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Initial implementation of $display()

This commit is contained in:
Andrew Zonenberg 2015-09-17 20:34:56 -07:00 committed by Clifford Wolf
parent e446e651cb
commit 7141f65533
1 changed files with 84 additions and 1 deletions
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85
frontends/ast/simplify.cc
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@ -174,13 +174,96 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
}
// deactivate all calls to non-synthesis system tasks
if ((type == AST_FCALL || type == AST_TCALL) && (str == "$display" || str == "$strobe" || str == "$monitor" || str == "$time" || str == "$stop" ||
// note that $display and $finish are used for synthesis-time DRC so they're not in this list
if ((type == AST_FCALL || type == AST_TCALL) && (str == "$strobe" || str == "$monitor" || str == "$time" || str == "$stop" ||
str == "$dumpfile" || str == "$dumpvars" || str == "$dumpon" || str == "$dumpoff" || str == "$dumpall")) {
log_warning("Ignoring call to system %s %s at %s:%d.\n", type == AST_FCALL ? "function" : "task", str.c_str(), filename.c_str(), linenum);
delete_children();
str = std::string();
}
// print messages if this a call to $display() or $write()
// This code implements only a small subset of Verilog-2005 $display() format specifiers,
// but should be good enough for most uses
if ((type == AST_TCALL) && ((str == "$display") || (str == "$write")))
{
size_t nargs = GetSize(children);
if(nargs < 1)
{
log_error("System task ``$display\" got %d arguments, expected >= 1 at %s:%d.\n",
int(children.size()), filename.c_str(), linenum);
}
// First argument is the format string
AstNode *node_string = children[0]->clone();
while (node_string->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
if (node_string->type != AST_CONSTANT)
log_error("Failed to evaluate system task `%s' with non-constant 1st argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
std::string sformat = node_string->bitsAsConst().decode_string();
// Other arguments are placeholders. Process the string as we go through it
std::string sout;
size_t next_arg = 1;
for(size_t i=0; i<sformat.length(); i++)
{
// format specifier
if(sformat[i] == '%')
{
// If we're out of arguments, that's a problem!
if(next_arg >= nargs)
log_error("System task `%s' called with more format specifiers than arguments at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
// Simplify the argument
AstNode *node_arg = children[next_arg ++]->clone();
while (node_arg->simplify(true, false, false, stage, width_hint, sign_hint, false)) { }
if (node_arg->type != AST_CONSTANT)
log_error("Failed to evaluate system task `%s' with non-constant argument at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
// If there's no next character, that's a problem
if(i+1 >= sformat.length())
log_error("System task `%s' called with `%%' at end of string at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
// Everything from here on depends on the format specifier
char cformat = sformat[++i];
switch(cformat)
{
case '%':
sout += '%';
break;
case 's':
case 'S':
sout += node_arg->bitsAsConst().decode_string();
break;
case 'd':
case 'D':
{
char tmp[128];
snprintf(tmp, sizeof(tmp), "%d", node_arg->bitsAsConst().as_int());
sout += tmp;
}
break;
default:
log_error("System task `%s' called with invalid format specifier at %s:%d.\n", str.c_str(), filename.c_str(), linenum);
break;
}
}
// not a format specifier
else
sout += sformat[i];
}
// Finally, print the message (only include a \n for $display, not for $write)
log("%s", sout.c_str());
if(str == "$display")
log("\n");
delete_children();
str = std::string();
}
// activate const folding if this is anything that must be evaluated statically (ranges, parameters, attributes, etc.)
if (type == AST_WIRE || type == AST_PARAMETER || type == AST_LOCALPARAM || type == AST_DEFPARAM || type == AST_PARASET || type == AST_RANGE || type == AST_PREFIX)
const_fold = true;