override->segment = PREFIX_SS_;`
617			`goto do_next_byte;`
618			`case PREFIX_FS:`
619			`override->segment = PREFIX_FS_;`
620			`goto do_next_byte;`
621			`case PREFIX_GS:`
622			`override->segment = PREFIX_GS_;`
623			`goto do_next_byte;`
624			`case PREFIX_DS:`
625			`override->segment = PREFIX_DS_;`
626			`goto do_next_byte;`
627
628			`/* lock is not a valid prefix for FPU instructions,`
629			`let the cpu handle it to generate a SIGILL. */`
630			`/* case PREFIX_LOCK: */`
631
632			`/* rep.. prefixes have no meaning for FPU instructions */`
633			`case PREFIX_REPE:`
634			`case PREFIX_REPNE:`
635
636			`do_next_byte:`
637			`ip++;`
638			`RE_ENTRANT_CHECK_OFF;`
639			`FPU_code_verify_area(1);`
640			`byte = get_fs_byte(ip);`
641			`RE_ENTRANT_CHECK_ON;`
642			`break;`
643			`case FWAIT_OPCODE:`
644			`*Byte = byte;`
645			`return 1;`
646			`default:`
647			`if ( (byte & 0xf8) == 0xd8 )`
648			`{`
649			`*Byte = byte;`
650			`*fpu_eip = ip;`
651			`return 1;`
652			`}`
653			`else`
654			`{`
655			`/* Not a valid sequence of prefix bytes followed by`
656			`an FPU instruction. */`
657			`Byte = byte; / Needed for error message. */`
658			`return 0;`
659			`}`
660			`}`
661			`}`
662			`}`
663
664
665			`void math_abort(struct info * info, unsigned int signal)`
666			`{`
667			`FPU_EIP = FPU_ORIG_EIP;`
668			`current->tss.trap_no = 16;`
669			`current->tss.error_code = 0;`
670			`send_sig(signal,current,1);`
671			`RE_ENTRANT_CHECK_OFF;`
672			`__asm__("movl %0,%%esp ; ret": :"g" (((long) info)-4));`
673			`#ifdef PARANOID`
674			`printk("ERROR: wm-FPU-emu math_abort failed!\n");`
675			`#endif PARANOID`
676			`}`
677
678
679
680			`void restore_i387_soft(struct _fpstate *buf)`
681			`{`
682			`fpu_addr_modes addr_modes = {{ 0, 0, PREFIX_DEFAULT }, 0};`
683
684			`frstor(addr_modes, (char *)buf);`
685			`}`
686
687
688			`struct _fpstate * save_i387_soft(struct _fpstate * buf)`
689			`{`
690			`fpu_addr_modes addr_modes = {{ 0, 0, PREFIX_DEFAULT }, 0};`
691
692			`fsave(addr_modes, (char *)buf);`
693
694			`return buf;`
695			`}`