Hi all,
First my congrats for this tool that i just discovered : huge !
I experimented an issue with signals of type 'real' :
consider the following simple test bench :
*library std;**
** use std.textio.all;**
**
** entity real_array is**
** end real_array;**
****
** architecture behav of real_array is**
****
** signal r1 , r2 : real := 0.1;**
** signal i1 , i2 : integer := 0;**
** begin**
****
** process**
** variable line_v : line;**
** file out_file : text open write_mode is "out.txt";**
****
** type real_array is array (natural range <>) of real;**
** constant real_tab : real_array := (1.0,5.0 , 10.0, 100.0);**
****
** begin**
** -- Check each pattern.**
** for i in real_tab'range loop**
** r1 <= real_tab(i mod 4);**
** r2 <= r1*r1;**
** i1 <= integer(r1);**
** i2 <= integer(r2);**
****
** write(line_v, i);**
** write(line_v, string'(" "));**
** write(line_v, r1);**
** write(line_v, string'(" "));**
** write(line_v, r2);**
** write(line_v, string'(" "));**
** writeline(out_file, line_v);**
****
** wait for 1 ns;**
** -- Check the outputs.**
** assert r1 < 1000.0**
** report "bad r1 high value" severity note;**
** assert r1 > 1.0e-5**
** report "bad r1 low value" severity note;**
****
** end loop;**
** assert false report "end of test" severity note;**
** -- Wait forever; this will finish the simulation.**
** wait;**
** end process;**
** end behav;*
when i execute it with *ghdl -r real_array --vcd=real_array.vcd : *
execution is fine, no error and output is as expected :
0 1.0e-1 1.0e-1
1 1.0e0 1.0e-2
2 5.0e0 1.0e0
3 1.0e1 2.5e1
but when i look the wave form with gtkwave, some values of real signals
are wrong
the issue is inside the generated VCD file (i added the comments OK /
not OK for the real signals )
$date
Fri Mar 24 07:23:42 2017
$end
$version
GHDL v0
$end
$timescale
1 fs
$end
$var real 64 ! r1 $end
$var real 64 " r2 $end
$var integer 32 # i1 $end
$var integer 32 $ i2 $end
$enddefinitions $end
#0
r1.00000E000 ! OK
r1.00000E-002 " OK
b0 #
b0 $
#1000000
r5.00000E000 ! OK
r1.00000E000 " OK
b1 #
#2000000
r:.00000E000 ! NOK
r2.50000E001 " OK
b101 #
b1 $
#3000000
r:.00000E001 ! NOK ???
r:.00000E001 " NOK ???
b1010 #
b11001 $
#4000000
Any idea ?
the storage of real in VCD seems to fail sometimes
Regards
pm
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