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Add support for SystemVerilog style time literals 

SystemVerilog has support for time literals. The time literal for
example #10ns, adds a delay of 10ns no matter the time unit currently
in effect. For more details please refer to
http://iverilog.wikia.com/wiki/Projects#SystemVerilog_Style_Time_Literals

Tested-by: Oswaldo Cadenas <oswaldo.cadenas@gmail.com>
Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
This commit is contained in:
Prasad Joshi 2011-07-05 18:11:56 +01:00 committed by Stephen Williams
parent 537b8cba34
commit 2cb9a2360c
3 changed files with 62 additions and 0 deletions
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17
parse.y
View File

@ -975,6 +975,23 @@ delay_value_simple
$$ = tmp;
delete[]$1;
}
| TIME_LITERAL
{
int unit;
based_size = 0;
$$ = 0;
if ($1 == 0 || !get_time_unit($1, unit))
yyerror(@1, "internal error: delay.");
else {
double p = pow(10, unit - pform_get_timeunit());
double time = atof($1) * p;
verireal *v = new verireal(time);
$$ = new PEFNumber(v);
FILE_NAME($$, @1);
}
}
;
description

43
pform.cc
View File

@ -502,6 +502,44 @@ void pform_set_timescale(int unit, int prec,
}
}
bool get_time_unit(const char*cp, int &unit)
{
const char *c;
bool rc = true;
if (strchr(cp, '_')) {
VLerror(yylloc, "Invalid timeunit constant ('_' is not "
"supported).");
return false;
}
c = strpbrk(cp, "munpfs");
if (!c)
return false;
if (*c == 's')
unit = 0;
else if (!strncmp(c, "ms", 2))
unit = -3;
else if (!strncmp(c, "us", 2))
unit = -6;
else if (!strncmp(c, "ns", 2))
unit = -9;
else if (!strncmp(c, "ps", 2))
unit = -12;
else if (!strncmp(c, "fs", 2))
unit = -15;
else {
rc = false;
ostringstream msg;
msg << "Invalid timeunit scale '" << cp << "'.";
VLerror(msg.str().c_str());
}
return rc;
}
/*
* Get a timeunit or timeprecision value from a string. This is
* similar to the code in lexor.lex for the `timescale directive.
@ -611,6 +649,11 @@ void pform_set_timeunit(const char*txt, bool in_module, bool only_check)
}
}
int pform_get_timeunit()
{
return pform_cur_module->time_unit;
}
void pform_set_timeprecision(const char*txt, bool in_module, bool only_check)
{
int val;

2
pform.h
View File

@ -434,6 +434,8 @@ extern void parm_to_defparam_list(const string&param);
/*
* Tasks to set the timeunit or timeprecision for SystemVerilog.
*/
extern bool get_time_unit(const char*cp, int &unit);
extern int pform_get_timeunit();
extern void pform_set_timeunit(const char*txt, bool in_module, bool only_check);
extern void pform_set_timeprecision(const char*txt, bool in_module,
bool only_check);