From e6b1726587d3a2be8f18c2f6473ff8651cc15ca3 Mon Sep 17 00:00:00 2001
From: Eric Kooistra <kooistra@astron.nl>
Date: Thu, 4 Nov 2021 13:05:02 +0100
Subject: [PATCH] Use s_clip and u_clip to simplify the code of s_round() and
u_round().
---
libraries/base/common/src/vhdl/common_pkg.vhd | 26 ++++++++++---------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/libraries/base/common/src/vhdl/common_pkg.vhd b/libraries/base/common/src/vhdl/common_pkg.vhd
index c6ca6f3c92..63a769e7f4 100644
--- a/libraries/base/common/src/vhdl/common_pkg.vhd
+++ b/libraries/base/common/src/vhdl/common_pkg.vhd
@@ -2392,8 +2392,9 @@ PACKAGE BODY common_pkg IS
CONSTANT c_in_w : NATURAL := vec'LENGTH;
CONSTANT c_out_w : NATURAL := vec'LENGTH - n;
CONSTANT c_half : NATURAL := 2**(n-1);
- CONSTANT c_max : SIGNED(c_in_w-1 DOWNTO 0) := SIGNED('0' & c_slv1(c_in_w-2 DOWNTO 0)) - c_half; -- = 2**(c_in_w-1)-1 - c_half
- CONSTANT c_clip : SIGNED(c_out_w-1 DOWNTO 0) := SIGNED('0' & c_slv1(c_out_w-2 DOWNTO 0)); -- = 2**(c_out_w-1)-1
+ CONSTANT c_max : INTEGER := 2**(c_in_w-1)-1 - c_half;
+ CONSTANT c_clip : INTEGER := 2**(c_out_w-1)-1;
+ CONSTANT s_clip : SIGNED(c_out_w-1 DOWNTO 0) := TO_SIGNED(c_clip, c_out_w);
VARIABLE v_in : SIGNED(c_in_w-1 DOWNTO 0);
VARIABLE v_fraction : UNSIGNED(n-1 DOWNTO 0);
VARIABLE v_out : SIGNED(c_out_w-1 DOWNTO 0);
@@ -2401,7 +2402,7 @@ PACKAGE BODY common_pkg IS
v_in := SIGNED(vec);
IF n > 0 THEN
IF clip = TRUE AND v_in > c_max THEN
- v_out := c_clip; -- Round clip to maximum positive to avoid wrap to negative
+ v_out := s_clip; -- Round clip to maximum positive to avoid wrap to negative
ELSE
IF even = FALSE THEN
-- Round half away
@@ -2414,13 +2415,13 @@ PACKAGE BODY common_pkg IS
-- Round half to even
v_out := RESIZE_NUM(SHIFT_RIGHT(v_in + c_half, n), c_out_w); -- Round to nearest using floor(vec + 0.5)
v_fraction := UNSIGNED(vec(n-1 DOWNTO 0));
- IF v_fraction = c_half AND v_out(0) = '1' THEN -- Round half to even, so when odd subtract 1
- v_out := v_out - 1; -- to make v_out even
+ IF v_fraction = c_half AND v_out(0) = '1' THEN -- Round half to even, so when odd subtract 1
+ v_out := v_out - 1; -- to make v_out even
END IF;
END IF;
END IF;
ELSE
- v_out := RESIZE_NUM(v_in, c_out_w); -- NOP
+ v_out := RESIZE_NUM(v_in, c_out_w); -- NOP
END IF;
RETURN STD_LOGIC_VECTOR(v_out);
END;
@@ -2451,8 +2452,9 @@ PACKAGE BODY common_pkg IS
CONSTANT c_in_w : NATURAL := vec'LENGTH;
CONSTANT c_out_w : NATURAL := vec'LENGTH - n;
CONSTANT c_half : NATURAL := 2**(n-1);
- CONSTANT c_max : UNSIGNED(c_in_w-1 DOWNTO 0) := UNSIGNED(c_slv1(c_in_w-1 DOWNTO 0)) - c_half; -- = 2**c_in_w-1 - c_half
- CONSTANT c_clip : UNSIGNED(c_out_w-1 DOWNTO 0) := UNSIGNED(c_slv1(c_out_w-1 DOWNTO 0)); -- = 2**c_out_w-1
+ CONSTANT c_max : NATURAL := 2**c_in_w-1 - c_half;
+ CONSTANT c_clip : NATURAL := 2**c_out_w-1;
+ CONSTANT u_clip : UNSIGNED(c_out_w-1 DOWNTO 0) := TO_UNSIGNED(c_clip, c_out_w);
VARIABLE v_in : UNSIGNED(c_in_w-1 DOWNTO 0);
VARIABLE v_fraction : UNSIGNED(n-1 DOWNTO 0);
VARIABLE v_out : UNSIGNED(c_out_w-1 DOWNTO 0);
@@ -2460,7 +2462,7 @@ PACKAGE BODY common_pkg IS
v_in := UNSIGNED(vec);
IF n > 0 THEN
IF clip = TRUE AND v_in > c_max THEN
- v_out := c_clip; -- Round clip to +max to avoid wrap to 0
+ v_out := u_clip; -- Round clip to +max to avoid wrap to 0
ELSE
IF even = FALSE THEN
-- Round half up
@@ -2469,13 +2471,13 @@ PACKAGE BODY common_pkg IS
-- Round half to even
v_out := RESIZE_NUM(SHIFT_RIGHT(v_in + c_half, n), c_out_w); -- Round to nearest using floor(vec + 0.5)
v_fraction := UNSIGNED(vec(n-1 DOWNTO 0));
- IF v_fraction = c_half AND v_out(0) = '1' THEN -- Round half to even, so when odd subtract 1
- v_out := v_out - 1; -- to make v_out even
+ IF v_fraction = c_half AND v_out(0) = '1' THEN -- Round half to even, so when odd subtract 1
+ v_out := v_out - 1; -- to make v_out even
END IF;
END IF;
END IF;
ELSE
- v_out := RESIZE_NUM(v_in, c_out_w); -- NOP
+ v_out := RESIZE_NUM(v_in, c_out_w); -- NOP
END IF;
RETURN STD_LOGIC_VECTOR(v_out);
END;
--
GitLab