VHDL FAQ

Conversion from CHARACTER to STD_LOGIC_VECTOR

function conversion_X(char:character) return std_logic_vector is

begin

return std_logic_vector(to_unsigned(character'pos(char),8));

end conversion_X;

This should work w/ either packages STD_LOGIC_ARITH or NUMERIC_STD.

Package NUMERIC_BIT_TEXTIO

--============================================================================
--============================================================================
--
-- Numeric_Bit_TextIO package (c)TransEDA Limited
-- All rights reserved
-- This source code can be distributed freely provided it contains the copyright
--
-- This package extends TextIO to allow the reading and writing of the types
-- defined in 1076.3 package Numeric_Bit
--
-- This version of the package is completely portable since it is layered onto TextIO
-- and makes no use of the internal operation of TextIO.
--
-- version history:
-- v0.0 AR 27-11-95 basic package with complete set of read/write procedures
--
--============================================================================
--============================================================================

use std.textio.all;
library ieee; use ieee.numeric_bit.all;
package numeric_bit_textio is
      procedure read (l : inout line; value : out signed);
      procedure read (l : inout line; value : out unsigned);
      procedure read (l : inout line; value : out signed; good : out boolean);
      procedure read (l : inout line; value : out unsigned; good : out boolean);

      procedure write (l : inout line; value : in signed; justified : in side := right; field : in width := 0);
      procedure write (l : inout line; value : in unsigned; justified : in side := right; field : in width := 0);
end numeric_bit_textio;

package body numeric_bit_textio is
      procedure read(l : inout line; value : out signed; good : out boolean) is
            variable bv_value : bit_vector(value'range);
      begin
            read (l, bv_value, good);
            value := signed(bv_value);
      end;

      procedure read (l : inout line; value : out signed) is
            variable good: boolean;
      begin
            read (l, value, good);
            assert good report "numeric_bit_textio: read(line,signed) failed" severity error;
      end;

      procedure read(l : inout line; value : out unsigned; good : out boolean) is
            variable bv_value : bit_vector(value'range);
      begin
            read (l, bv_value, good);
            value := unsigned(bv_value);
      end;

      procedure read (l : inout line; value : out unsigned) is
            variable good: boolean;
      begin
            read (l, value, good);
            assert good report "numeric_bit_textio: read(line,unsigned) failed" severity error;
      end;

      procedure write(l : inout line; value : in signed; justified : in side := right; field : in width := 0) is
      begin
            write (l, bit_vector(value), justified, field);
      end;

      procedure write(l : inout line; value : in unsigned; justified : in side := right; field : in width := 0) is
      begin
            write (l, bit_vector(value), justified, field);
      end;
end;

Package NUMERIC_STD_TEXTIO

--============================================================================
--============================================================================
--
-- Numeric_Std_TextIO package (c)TransEDA Limited
-- All rights reserved
-- This source code can be distributed freely provided it contains the copyright
--
-- This package extends TextIO to allow the reading and writing of the types
-- defined in 1076.3 package Numeric_Std
--
-- This version of the package is completely portable since it is layered onto TextIO
-- and makes no use of the internal operation of TextIO.
--
-- version history:
-- v0.0 AR 27-11-95 basic package with complete set of read/write procedures
--
--============================================================================
--============================================================================

use std.textio.all;
library ieee; use ieee.numeric_std.all, ieee.std_logic_1164.all;
package numeric_std_textio is
    procedure read (l : inout line; value : out signed);
    procedure read (l : inout line; value : out unsigned);
    procedure read (l : inout line; value : out signed; good : out boolean);
    procedure read (l : inout line; value : out unsigned; good : out boolean);
      procedure write (l : inout line; value : in signed; justified : in side := right; field : in width := 0);
      procedure write (l : inout line; value : in unsigned; justified : in side := right; field : in width := 0);
end numeric_std_textio;

library ieee; use ieee.std_logic_textio.all;
package body numeric_std_textio is
      procedure read(l : inout line; value : out signed; good : out boolean) is
            variable bv_value : std_logic_vector(value'range);
      begin
            read (l, bv_value, good);
            value := signed(bv_value);
      end;

procedure read (l : inout line; value : out signed) is
variable good: boolean;
begin
read (l, value, good);
assert good report "numeric_std_textio: read(line,signed) failed" severity error;
end;

procedure read(l : inout line; value : out unsigned; good : out boolean) is
variable bv_value : std_logic_vector(value'range);
begin
read (l, bv_value, good);
value := unsigned(bv_value);
end;

procedure read (l : inout line; value : out unsigned) is
variable good: boolean;
begin
read (l, value, good);
assert good report "numeric_std_textio: read(line,unsigned) failed" severity error;
end;

procedure write(l : inout line; value : in signed; justified : in side := right; field : in width := 0) is
begin
write (l, std_logic_vector(value), justified, field);
end;

procedure write(l : inout line; value : in unsigned; justified : in side := right; field : in width := 0) is
begin
write (l, std_logic_vector(value), justified, field);
end;

end;

Last updated: September 28, 2000