900-nios2.patch

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

+	return nan ();
+      return a;
+    }
+
+  if (isinf (b))
+    {
+      a->fraction.ll = 0;
+      a->normal_exp = 0;
+      return a;
+    }
+  if (iszero (b))
+    {
+      a->class = CLASS_INFINITY;
+      return a;
+    }
+
+  /* Calculate the mantissa by multiplying both 64bit numbers to get a
+     128 bit number */
+  {
+    /* quotient =
+       ( numerator / denominator) * 2^(numerator exponent -  denominator exponent)
+     */
+
+    a->normal_exp = a->normal_exp - b->normal_exp;
+    numerator = a->fraction.ll;
+    denominator = b->fraction.ll;
+
+    if (numerator < denominator)
+      {
+	/* Fraction will be less than 1.0 */
+	numerator *= 2;
+	a->normal_exp--;
+      }
+    bit = IMPLICIT_1;
+    quotient = 0;
+    /* ??? Does divide one bit at a time.  Optimize.  */
+    while (bit)
+      {
+	if (numerator >= denominator)
+	  {
+	    quotient |= bit;
+	    numerator -= denominator;
+	  }
+	bit >>= 1;
+	numerator *= 2;
+      }
+
+    if (!ROUND_TOWARDS_ZERO && (quotient & GARDMASK) == GARDMSB)
+      {
+	if (quotient & (1 << NGARDS))
+	  {
+	    /* half way, so round to even */
+	    quotient += GARDROUND + 1;
+	  }
+	else if (numerator)
+	  {
+	    /* but we really weren't half way, more bits exist */
+	    quotient += GARDROUND + 1;
+	  }
+      }
+
+    a->fraction.ll = quotient;
+    return (a);
+  }
+}
+
+FLO_type
+divide (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  fp_number_type *res;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  res = _fpdiv_parts (&a, &b);
+
+  return pack_d (res);
+}
+#endif /* L_div_sf || L_div_df */
+
+#if defined(L_fpcmp_parts_sf) || defined(L_fpcmp_parts_df) \
+    || defined(L_fpcmp_parts_tf)
+/* according to the demo, fpcmp returns a comparison with 0... thus
+   a<b -> -1
+   a==b -> 0
+   a>b -> +1
+ */
+
+int
+__fpcmp_parts (fp_number_type * a, fp_number_type * b)
+{
+#if 0
+  /* either nan -> unordered. Must be checked outside of this routine.  */
+  if (isnan (a) && isnan (b))
+    {
+      return 1;			/* still unordered! */
+    }
+#endif
+
+  if (isnan (a) || isnan (b))
+    {
+      return 1;			/* how to indicate unordered compare? */
+    }
+  if (isinf (a) && isinf (b))
+    {
+      /* +inf > -inf, but +inf != +inf */
+      /* b    \a| +inf(0)| -inf(1)
+       ______\+--------+--------
+       +inf(0)| a==b(0)| a<b(-1)
+       -------+--------+--------
+       -inf(1)| a>b(1) | a==b(0)
+       -------+--------+--------
+       So since unordered must be nonzero, just line up the columns...
+       */
+      return b->sign - a->sign;
+    }
+  /* but not both...  */
+  if (isinf (a))
+    {
+      return a->sign ? -1 : 1;
+    }
+  if (isinf (b))
+    {
+      return b->sign ? 1 : -1;
+    }
+  if (iszero (a) && iszero (b))
+    {
+      return 0;
+    }
+  if (iszero (a))
+    {
+      return b->sign ? 1 : -1;
+    }
+  if (iszero (b))
+    {
+      return a->sign ? -1 : 1;
+    }
+  /* now both are "normal".  */
+  if (a->sign != b->sign)
+    {
+      /* opposite signs */
+      return a->sign ? -1 : 1;
+    }
+  /* same sign; exponents? */
+  if (a->normal_exp > b->normal_exp)
+    {
+      return a->sign ? -1 : 1;
+    }
+  if (a->normal_exp < b->normal_exp)
+    {
+      return a->sign ? 1 : -1;
+    }
+  /* same exponents; check size.  */
+  if (a->fraction.ll > b->fraction.ll)
+    {
+      return a->sign ? -1 : 1;
+    }
+  if (a->fraction.ll < b->fraction.ll)
+    {
+      return a->sign ? 1 : -1;
+    }
+  /* after all that, they're equal.  */
+  return 0;
+}
+#endif
+
+#if defined(L_compare_sf) || defined(L_compare_df) || defined(L_compoare_tf)
+CMPtype
+compare (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  return __fpcmp_parts (&a, &b);
+}
+#endif /* L_compare_sf || L_compare_df */
+
+#ifndef US_SOFTWARE_GOFAST
+
+/* These should be optimized for their specific tasks someday.  */
+
+#if defined(L_eq_sf) || defined(L_eq_df) || defined(L_eq_tf)
+CMPtype
+_eq_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  if (isnan (&a) || isnan (&b))
+    return 1;			/* false, truth == 0 */
+
+  return __fpcmp_parts (&a, &b) ;
+}
+#endif /* L_eq_sf || L_eq_df */
+
+#if defined(L_ne_sf) || defined(L_ne_df) || defined(L_ne_tf)
+CMPtype
+_ne_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  if (isnan (&a) || isnan (&b))
+    return 1;			/* true, truth != 0 */
+
+  return  __fpcmp_parts (&a, &b) ;
+}
+#endif /* L_ne_sf || L_ne_df */
+
+#if defined(L_gt_sf) || defined(L_gt_df) || defined(L_gt_tf)
+CMPtype
+_gt_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  if (isnan (&a) || isnan (&b))
+    return -1;			/* false, truth > 0 */
+
+  return __fpcmp_parts (&a, &b);
+}
+#endif /* L_gt_sf || L_gt_df */
+
+#if defined(L_ge_sf) || defined(L_ge_df) || defined(L_ge_tf)
+CMPtype
+_ge_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  if (isnan (&a) || isnan (&b))
+    return -1;			/* false, truth >= 0 */
+  return __fpcmp_parts (&a, &b) ;
+}
+#endif /* L_ge_sf || L_ge_df */
+
+#if defined(L_lt_sf) || defined(L_lt_df) || defined(L_lt_tf)
+CMPtype
+_lt_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  if (isnan (&a) || isnan (&b))
+    return 1;			/* false, truth < 0 */
+
+  return __fpcmp_parts (&a, &b);
+}
+#endif /* L_lt_sf || L_lt_df */
+
+#if defined(L_le_sf) || defined(L_le_df) || defined(L_le_tf)
+CMPtype
+_le_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  if (isnan (&a) || isnan (&b))
+    return 1;			/* false, truth <= 0 */
+
+  return __fpcmp_parts (&a, &b) ;
+}
+#endif /* L_le_sf || L_le_df */
+
+#endif /* ! US_SOFTWARE_GOFAST */
+
+#if defined(L_unord_sf) || defined(L_unord_df) || defined(L_unord_tf)
+CMPtype
+_unord_f2 (FLO_type arg_a, FLO_type arg_b)
+{
+  fp_number_type a;
+  fp_number_type b;
+  FLO_union_type au, bu;
+
+  au.value = arg_a;
+  bu.value = arg_b;
+
+  unpack_d (&au, &a);
+  unpack_d (&bu, &b);
+
+  return (isnan (&a) || isnan (&b));
+}
+#endif /* L_unord_sf || L_unord_df */
+
+#if defined(L_si_to_sf) || defined(L_si_to_df) || defined(L_si_to_tf)
+FLO_type
+si_to_float (SItype arg_a)
+{
+  fp_number_type in;
+
+  in.class = CLASS_NUMBER;
+  in.sign = arg_a < 0;
+  if (!arg_a)
+    {
+      in.class = CLASS_ZERO;
+    }
+  else
+    {
+      in.normal_exp = FRACBITS + NGARDS;
+      if (in.sign) 
+	{
+	  /* Special case for minint, since there is no +ve integer
+	     representation for it */
+	  if (arg_a == (- MAX_SI_INT - 1))
+	    {
+	      return (FLO_type)(- MAX_SI_INT - 1);
+	    }
+	  in.fraction.ll = (-arg_a);
+	}
+      else
+	in.fraction.ll = arg_a;
+
+      while (in.fraction.ll < ((fractype)1 << (FRACBITS + NGARDS)))
+	{
+	  in.fraction.ll <<= 1;
+	  in.normal_exp -= 1;
+	}
+    }
+  return pack_d (&in);
+}
+#endif /* L_si_to_sf || L_si_to_df */
+
+#if defined(L_usi_to_sf) || defined(L_usi_to_df) || defined(L_usi_to_tf)
+FLO_type
+usi_to_float (USItype arg_a)
+{
+  fp_number_type in;
+
+  in.sign = 0;
+  if (!arg_a)
+    {
+      in.class = CLASS_ZERO;
+    }
+  else
+    {
+      in.class = CLASS_NUMBER;
+      in.normal_exp = FRACBITS + NGARDS;
+      in.fraction.ll = arg_a;
+
+      while (in.fraction.ll > ((fractype)1 << (FRACBITS + NGARDS)))
+        {
+          in.fraction.ll >>= 1;
+          in.normal_exp += 1;
+        }
+      while (in.fraction.ll < ((fractype)1 << (FRACBITS + NGARDS)))
+	{
+	  in.fraction.ll <<= 1;
+	  in.normal_exp -= 1;
+	}
+    }
+  return pack_d (&in);
+}
+#endif
+
+#if defined(L_sf_to_si) || defined(L_df_to_si) || defined(L_tf_to_si)
+SItype
+float_to_si (FLO_type arg_a)
+{
+  fp_number_type a;
+  SItype tmp;
+  FLO_union_type au;
+
+  au.value = arg_a;
+  unpack_d (&au, &a);
+
+  if (iszero (&a))
+    return 0;
+  if (isnan (&a))
+    return 0;
+  /* get reasonable MAX_SI_INT...  */
+  if (isinf (&a))
+    return a.sign ? (-MAX_SI_INT)-1 : MAX_SI_INT;
+  /* it is a number, but a small one */
+  if (a.normal_exp < 0)
+    return 0;
+  if (a.normal_exp > BITS_PER_SI - 2)
+    return a.sign ? (-MAX_SI_INT)-1 : MAX_SI_INT;
+  tmp = a.fraction.ll >> ((FRACBITS + NGARDS) - a.normal_exp);
+  return a.sign ? (-tmp) : (tmp);
+}
+#endif /* L_sf_to_si || L_df_to_si */
+
+#if defined(L_sf_to_usi) || defined(L_df_to_usi) || defined(L_tf_to_usi)
+#if defined US_SOFTWARE_GOFAST || defined(L_tf_to_usi)
+/* While libgcc2.c defines its own __fixunssfsi and __fixunsdfsi routines,
+   we also define them for GOFAST because the ones in libgcc2.c have the
+   wrong names and I'd rather define these here and keep GOFAST CYG-LOC's
+   out of libgcc2.c.  We can't define these here if not GOFAST because then
+   there'd be duplicate copies.  */
+
+USItype
+float_to_usi (FLO_type arg_a)
+{
+  fp_number_type a;
+  FLO_union_type au;
+
+  au.value = arg_a;
+  unpack_d (&au, &a);
+
+  if (iszero (&a))
+    return 0;
+  if (isnan (&a))
+    return 0;
+  /* it is a negative number */
+  if (a.sign)
+    return 0;
+  /* get reasonable MAX_USI_INT...  */
+  if (isinf (&a))
+    return MAX_USI_INT;
+  /* it is a number, but a small one */
+  if (a.normal_exp < 0)
+    return 0;
+  if (a.normal_exp > BITS_PER_SI - 1)
+    return MAX_USI_INT;
+  else if (a.normal_exp > (FRACBITS + NGARDS))
+    return a.fraction.ll << (a.normal_exp - (FRACBITS + NGARDS));
+  else
+    return a.fraction.ll >> ((FRACBITS + NGARDS) - a.normal_exp);
+}
+#endif /* US_SOFTWARE_GOFAST */
+#endif /* L_sf_to_usi || L_df_to_usi */
+
+#if defined(L_negate_sf) || defined(L_negate_df) || defined(L_negate_tf)
+FLO_type
+negate (FLO_type arg_a)
+{
+  fp_number_type a;
+  FLO_union_type au;
+
+  au.value = arg_a;
+  unpack_d (&au, &a);
+
+  flip_sign (&a);
+  return pack_d (&a);
+}
+#endif /* L_negate_sf || L_negate_df */
+
+#ifdef FLOAT
+
+#if defined(L_make_sf)
+SFtype
+__make_fp(fp_class_type class,
+	     unsigned int sign,
+	     int exp, 
+	     USItype frac)
+{
+  fp_number_type in;
+
+  in.class = class;
+  in.sign = sign;
+  in.normal_exp = exp;
+  in.fraction.ll = frac;
+  return pack_d (&in);
+}
+#endif /* L_make_sf */
+
+#ifndef FLOAT_ONLY
+
+/* This enables one to build an fp library that supports float but not double.
+   Otherwise, we would get an undefined reference to __make_dp.
+   This is needed for some 8-bit ports that can't handle well values that
+   are 8-bytes in size, so we just don't support double for them at all.  */
+
+#if defined(L_sf_to_df)
+DFtype
+sf_to_df (SFtype arg_a)
+{
+  fp_number_type in;
+  FLO_union_type au;
+
+  au.value = arg_a;
+  unpack_d (&au, &in);
+
+  return __make_dp (in.class, in.sign, in.normal_exp,
+		    ((UDItype) in.fraction.ll) << F_D_BITOFF);
+}