65f01153ab
2005-11-14 Robert Dewar <dewar@adacore.com> Hristian Kirtchev <kirtchev@adacore.com> * sem_attr.adb: Implement Machine_Rounding attribute (Analyze_Access_Attribute): The access attribute may appear within an aggregate that has been expanded into a loop. (Check_Task_Prefix): Add semantic check for attribute 'Callable and 'Terminated whenever the prefix is of a task interface class-wide type. (Analyze_Attribute): Add semantic check for attribute 'Identity whenever the prefix is of a task interface class-wide type. * s-vaflop-vms-alpha.adb: Valid_D, Valid_F, Valid_G: Make Val constant to avoid warnings. * s-fatgen.ads, s-fatgen.adb (Machine_Rounding): New function Remove pragma Inline for [Unaligned_]Valid. Add comments that Valid routines do not work for Vax_Float * exp_attr.adb: Implement Machine_Rounding attribute * snames.h: Add entry for Machine_Rounding attribute From-SVN: r106970
132 lines
6.8 KiB
Ada
132 lines
6.8 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . F A T _ G E N --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2005 Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This generic package provides a target independent implementation of the
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-- floating-point attributes that denote functions. The implementations here
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-- are portable, but very slow. The runtime contains a set of instantiations
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-- of this package for all predefined floating-point types, and these should
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-- be replaced by efficient assembly language code where possible.
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generic
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type T is digits <>;
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package System.Fat_Gen is
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pragma Pure;
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subtype UI is Integer;
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-- The runtime representation of universal integer for the purposes of
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-- this package is integer. The expander generates conversions for the
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-- actual type used. For functions returning universal integer, there
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-- is no problem, since the result always is in range of integer. For
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-- input arguments, the expander has to do some special casing to deal
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-- with the (very annoying!) cases of out of range values. If we used
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-- Long_Long_Integer to represent universal, then there would be no
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-- problem, but the resulting inefficiency would be annoying.
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function Adjacent (X, Towards : T) return T;
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function Ceiling (X : T) return T;
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function Compose (Fraction : T; Exponent : UI) return T;
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function Copy_Sign (Value, Sign : T) return T;
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function Exponent (X : T) return UI;
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function Floor (X : T) return T;
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function Fraction (X : T) return T;
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function Leading_Part (X : T; Radix_Digits : UI) return T;
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function Machine (X : T) return T;
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function Machine_Rounding (X : T) return T;
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function Model (X : T) return T;
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function Pred (X : T) return T;
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function Remainder (X, Y : T) return T;
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function Rounding (X : T) return T;
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function Scaling (X : T; Adjustment : UI) return T;
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function Succ (X : T) return T;
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function Truncation (X : T) return T;
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function Unbiased_Rounding (X : T) return T;
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function Valid (X : access T) return Boolean;
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-- This function checks if the object of type T referenced by X
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-- is valid, and returns True/False accordingly. The parameter is
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-- passed by reference (access) here, as the object of type T may
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-- be an abnormal value that cannot be passed in a floating-point
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-- register, and the whole point of 'Valid is to prevent exceptions.
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-- Note that the object of type T must have the natural alignment
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-- for type T. See Unaligned_Valid for further discussion.
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--
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-- Note: this routine does not work for Vax_Float ???
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function Unaligned_Valid (A : System.Address) return Boolean;
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-- This version of Valid is used if the floating-point value to
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-- be checked is not known to be aligned (for example it appears
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-- in a packed record). In this case, we cannot call Valid since
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-- Valid assumes proper full alignment. Instead Unaligned_Valid
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-- performs the same processing for a possibly unaligned float,
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-- by first doing a copy and then calling Valid. One might think
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-- that the front end could simply do a copy to an aligned temp,
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-- but remember that we may have an abnormal value that cannot
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-- be copied into a floating-point register, so things are a bit
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-- trickier than one might expect.
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--
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-- Note: Unaligned_Valid is never called for a target which does
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-- not require strict alignment (e.g. the ia32/x86), since on a
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-- target not requiring strict alignment, it is fine to pass a
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-- non-aligned value to the standard Valid routine.
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--
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-- Note: this routine does not work for Vax_Float ???
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private
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pragma Inline (Machine);
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pragma Inline (Model);
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-- Note: previously the validity checking subprograms (Unaligned_Valid and
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-- Valid) were also inlined, but this was changed since there were some
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-- problems with this inlining in optimized mode, and in any case it seems
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-- better to avoid this inlining (space and robustness considerations).
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end System.Fat_Gen;
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