예제 #1
0
static int
math_emulate(struct trapframe * tframe)
{

	unsigned char FPU_modrm;
	unsigned short code;
#ifdef LOOKAHEAD_LIMIT
	int lookahead_limit = LOOKAHEAD_LIMIT;
#endif
#ifdef PARANOID
	if (emulating) {
		printf("ERROR: wm-FPU-emu is not RE-ENTRANT!\n");
	}
	REENTRANT_CHECK(ON);
#endif				/* PARANOID */

	if ((((struct pcb *) curproc->p_addr)->pcb_flags & FP_SOFTFP) == 0) {
		finit();
		control_word = __INITIAL_NPXCW__;
		((struct pcb *) curproc->p_addr)->pcb_flags |= FP_SOFTFP;
	}
	FPU_info = tframe;
	FPU_ORIG_EIP = FPU_EIP;	/* --pink-- */

	if (FPU_CS != 0x001f) {
		printf("math_emulate: %x : %x\n", FPU_CS, FPU_EIP);
		panic("FPU emulation in kernel");
	}
#ifdef notyet
	/* We cannot handle emulation in v86-mode */
	if (FPU_EFLAGS & 0x00020000) {
		FPU_ORIG_EIP = FPU_EIP;
		math_abort(FPU_info, SIGILL);
	}
#endif

	FPU_lookahead = FPU_LOOKAHEAD;
	if (curproc->p_flag & P_TRACED)
		FPU_lookahead = 0;

do_another_FPU_instruction:

	REENTRANT_CHECK(OFF);
	code = fuword((u_int *) FPU_EIP);
	REENTRANT_CHECK(ON);
	if ((code & 0xff) == 0x9b) {	/* fwait */
		if (status_word & SW_Summary)
			goto do_the_FPU_interrupt;
		else {
			FPU_EIP++;
			goto FPU_instruction_done;
		}
	}
	if (status_word & 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, so I use
		 * the following list of such instructions until I can check
		 * on a real 80486: fninit, fnstenv, fnsave, fnstsw, fnstenv,
		 * fnclex. */
		if (!((((code & 0xf803) == 0xe003) ||	/* fnclex, fninit,
							 * fnstsw */
			    (((code & 0x3003) == 0x3001) &&	/* fnsave, fnstcw,
								 * fnstenv, fnstsw */
				((code & 0xc000) != 0xc000))))) {
			/* This is a guess about what a real FPU might do to
			 * this bit: */
/*	  status_word &= ~SW_Summary; ****/

			/* We need to simulate the action of the kernel to FPU
			 * interrupts here. Currently, the "real FPU" part of
			 * the kernel (0.99.10) clears the exception flags,
			 * sets the registers to empty, and passes information
			 * back to the interrupted process via the cs selector
			 * and operand selector, so we do the same. */
	do_the_FPU_interrupt:
			cs_selector &= 0xffff0000;
			cs_selector |= (status_word & ~SW_Top) | ((top & 7) << SW_Top_Shift);
			operand_selector = tag_word();
			status_word = 0;
			top = 0;
			{
				int     r;
				for (r = 0; r < 8; r++) {
					regs[r].tag = TW_Empty;
				}
			}
			REENTRANT_CHECK(OFF);
			math_abort(SIGFPE);
		}
	}
	FPU_entry_eip = FPU_ORIG_EIP = FPU_EIP;

	if ((code & 0xff) == 0x66) {	/* size prefix */
		FPU_EIP++;
		REENTRANT_CHECK(OFF);
		code = fuword((u_int *) FPU_EIP);
		REENTRANT_CHECK(ON);
	}
	FPU_EIP += 2;

	FPU_modrm = code >> 8;
	FPU_rm = FPU_modrm & 7;

	if (FPU_modrm < 0300) {
		/* All of these instructions use the mod/rm byte to get a data
		 * address */
		get_address(FPU_modrm);
		if (!(code & 1)) {
			unsigned short status1 = status_word;
			FPU_st0_ptr = &st(0);
			FPU_st0_tag = FPU_st0_ptr->tag;

			/* Stack underflow has priority */
			if (NOT_EMPTY_0) {
				switch ((code >> 1) & 3) {
				case 0:
					reg_load_single();
					break;
				case 1:
					reg_load_int32();
					break;
				case 2:
					reg_load_double();
					break;
				case 3:
					reg_load_int16();
					break;
				}

				/* No more access to user memory, it is safe
				 * to use static data now */
				FPU_st0_ptr = &st(0);
				FPU_st0_tag = FPU_st0_ptr->tag;

				/* 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 ((FPU_st0_tag == TW_NaN) ||
				    (FPU_loaded_data.tag == TW_NaN)) {
					/* Restore the status word; we might
					 * have loaded a denormal. */
					status_word = status1;
					if ((FPU_modrm & 0x30) == 0x10) {
						/* fcom or fcomp */
						EXCEPTION(EX_Invalid);
						setcc(SW_C3 | SW_C2 | SW_C0);
						if (FPU_modrm & 0x08)
							pop();	/* fcomp, so we pop. */
					} else
						real_2op_NaN(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr);
					goto reg_mem_instr_done;
				}
				switch ((FPU_modrm >> 3) & 7) {
				case 0:	/* fadd */
					reg_add(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr, control_word);
					break;
				case 1:	/* fmul */
					reg_mul(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr, control_word);
					break;
				case 2:	/* fcom */
					compare_st_data();
					break;
				case 3:	/* fcomp */
					compare_st_data();
					pop();
					break;
				case 4:	/* fsub */
					reg_sub(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr, control_word);
					break;
				case 5:	/* fsubr */
					reg_sub(&FPU_loaded_data, FPU_st0_ptr, FPU_st0_ptr, control_word);
					break;
				case 6:	/* fdiv */
					reg_div(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr, control_word);
					break;
				case 7:	/* fdivr */
					if (FPU_st0_tag == TW_Zero)
						status_word = status1;	/* Undo any denorm tag,
									 * zero-divide has
									 * priority. */
					reg_div(&FPU_loaded_data, FPU_st0_ptr, FPU_st0_ptr, control_word);
					break;
				}
			} else {
				if ((FPU_modrm & 0x30) == 0x10) {
예제 #2
0
void load_store_instr(char type)
{
  FPU_REG *pop_ptr;  /* We need a version of FPU_st0_ptr which won't change. */

  pop_ptr = NULL;    /* Initialized just to stop compiler warnings. */
  switch ( type_table[(int) (unsigned) type] )
    {
    case _NONE_:
      break;
    case _REG0_:
      pop_ptr = &st(0);       /* Some of these instructions pop after
				 storing */

      FPU_st0_ptr = pop_ptr;      /* Set the global variables. */
      FPU_st0_tag = FPU_st0_ptr->tag;
      break;
    case _PUSH_:
      {
	pop_ptr = &st(-1);
	if ( pop_ptr->tag != TW_Empty )
	  { stack_overflow(); return; }
	top--;
      }
      break;
    case _null_:
      return Un_impl();
#ifdef PARANOID
    default:
      return EXCEPTION(EX_INTERNAL);
#endif PARANOID
    }

switch ( type )
  {
  case 000:       /* fld m32real */
    reg_load_single();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 001:      /* fild m32int */
    reg_load_int32();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 002:      /* fld m64real */
    reg_load_double();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 003:      /* fild m16int */
    reg_load_int16();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 010:      /* fst m32real */
    reg_store_single();
    break;
  case 011:      /* fist m32int */
    reg_store_int32();
    break;
  case 012:     /* fst m64real */
    reg_store_double();
    break;
  case 013:     /* fist m16int */
    reg_store_int16();
    break;
  case 014:     /* fstp m32real */
    if ( reg_store_single() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  case 015:     /* fistp m32int */
    if ( reg_store_int32() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  case 016:     /* fstp m64real */
    if ( reg_store_double() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  case 017:     /* fistp m16int */
    if ( reg_store_int16() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  case 020:     /* fldenv  m14/28byte */
    fldenv();
    break;
  case 022:     /* frstor m94/108byte */
    frstor();
    break;
  case 023:     /* fbld m80dec */
    reg_load_bcd();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 024:     /* fldcw */
    RE_ENTRANT_CHECK_OFF
    control_word = get_fs_word((unsigned short *) FPU_data_address);
    RE_ENTRANT_CHECK_ON
#ifdef NO_UNDERFLOW_TRAP
    if ( !(control_word & EX_Underflow) )
      {
	control_word |= EX_Underflow;
      }
#endif
    FPU_data_address = (void *)data_operand_offset; /* We want no net effect */
    FPU_entry_eip = ip_offset;               /* We want no net effect */
    break;
  case 025:      /* fld m80real */
    reg_load_extended();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 027:      /* fild m64int */
    reg_load_int64();
    reg_move(&FPU_loaded_data, pop_ptr);
    break;
  case 030:     /* fstenv  m14/28byte */
    fstenv();
    FPU_data_address = (void *)data_operand_offset; /* We want no net effect */
    FPU_entry_eip = ip_offset;               /* We want no net effect */
    break;
  case 032:      /* fsave */
    fsave();
    FPU_data_address = (void *)data_operand_offset; /* We want no net effect */
    FPU_entry_eip = ip_offset;               /* We want no net effect */
    break;
  case 033:      /* fbstp m80dec */
    if ( reg_store_bcd() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  case 034:      /* fstcw m16int */
    RE_ENTRANT_CHECK_OFF
    verify_area(VERIFY_WRITE,FPU_data_address,2);
    put_fs_word(control_word, (short *) FPU_data_address);
    RE_ENTRANT_CHECK_ON
    FPU_data_address = (void *)data_operand_offset; /* We want no net effect */
    FPU_entry_eip = ip_offset;               /* We want no net effect */
    break;
  case 035:      /* fstp m80real */
    if ( reg_store_extended() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  case 036:      /* fstsw m2byte */
    status_word &= ~SW_TOP;
    status_word |= (top&7) << SW_TOPS;
    RE_ENTRANT_CHECK_OFF
    verify_area(VERIFY_WRITE,FPU_data_address,2);
    put_fs_word(status_word,(short *) FPU_data_address);
    RE_ENTRANT_CHECK_ON
    FPU_data_address = (void *)data_operand_offset; /* We want no net effect */
    FPU_entry_eip = ip_offset;               /* We want no net effect */
    break;
  case 037:      /* fistp m64int */
    if ( reg_store_int64() )
      pop_0();  /* pop only if the number was actually stored
		 (see the 80486 manual p16-28) */
    break;
  }
}