fpu_trig.c

freebsd v4.4内核源码

			reg_sub(&CONST_PI, &sum, &sum, FULL_PRECISION);
		}
		if (quadrant & 1)
			sum.sign ^= SIGN_POS ^ SIGN_NEG;

		/* All of the basic arithmetic is done now */
		control_word = saved_control;
		status_word = saved_status;

		reg_move(&sum, st1_ptr);
	} else
		if ((FPU_st0_tag == TW_Empty) || (st1_tag == TW_Empty)) {
			stack_underflow_pop(1);
			return;
		} else
			if ((FPU_st0_tag == TW_NaN) || (st1_tag == TW_NaN)) {
				real_2op_NaN(FPU_st0_ptr, st1_ptr, st1_ptr);
				pop();
				return;
			} else
				if ((FPU_st0_tag == TW_Infinity) || (st1_tag == TW_Infinity)) {
					char    sign = st1_ptr->sign;
					if (FPU_st0_tag == TW_Infinity) {
						if (st1_tag == TW_Infinity) {
							if (FPU_st0_ptr->sign == SIGN_POS) {
								reg_move(&CONST_PI4, st1_ptr);
							} else
								reg_add(&CONST_PI4, &CONST_PI2, st1_ptr, FULL_PRECISION);
						} else {

#ifdef DENORM_OPERAND
							if ((st1_ptr->exp <= EXP_UNDER) && (denormal_operand()))
								return;
#endif				/* DENORM_OPERAND */

							if (FPU_st0_ptr->sign == SIGN_POS) {
								reg_move(&CONST_Z, st1_ptr);
								pop();
								return;
							} else
								reg_move(&CONST_PI, st1_ptr);
						}
					} else {
						/* st(1) is infinity, st(0)
						 * not infinity */
#ifdef DENORM_OPERAND
						if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
							return;
#endif				/* DENORM_OPERAND */

						reg_move(&CONST_PI2, st1_ptr);
					}
					st1_ptr->sign = sign;
				} else
					if (st1_tag == TW_Zero) {
						/* st(0) must be valid or zero */
						char    sign = st1_ptr->sign;

#ifdef DENORM_OPERAND
						if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
							return;
#endif				/* DENORM_OPERAND */

						if (FPU_st0_ptr->sign == SIGN_POS) {
							reg_move(&CONST_Z, st1_ptr);
							pop();
							return;
						} else
							reg_move(&CONST_PI, st1_ptr);
						st1_ptr->sign = sign;
					} else
						if (FPU_st0_tag == TW_Zero) {
							/* st(1) must be
							 * TW_Valid here */
							char    sign = st1_ptr->sign;

#ifdef DENORM_OPERAND
							if ((st1_ptr->exp <= EXP_UNDER) && (denormal_operand()))
								return;
#endif				/* DENORM_OPERAND */

							reg_move(&CONST_PI2, st1_ptr);
							st1_ptr->sign = sign;
						}
#ifdef PARANOID
						else
							EXCEPTION(EX_INTERNAL | 0x220);
#endif				/* PARANOID */

	pop();
	set_precision_flag_up();/* We do not really know if up or down */
}


static void
fprem(void)
{
	fprem_kernel(RC_CHOP);
}


static void
fprem1(void)
{
	fprem_kernel(RC_RND);
}


static void
fyl2xp1(void)
{
	FPU_REG *st1_ptr = &st(1);
	char    st1_tag = st1_ptr->tag;

	if (!((FPU_st0_tag ^ TW_Valid) | (st1_tag ^ TW_Valid))) {
		int     saved_control, saved_status;

#ifdef DENORM_OPERAND
		if (((FPU_st0_ptr->exp <= EXP_UNDER) ||
			(st1_ptr->exp <= EXP_UNDER)) && (denormal_operand()))
			return;
#endif				/* DENORM_OPERAND */

		/* We use the general purpose arithmetic so we need to save
		 * these. */
		saved_status = status_word;
		saved_control = control_word;
		control_word = FULL_PRECISION;

		if (poly_l2p1(FPU_st0_ptr, FPU_st0_ptr)) {
			arith_invalid(st1_ptr);	/* poly_l2p1() returned
						 * invalid */
			pop();
			return;
		}
		/* Enough of the basic arithmetic is done now */
		control_word = saved_control;
		status_word = saved_status;

		/* Let the multiply set the flags */
		reg_mul(FPU_st0_ptr, st1_ptr, st1_ptr, FULL_PRECISION);

		pop();
	} else
		if ((FPU_st0_tag == TW_Empty) | (st1_tag == TW_Empty)) {
			stack_underflow_pop(1);
			return;
		} else
			if (FPU_st0_tag == TW_Zero) {
				if (st1_tag <= TW_Zero) {

#ifdef DENORM_OPERAND
					if ((st1_tag == TW_Valid) && (st1_ptr->exp <= EXP_UNDER) &&
					    (denormal_operand()))
						return;
#endif				/* DENORM_OPERAND */

					st1_ptr->sign ^= FPU_st0_ptr->sign;
					reg_move(FPU_st0_ptr, st1_ptr);
				} else
					if (st1_tag == TW_Infinity) {
						arith_invalid(st1_ptr);	/* Infinity*log(1) */
						pop();
						return;
					} else
						if (st1_tag == TW_NaN) {
							real_2op_NaN(FPU_st0_ptr, st1_ptr, st1_ptr);
							pop();
							return;
						}
#ifdef PARANOID
						else {
							EXCEPTION(EX_INTERNAL | 0x116);
							return;
						}
#endif				/* PARANOID */
				pop();
				return;
			} else
				if (FPU_st0_tag == TW_Valid) {
					if (st1_tag == TW_Zero) {
						if (FPU_st0_ptr->sign == SIGN_NEG) {
							if (FPU_st0_ptr->exp >= EXP_BIAS) {
								/* st(0) holds
								 * <= -1.0 */
								arith_invalid(st1_ptr);	/* infinity*log(1) */
								pop();
								return;
							}
#ifdef DENORM_OPERAND
							if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
								return;
#endif				/* DENORM_OPERAND */
							st1_ptr->sign ^= SIGN_POS ^ SIGN_NEG;
							pop();
							return;
						}
#ifdef DENORM_OPERAND
						if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
							return;
#endif				/* DENORM_OPERAND */
						pop();
						return;
					}
					if (st1_tag == TW_Infinity) {
						if (FPU_st0_ptr->sign == SIGN_NEG) {
							if ((FPU_st0_ptr->exp >= EXP_BIAS) &&
							    !((FPU_st0_ptr->sigh == 0x80000000) &&
								(FPU_st0_ptr->sigl == 0))) {
								/* st(0) holds
								 * < -1.0 */
								arith_invalid(st1_ptr);
								pop();
								return;
							}
#ifdef DENORM_OPERAND
							if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
								return;
#endif				/* DENORM_OPERAND */
							st1_ptr->sign ^= SIGN_POS ^ SIGN_NEG;
							pop();
							return;
						}
#ifdef DENORM_OPERAND
						if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
							return;
#endif				/* DENORM_OPERAND */
						pop();
						return;
					}
					if (st1_tag == TW_NaN) {
						real_2op_NaN(FPU_st0_ptr, st1_ptr, st1_ptr);
						pop();
						return;
					}
				} else
					if (FPU_st0_tag == TW_NaN) {
						real_2op_NaN(FPU_st0_ptr, st1_ptr, st1_ptr);
						pop();
						return;
					} else
						if (FPU_st0_tag == TW_Infinity) {
							if (st1_tag == TW_NaN) {
								real_2op_NaN(FPU_st0_ptr, st1_ptr, st1_ptr);
								pop();
								return;
							} else
								if ((FPU_st0_ptr->sign == SIGN_NEG) ||
								    (st1_tag == TW_Zero)) {
									arith_invalid(st1_ptr);	/* log(infinity) */
									pop();
									return;
								}
							/* st(1) must be valid
							 * here. */

#ifdef DENORM_OPERAND
							if ((st1_ptr->exp <= EXP_UNDER) && (denormal_operand()))
								return;
#endif				/* DENORM_OPERAND */

							/* The Manual says
							 * that log(Infinity)
							 * is invalid, but a
							 * real 80486 sensibly
							 * says that it is
							 * o.k. */
							{
								char    sign = st1_ptr->sign;
								reg_move(&CONST_INF, st1_ptr);
								st1_ptr->sign = sign;
							}
							pop();
							return;
						}
#ifdef PARANOID
						else {
							EXCEPTION(EX_INTERNAL | 0x117);
						}
#endif				/* PARANOID */
}


static void
emu_fscale(void)
{
	FPU_REG *st1_ptr = &st(1);
	char    st1_tag = st1_ptr->tag;
	int     old_cw = control_word;

	if (!((FPU_st0_tag ^ TW_Valid) | (st1_tag ^ TW_Valid))) {
		long    scale;
		FPU_REG tmp;

#ifdef DENORM_OPERAND
		if (((FPU_st0_ptr->exp <= EXP_UNDER) ||
			(st1_ptr->exp <= EXP_UNDER)) && (denormal_operand()))
			return;
#endif				/* DENORM_OPERAND */

		if (st1_ptr->exp > EXP_BIAS + 30) {
			/* 2^31 is far too large, would require 2^(2^30) or
			 * 2^(-2^30) */
			char    sign;

			if (st1_ptr->sign == SIGN_POS) {
				EXCEPTION(EX_Overflow);
				sign = FPU_st0_ptr->sign;
				reg_move(&CONST_INF, FPU_st0_ptr);
				FPU_st0_ptr->sign = sign;
			} else {
				EXCEPTION(EX_Underflow);
				sign = FPU_st0_ptr->sign;
				reg_move(&CONST_Z, FPU_st0_ptr);
				FPU_st0_ptr->sign = sign;
			}
			return;
		}
		control_word &= ~CW_RC;
		control_word |= RC_CHOP;
		reg_move(st1_ptr, &tmp);
		round_to_int(&tmp);	/* This can never overflow here */
		control_word = old_cw;
		scale = st1_ptr->sign ? -tmp.sigl : tmp.sigl;
		scale += FPU_st0_ptr->exp;
		FPU_st0_ptr->exp = scale;

		/* Use round_reg() to properly detect under/overflow etc */
		round_reg(FPU_st0_ptr, 0, control_word);

		return;
	} else
		if (FPU_st0_tag == TW_Valid) {
			if (st1_tag == TW_Zero) {

#ifdef DENORM_OPERAND
				if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
					return;
#endif				/* DENORM_OPERAND */

				return;
			}
			if (st1_tag == TW_Infinity) {
				char    sign = st1_ptr->sign;

#ifdef DENORM_OPERAND
				if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
					return;
#endif				/* DENORM_OPERAND */

				if (sign == SIGN_POS) {
					reg_move(&CONST_INF, FPU_st0_ptr);
				} else
					reg_move(&CONST_Z, FPU_st0_ptr);
				FPU_st0_ptr->sign = sign;
				return;
			}
			if (st1_tag == TW_NaN) {
				real_2op_NaN(FPU_st0_ptr, st1_ptr, FPU_st0_ptr);
				return;
			}
		} else
			if (FPU_st0_tag == TW_Zero) {
				if (st1_tag == TW_Valid) {

#ifdef DENORM_OPERAND
					if ((st1_ptr->exp <= EXP_UNDER) && (denormal_operand()))
						return;
#endif				/* DENORM_OPERAND */

					return;
				} else
					if (st1_tag == TW_Zero) {
						return;
					} else
						if (st1_tag == TW_Infinity) {
							if (st1_ptr->sign == SIGN_NEG)
								return;
							else {
								arith_invalid(FPU_st0_ptr);	/* Zero scaled by
												 * +Infinity */
								return;
							}
						} else
							if (st1_tag == TW_NaN) {
								real_2op_NaN(FPU_st0_ptr, st1_ptr, FPU_st0_ptr);
								return;
							}
			} else
				if (FPU_st0_tag == TW_Infinity) {
					if (st1_tag == TW_Valid) {

#ifdef DENORM_OPERAND
						if ((st1_ptr->exp <= EXP_UNDER) && (denormal_operand()))
							return;
#endif				/* DENORM_OPERAND */

						return;
					}
					if (((st1_tag == TW_Infinity) && (st1_ptr->sign == SIGN_POS))
					    || (st1_tag == TW_Zero))
						return;
					else
						if (st1_tag == TW_Infinity) {
							arith_invalid(FPU_st0_ptr);	/* Infinity scaled by
											 * -Infinity */
							return;
						} else
							if (st1_tag == TW_NaN) {
								real_2op_NaN(FPU_st0_ptr, st1_ptr, FPU_st0_ptr);
								return;
							}
				} else
					if (FPU_st0_tag == TW_NaN) {
						if (st1_tag != TW_Empty) {
							real_2op_NaN(FPU_st0_ptr, st1_ptr, FPU_st0_ptr);
							return;
						}
					}
#ifdef PARANOID
	if (!((FPU_st0_tag == TW_Empty) || (st1_tag == TW_Empty))) {
		EXCEPTION(EX_INTERNAL | 0x115);
		return;
	}
#endif

	/* At least one of st(0), st(1) must be empty */
	stack_underflow();

}


/*---------------------------------------------------------------------------*/

static FUNC trig_table_a[] = {
	f2xm1, fyl2x, fptan, fpatan, fxtract, fprem1, fdecstp, fincstp
};

void
trig_a(void)
{
	(trig_table_a[FPU_rm]) ();
}


static FUNC trig_table_b[] =
{
	fprem, fyl2xp1, fsqrt_, fsincos, frndint_, emu_fscale, fsin, fcos
};

void
trig_b(void)
{
	(trig_table_b[FPU_rm]) ();
}