-- +---------------------------+
-- | Copyright 1996 DOULOS |
-- | Generic Library |
-- | opened: 17 Nov 1995 |
-- +---------------------------+
-- Synthesis script: read -f vhdl mvl_ops.bdy
library ieee;
library vfp;
package body std_operators is
use ieee.std_logic_1164.all;
use vfp.generic_functions.all;
-- type logical_map is array (mvl) of mvl;
-- type truth_table is array (mvl, mvl) of mvl;
--
-- constant not_a : logical_map := -- 22.11.95
-- -------------------------------------------
-- U X 0 1 Z W L H -
-- -------------------------------------------
-- ('u', 'x', '1', '0', 'x', 'x', '1', '0', 'x');
--
-- constant and_a_b : truth_table := ( -- 22.11.95
-- -------------------------------------------
-- U X 0 1 Z W L H -
-- -------------------------------------------
-- ('u', 'u', '0', 'u', 'u', 'u', '0', 'u', 'u'), -- | U |
-- ('u', 'x', '0', 'x', 'x', 'x', '0', 'x', 'x'), -- | X |
-- ('0', '0', '0', '0', '0', '0', '0', '0', '0'), -- | 0 |
-- ('u', 'x', '0', '1', 'x', 'x', '0', '1', 'x'), -- | 1 |
-- ('u', 'x', '0', 'x', 'x', 'x', '0', 'x', 'x'), -- | Z |
-- ('u', 'x', '0', 'x', 'x', 'x', '0', 'x', 'x'), -- | W |
-- ('0', '0', '0', '0', '0', '0', '0', '0', '0'), -- | L |
-- ('u', 'x', '0', '1', 'x', 'x', '0', '1', 'x'), -- | H |
-- ('u', 'x', '0', 'x', 'x', 'x', '0', 'x', 'x') -- | - |
-- );
--
-- constant or_a_b : truth_table := ( -- 22.11.95
-- -------------------------------------------
-- U X 0 1 Z W L H -
-- -------------------------------------------
-- ('u', 'u', 'u', '1', 'u', 'u', 'u', '1', 'u'), -- | U |
-- ('u', 'x', 'x', '1', 'x', 'x', 'x', '1', 'x'), -- | X |
-- ('u', 'x', '0', '1', 'x', 'x', '0', '1', 'x'), -- | 0 |
-- ('1', '1', '1', '1', '1', '1', '1', '1', '1'), -- | 1 |
-- ('u', 'x', 'x', '1', 'x', 'x', 'x', '1', 'x'), -- | Z |
-- ('u', 'x', 'x', '1', 'x', 'x', 'x', '1', 'x'), -- | W |
-- ('u', 'x', '0', '1', 'x', 'x', '0', '1', 'x'), -- | L |
-- ('1', '1', '1', '1', '1', '1', '1', '1', '1'), -- | H |
-- ('u', 'x', 'x', '1', 'x', 'x', 'x', '1', 'x') -- | - |
-- );
--
-- constant xor_a_b : truth_table := ( -- 22.11.95
-- -------------------------------------------
-- U X 0 1 Z W L H -
-- -------------------------------------------
-- ('u', 'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u'), -- | U |
-- ('u', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x'), -- | X |
-- ('u', 'x', '0', '1', 'x', 'x', '0', '1', 'x'), -- | 0 |
-- ('u', 'x', '1', '0', 'x', 'x', '1', '0', 'x'), -- | 1 |
-- ('u', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x'), -- | Z |
-- ('u', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x'), -- | W |
-- ('u', 'x', '0', '1', 'x', 'x', '0', '1', 'x'), -- | L |
-- ('u', 'x', '1', '0', 'x', 'x', '1', '0', 'x'), -- | H |
-- ('u', 'x', 'x', 'x', 'x', 'x', 'x', 'x', 'x') -- | - |
-- );
--
-- -- function "not" ( -- 24.11.95
-- a: mvl
-- ) return mvl is
-- begin
-- return (not_a (a));
-- end "not";
--
-- function "and" ( -- 24.11.95
-- a, b: mvl
-- ) return mvl is
-- begin
-- return (and_a_b (a, b));
-- end "and";
--
-- function "or" ( -- 24.11.95
-- a, b: mvl
-- ) return mvl is
-- begin
-- return (or_a_b (a, b));
-- end "or";
--
-- function "xor" ( -- 24.11.95
-- a, b: mvl
-- ) return mvl is
-- begin
-- return (xor_a_b (a, b));
-- end "xor";
--
-- function "nand" ( -- 24.11.95
-- a, b: mvl
-- ) return mvl is
-- begin
-- return not (a and b);
-- end "nand";
--
-- function "nor" ( -- 24.11.95
-- a, b: mvl
-- ) return mvl is
-- begin
-- return not (a or b);
-- end "nor";
--
-- --function "xnor" ( -- 24.11.95
-- -- a, b: mvl
-- --) return mvl is
-- --begin
-- -- return not (a xor b);
-- --end "xnor";
--
-- function "not" ( -- 25.11.95
-- a: mvl_vector
-- ) return mvl_vector is
-- variable yi: mvl_vector(a'length-1 downto 0);
-- begin
-- for i in 0 to a'length-1 loop
-- yi(i) := not a(i);
-- end loop;
-- return yi;
-- end "not";
--
-- function "and" ( -- 24.11.95
-- a, b: mvl_vector
-- ) return mvl_vector is
-- variable y: mvl_vector(a'length-1 downto 0);
-- begin
-- if (a'length /= b'length) then
-- assert false
-- report "Error 0000." &
-- "Library = vfp." &
-- "Package Body = mvl_operators." &
-- "Function = and." &
-- "The wordlength of a and b MUST be the same."
-- severity error;
-- else
-- for i in 0 to a'length-1 loop
-- y(i) := a(i) and b(i);
-- end loop;
-- end if;
-- return y;
-- end "and";
--
-- function "or" ( -- 25.11.95
-- a, b: mvl_vector
-- ) return mvl_vector is
-- variable y: mvl_vector(a'length-1 downto 0);
-- begin
-- if (a'length /= b'length) then
-- assert false
-- report "Error 0001." &
-- "Library = vfp." &
-- "Package Body = mvl_operators." &
-- "Function = or." &
-- "The wordlength of a and b MUST be the same."
-- severity error;
-- else
-- for i in 0 to a'length-1 loop
-- y(i) := a(i) or b(i);
-- end loop;
-- end if;
-- return y;
-- end "or";
--
-- function "xor" ( -- 25.11.95
-- a, b: mvl_vector
-- ) return mvl_vector is
-- variable y: mvl_vector(a'length-1 downto 0);
-- begin
-- if (a'length /= b'length) then
-- assert false
-- report "Error 0002." &
-- "Library = vfp." &
-- "Package Body = mvl_operators." &
-- "Function = xor." &
-- "The wordlength of a and b MUST be the same."
-- severity error;
-- else
-- for i in 0 to a'length-1 loop
-- y(i) := a(i) xor b(i);
-- end loop;
-- end if;
-- return y;
-- end "xor";
--
-- function "nand" ( -- 25.11.95
-- a, b: mvl_vector
-- ) return mvl_vector is
-- variable yi: mvl_vector(a'length-1 downto 0);
-- begin
-- if (a'length /= b'length) then
-- assert false
-- report "Error 0003." &
-- "Library = vfp." &
-- "Package Body = mvl_operators." &
-- "Function = nand." &
-- "The wordlength of a and b MUST be the same."
-- severity error;
-- else
-- for i in 0 to a'length-1 loop
-- yi(i) := not (a(i) and b(i));
-- end loop;
-- end if;
-- return yi;
-- end "nand";
--
-- function "nor" ( -- 25.11.95
-- a, b: mvl_vector
-- ) return mvl_vector is
-- variable yi: mvl_vector(a'length-1 downto 0);
-- begin
-- if (a'length /= b'length) then
-- assert false
-- report "Error 0004." &
-- "Library = vfp." &
-- "Package Body = mvl_operators." &
-- "Function = nor." &
-- "The wordlength of a and b MUST be the same."
-- severity error;
-- else
-- for i in 0 to a'length-1 loop
-- yi(i) := not (a(i) or b(i));
-- end loop;
-- end if;
-- return yi;
-- end "nor";
--
-- --function "xnor" ( -- 25.11.95
-- -- a, b: mvl_vector
-- --) return mvl_vector is
-- -- variable yi: mvl_vector(a'length-1 downto 0);
-- --begin
-- -- if (a'length /= b'length) then
-- -- assert false
-- -- report "Error 0005." &
-- -- "Library = vfp." &
-- -- "Package Body = mvl_operators." &
-- -- "Function = xnor." &
-- -- "The wordlength of a and b MUST be the same."
-- -- severity error;
-- -- else
-- -- for i in 0 to a'length-1 loop
-- -- yi(i) := not (a(i) xor b(i));
-- -- end loop;
-- -- end if;
-- -- return yi;
-- --end "xnor";
function "+" ( -- 11.03.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
constant y_length: integer := longest (a, b);
variable a_extended, b_extended: std_ulogic_vector(y_length-1 downto 0);
variable y: std_ulogic_vector(y_length-1 downto 0);
variable carry: std_ulogic;
variable a_add, b_add: std_ulogic_vector(y_length-1 downto 0);
begin
carry := '0';
if (a'length < b'length) then
for i in b'length-1 downto a'length loop
a_extended(i) := '0';
end loop;
a_extended(a'length-1 downto 0) := a;
b_add := b;
for i in 0 to b'length-1 loop
y(i) := a_extended(i) xor b_add(i) xor carry;
carry := (a_extended(i) and b_add(i)) or
(a_extended(i) and carry) or
(b_add(i) and carry);
end loop;
elsif (a'length > b'length) then
for i in a'length-1 downto b'length loop
b_extended(i) := '0';
end loop;
b_extended(b'length-1 downto 0) := b;
a_add := a;
for i in 0 to a'length-1 loop
y(i) := a_add(i) xor b_extended(i) xor carry;
carry := (a_add(i) and b_extended(i)) or
(a_add(i) and carry) or
(b_extended(i) and carry);
end loop;
else -- i.e., (a'length = b'length)
a_add := a;
b_add := b;
for i in 0 to a'length-1 loop
y(i) := a_add(i) xor b_add(i) xor carry;
carry := (a_add(i) and b_add(i)) or
(a_add(i) and carry) or
(b_add(i) and carry);
end loop;
end if;
return y;
end "+";
function "+" ( -- 11.03.95
a, b: std_logic_vector
) return std_logic_vector is
constant y_length: integer := longest (a, b);
variable a_extended, b_extended: std_logic_vector(y_length-1 downto 0);
variable y: std_logic_vector(y_length-1 downto 0);
variable carry: std_logic;
variable a_add, b_add: std_logic_vector(y_length-1 downto 0);
begin
carry := '0';
if (a'length < b'length) then
for i in b'length-1 downto a'length loop
a_extended(i) := '0';
end loop;
a_extended(a'length-1 downto 0) := a;
b_add := b;
for i in 0 to b'length-1 loop
y(i) := a_extended(i) xor b_add(i) xor carry;
carry := (a_extended(i) and b_add(i)) or
(a_extended(i) and carry) or
(b_add(i) and carry);
end loop;
elsif (a'length > b'length) then
for i in a'length-1 downto b'length loop
b_extended(i) := '0';
end loop;
b_extended(b'length-1 downto 0) := b;
a_add := a;
for i in 0 to a'length-1 loop
y(i) := a_add(i) xor b_extended(i) xor carry;
carry := (a_add(i) and b_extended(i)) or
(a_add(i) and carry) or
(b_extended(i) and carry);
end loop;
else -- i.e., (a'length = b'length)
a_add := a;
b_add := b;
for i in 0 to a'length-1 loop
y(i) := a_add(i) xor b_add(i) xor carry;
carry := (a_add(i) and b_add(i)) or
(a_add(i) and carry) or
(b_add(i) and carry);
end loop;
end if;
return y;
end "+";
function "-" ( -- 29.11.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
constant y_length: integer := longest (a, b);
variable a_extended, b_extended: std_ulogic_vector(y_length-1 downto 0);
variable y: std_ulogic_vector(y_length-1 downto 0);
variable carry: std_ulogic;
begin
carry := '1';
if (a'length < b'length) then
for i in b'length-1 downto a'length loop
a_extended(i) := '0';
end loop;
a_extended(a'length-1 downto 0) := a;
for i in 0 to b'length-1 loop
y(i) := a_extended(i) xor (not b(i)) xor carry;
carry := (a_extended(i) and (not b(i))) or
(a_extended(i) and carry) or
((not b(i)) and carry);
end loop;
elsif (a'length > b'length) then
for i in a'length-1 downto b'length loop
b_extended(i) := '0';
end loop;
b_extended(b'length-1 downto 0) := b;
for i in 0 to a'length-1 loop
y(i) := a(i) xor (not b_extended(i)) xor carry;
carry := (a(i) and (not b_extended(i))) or
(a(i) and carry) or
((not b_extended(i)) and carry);
end loop;
else -- i.e., (a'length = b'length)
for i in 0 to a'length-1 loop
y(i) := a(i) xor (not b(i)) xor carry;
carry := (a(i) and (not b(i))) or
(a(i) and carry) or
((not b(i)) and carry);
end loop;
end if;
return y;
end "-";
function "*" ( -- 30.11.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
constant y_length: integer := a'length + b'length;
variable y_sign: std_ulogic;
variable multiplicand: std_ulogic_vector(a'length-1 downto 0);
variable multiplier: std_ulogic_vector(b'length-1 downto 0);
variable partial_product: std_ulogic_vector(a'length-1 downto 0);
variable product_lsb: std_ulogic_vector(b'length-1 downto 0);
variable product: std_ulogic_vector(y_length-1 downto 0);
variable y: std_ulogic_vector(y_length-1 downto 0);
begin
multiplicand := a;
multiplier := b;
for i in 0 to multiplicand'length-1 loop
partial_product(i) := '0';
end loop;
for i in 0 to multiplier'length-1 loop
if (multiplier(i) = '1') then
partial_product := partial_product(a'length-1 downto 1) + multiplicand;
product_lsb(i) := partial_product(0);
else
partial_product := '0' & partial_product(a'length-1 downto 1);
product_lsb(i) := partial_product(0);
end if;
end loop;
product := partial_product & product_lsb;
y := product;
return y;
end "*";
function "/" ( -- 29.11.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
constant y_length: integer := a'length + b'length;
constant a_extended_length: integer := b'length-1;
variable a_extended: std_ulogic_vector(a_extended_length-1 downto 0);
variable dividend_match: std_ulogic_vector(b'length-1 downto 0);
variable quotient: std_ulogic_vector(a'length-1 downto 0);
variable remainder: std_ulogic_vector(b'length-1 downto 0);
variable y: std_ulogic_vector(y_length-1 downto 0);
begin
for i in a_extended_length-1 downto 0 loop
a_extended(i) := '0';
end loop;
dividend_match(b'length-1 downto 1) := a_extended;
for i in a'length-1 downto 0 loop
dividend_match := dividend_match(b'length-1 downto 1) & a(i);
if (b <= dividend_match) then
dividend_match := dividend_match - b;
quotient(i) := '1';
else
quotient(i) := '0';
end if;
end loop;
remainder := dividend_match;
y := quotient & remainder;
return y;
end "/";
function "mod" ( -- 2.12.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
constant y_length: integer := a'length + b'length;
constant a_extended_length: integer := b'length-1;
variable a_extended: std_ulogic_vector(a_extended_length-1 downto 0);
variable dividend_match: std_ulogic_vector(b'length-1 downto 0);
variable remainder: std_ulogic_vector(b'length-1 downto 0);
variable y: std_ulogic_vector(b'length-1 downto 0);
begin
for i in a_extended_length-1 downto 0 loop
a_extended(i) := '0';
end loop;
dividend_match(b'length-1 downto 1) := a_extended;
for i in a'length-1 downto 0 loop
dividend_match := dividend_match(b'length-1 downto 1) & a(i);
if (b <= dividend_match) then
dividend_match := dividend_match - b;
end if;
end loop;
remainder := dividend_match;
y := remainder;
return y;
end "mod";
function "rem" ( -- 2.12.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
constant y_length: integer := a'length + b'length;
constant a_extended_length: integer := b'length-1;
variable a_extended: std_ulogic_vector(a_extended_length-1 downto 0);
variable dividend_match: std_ulogic_vector(b'length-1 downto 0);
variable remainder: std_ulogic_vector(b'length-1 downto 0);
variable y: std_ulogic_vector(b'length-1 downto 0);
begin
for i in a_extended_length-1 downto 0 loop
a_extended(i) := '0';
end loop;
dividend_match(b'length-1 downto 1) := a_extended;
for i in a'length-1 downto 0 loop
dividend_match := dividend_match(b'length-1 downto 1) & a(i);
if (b <= dividend_match) then
dividend_match := dividend_match - b;
end if;
end loop;
remainder := dividend_match;
y := remainder;
return y;
end "rem";
function "abs" ( -- 2.12.95
a: std_ulogic_vector
) return std_ulogic_vector is
variable y: std_ulogic_vector(a'length-1 downto 0);
begin
assert false
report "Warning 0001." &
"Library = vfp." &
"Package Body = std_ulogic_operators." &
"Function = abs." &
"The function abs (std_ulogic_vector) is defined as ... " &
" <return_value> := <actual_parameter> " &
"Thus there is no point in taking the absolute value of an std_ulogic_vector."
severity warning;
y := a;
return y;
end "abs";
function "+" ( -- 2.12.95
a: std_ulogic_vector
) return std_ulogic_vector is
variable y: std_ulogic_vector(a'length-1 downto 0);
begin
assert false
report "Warning 0001." &
"Library = vfp." &
"Package Body = std_ulogic_operators." &
"Function = +." &
"The function + (std_ulogic_vector) is defined as ... " &
" <return_value> := <actual_parameter> " &
"Thus there is no point in taking the positive value of an std_ulogic_vector."
severity warning;
y := a;
return y;
end "+";
function "-" ( -- 2.12.95
a: std_ulogic_vector
) return std_ulogic_vector is
variable y: std_ulogic_vector(a'length-1 downto 0);
begin
assert false
report "Error 0001." &
"Library = vfp." &
"Package Body = std_ulogic_operators." &
"Function = -." &
"The function - (std_ulogic_vector) is not supported." &
"However, 0 - <std_ulogic_vector_expression> IS supported."
-- See the integer - std_ulogic_vector overloaded operator
severity error;
y := a;
return y;
end "-";
function "**" ( -- 2.12.95
a, b: std_ulogic_vector
) return std_ulogic_vector is
variable y: std_ulogic_vector(a'length-1 downto 0);
begin
assert false
report "Error 0001." &
"Library = vfp." &
"Package Body = std_ulogic_operators." &
"Function = **." &
"The function (std_ulogic_vector) ** (std_ulogic_vector) is not supported." &
"However, to_std_ulogic_vector(to_integer(std_ulogic_vector) ** to_integer(std_ulogic_vector)) is supported."
-- See the to_integer and the to_std_ulogic_vector conversion functions
severity error;
y := a;
return y;
end "**";
end std_operators;
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