1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.fixed_float_types.all;
use work.Package_Float32.all;
use work.Package_Fixed.all;
entity test_Float_To_sFixed is
end entity test_Float_To_sFixed;
architecture RTL of test_Float_To_sFixed is
procedure compute_and_show(sign : in std_logic; exponent : in Integer; fraction : in std_logic_vector(23-1 downto 0)) is
variable s : std_logic_vector(32-1 downto 0);
variable f : float32;
variable sf : sFixed(4-1 downto -2);
variable r : Real;
begin
s := sign & std_logic_vector(to_unsigned(exponent, 8)) & fraction;
f := to_float(s, f);
sf := to_sFixed(f, sf, round_style => fixed_truncate);
r := to_real(f);
report "s : " & to_string(sign) & "."
& to_string(to_unsigned(exponent, 8)) & "."
& to_string(fraction)
& " -> " & to_string(r);
report "sf : " & to_string(sf);
report "";
end compute_and_show;
begin
process
begin
compute_and_show('0', 0, "00000000000000000000000"); -- 0
compute_and_show('0', 123, "00000000000000000000000"); -- 0.0625
compute_and_show('0', 124, "00000000000000000000000"); -- 0.125
compute_and_show('0', 125, "00000000000000000000000"); -- 0.25
compute_and_show('0', 126, "00000000000000000000000"); -- 0.5
compute_and_show('0', 127, "00000000000000000000000"); -- 1
compute_and_show('0', 127, "10000000000000000000000"); -- 1.5
compute_and_show('0', 127, "11000000000000000000000"); -- 1.75
compute_and_show('0', 127, "11100000000000000000000"); -- 1.875
compute_and_show('0', 127, "11110000000000000000000"); -- 1.875
report "------";
report "";
compute_and_show('1', 0, "00000000000000000000000"); -- -0
compute_and_show('1', 123, "00000000000000000000000"); -- -0.0625
compute_and_show('1', 124, "00000000000000000000000"); -- -0.125
compute_and_show('1', 125, "00000000000000000000000"); -- -0.25
compute_and_show('1', 126, "00000000000000000000000"); -- -0.5
compute_and_show('1', 127, "00000000000000000000000"); -- -1
compute_and_show('1', 127, "10000000000000000000000"); -- -1.5
compute_and_show('1', 127, "11000000000000000000000"); -- -1.75
compute_and_show('1', 127, "11100000000000000000000"); -- -1.875
compute_and_show('1', 127, "11110000000000000000000"); -- -1.9375
compute_and_show('1', 127, "11111000000000000000000"); -- -1.9375
compute_and_show('1', 127, "11111100000000000000000"); -- -1.9375
compute_and_show('1', 127, "11111110000000000000000"); -- -1.9375
compute_and_show('1', 127, "11111111000000000000000"); -- -1.9375
wait;
end process;
end architecture RTL;
|
