diff options
Diffstat (limited to 'testsuite/gna/issue50/idct.d/sub_160.vhd')
-rw-r--r-- | testsuite/gna/issue50/idct.d/sub_160.vhd | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/testsuite/gna/issue50/idct.d/sub_160.vhd b/testsuite/gna/issue50/idct.d/sub_160.vhd new file mode 100644 index 000000000..33dfaecd3 --- /dev/null +++ b/testsuite/gna/issue50/idct.d/sub_160.vhd @@ -0,0 +1,64 @@ +library ieee; +use ieee.std_logic_1164.all; + +library ieee; +use ieee.numeric_std.all; + +entity sub_160 is + port ( + le : out std_logic; + result : out std_logic_vector(31 downto 0); + in_a : in std_logic_vector(31 downto 0); + in_b : in std_logic_vector(31 downto 0); + sign : in std_logic + ); +end sub_160; + +architecture augh of sub_160 is + + signal carry_inA : std_logic_vector(33 downto 0); + signal carry_inB : std_logic_vector(33 downto 0); + signal carry_res : std_logic_vector(33 downto 0); + + -- Signals to generate the comparison outputs + signal msb_abr : std_logic_vector(2 downto 0); + signal tmp_sign : std_logic; + signal tmp_eq : std_logic; + signal tmp_le : std_logic; + signal tmp_ge : std_logic; + +begin + + -- To handle the CI input, the operation is '0' - CI + -- If CI is not present, the operation is '0' - '0' + carry_inA <= '0' & in_a & '0'; + carry_inB <= '0' & in_b & '0'; + -- Compute the result + carry_res <= std_logic_vector(unsigned(carry_inA) - unsigned(carry_inB)); + + -- Set the outputs + result <= carry_res(32 downto 1); + + -- Other comparison outputs + + -- Temporary signals + msb_abr <= carry_inA(32) & carry_inB(32) & carry_res(32); + tmp_sign <= sign; + tmp_eq <= '1' when in_a = in_b else '0'; + + tmp_le <= + tmp_eq when msb_abr = "000" or msb_abr = "110" else + '1' when msb_abr = "001" or msb_abr = "111" else + '1' when tmp_sign = '0' and (msb_abr = "010" or msb_abr = "011") else + '1' when tmp_sign = '1' and (msb_abr = "100" or msb_abr = "101") else + '0'; + + tmp_ge <= + '1' when msb_abr = "000" or msb_abr = "110" else + '1' when tmp_sign = '0' and (msb_abr = "100" or msb_abr = "101") else + '1' when tmp_sign = '1' and (msb_abr = "010" or msb_abr = "011") else + '0'; + + le <= tmp_le; + +end architecture; |