From 2f4337f027ec97dd93642ea2db70873e9192fb3b Mon Sep 17 00:00:00 2001
From: Tristan Gingold
Date: Sun, 7 Dec 2014 11:40:58 +0100
Subject: Add perf02 (performance issue).

---
 testsuite/gna/perf02/sub_143.vhd | 68 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 testsuite/gna/perf02/sub_143.vhd

(limited to 'testsuite/gna/perf02/sub_143.vhd')

diff --git a/testsuite/gna/perf02/sub_143.vhd b/testsuite/gna/perf02/sub_143.vhd
new file mode 100644
index 0000000..354af44
--- /dev/null
+++ b/testsuite/gna/perf02/sub_143.vhd
@@ -0,0 +1,68 @@
+library ieee;
+use ieee.std_logic_1164.all;
+
+library ieee;
+use ieee.numeric_std.all;
+
+entity sub_143 is
+	port (
+		output : out std_logic_vector(63 downto 0);
+		lt : out std_logic;
+		le : out std_logic;
+		sign : in  std_logic;
+		gt : out std_logic;
+		in_a : in  std_logic_vector(63 downto 0);
+		in_b : in  std_logic_vector(63 downto 0)
+	);
+end sub_143;
+
+architecture augh of sub_143 is
+
+	signal carry_inA : std_logic_vector(65 downto 0);
+	signal carry_inB : std_logic_vector(65 downto 0);
+	signal carry_res : std_logic_vector(65 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
+	output <= carry_res(64 downto 1);
+
+	-- Other comparison outputs
+
+	-- Temporary signals
+	msb_abr <= in_a(63) & in_b(63) & carry_res(64);
+	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"  else
+		'1' when tmp_sign = '0' and (msb_abr = "010" or msb_abr = "001" or msb_abr = "111") 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" or msb_abr = "111") else
+		'0';
+
+	gt <= not(tmp_le);
+	lt <= not(tmp_ge);
+	le <= tmp_le;
+
+end architecture;
-- 
cgit