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|
-- Lexical analysis for numbers.
-- Copyright (C) 2002 - 2014 Tristan Gingold
--
-- GHDL is free software; you can redistribute it and/or modify it under
-- the terms of the GNU General Public License as published by the Free
-- Software Foundation; either version 2, or (at your option) any later
-- version.
--
-- GHDL is distributed in the hope that it will be useful, but WITHOUT ANY
-- WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with GHDL; see the file COPYING. If not, write to the Free
-- Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-- 02111-1307, USA.
with Interfaces; use Interfaces;
with Grt.Fcvt; use Grt.Fcvt;
separate (Vhdl.Scanner)
-- scan a decimal literal or a based literal.
--
-- LRM93 13.4.1
-- DECIMAL_LITERAL ::= INTEGER [ . INTEGER ] [ EXPONENT ]
-- EXPONENT ::= E [ + ] INTEGER | E - INTEGER
--
-- LRM93 13.4.2
-- BASED_LITERAL ::= BASE # BASED_INTEGER [ . BASED_INTEGER ] # EXPONENT
-- BASE ::= INTEGER
procedure Scan_Literal is
-- Numbers of digits.
Scale : Integer;
Res : Bignum;
-- LRM 13.4.1
-- INTEGER ::= DIGIT { [ UNDERLINE ] DIGIT }
--
-- Update SCALE, RES.
-- The first character must be a digit.
procedure Scan_Integer
is
C : Character;
begin
C := Source (Pos);
loop
-- C is a digit.
Bignum_Mul_Int (Res, 10, Character'Pos (C) - Character'Pos ('0'));
Scale := Scale + 1;
Pos := Pos + 1;
C := Source (Pos);
if C = '_' then
loop
Pos := Pos + 1;
C := Source (Pos);
exit when C /= '_';
Error_Msg_Scan ("double underscore in number");
end loop;
if C not in '0' .. '9' then
Error_Msg_Scan ("underscore must be followed by a digit");
end if;
end if;
exit when C not in '0' .. '9';
end loop;
end Scan_Integer;
C : Character;
D : Natural;
Ok : Boolean;
Has_Dot : Boolean;
Exp : Integer;
Exp_Neg : Boolean;
Base : Positive;
begin
-- Start with a simple and fast conversion.
C := Source (Pos);
D := 0;
loop
D := D * 10 + Character'Pos (C) - Character'Pos ('0');
Pos := Pos + 1;
C := Source (Pos);
if C = '_' then
loop
Pos := Pos + 1;
C := Source (Pos);
exit when C /= '_';
Error_Msg_Scan ("double underscore in number");
end loop;
if C not in '0' .. '9' then
Error_Msg_Scan ("underscore must be followed by a digit");
end if;
end if;
if C not in '0' .. '9' then
if C = '.' or else C = '#' or else (C = 'e' or C = 'E' or C = ':')
then
-- Continue scanning.
Bignum_Int (Res, D);
exit;
end if;
-- Finished.
-- a universal integer.
Current_Token := Tok_Integer;
-- No possible overflow.
Current_Context.Lit_Int64 := Int64 (D);
return;
elsif D >= (Natural'Last / 10) - 1 then
-- Number may be greather than the natural limit.
Scale := 0;
Bignum_Int (Res, D);
Scan_Integer;
exit;
end if;
end loop;
Has_Dot := False;
Base := 10;
Scale := 0;
C := Source (Pos);
if C = '.' then
-- Decimal integer.
Has_Dot := True;
Pos := Pos + 1;
C := Source (Pos);
if C not in '0' .. '9' then
Error_Msg_Scan ("a dot must be followed by a digit");
Current_Token := Tok_Real;
Current_Context.Lit_Fp64 := Fp64 (To_Float_64 (False, Res, Base, 0));
return;
end if;
Scan_Integer;
elsif C = '#'
or else (C = ':' and then (Source (Pos + 1) in '0' .. '9'
or else Source (Pos + 1) in 'a' .. 'f'
or else Source (Pos + 1) in 'A' .. 'F'))
then
-- LRM 13.10
-- The number sign (#) of a based literal can be replaced by colon (:),
-- provided that the replacement is done for both occurrences.
-- GHDL: correctly handle 'variable v : integer range 0 to 7:= 3'.
-- Is there any other places where a digit can be followed
-- by a colon ? (See IR 1093).
-- Based integer.
declare
Number_Sign : constant Character := C;
Res_Int : Interfaces.Unsigned_64;
begin
Bignum_To_Int (Res, Res_Int, Ok);
if not Ok or else Res_Int > 16 then
-- LRM 13.4.2
-- The base must be [...] at most sixteen.
Error_Msg_Scan ("base must be at most 16");
-- Fallback.
Base := 16;
elsif Res_Int < 2 then
-- LRM 13.4.2
-- The base must be at least two [...].
Error_Msg_Scan ("base must be at least 2");
-- Fallback.
Base := 2;
else
Base := Natural (Res_Int);
end if;
Pos := Pos + 1;
Bignum_Int (Res, 0);
C := Source (Pos);
loop
if C >= '0' and C <= '9' then
D := Character'Pos (C) - Character'Pos ('0');
elsif C >= 'A' and C <= 'F' then
D := Character'Pos (C) - Character'Pos ('A') + 10;
elsif C >= 'a' and C <= 'f' then
D := Character'Pos (C) - Character'Pos ('a') + 10;
else
Error_Msg_Scan ("bad extended digit");
exit;
end if;
if D >= Base then
-- LRM 13.4.2
-- The conventional meaning of base notation is
-- assumed; in particular the value of each extended
-- digit of a based literal must be less then the base.
Error_Msg_Scan ("digit beyond base");
D := 1;
end if;
Pos := Pos + 1;
Bignum_Mul_Int (Res, Base, D);
Scale := Scale + 1;
C := Source (Pos);
if C = '_' then
loop
Pos := Pos + 1;
C := Source (Pos);
exit when C /= '_';
Error_Msg_Scan ("double underscore in based integer");
end loop;
elsif C = '.' then
if Has_Dot then
Error_Msg_Scan ("double dot ignored");
else
Has_Dot := True;
Scale := 0;
end if;
Pos := Pos + 1;
C := Source (Pos);
elsif C = Number_Sign then
Pos := Pos + 1;
exit;
elsif C = '#' or C = ':' then
Error_Msg_Scan ("bad number sign replacement character");
exit;
end if;
end loop;
end;
end if;
-- Exponent.
C := Source (Pos);
Exp := 0;
if C = 'E' or else C = 'e' then
Pos := Pos + 1;
C := Source (Pos);
Exp_Neg := False;
if C = '+' then
Pos := Pos + 1;
C := Source (Pos);
elsif C = '-' then
if Has_Dot then
Exp_Neg := True;
else
-- LRM 13.4.1
-- An exponent for an integer literal must not have a minus sign.
--
-- LRM 13.4.2
-- An exponent for a based integer literal must not have a minus
-- sign.
Error_Msg_Scan
("negative exponent not allowed for integer literal");
end if;
Pos := Pos + 1;
C := Source (Pos);
end if;
if C not in '0' .. '9' then
Error_Msg_Scan ("digit expected after exponent");
else
loop
-- C is a digit.
Exp := Exp * 10 + (Character'Pos (C) - Character'Pos ('0'));
Pos := Pos + 1;
C := Source (Pos);
if C = '_' then
loop
Pos := Pos + 1;
C := Source (Pos);
exit when C /= '_';
Error_Msg_Scan ("double underscore not allowed in integer");
end loop;
if C not in '0' .. '9' then
Error_Msg_Scan ("digit expected after underscore");
exit;
end if;
elsif C not in '0' .. '9' then
exit;
end if;
end loop;
end if;
if Exp_Neg then
Exp := -Exp;
end if;
end if;
if Has_Dot then
-- a universal real.
Current_Token := Tok_Real;
Current_Context.Lit_Fp64 :=
Fp64 (To_Float_64 (False, Res, Base, Exp - Scale));
else
-- a universal integer.
Current_Token := Tok_Integer;
-- Set to a valid literal, in case of constraint error.
if Exp /= 0 then
Res := Bignum_Mul (Res, Bignum_Pow (Base, Exp));
end if;
declare
U : Unsigned_64;
begin
Bignum_To_Int (Res, U, Ok);
if U > Unsigned_64 (Int64'Last) then
Ok := False;
else
Current_Context.Lit_Int64 := Int64 (U);
end if;
end;
if not Ok then
Error_Msg_Scan ("literal beyond integer bounds");
end if;
end if;
exception
when Constraint_Error =>
Error_Msg_Scan ("literal overflow");
Current_Token := Tok_Integer;
Current_Context.Lit_Int64 := 0;
end Scan_Literal;
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