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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- U R E A L P -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2009 Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- <http://www.gnu.org/licenses/>. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Alloc; with Output; use Output; with Table; with Tree_IO; use Tree_IO; package body Urealp is Ureal_First_Entry : constant Ureal := Ureal'Succ (No_Ureal); -- First subscript allocated in Ureal table (note that we can't just -- add 1 to No_Ureal, since "+" means something different for Ureals! type Ureal_Entry is record Num : Uint; -- Numerator (always non-negative) Den : Uint; -- Denominator (always non-zero, always positive if base is zero) Rbase : Nat; -- Base value. If Rbase is zero, then the value is simply Num / Den. -- If Rbase is non-zero, then the value is Num / (Rbase ** Den) Negative : Boolean; -- Flag set if value is negative end record; -- The following representation clause ensures that the above record -- has no holes. We do this so that when instances of this record are -- written by Tree_Gen, we do not write uninitialized values to the file. for Ureal_Entry use record Num at 0 range 0 .. 31; Den at 4 range 0 .. 31; Rbase at 8 range 0 .. 31; Negative at 12 range 0 .. 31; end record; for Ureal_Entry'Size use 16 * 8; -- This ensures that we did not leave out any fields package Ureals is new Table.Table ( Table_Component_Type => Ureal_Entry, Table_Index_Type => Ureal'Base, Table_Low_Bound => Ureal_First_Entry, Table_Initial => Alloc.Ureals_Initial, Table_Increment => Alloc.Ureals_Increment, Table_Name => "Ureals"); -- The following universal reals are the values returned by the constant -- functions. They are initialized by the initialization procedure. UR_0 : Ureal; UR_M_0 : Ureal; UR_Tenth : Ureal; UR_Half : Ureal; UR_1 : Ureal; UR_2 : Ureal; UR_10 : Ureal; UR_10_36 : Ureal; UR_M_10_36 : Ureal; UR_100 : Ureal; UR_2_128 : Ureal; UR_2_80 : Ureal; UR_2_M_128 : Ureal; UR_2_M_80 : Ureal; Num_Ureal_Constants : constant := 10; -- This is used for an assertion check in Tree_Read and Tree_Write to -- help remember to add values to these routines when we add to the list. Normalized_Real : Ureal := No_Ureal; -- Used to memoize Norm_Num and Norm_Den, if either of these functions -- is called, this value is set and Normalized_Entry contains the result -- of the normalization. On subsequent calls, this is used to avoid the -- call to Normalize if it has already been made. Normalized_Entry : Ureal_Entry; -- Entry built by most recent call to Normalize ----------------------- -- Local Subprograms -- ----------------------- function Decimal_Exponent_Hi (V : Ureal) return Int; -- Returns an estimate of the exponent of Val represented as a normalized -- decimal number (non-zero digit before decimal point), The estimate is -- either correct, or high, but never low. The accuracy of the estimate -- affects only the efficiency of the comparison routines. function Decimal_Exponent_Lo (V : Ureal) return Int; -- Returns an estimate of the exponent of Val represented as a normalized -- decimal number (non-zero digit before decimal point), The estimate is -- either correct, or low, but never high. The accuracy of the estimate -- affects only the efficiency of the comparison routines. function Equivalent_Decimal_Exponent (U : Ureal_Entry) return Int; -- U is a Ureal entry for which the base value is non-zero, the value -- returned is the equivalent decimal exponent value, i.e. the value of -- Den, adjusted as though the base were base 10. The value is rounded -- to the nearest integer, and so can be one off. function Is_Integer (Num, Den : Uint) return Boolean; -- Return true if the real quotient of Num / Den is an integer value function Normalize (Val : Ureal_Entry) return Ureal_Entry; -- Normalizes the Ureal_Entry by reducing it to lowest terms (with a -- base value of 0). function Same (U1, U2 : Ureal) return Boolean; pragma Inline (Same); -- Determines if U1 and U2 are the same Ureal. Note that we cannot use -- the equals operator for this test, since that tests for equality, -- not identity. function Store_Ureal (Val : Ureal_Entry) return Ureal; -- This store a new entry in the universal reals table and return -- its index in the table. ------------------------- -- Decimal_Exponent_Hi -- ------------------------- function Decimal_Exponent_Hi (V : Ureal) return Int is Val : constant Ureal_Entry := Ureals.Table (V); begin -- Zero always returns zero if UR_Is_Zero (V) then return 0; -- For numbers in rational form, get the maximum number of digits in the -- numerator and the minimum number of digits in the denominator, and -- subtract. For example: -- 1000 / 99 = 1.010E+1 -- 9999 / 10 = 9.999E+2 -- This estimate may of course be high, but that is acceptable elsif Val.Rbase = 0 then return UI_Decimal_Digits_Hi (Val.Num) - UI_Decimal_Digits_Lo (Val.Den); -- For based numbers, just subtract the decimal exponent from the -- high estimate of the number of digits in the numerator and add -- one to accommodate possible round off errors for non-decimal -- bases. For example: -- 1_500_000 / 10**4 = 1.50E-2 else -- Val.Rbase /= 0 return UI_Decimal_Digits_Hi (Val.Num) - Equivalent_Decimal_Exponent (Val) + 1; end if; end Decimal_Exponent_Hi; ------------------------- -- Decimal_Exponent_Lo -- ------------------------- function Decimal_Exponent_Lo (V : Ureal) return Int is Val : constant Ureal_Entry := Ureals.Table (V); begin -- Zero always returns zero if UR_Is_Zero (V) then return 0; -- For numbers in rational form, get min digits in numerator, max digits -- in denominator, and subtract and subtract one more for possible loss -- during the division. For example: -- 1000 / 99 = 1.010E+1 -- 9999 / 10 = 9.999E+2 -- This estimate may of course be low, but that is acceptable elsif Val.Rbase = 0 then return UI_Decimal_Digits_Lo (Val.Num) - UI_Decimal_Digits_Hi (Val.Den) - 1; -- For based numbers, just subtract the decimal exponent from the -- low estimate of the number of digits in the numerator and subtract -- one to accommodate possible round off errors for non-decimal -- bases. For example: -- 1_500_000 / 10**4 = 1.50E-2 else -- Val.Rbase /= 0 return UI_Decimal_Digits_Lo (Val.Num) - Equivalent_Decimal_Exponent (Val) - 1; end if; end Decimal_Exponent_Lo; ----------------- -- Denominator -- ----------------- function Denominator (Real : Ureal) return Uint is begin return Ureals.Table (Real).Den; end Denominator; --------------------------------- -- Equivalent_Decimal_Exponent -- --------------------------------- function Equivalent_Decimal_Exponent (U : Ureal_Entry) return Int is -- The following table is a table of logs to the base 10 Logs : constant array (Nat range 1 .. 16) of Long_Float := ( 1 => 0.000000000000000, 2 => 0.301029995663981, 3 => 0.477121254719662, 4 => 0.602059991327962, 5 => 0.698970004336019, 6 => 0.778151250383644, 7 => 0.845098040014257, 8 => 0.903089986991944, 9 => 0.954242509439325, 10 => 1.000000000000000, 11 => 1.041392685158230, 12 => 1.079181246047620, 13 => 1.113943352306840, 14 => 1.146128035678240, 15 => 1.176091259055680, 16 => 1.204119982655920); begin pragma Assert (U.Rbase /= 0); return Int (Long_Float (UI_To_Int (U.Den)) * Logs (U.Rbase)); end Equivalent_Decimal_Exponent; ---------------- -- Initialize -- ---------------- procedure Initialize is begin Ureals.Init; UR_0 := UR_From_Components (Uint_0, Uint_1, 0, False); UR_M_0 := UR_From_Components (Uint_0, Uint_1, 0, True); UR_Half := UR_From_Components (Uint_1, Uint_1, 2, False); UR_Tenth := UR_From_Components (Uint_1, Uint_1, 10, False); UR_1 := UR_From_Components (Uint_1, Uint_1, 0, False); UR_2 := UR_From_Components (Uint_1, Uint_Minus_1, 2, False); UR_10 := UR_From_Components (Uint_1, Uint_Minus_1, 10, False); UR_10_36 := UR_From_Components (Uint_1, Uint_Minus_36, 10, False); UR_M_10_36 := UR_From_Components (Uint_1, Uint_Minus_36, 10, True); UR_100 := UR_From_Components (Uint_1, Uint_Minus_2, 10, False); UR_2_128 := UR_From_Components (Uint_1, Uint_Minus_128, 2, False); UR_2_M_128 := UR_From_Components (Uint_1, Uint_128, 2, False); UR_2_80 := UR_From_Components (Uint_1, Uint_Minus_80, 2, False); UR_2_M_80 := UR_From_Components (Uint_1, Uint_80, 2, False); end Initialize; ---------------- -- Is_Integer -- ---------------- function Is_Integer (Num, Den : Uint) return Boolean is begin return (Num / Den) * Den = Num; end Is_Integer; ---------- -- Mark -- ---------- function Mark return Save_Mark is begin return Save_Mark (Ureals.Last); end Mark; -------------- -- Norm_Den -- -------------- function Norm_Den (Real : Ureal) return Uint is begin if not Same (Real, Normalized_Real) then Normalized_Real := Real; Normalized_Entry := Normalize (Ureals.Table (Real)); end if; return Normalized_Entry.Den; end Norm_Den; -------------- -- Norm_Num -- -------------- function Norm_Num (Real : Ureal) return Uint is begin if not Same (Real, Normalized_Real) then Normalized_Real := Real; Normalized_Entry := Normalize (Ureals.Table (Real)); end if; return Normalized_Entry.Num; end Norm_Num; --------------- -- Normalize -- --------------- function Normalize (Val : Ureal_Entry) return Ureal_Entry is J : Uint; K : Uint; Tmp : Uint; Num : Uint; Den : Uint; M : constant Uintp.Save_Mark := Uintp.Mark; begin -- Start by setting J to the greatest of the absolute values of the -- numerator and the denominator (taking into account the base value), -- and K to the lesser of the two absolute values. The gcd of Num and -- Den is the gcd of J and K. if Val.Rbase = 0 then J := Val.Num; K := Val.Den; elsif Val.Den < 0 then J := Val.Num * Val.Rbase ** (-Val.Den); K := Uint_1; else J := Val.Num; K := Val.Rbase ** Val.Den; end if; Num := J; Den := K; if K > J then Tmp := J; J := K; K := Tmp; end if; J := UI_GCD (J, K); Num := Num / J; Den := Den / J; Uintp.Release_And_Save (M, Num, Den); -- Divide numerator and denominator by gcd and return result return (Num => Num, Den => Den, Rbase => 0, Negative => Val.Negative); end Normalize; --------------- -- Numerator -- --------------- function Numerator (Real : Ureal) return Uint is begin return Ureals.Table (Real).Num; end Numerator; -------- -- pr -- -------- procedure pr (Real : Ureal) is begin UR_Write (Real); Write_Eol; end pr; ----------- -- Rbase -- ----------- function Rbase (Real : Ureal) return Nat is begin return Ureals.Table (Real).Rbase; end Rbase; ------------- -- Release -- ------------- procedure Release (M : Save_Mark) is begin Ureals.Set_Last (Ureal (M)); end Release; ---------- -- Same -- ---------- function Same (U1, U2 : Ureal) return Boolean is begin return Int (U1) = Int (U2); end Same; ----------------- -- Store_Ureal -- ----------------- function Store_Ureal (Val : Ureal_Entry) return Ureal is begin Ureals.Append (Val); -- Normalize representation of signed values if Val.Num < 0 then Ureals.Table (Ureals.Last).Negative := True; Ureals.Table (Ureals.Last).Num := -Val.Num; end if; return Ureals.Last; end Store_Ureal; --------------- -- Tree_Read -- --------------- procedure Tree_Read is begin pragma Assert (Num_Ureal_Constants = 10); Ureals.Tree_Read; Tree_Read_Int (Int (UR_0)); Tree_Read_Int (Int (UR_M_0)); Tree_Read_Int (Int (UR_Tenth)); Tree_Read_Int (Int (UR_Half)); Tree_Read_Int (Int (UR_1)); Tree_Read_Int (Int (UR_2)); Tree_Read_Int (Int (UR_10)); Tree_Read_Int (Int (UR_100)); Tree_Read_Int (Int (UR_2_128)); Tree_Read_Int (Int (UR_2_M_128)); -- Clear the normalization cache Normalized_Real := No_Ureal; end Tree_Read; ---------------- -- Tree_Write -- ---------------- procedure Tree_Write is begin pragma Assert (Num_Ureal_Constants = 10); Ureals.Tree_Write; Tree_Write_Int (Int (UR_0)); Tree_Write_Int (Int (UR_M_0)); Tree_Write_Int (Int (UR_Tenth)); Tree_Write_Int (Int (UR_Half)); Tree_Write_Int (Int (UR_1)); Tree_Write_Int (Int (UR_2)); Tree_Write_Int (Int (UR_10)); Tree_Write_Int (Int (UR_100)); Tree_Write_Int (Int (UR_2_128)); Tree_Write_Int (Int (UR_2_M_128)); end Tree_Write; ------------ -- UR_Abs -- ------------ function UR_Abs (Real : Ureal) return Ureal is Val : constant Ureal_Entry := Ureals.Table (Real); begin return Store_Ureal ( (Num => Val.Num, Den => Val.Den, Rbase => Val.Rbase, Negative => False)); end UR_Abs; ------------ -- UR_Add -- ------------ function UR_Add (Left : Uint; Right : Ureal) return Ureal is begin return UR_From_Uint (Left) + Right; end UR_Add; function UR_Add (Left : Ureal; Right : Uint) return Ureal is begin return Left + UR_From_Uint (Right); end UR_Add; function UR_Add (Left : Ureal; Right : Ureal) return Ureal is Lval : Ureal_Entry := Ureals.Table (Left); Rval : Ureal_Entry := Ureals.Table (Right); Num : Uint; begin -- Note, in the temporary Ureal_Entry values used in this procedure, -- we store the sign as the sign of the numerator (i.e. xxx.Num may -- be negative, even though in stored entries this can never be so) if Lval.Rbase /= 0 and then Lval.Rbase = Rval.Rbase then declare Opd_Min, Opd_Max : Ureal_Entry; Exp_Min, Exp_Max : Uint; begin if Lval.Negative then Lval.Num := (-Lval.Num); end if; if Rval.Negative then Rval.Num := (-Rval.Num); end if; if Lval.Den < Rval.Den then Exp_Min := Lval.Den; Exp_Max := Rval.Den; Opd_Min := Lval; Opd_Max := Rval; else Exp_Min := Rval.Den; Exp_Max := Lval.Den; Opd_Min := Rval; Opd_Max := Lval; end if; Num := Opd_Min.Num * Lval.Rbase ** (Exp_Max - Exp_Min) + Opd_Max.Num; if Num = 0 then return Store_Ureal ( (Num => Uint_0, Den => Uint_1, Rbase => 0, Negative => Lval.Negative)); else return Store_Ureal ( (Num => abs Num, Den => Exp_Max, Rbase => Lval.Rbase, Negative => (Num < 0))); end if; end; else declare Ln : Ureal_Entry := Normalize (Lval); Rn : Ureal_Entry := Normalize (Rval); begin if Ln.Negative then Ln.Num := (-Ln.Num); end if; if Rn.Negative then Rn.Num := (-Rn.Num); end if; Num := (Ln.Num * Rn.Den) + (Rn.Num * Ln.Den); if Num = 0 then return Store_Ureal ( (Num => Uint_0, Den => Uint_1, Rbase => 0, Negative => Lval.Negative)); else return Store_Ureal ( Normalize ( (Num => abs Num, Den => Ln.Den * Rn.Den, Rbase => 0, Negative => (Num < 0)))); end if; end; end if; end UR_Add; ---------------- -- UR_Ceiling -- ---------------- function UR_Ceiling (Real : Ureal) return Uint is Val : constant Ureal_Entry := Normalize (Ureals.Table (Real)); begin if Val.Negative then return UI_Negate (Val.Num / Val.Den); else return (Val.Num + Val.Den - 1) / Val.Den; end if; end UR_Ceiling; ------------ -- UR_Div -- ------------ function UR_Div (Left : Uint; Right : Ureal) return Ureal is begin return UR_From_Uint (Left) / Right; end UR_Div; function UR_Div (Left : Ureal; Right : Uint) return Ureal is begin return Left / UR_From_Uint (Right); end UR_Div; function UR_Div (Left, Right : Ureal) return Ureal is Lval : constant Ureal_Entry := Ureals.Table (Left); Rval : constant Ureal_Entry := Ureals.Table (Right); Rneg : constant Boolean := Rval.Negative xor Lval.Negative; begin pragma Assert (Rval.Num /= Uint_0); if Lval.Rbase = 0 then if Rval.Rbase = 0 then return Store_Ureal ( Normalize ( (Num => Lval.Num * Rval.Den, Den => Lval.Den * Rval.Num, Rbase => 0, Negative => Rneg))); elsif Is_Integer (Lval.Num, Rval.Num * Lval.Den) then return Store_Ureal ( (Num => Lval.Num / (Rval.Num * Lval.Den), Den => (-Rval.Den), Rbase => Rval.Rbase, Negative => Rneg)); elsif Rval.Den < 0 then return Store_Ureal ( Normalize ( (Num => Lval.Num, Den => Rval.Rbase ** (-Rval.Den) * Rval.Num * Lval.Den, Rbase => 0, Negative => Rneg))); else return Store_Ureal ( Normalize ( (Num => Lval.Num * Rval.Rbase ** Rval.Den, Den => Rval.Num * Lval.Den, Rbase => 0, Negative => Rneg))); end if; elsif Is_Integer (Lval.Num, Rval.Num) then if Rval.Rbase = Lval.Rbase then return Store_Ureal ( (Num => Lval.Num / Rval.Num, Den => Lval.Den - Rval.Den, Rbase => Lval.Rbase, Negative => Rneg)); elsif Rval.Rbase = 0 then return Store_Ureal ( (Num => (Lval.Num / Rval.Num) * Rval.Den, Den => Lval.Den, Rbase => Lval.Rbase, Negative => Rneg)); elsif Rval.Den < 0 then declare Num, Den : Uint; begin if Lval.Den < 0 then Num := (Lval.Num / Rval.Num) * (Lval.Rbase ** (-Lval.Den)); Den := Rval.Rbase ** (-Rval.Den); else Num := Lval.Num / Rval.Num; Den := (Lval.Rbase ** Lval.Den) * (Rval.Rbase ** (-Rval.Den)); end if; return Store_Ureal ( (Num => Num, Den => Den, Rbase => 0, Negative => Rneg)); end; else return Store_Ureal ( (Num => (Lval.Num / Rval.Num) * (Rval.Rbase ** Rval.Den), Den => Lval.Den, Rbase => Lval.Rbase, Negative => Rneg)); end if; else declare Num, Den : Uint; begin if Lval.Den < 0 then Num := Lval.Num * (Lval.Rbase ** (-Lval.Den)); Den := Rval.Num; else Num := Lval.Num; Den := Rval.Num * (Lval.Rbase ** Lval.Den); end if; if Rval.Rbase /= 0 then if Rval.Den < 0 then Den := Den * (Rval.Rbase ** (-Rval.Den)); else Num := Num * (Rval.Rbase ** Rval.Den); end if; else Num := Num * Rval.Den; end if; return Store_Ureal ( Normalize ( (Num => Num, Den => Den, Rbase => 0, Negative => Rneg))); end; end if; end UR_Div; ----------- -- UR_Eq -- ----------- function UR_Eq (Left, Right : Ureal) return Boolean is begin return not UR_Ne (Left, Right); end UR_Eq; --------------------- -- UR_Exponentiate -- --------------------- function UR_Exponentiate (Real : Ureal; N : Uint) return Ureal is X : constant Uint := abs N; Bas : Ureal; Val : Ureal_Entry; Neg : Boolean; IBas : Uint; begin -- If base is negative, then the resulting sign depends on whether -- the exponent is even or odd (even => positive, odd = negative) if UR_Is_Negative (Real) then Neg := (N mod 2) /= 0; Bas := UR_Negate (Real); else Neg := False; Bas := Real; end if; Val := Ureals.Table (Bas); -- If the base is a small integer, then we can return the result in -- exponential form, which can save a lot of time for junk exponents. IBas := UR_Trunc (Bas); if IBas <= 16 and then UR_From_Uint (IBas) = Bas then return Store_Ureal ( (Num => Uint_1, Den => -N, Rbase => UI_To_Int (UR_Trunc (Bas)), Negative => Neg)); -- If the exponent is negative then we raise the numerator and the -- denominator (after normalization) to the absolute value of the -- exponent and we return the reciprocal. An assert error will happen -- if the numerator is zero. elsif N < 0 then pragma Assert (Val.Num /= 0); Val := Normalize (Val); return Store_Ureal ( (Num => Val.Den ** X, Den => Val.Num ** X, Rbase => 0, Negative => Neg)); -- If positive, we distinguish the case when the base is not zero, in -- which case the new denominator is just the product of the old one -- with the exponent, else if Val.Rbase /= 0 then return Store_Ureal ( (Num => Val.Num ** X, Den => Val.Den * X, Rbase => Val.Rbase, Negative => Neg)); -- And when the base is zero, in which case we exponentiate -- the old denominator. else return Store_Ureal ( (Num => Val.Num ** X, Den => Val.Den ** X, Rbase => 0, Negative => Neg)); end if; end if; end UR_Exponentiate; -------------- -- UR_Floor -- -------------- function UR_Floor (Real : Ureal) return Uint is Val : constant Ureal_Entry := Normalize (Ureals.Table (Real)); begin if Val.Negative then return UI_Negate ((Val.Num + Val.Den - 1) / Val.Den); else return Val.Num / Val.Den; end if; end UR_Floor; ------------------------ -- UR_From_Components -- ------------------------ function UR_From_Components (Num : Uint; Den : Uint; Rbase : Nat := 0; Negative : Boolean := False) return Ureal is begin return Store_Ureal ( (Num => Num, Den => Den, Rbase => Rbase, Negative => Negative)); end UR_From_Components; ------------------ -- UR_From_Uint -- ------------------ function UR_From_Uint (UI : Uint) return Ureal is begin return UR_From_Components (abs UI, Uint_1, Negative => (UI < 0)); end UR_From_Uint; ----------- -- UR_Ge -- ----------- function UR_Ge (Left, Right : Ureal) return Boolean is begin return not (Left < Right); end UR_Ge; ----------- -- UR_Gt -- ----------- function UR_Gt (Left, Right : Ureal) return Boolean is begin return (Right < Left); end UR_Gt; -------------------- -- UR_Is_Negative -- -------------------- function UR_Is_Negative (Real : Ureal) return Boolean is begin return Ureals.Table (Real).Negative; end UR_Is_Negative; -------------------- -- UR_Is_Positive -- -------------------- function UR_Is_Positive (Real : Ureal) return Boolean is begin return not Ureals.Table (Real).Negative and then Ureals.Table (Real).Num /= 0; end UR_Is_Positive; ---------------- -- UR_Is_Zero -- ---------------- function UR_Is_Zero (Real : Ureal) return Boolean is begin return Ureals.Table (Real).Num = 0; end UR_Is_Zero; ----------- -- UR_Le -- ----------- function UR_Le (Left, Right : Ureal) return Boolean is begin return not (Right < Left); end UR_Le; ----------- -- UR_Lt -- ----------- function UR_Lt (Left, Right : Ureal) return Boolean is begin -- An operand is not less than itself if Same (Left, Right) then return False; -- Deal with zero cases elsif UR_Is_Zero (Left) then return UR_Is_Positive (Right); elsif UR_Is_Zero (Right) then return Ureals.Table (Left).Negative; -- Different signs are decisive (note we dealt with zero cases) elsif Ureals.Table (Left).Negative and then not Ureals.Table (Right).Negative then return True; elsif not Ureals.Table (Left).Negative and then Ureals.Table (Right).Negative then return False; -- Signs are same, do rapid check based on worst case estimates of -- decimal exponent, which will often be decisive. Precise test -- depends on whether operands are positive or negative. elsif Decimal_Exponent_Hi (Left) < Decimal_Exponent_Lo (Right) then return UR_Is_Positive (Left); elsif Decimal_Exponent_Lo (Left) > Decimal_Exponent_Hi (Right) then return UR_Is_Negative (Left); -- If we fall through, full gruesome test is required. This happens -- if the numbers are close together, or in some weird (/=10) base. else declare Imrk : constant Uintp.Save_Mark := Mark; Rmrk : constant Urealp.Save_Mark := Mark; Lval : Ureal_Entry; Rval : Ureal_Entry; Result : Boolean; begin Lval := Ureals.Table (Left); Rval := Ureals.Table (Right); -- An optimization. If both numbers are based, then subtract -- common value of base to avoid unnecessarily giant numbers if Lval.Rbase = Rval.Rbase and then Lval.Rbase /= 0 then if Lval.Den < Rval.Den then Rval.Den := Rval.Den - Lval.Den; Lval.Den := Uint_0; else Lval.Den := Lval.Den - Rval.Den; Rval.Den := Uint_0; end if; end if; Lval := Normalize (Lval); Rval := Normalize (Rval); if Lval.Negative then Result := (Lval.Num * Rval.Den) > (Rval.Num * Lval.Den); else Result := (Lval.Num * Rval.Den) < (Rval.Num * Lval.Den); end if; Release (Imrk); Release (Rmrk); return Result; end; end if; end UR_Lt; ------------ -- UR_Max -- ------------ function UR_Max (Left, Right : Ureal) return Ureal is begin if Left >= Right then return Left; else return Right; end if; end UR_Max; ------------ -- UR_Min -- ------------ function UR_Min (Left, Right : Ureal) return Ureal is begin if Left <= Right then return Left; else return Right; end if; end UR_Min; ------------ -- UR_Mul -- ------------ function UR_Mul (Left : Uint; Right : Ureal) return Ureal is begin return UR_From_Uint (Left) * Right; end UR_Mul; function UR_Mul (Left : Ureal; Right : Uint) return Ureal is begin return Left * UR_From_Uint (Right); end UR_Mul; function UR_Mul (Left, Right : Ureal) return Ureal is Lval : constant Ureal_Entry := Ureals.Table (Left); Rval : constant Ureal_Entry := Ureals.Table (Right); Num : Uint := Lval.Num * Rval.Num; Den : Uint; Rneg : constant Boolean := Lval.Negative xor Rval.Negative; begin if Lval.Rbase = 0 then if Rval.Rbase = 0 then return Store_Ureal ( Normalize ( (Num => Num, Den => Lval.Den * Rval.Den, Rbase => 0, Negative => Rneg))); elsif Is_Integer (Num, Lval.Den) then return Store_Ureal ( (Num => Num / Lval.Den, Den => Rval.Den, Rbase => Rval.Rbase, Negative => Rneg)); elsif Rval.Den < 0 then return Store_Ureal ( Normalize ( (Num => Num * (Rval.Rbase ** (-Rval.Den)), Den => Lval.Den, Rbase => 0, Negative => Rneg))); else return Store_Ureal ( Normalize ( (Num => Num, Den => Lval.Den * (Rval.Rbase ** Rval.Den), Rbase => 0, Negative => Rneg))); end if; elsif Lval.Rbase = Rval.Rbase then return Store_Ureal ( (Num => Num, Den => Lval.Den + Rval.Den, Rbase => Lval.Rbase, Negative => Rneg)); elsif Rval.Rbase = 0 then if Is_Integer (Num, Rval.Den) then return Store_Ureal ( (Num => Num / Rval.Den, Den => Lval.Den, Rbase => Lval.Rbase, Negative => Rneg)); elsif Lval.Den < 0 then return Store_Ureal ( Normalize ( (Num => Num * (Lval.Rbase ** (-Lval.Den)), Den => Rval.Den, Rbase => 0, Negative => Rneg))); else return Store_Ureal ( Normalize ( (Num => Num, Den => Rval.Den * (Lval.Rbase ** Lval.Den), Rbase => 0, Negative => Rneg))); end if; else Den := Uint_1; if Lval.Den < 0 then Num := Num * (Lval.Rbase ** (-Lval.Den)); else Den := Den * (Lval.Rbase ** Lval.Den); end if; if Rval.Den < 0 then Num := Num * (Rval.Rbase ** (-Rval.Den)); else Den := Den * (Rval.Rbase ** Rval.Den); end if; return Store_Ureal ( Normalize ( (Num => Num, Den => Den, Rbase => 0, Negative => Rneg))); end if; end UR_Mul; ----------- -- UR_Ne -- ----------- function UR_Ne (Left, Right : Ureal) return Boolean is begin -- Quick processing for case of identical Ureal values (note that -- this also deals with comparing two No_Ureal values). if Same (Left, Right) then return False; -- Deal with case of one or other operand is No_Ureal, but not both elsif Same (Left, No_Ureal) or else Same (Right, No_Ureal) then return True; -- Do quick check based on number of decimal digits elsif Decimal_Exponent_Hi (Left) < Decimal_Exponent_Lo (Right) or else Decimal_Exponent_Lo (Left) > Decimal_Exponent_Hi (Right) then return True; -- Otherwise full comparison is required else declare Imrk : constant Uintp.Save_Mark := Mark; Rmrk : constant Urealp.Save_Mark := Mark; Lval : constant Ureal_Entry := Normalize (Ureals.Table (Left)); Rval : constant Ureal_Entry := Normalize (Ureals.Table (Right)); Result : Boolean; begin if UR_Is_Zero (Left) then return not UR_Is_Zero (Right); elsif UR_Is_Zero (Right) then return not UR_Is_Zero (Left); -- Both operands are non-zero else Result := Rval.Negative /= Lval.Negative or else Rval.Num /= Lval.Num or else Rval.Den /= Lval.Den; Release (Imrk); Release (Rmrk); return Result; end if; end; end if; end UR_Ne; --------------- -- UR_Negate -- --------------- function UR_Negate (Real : Ureal) return Ureal is begin return Store_Ureal ( (Num => Ureals.Table (Real).Num, Den => Ureals.Table (Real).Den, Rbase => Ureals.Table (Real).Rbase, Negative => not Ureals.Table (Real).Negative)); end UR_Negate; ------------ -- UR_Sub -- ------------ function UR_Sub (Left : Uint; Right : Ureal) return Ureal is begin return UR_From_Uint (Left) + UR_Negate (Right); end UR_Sub; function UR_Sub (Left : Ureal; Right : Uint) return Ureal is begin return Left + UR_From_Uint (-Right); end UR_Sub; function UR_Sub (Left, Right : Ureal) return Ureal is begin return Left + UR_Negate (Right); end UR_Sub; ---------------- -- UR_To_Uint -- ---------------- function UR_To_Uint (Real : Ureal) return Uint is Val : constant Ureal_Entry := Normalize (Ureals.Table (Real)); Res : Uint; begin Res := (Val.Num + (Val.Den / 2)) / Val.Den; if Val.Negative then return UI_Negate (Res); else return Res; end if; end UR_To_Uint; -------------- -- UR_Trunc -- -------------- function UR_Trunc (Real : Ureal) return Uint is Val : constant Ureal_Entry := Normalize (Ureals.Table (Real)); begin if Val.Negative then return -(Val.Num / Val.Den); else return Val.Num / Val.Den; end if; end UR_Trunc; -------------- -- UR_Write -- -------------- procedure UR_Write (Real : Ureal) is Val : constant Ureal_Entry := Ureals.Table (Real); begin -- If value is negative, we precede the constant by a minus sign -- and add an extra layer of parentheses on the outside since the -- minus sign is part of the value, not a negation operator. if Val.Negative then Write_Str ("(-"); end if; -- Constants in base 10 can be written in normal Ada literal style if Val.Rbase = 10 then UI_Write (Val.Num / 10); Write_Char ('.'); UI_Write (Val.Num mod 10); if Val.Den /= 0 then Write_Char ('E'); UI_Write (1 - Val.Den); end if; -- Constants in a base other than 10 can still be easily written -- in normal Ada literal style if the numerator is one. elsif Val.Rbase /= 0 and then Val.Num = 1 then Write_Int (Val.Rbase); Write_Str ("#1.0#E"); UI_Write (-Val.Den); -- Other constants with a base other than 10 are written using one -- of the following forms, depending on the sign of the number -- and the sign of the exponent (= minus denominator value) -- (numerator.0*base**exponent) -- (numerator.0*base**(-exponent)) elsif Val.Rbase /= 0 then Write_Char ('('); UI_Write (Val.Num, Decimal); Write_Str (".0*"); Write_Int (Val.Rbase); Write_Str ("**"); if Val.Den <= 0 then UI_Write (-Val.Den, Decimal); else Write_Str ("(-"); UI_Write (Val.Den, Decimal); Write_Char (')'); end if; Write_Char (')'); -- Rational constants with a denominator of 1 can be written as -- a real literal for the numerator integer. elsif Val.Den = 1 then UI_Write (Val.Num, Decimal); Write_Str (".0"); -- Non-based (rational) constants are written in (num/den) style else Write_Char ('('); UI_Write (Val.Num, Decimal); Write_Str (".0/"); UI_Write (Val.Den, Decimal); Write_Str (".0)"); end if; -- Add trailing paren for negative values if Val.Negative then Write_Char (')'); end if; end UR_Write; ------------- -- Ureal_0 -- ------------- function Ureal_0 return Ureal is begin return UR_0; end Ureal_0; ------------- -- Ureal_1 -- ------------- function Ureal_1 return Ureal is begin return UR_1; end Ureal_1; ------------- -- Ureal_2 -- ------------- function Ureal_2 return Ureal is begin return UR_2; end Ureal_2; -------------- -- Ureal_10 -- -------------- function Ureal_10 return Ureal is begin return UR_10; end Ureal_10; --------------- -- Ureal_100 -- --------------- function Ureal_100 return Ureal is begin return UR_100; end Ureal_100; ----------------- -- Ureal_10_36 -- ----------------- function Ureal_10_36 return Ureal is begin return UR_10_36; end Ureal_10_36; ---------------- -- Ureal_2_80 -- ---------------- function Ureal_2_80 return Ureal is begin return UR_2_80; end Ureal_2_80; ----------------- -- Ureal_2_128 -- ----------------- function Ureal_2_128 return Ureal is begin return UR_2_128; end Ureal_2_128; ------------------- -- Ureal_2_M_80 -- ------------------- function Ureal_2_M_80 return Ureal is begin return UR_2_M_80; end Ureal_2_M_80; ------------------- -- Ureal_2_M_128 -- ------------------- function Ureal_2_M_128 return Ureal is begin return UR_2_M_128; end Ureal_2_M_128; ---------------- -- Ureal_Half -- ---------------- function Ureal_Half return Ureal is begin return UR_Half; end Ureal_Half; --------------- -- Ureal_M_0 -- --------------- function Ureal_M_0 return Ureal is begin return UR_M_0; end Ureal_M_0; ------------------- -- Ureal_M_10_36 -- ------------------- function Ureal_M_10_36 return Ureal is begin return UR_M_10_36; end Ureal_M_10_36; ----------------- -- Ureal_Tenth -- ----------------- function Ureal_Tenth return Ureal is begin return UR_Tenth; end Ureal_Tenth; end Urealp;
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