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-- numeric_std
-- Copyright (C) 2019 Tristan Gingold
--
-- This file is part of GHDL.
--
-- This program 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 of the License, or
-- (at your option) any later version.
--
-- This program 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 this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
-- MA 02110-1301, USA.
with Types_Utils; use Types_Utils;
package body Synth.Ieee.Numeric_Std is
Null_Vec : constant Std_Logic_Vector (1 .. 0) := (others => '0');
subtype Sl_01 is Std_Ulogic range '0' .. '1';
subtype Sl_X01 is Std_Ulogic range 'X' .. '1';
type Carry_Array is array (Sl_01, Sl_01, Sl_01) of Sl_01;
Compute_Carry : constant Carry_Array :=
('0' => ('0' => ('0' => '0', '1' => '0'),
'1' => ('0' => '0', '1' => '1')),
'1' => ('0' => ('0' => '0', '1' => '1'),
'1' => ('0' => '1', '1' => '1')));
Compute_Sum : constant Carry_Array :=
('0' => ('0' => ('0' => '0', '1' => '1'),
'1' => ('0' => '1', '1' => '0')),
'1' => ('0' => ('0' => '1', '1' => '0'),
'1' => ('0' => '0', '1' => '1')));
type Sl_To_X01_Array is array (Std_Ulogic) of Sl_X01;
Sl_To_X01 : constant Sl_To_X01_Array :=
('0' | 'L' => '0', '1' | 'H' => '1', others => 'X');
type Uns_To_01_Array is array (Uns64 range 0 .. 1) of Sl_X01;
Uns_To_01 : constant Uns_To_01_Array := (0 => '0', 1 => '1');
function Add_Uns_Uns (L, R : Std_Logic_Vector) return Std_Logic_Vector
is
pragma Assert (L'First = 1);
pragma Assert (R'First = 1);
Len : constant Integer := Integer'Max (L'Last, R'Last);
subtype Res_Type is Std_Logic_Vector (1 .. Len);
Res : Res_Type;
Lb, Rb, Carry : Sl_X01;
begin
if L'Last < 1 or R'Last < 1 then
return Null_Vec;
end if;
Carry := '0';
for I in 0 .. Len - 1 loop
if I >= L'Last then
Lb := '0';
else
Lb := Sl_To_X01 (L (L'Last - I));
end if;
if I >= R'Last then
Rb := '0';
else
Rb := Sl_To_X01 (R (R'Last - I));
end if;
if Lb = 'X' or Rb = 'X' then
--assert NO_WARNING
-- report "NUMERIC_STD.""+"": non logical value detected"
-- severity warning;
Res := (others => 'X');
exit;
end if;
Res (Res'Last - I) := Compute_Sum (Carry, Rb, Lb);
Carry := Compute_Carry (Carry, Rb, Lb);
end loop;
return Res;
end Add_Uns_Uns;
function Add_Sgn_Int (L : Std_Logic_Vector; R : Int64)
return Std_Logic_Vector
is
pragma Assert (L'First = 1);
Res : Std_Logic_Vector (1 .. L'Last);
V : Uns64;
Lb, Rb, Carry : Sl_X01;
begin
if L'Last < 1 then
return Null_Vec;
end if;
V := To_Uns64 (R);
Carry := '0';
for I in reverse Res'Range loop
Lb := Sl_To_X01 (L (I));
Rb := Uns_To_01 (V and 1);
if Lb = 'X' then
--assert NO_WARNING
-- report "NUMERIC_STD.""+"": non logical value detected"
-- severity warning;
Res := (others => 'X');
exit;
end if;
Res (I) := Compute_Sum (Carry, Rb, Lb);
Carry := Compute_Carry (Carry, Rb, Lb);
V := Shift_Right_Arithmetic (V, 1);
end loop;
return Res;
end Add_Sgn_Int;
function Add_Uns_Nat (L : Std_Logic_Vector; R : Uns64)
return Std_Logic_Vector
is
pragma Assert (L'First = 1);
Res : Std_Logic_Vector (1 .. L'Last);
V : Uns64;
Lb, Rb, Carry : Sl_X01;
begin
if L'Last < 1 then
return Null_Vec;
end if;
V := R;
Carry := '0';
for I in reverse Res'Range loop
Lb := Sl_To_X01 (L (I));
Rb := Uns_To_01 (V and 1);
if Lb = 'X' then
--assert NO_WARNING
-- report "NUMERIC_STD.""+"": non logical value detected"
-- severity warning;
Res := (others => 'X');
exit;
end if;
Res (I) := Compute_Sum (Carry, Rb, Lb);
Carry := Compute_Carry (Carry, Rb, Lb);
V := Shift_Right (V, 1);
end loop;
return Res;
end Add_Uns_Nat;
function Sub_Uns_Uns (L, R : Std_Logic_Vector) return Std_Logic_Vector
is
pragma Assert (L'First = 1);
pragma Assert (R'First = 1);
Len : constant Integer := Integer'Max (L'Last, R'Last);
subtype Res_Type is Std_Logic_Vector (1 .. Len);
Res : Res_Type;
Lb, Rb, Carry : Sl_X01;
begin
if L'Last < 1 or R'Last < 1 then
return Null_Vec;
end if;
Carry := '1';
for I in 0 .. Len - 1 loop
if I >= L'Last then
Lb := '0';
else
Lb := Sl_To_X01 (L (L'Last - I));
end if;
if I >= R'Last then
Rb := '1';
else
Rb := Sl_To_X01 (R (R'Last - I));
Rb := Not_Table (Rb);
end if;
if Lb = 'X' or Rb = 'X' then
--assert NO_WARNING
-- report "NUMERIC_STD.""+"": non logical value detected"
-- severity warning;
Res := (others => 'X');
exit;
end if;
Res (Res'Last - I) := Compute_Sum (Carry, Rb, Lb);
Carry := Compute_Carry (Carry, Rb, Lb);
end loop;
return Res;
end Sub_Uns_Uns;
function Mul_Uns_Uns (L, R : Std_Logic_Vector) return Std_Logic_Vector
is
pragma Assert (L'First = 1);
pragma Assert (R'First = 1);
Len : constant Integer := L'Last + R'Last;
Res : Std_Logic_Vector (1 .. Len);
Lb, Rb, Vb, Carry : Sl_X01;
begin
if L'Last < 1 or R'Last < 1 then
return Null_Vec;
end if;
Res := (others => '0');
-- Shift and add L.
for I in 0 .. R'Last - 1 loop
Rb := Sl_To_X01 (R (R'Last - I));
if Rb = '1' then
-- Compute res := res + shift_left (l, i).
Carry := '0';
for J in 0 .. L'Last - 1 loop
Lb := L (L'Last - J);
Vb := Res (Len - (I + J));
Res (Len - (I + J)) := Compute_Sum (Carry, Vb, Lb);
Carry := Compute_Carry (Carry, Vb, Lb);
end loop;
-- Propagate carry.
for J in I + L'Last .. Res'Last loop
exit when Carry = '0';
Vb := Res (Len - J);
Res (Len - J) := Xor_Table (Carry, Vb);
Carry := And_Table (Carry, Vb);
end loop;
elsif Rb = 'X' then
null;
-- assert NO_WARNING
-- report "NUMERIC_STD.""*"": non logical value detected"
-- severity warning;
end if;
end loop;
return Res;
end Mul_Uns_Uns;
function Mul_Sgn_Sgn (L, R : Std_Logic_Vector) return Std_Logic_Vector
is
pragma Assert (L'First = 1);
pragma Assert (R'First = 1);
Res : Std_Logic_Vector (1 .. L'Last + R'Last);
Lb, Rb, Vb, Carry : Sl_X01;
begin
if L'Last < 1 or R'Last < 1 then
return Null_Vec;
end if;
Res := (others => '0');
-- Shift and add L, do not consider (yet) the sign bit of R.
for I in 0 .. R'Last - 2 loop
Rb := Sl_To_X01 (R (R'Last - I));
if Rb = '1' then
-- Compute res := res + shift_left (l, i).
Carry := '0';
for J in 0 .. L'Last - 1 loop
Lb := L (L'Last - J);
Vb := Res (Res'Last - (I + J));
Res (Res'Last - (I + J)) := Compute_Sum (Carry, Vb, Lb);
Carry := Compute_Carry (Carry, Vb, Lb);
end loop;
-- Sign extend and propagate carry.
Lb := R (1);
for J in I + L'Last .. Res'Last - 1 loop
Vb := Res (Res'Last - J);
Res (Res'Last - J) := Compute_Sum (Carry, Vb, Lb);
Carry := Compute_Carry (Carry, Vb, Lb);
end loop;
elsif Rb = 'X' then
null;
-- assert NO_WARNING
-- report "NUMERIC_STD.""*"": non logical value detected"
-- severity warning;
end if;
end loop;
if R (1) = '1' then
-- R is a negative number. It is considered as:
-- -2**n + (Rn-1 Rn-2 ... R0).
-- Compute res := res - 2**n * l.
Carry := '1';
for I in 0 .. L'Last - 1 loop
Vb := Res (Res'Last - (R'Last - 1 + I));
Lb := Not_Table (L (L'Last - I));
Res (Res'Last - (R'Last - 1 + I)) := Compute_Sum (Carry, Vb, Lb);
Carry := Compute_Carry (Carry, Vb, Lb);
end loop;
Vb := Res (1);
Lb := Not_Table (L (1));
Res (1) := Compute_Sum (Carry, Vb, Lb);
end if;
return Res;
end Mul_Sgn_Sgn;
function Neg_Sgn (V : Std_Logic_Vector) return Std_Logic_Vector
is
pragma Assert (V'First = 1);
Len : constant Integer := V'Last;
subtype Res_Type is Std_Logic_Vector (1 .. Len);
Res : Res_Type;
Vb, Carry : Sl_X01;
begin
if Len < 1 then
return Null_Vec;
end if;
Carry := '1';
for I in 0 .. Len - 1 loop
Vb := Sl_To_X01 (V (V'Last - I));
if Vb = 'X' then
--assert NO_WARNING
-- report "NUMERIC_STD.""+"": non logical value detected"
-- severity warning;
Res := (others => 'X');
exit;
end if;
Vb := Not_Table (Vb);
Res (Res'Last - I) := Xor_Table (Carry, Vb);
Carry := And_Table (Carry, Vb);
end loop;
return Res;
end Neg_Sgn;
end Synth.Ieee.Numeric_Std;
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