[Ada] Small adjustments to fixed-point I/O units

gcc/ada/

	* libgnat/a-tifiio.adb: Adjust documentation.
	(OK_Get_32): Compare the object size of the base type.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	* libgnat/a-tifiio__128.adb: Adjust documentation.
	(OK_Get_32): Compare the object size of the base type.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	(OK_Get_128): Likewise.
	(OK_Put_128): Likewise.
	* libgnat/a-wtfiio.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise
	* libgnat/a-wtfiio__128.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	(OK_Get_128): Likewise.
	(OK_Put_128): Likewise.
	* libgnat/a-ztfiio.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise
	* libgnat/a-ztfiio__128.adb (OK_Get_32): Likewise.
	(OK_Put_32): Likewise.
	(OK_Get_64): Likewise.
	(OK_Put_64): Likewise.
	(OK_Get_128): Likewise.
	(OK_Put_128): Likewise.

6 files changed, 72 insertions, 46 deletions

diff --git a/gcc/ada/libgnat/a-tifiio.adb b/gcc/ada/libgnat/a-tifiio.adb
index b7d9471..61c68ec 100644
--- a/gcc/ada/libgnat/a-tifiio.adb
+++ b/gcc/ada/libgnat/a-tifiio.adb
@@ -29,8 +29,9 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
---  Fixed point I/O
---  ---------------
+--  -------------------
+--  - Fixed point I/O -
+--  -------------------
 
 --  The following text documents implementation details of the fixed point
 --  input/output routines in the GNAT runtime. The first part describes the
@@ -40,7 +41,7 @@
 --  Subsequently these are reduced to implementation constraints and the impact
 --  of these constraints on a few possible approaches to input/output is given.
 --  Based on this analysis, a specific implementation is selected for use in
---  the GNAT runtime. Finally, the chosen algorithm is analyzed numerically in
+--  the GNAT runtime. Finally the chosen algorithms are analyzed numerically in
 --  order to provide user-level documentation on limits for range and precision
 --  of fixed point types as well as accuracy of input/output conversions.
 
@@ -68,7 +69,7 @@
 --  Operations
 --  ----------
 
---  'Image and 'Wide_Image (see RM 3.5(34))
+--  [Wide_[Wide_]]Image attribute (see RM 3.5(27.1/2))
 
 --          These attributes return a decimal real literal best approximating
 --          the value (rounded away from zero if halfway between) with a
@@ -88,7 +89,7 @@
 --          attributes, although it would be nice to be able to output more
 --          than S'Aft digits after the decimal point for values of subtype S.
 
---  'Value and 'Wide_Value attribute (RM 3.5(40-55))
+--  [Wide_[Wide_]]Value attribute (RM 3.5(39.1/2))
 
 --          Since the input can be given in any base in the range 2..16,
 --          accurate conversion to a fixed point number may require
@@ -121,7 +122,7 @@
 --  be less than 2.0**(-53).
 
 --  In GNAT, Fine_Delta is 2.0**(-63), and Duration for example is a 64-bit
---  type. This means that a floating-point type with 63 bits of mantissa needs
+--  type. This means that a floating-point type with 64 bits of mantissa needs
 --  to be used, which is only generally available on the x86 architecture. It
 --  would still be possible to use multi-precision floating point to perform
 --  calculations using longer mantissas, but this is a much harder approach.
@@ -137,9 +138,21 @@
 
 --  Fixed-precision integer arithmetic has the advantage of simplicity and
 --  speed. For the most common fixed point types this would be a perfect
---  solution. The downside however may be a too limited set of acceptable
+--  solution. The downside however may be a restricted set of acceptable
 --  fixed point types.
 
+--  Implementation Choices
+--  ----------------------
+
+--  The current implementation in the GNAT runtime uses fixed-precision integer
+--  arithmetic for fixed point types whose Small is the ratio of two integers
+--  whose magnitude is bounded relatively to the size of the mantissa, with a
+--  two-tiered approach for 32-bit and 64-bit fixed point types. For the other
+--  fixed point types, the implementation uses floating-point arithmetic.
+
+--  The exact requirements of the algorithms are analyzed and documented along
+--  with the implementation in their respective units.
+
 with Interfaces;
 with Ada.Text_IO.Fixed_Aux;
 with Ada.Text_IO.Float_Aux;
@@ -171,7 +184,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  static (although it is not a static expressions in the RM sense).
 
    OK_Get_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -182,7 +195,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -196,7 +209,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -207,7 +220,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
diff --git a/gcc/ada/libgnat/a-tifiio__128.adb b/gcc/ada/libgnat/a-tifiio__128.adb
index 4dea63c..578beb1 100644
--- a/gcc/ada/libgnat/a-tifiio__128.adb
+++ b/gcc/ada/libgnat/a-tifiio__128.adb
@@ -29,8 +29,9 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
---  Fixed point I/O
---  ---------------
+--  -------------------
+--  - Fixed point I/O -
+--  -------------------
 
 --  The following text documents implementation details of the fixed point
 --  input/output routines in the GNAT runtime. The first part describes the
@@ -40,7 +41,7 @@
 --  Subsequently these are reduced to implementation constraints and the impact
 --  of these constraints on a few possible approaches to input/output is given.
 --  Based on this analysis, a specific implementation is selected for use in
---  the GNAT runtime. Finally, the chosen algorithm is analyzed numerically in
+--  the GNAT runtime. Finally the chosen algorithms are analyzed numerically in
 --  order to provide user-level documentation on limits for range and precision
 --  of fixed point types as well as accuracy of input/output conversions.
 
@@ -68,7 +69,7 @@
 --  Operations
 --  ----------
 
---  'Image and 'Wide_Image (see RM 3.5(34))
+--  [Wide_[Wide_]]Image attribute (see RM 3.5(27.1/2))
 
 --          These attributes return a decimal real literal best approximating
 --          the value (rounded away from zero if halfway between) with a
@@ -88,7 +89,7 @@
 --          attributes, although it would be nice to be able to output more
 --          than S'Aft digits after the decimal point for values of subtype S.
 
---  'Value and 'Wide_Value attribute (RM 3.5(40-55))
+--  [Wide_[Wide_]]Value attribute (RM 3.5(39.1/2))
 
 --          Since the input can be given in any base in the range 2..16,
 --          accurate conversion to a fixed point number may require
@@ -120,9 +121,9 @@
 --  available has 53 bits of mantissa. This means that Fine_Delta cannot
 --  be less than 2.0**(-53).
 
---  In GNAT, Fine_Delta is 2.0**(-63), and Duration for example is a 64-bit
---  type. This means that a floating-point type with 63 bits of mantissa needs
---  to be used, which is only generally available on the x86 architecture. It
+--  In GNAT, Fine_Delta is 2.0**(-127), and Duration for example is a 64-bit
+--  type. This means that a floating-point type with 128 bits of mantissa needs
+--  to be used, which currently does not exist in any common architecture. It
 --  would still be possible to use multi-precision floating point to perform
 --  calculations using longer mantissas, but this is a much harder approach.
 
@@ -137,9 +138,21 @@
 
 --  Fixed-precision integer arithmetic has the advantage of simplicity and
 --  speed. For the most common fixed point types this would be a perfect
---  solution. The downside however may be a too limited set of acceptable
+--  solution. The downside however may be a restricted set of acceptable
 --  fixed point types.
 
+--  Implementation Choices
+--  ----------------------
+
+--  The current implementation in the GNAT runtime uses fixed-precision integer
+--  arithmetic for fixed point types whose Small is the ratio of two integers
+--  whose magnitude is bounded relatively to the size of the mantissa, with a
+--  three-tiered approach for 32-bit, 64-bit and 128-bit fixed point types. For
+--  other fixed point types, the implementation uses floating-point arithmetic.
+
+--  The exact requirements of the algorithms are analyzed and documented along
+--  with the implementation in their respective units.
+
 with Interfaces;
 with Ada.Text_IO.Fixed_Aux;
 with Ada.Text_IO.Float_Aux;
@@ -178,7 +191,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  in the RM sense).
 
    OK_Get_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -189,7 +202,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -203,7 +216,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -214,7 +227,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -228,7 +241,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_128 : constant Boolean :=
-     Num'Object_Size <= 128
+     Num'Base'Object_Size <= 128
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**127)
            or else
@@ -239,7 +252,7 @@ package body Ada.Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_128 : constant Boolean :=
-     Num'Object_Size <= 128
+     Num'Base'Object_Size <= 128
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**127)
            or else
diff --git a/gcc/ada/libgnat/a-wtfiio.adb b/gcc/ada/libgnat/a-wtfiio.adb
index fa9c1e0..570c5da 100644
--- a/gcc/ada/libgnat/a-wtfiio.adb
+++ b/gcc/ada/libgnat/a-wtfiio.adb
@@ -62,7 +62,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  static (although it is not a static expressions in the RM sense).
 
    OK_Get_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -73,7 +73,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -87,7 +87,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -98,7 +98,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
diff --git a/gcc/ada/libgnat/a-wtfiio__128.adb b/gcc/ada/libgnat/a-wtfiio__128.adb
index 846c036..aa45e5d 100644
--- a/gcc/ada/libgnat/a-wtfiio__128.adb
+++ b/gcc/ada/libgnat/a-wtfiio__128.adb
@@ -69,7 +69,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  in the RM sense).
 
    OK_Get_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -80,7 +80,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -94,7 +94,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -105,7 +105,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -119,7 +119,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_128 : constant Boolean :=
-     Num'Object_Size <= 128
+     Num'Base'Object_Size <= 128
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**127)
            or else
@@ -130,7 +130,7 @@ package body Ada.Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_128 : constant Boolean :=
-     Num'Object_Size <= 128
+     Num'Base'Object_Size <= 128
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**127)
            or else
diff --git a/gcc/ada/libgnat/a-ztfiio.adb b/gcc/ada/libgnat/a-ztfiio.adb
index 57b258e..3c3224d 100644
--- a/gcc/ada/libgnat/a-ztfiio.adb
+++ b/gcc/ada/libgnat/a-ztfiio.adb
@@ -62,7 +62,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  static (although it is not a static expressions in the RM sense).
 
    OK_Get_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -73,7 +73,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -87,7 +87,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -98,7 +98,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
diff --git a/gcc/ada/libgnat/a-ztfiio__128.adb b/gcc/ada/libgnat/a-ztfiio__128.adb
index fcb7077..3254fb8 100644
--- a/gcc/ada/libgnat/a-ztfiio__128.adb
+++ b/gcc/ada/libgnat/a-ztfiio__128.adb
@@ -70,7 +70,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  in the RM sense).
 
    OK_Get_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -81,7 +81,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_32 : constant Boolean :=
-     Num'Object_Size <= 32
+     Num'Base'Object_Size <= 32
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**31)
            or else
@@ -95,7 +95,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -106,7 +106,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_64 : constant Boolean :=
-     Num'Object_Size <= 64
+     Num'Base'Object_Size <= 64
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**63)
            or else
@@ -120,7 +120,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Image_F
 
    OK_Get_128 : constant Boolean :=
-     Num'Object_Size <= 128
+     Num'Base'Object_Size <= 128
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**127)
            or else
@@ -131,7 +131,7 @@ package body Ada.Wide_Wide_Text_IO.Fixed_IO is
    --  These conditions are derived from the prerequisites of System.Value_F
 
    OK_Put_128 : constant Boolean :=
-     Num'Object_Size <= 128
+     Num'Base'Object_Size <= 128
        and then
          ((Num'Small_Numerator = 1 and then Num'Small_Denominator <= 2**127)
            or else