Language.pm

# See copyright, etc in below POD section.
######################################################################

=pod

=head1 NAME

Verilog::Language - Verilog language utilities

=head1 SYNOPSIS

  use Verilog::Language;

  $result = Verilog::Language::is_keyword("wire");  # true
  $result = Verilog::Language::is_compdirect("`notundef");  # false
  $result = Verilog::Language::number_value("4'b111");  # 8
  $result = Verilog::Language::number_bits("32'h1b");  # 32
  $result = Verilog::Language::number_signed("1'sh1");  # 1
  @vec    = Verilog::Language::split_bus("[31,5:4]");  # 31, 5, 4
  @vec    = Verilog::Language::split_bus_nocomma("[31:29]");  # 31, 30, 29
  $result = Verilog::Language::strip_comments("a/*b*/c");  # ac

=head1 DESCRIPTION

Verilog::Language provides general utilities for using the Verilog
Language, such as parsing numbers or determining what keywords exist.
General functions will be added as needed.

=head1 FUNCTIONS

=over 4

=item Verilog::Language::is_keyword($symbol_string)

Return true if the given symbol string is a Verilog reserved keyword.
Value indicates the language standard as per the `begin_keywords macro,
'1364-1995', '1364-2001', '1364-2005', '1800-2005', '1800-2009',
'1800-2012', '1800-2017' or 'VAMS'.

=item Verilog::Language::is_compdirect($symbol_string)

Return true if the given symbol string is a Verilog compiler directive.

=item Verilog::Language::is_gateprim($symbol_string)

Return true if the given symbol is a built in gate primitive; for example
"buf", "xor", etc.

=item Verilog::Language::language_keywords($year)

Returns a hash for keywords for given language standard year, where the
value of the hash is the standard in which it was defined.

=item Verilog::Language::language_standard($year)

Sets the language standard to indicate what are keywords.  If undef, all
standards apply.  The year is indicates the language standard as per the
`begin_keywords macro, '1364-1995', '1364-2001', '1364-2005', '1800-2005'
'1800-2009', '1800-2012' or '1800-2017'.

=item Verilog::Language::language_maximum

Returns the greatest language currently standardized, presently
'1800-2017'.

=item Verilog::Language::number_bigint($number_string)

Return the numeric value of a Verilog value stored as a Math::BigInt, or
undef if incorrectly formed.  You must 'use Math::BigInt' yourself before
calling this function.  Note bigints do not have an exact size, so NOT of a
Math::BigInt may return a different value than verilog.  See also
number_value and number_bitvector.

=item Verilog::Language::number_bits($number_string)

Return the number of bits in a value string, or undef if incorrectly
formed, _or_ not specified.

=item Verilog::Language::number_bitvector($number_string)

Return the numeric value of a Verilog value stored as a Bit::Vector, or
undef if incorrectly formed.  You must 'use Bit::Vector' yourself before
calling this function.  The size of the Vector will be that returned by
number_bits.

=item Verilog::Language::number_signed($number_string)

Return true if the Verilog value is signed, else undef.

=item Verilog::Language::number_value($number_string)

Return the numeric value of a Verilog value, or undef if incorrectly
formed.  It ignores any signed Verilog attributes, but is is returned as a
perl signed integer, so it may fail for over 31 bit values.  See also
number_bigint and number_bitvector.

=item Verilog::Language::split_bus($bus)

Return a list of expanded arrays.  When passed a string like
"foo[5:1:2,10:9]", it will return a array with ("foo[5]", "foo[3]", ...).
It correctly handles connectivity expansion also, so that "x[1:0] = y[3:0]"
will get intuitive results.

=item Verilog::Language::split_bus_nocomma($bus)

As with split_bus, but faster.  Only supports simple decimal colon
separated array specifications, such as "foo[3:0]".

=item Verilog::Language::strip_comments($text)

Return text with any // or /**/ comments stripped, correctly handing quoted
strings.  Newlines will be preserved in this process.

=back

=head1 DISTRIBUTION

Verilog-Perl is part of the L<https://www.veripool.org/> free Verilog EDA
software tool suite.  The latest version is available from CPAN and from
L<https://www.veripool.org/verilog-perl>.

Copyright 2000-2020 by Wilson Snyder.  This package is free software; you
can redistribute it and/or modify it under the terms of either the GNU
Lesser General Public License Version 3 or the Perl Artistic License Version 2.0.

=head1 AUTHORS

Wilson Snyder <wsnyder@wsnyder.org>

=head1 SEE ALSO

L<Verilog-Perl>,
L<Verilog::EditFiles>
L<Verilog::Parser>,
L<Verilog::ParseSig>,
L<Verilog::Getopt>

And the L<https://www.veripool.org/verilog-mode>Verilog-Mode package for Emacs.

=cut
######################################################################

package Verilog::Language;
require 5.000;
require Exporter;

use strict;
use vars qw($VERSION %Keyword %Keywords %Compdirect $Standard %Gateprim);
use Carp;

######################################################################
#### Configuration Section

$VERSION = '3.475';

######################################################################
#### Internal Variables

foreach my $kwd (qw(
		    always and assign begin buf bufif0 bufif1 case
		    casex casez cmos deassign default defparam
		    disable else end endcase endfunction endmodule
		    endprimitive endspecify endtable endtask event
		    for force forever fork function highz0
		    highz1 if initial inout input integer join large
		    macromodule medium module nand negedge
		    nmos nor not notif0 notif1 or output parameter
		    pmos posedge primitive pull0 pull1 pulldown
		    pullup rcmos real realtime reg release repeat
		    rnmos rpmos rtran rtranif0 rtranif1 scalared
		    small specify strength strong0 strong1
		    supply0 supply1 table task time tran tranif0
		    tranif1 tri tri0 tri1 triand trior trireg
		    vectored wait wand weak0 weak1 while wire wor
		    xnor xor
		    )) { $Keywords{'1364-1995'}{$kwd} = '1364-1995'; }

foreach my $kwd (qw(
		    automatic cell config design edge endconfig endgenerate
		    generate genvar ifnone incdir include instance liblist
		    library localparam
		    noshowcancelled pulsestyle_ondetect pulsestyle_onevent
		    showcancelled signed specparam unsigned use
		    )) { $Keywords{'1364-2001'}{$kwd} = '1364-2001'; }

foreach my $kwd (qw(
		    uwire
		    )) { $Keywords{'1364-2005'}{$kwd} = '1364-2005'; }

foreach my $kwd (qw(
		    alias always_comb always_ff always_latch assert assume
		    before bind bins binsof bit break byte chandle class
		    clocking const constraint context continue cover
		    covergroup coverpoint cross dist do endclass endclocking
		    endgroup endinterface endpackage endprogram endproperty
		    endsequence enum expect export extends extern final
		    first_match foreach forkjoin iff ignore_bins
		    illegal_bins import inside int interface intersect
		    join_any join_none local logic longint matches modport
		    new null package packed priority program property
		    protected pure rand randc randcase randsequence ref
		    return sequence shortint shortreal solve static string
		    struct super tagged this throughout timeprecision
		    timeunit type typedef union unique var virtual void
		    wait_order wildcard with within
		    )) { $Keywords{'1800-2005'}{$kwd} = '1800-2005'; }

foreach my $kwd (qw(
		    accept_on checker endchecker eventually global implies
		    let nexttime reject_on restrict s_always s_eventually
		    s_nexttime s_until s_until_with strong sync_accept_on
		    sync_reject_on unique0 until until_with untyped weak
		    )) { $Keywords{'1800-2009'}{$kwd} = '1800-2009'; }

foreach my $kwd (qw(
		    implements nettype interconnect soft
		    )) { $Keywords{'1800-2012'}{$kwd} = '1800-2012'; }

foreach my $kwd (qw(
		    )) { $Keywords{'1800-2017'}{$kwd} = '1800-2017'; }

foreach my $kwd (qw(
		    above abs absdelay abstol ac_stim access acos acosh
		    aliasparam analog analysis asin asinh assert atan atan2
		    atanh branch ceil connect connectmodule connectrules
		    continuous cos cosh cross ddt ddt_nature ddx discipline
		    discrete domain driver_update endconnectrules
		    enddiscipline endnature endparamset exclude exp
		    final_step flicker_noise floor flow from ground hypot
		    idt idt_nature idtmod inf initial_step laplace_nd
		    laplace_np laplace_zd laplace_zp last_crossing limexp
		    ln log max merged min nature net_resolution noise_table
		    paramset potential pow resolveto sin sinh slew split
		    sqrt string tan tanh timer transition units white_noise
		    wreal zi_nd zi_np zi_zd zi_zp
		    )) { $Keywords{'VAMS'}{$kwd} = 'VAMS'; }

foreach my $kwd (
    # Speced
    "`celldefine",
    "`define",			# Preprocessor
    "`else",			# Preprocessor
    "`endcelldefine",
    "`endif",			# Preprocessor
    "`ifdef",			# Preprocessor
    "`include",			# Preprocessor
    "`nounconnected_drive",
    "`resetall",
    "`timescale",
    "`unconnected_drive",
    "`undef",			# Preprocessor
    "`undefineall",		# Preprocessor

    # Commercial Extensions
    "`accelerate",		# Verilog-XL compatibility
    "`autoexpand_vectornets",	# Verilog-XL compatibility
    "`default_decay_time",	# Verilog spec - delays only
    "`default_trireg_strength",	# Verilog spec
    "`delay_mode_distributed",	# Verilog spec - delays only
    "`delay_mode_path",		# Verilog spec - delays only
    "`delay_mode_unit",		# Verilog spec - delays only
    "`delay_mode_zero",		# Verilog spec - delays only
    "`disable_portfaults",	# Verilog-XL compatibility
    "`enable_portfaults",	# Verilog-XL compatibility
    "`endprotect",		# Many tools - pre encryption
    "`endprotected",		# Many tools - post encryption
    "`expand_vectornets",	# Verilog-XL compatibility
    "`noaccelerate",		# Verilog-XL compatibility
    "`noexpand_vectornets",	# Verilog-XL compatibility
    "`noremove_gatenames",	# Verilog-XL compatibility
    "`noremove_netnames",	# Verilog-XL compatibility
    "`nosuppress_faults",	# Verilog-XL compatibility
    "`nounconnected_drive",	# Verilog-XL compatibility
    "`portcoerce",		# Verilog-XL compatibility
    "`protect",			# Many tools - pre encryption
    "`protected",		# Many tools - post encryption
    "`remove_gatenames",	# Verilog-XL compatibility
    "`remove_netnames",		# Verilog-XL compatibility
    "`suppress_faults",		# Verilog-XL compatibility
    ) { $Keywords{$kwd}{'1364-1995'} = $Compdirect{$kwd} = '1364-1995'; }

foreach my $kwd (
		 "`default_nettype", "`elsif", "`undef", "`ifndef",
		 "`file", "`line",
		 ) { $Keywords{$kwd}{'1364-2001'} = $Compdirect{$kwd} = '1364-2001'; }

foreach my $kwd (
		 "`pragma",
		 ) { $Keywords{$kwd}{'1364-2005'} = $Compdirect{$kwd} = '1364-2005'; }

foreach my $kwd (
		 "`default_discipline", "`default_transition",
		 ) { $Keywords{$kwd}{'1364-2005'} = $Compdirect{$kwd} = '1364-2005'; }

language_standard(language_maximum());  # Default standard

foreach my $kwd (qw(
		    and buf bufif0 bufif1 cmos nand nmos nor not notif0
		    notif1 or pmos pulldown pullup rcmos rnmos rpmos rtran
		    rtranif0 rtranif1 tran tranif0 tranif1 xnor xor
		    )) { $Gateprim{$kwd} = '1364-1995'; }

######################################################################
#### Keyword utilities

sub language_maximum {
    return "1800-2017";
}

sub _language_kwd_hash {
    my $standard = shift;
    my @subsets;
    if ($standard eq '1995' || $standard eq '1364-1995') {
	$Standard = '1364-1995';
	@subsets = ('1364-1995');
    } elsif ($standard eq '2001' || $standard eq '1364-2001' || $standard eq '1364-2001-noconfig') {
	$Standard = '1364-2001';
	@subsets = ('1364-2001',
		    '1364-1995');
    } elsif ($standard eq '1364-2005') {
	$Standard = '1364-2005';
	@subsets = ('1364-2005',
		    '1364-2001', '1364-1995');
    } elsif ($standard eq 'sv31' || $standard eq '1800-2005') {
	$Standard = '1800-2005';
	@subsets = ('1800-2005',
		    '1364-2005', '1364-2001', '1364-1995');
    } elsif ($standard eq '1800-2009') {
	$Standard = '1800-2009';
	@subsets = ('1800-2009', '1800-2005',
		    '1364-2005', '1364-2001', '1364-1995');
    } elsif ($standard eq '1800-2012') {
	$Standard = '1800-2012';
	@subsets = ('1800-2012', '1800-2009', '1800-2005',
		    '1364-2005', '1364-2001', '1364-1995');
    } elsif ($standard eq 'latest' || $standard eq '1800-2017') {
	$Standard = '1800-2017';
	@subsets = ('1800-2017', '1800-2012', '1800-2009', '1800-2005',
		    '1364-2005', '1364-2001', '1364-1995');
    } elsif ($standard =~ /^V?AMS/) {
	$Standard = 'VAMS';
	@subsets = ('VAMS',
		    '1364-2005', '1364-2001', '1364-1995');
    } else {
	croak "%Error: Verilog::Language::language_standard passed bad value: $standard,";
    }
    # Update keyword list to present language
    # (We presume the language_standard rarely changes, so it's faster to compute the list.)
    my %keywords = ();
    foreach my $ss (@subsets) {
	foreach my $kwd (%{$Keywords{$ss}}) {
	    $keywords{$kwd} = $ss;
	}
    }
    return %keywords;
}

sub language_standard {
    my $standard = shift;
    if (defined $standard) {
	%Keyword = _language_kwd_hash($standard);
    }
    return $Standard;
}

sub language_keywords {
    my $standard = shift || $Standard;
    return _language_kwd_hash($standard);
}

sub is_keyword {
    my $symbol = shift;
    return ($Keyword{$symbol});
}

sub is_compdirect {
    my $symbol = shift;
    return ($Compdirect{$symbol});
}

sub is_gateprim {
    my $symbol = shift;
    return ($Gateprim{$symbol});
}

######################################################################
#### String utilities

sub strip_comments {
    return $_[0] if $_[0] !~ m!/!s;  # Fast path
    my $text = shift;
    # Spec says that // has no special meaning inside /**/
    my $quote; my $olcmt; my $cmt;
    my $out = "";
    while ($text =~ m!(.*?)(//|/\*|\*/|\n|\"|$)!sg) {
	$out .= $1 if !$olcmt && !$cmt;
	my $t = $2;
	if ($2 eq '"') {
	    $out .= $t;
	    $quote = ! $quote;
	} elsif (!$quote && !$olcmt && $t eq '/*') {
	    $cmt = 1;
	} elsif (!$quote && !$cmt && $t eq '//') {
	    $olcmt = 1;
	} elsif ($cmt && $t eq '*/') {
	    $cmt = 0;
	} elsif ($t eq "\n") {
	    $olcmt = 0;
	    $out .= $t;
	} else {
	    $out .= $t if !$olcmt && !$cmt;
	}
    }
    return $out;
}

######################################################################
#### Numeric utilities

sub number_bits {
    my $number = shift;
    if ($number =~ /^\s*([0-9]+)\s*\'/i) {
	return $1;
    }
    return undef;
}

sub number_signed {
    my $number = shift;
    if ($number =~ /\'\s*s/i) {
	return 1;
    }
    return undef;
}

sub number_value {
    my $number = shift;
    $number =~ s/[_ ]//g;
    if ($number =~ /\'s?h([0-9a-f]+)$/i) {
	return (hex ($1));
    }
    elsif ($number =~ /\'s?o([0-9a-f]+)$/i) {
	return (oct ($1));
    }
    elsif ($number =~ /\'s?b([0-1]+)$/i) {
	my $val = 0;
	$number = $1;
	foreach my $bit (split(//, $number)) {
	    $val = ($val<<1) | ($bit=='1'?1:0);
	}
	return ($val);
    }
    elsif ($number =~ /\'s?d?([0-9]+)$/i
	   || $number =~ /^(-?[0-9]+)$/i) {
	return ($1);
    }
    return undef;
}

sub number_bigint {
    my $number = shift;
    $number =~ s/[_ ]//g;
    if ($number =~ /\'s?h([0-9a-f]+)$/i) {
	return (Math::BigInt->new("0x".$1));
    }
    elsif ($number =~ /\'s?o([0-9a-f]+)$/i) {
	my $digits = $1;
	my $vec = Math::BigInt->new();
	my $len = length($digits);
	my $bit = 0;
	for (my $index=$len-1; $index>=0; $index--, $bit+=3) {
	    my $digit = substr($digits,$index,1);
	    my $val = Math::BigInt->new($digit);
	    $val = $val->blsft($bit,2);
	    $vec->bior($val);
	}
	return ($vec);
    }
    elsif ($number =~ /\'s?b([0-1]+)$/i) {
	return (Math::BigInt->new("0b".$1));
    }
    elsif ($number =~ /\'s?d?0*([0-9]+)$/i
	   || $number =~ /^0*([0-9]+)$/i) {
	return (Math::BigInt->new($1));
    }
    return undef;
}

sub number_bitvector {
    my $number = shift;
    $number =~ s/[_ ]//g;
    my $bits = number_bits($number) || 32;
    if ($number =~ /\'s?h([0-9a-f]+)$/i) {
	return (Bit::Vector->new_Hex($bits,$1));
    }
    elsif ($number =~ /\'s?o([0-9a-f]+)$/i) {
	my $digits = $1;
	my $vec = Bit::Vector->new($bits);
	my $len = length($digits);
	my $bit = 0;
	for (my $index=$len-1; $index>=0; $index--, $bit+=3) {
	    my $digit = substr($digits,$index,1);
	    $vec->Bit_On($bit+2) if ($digit & 4);
	    $vec->Bit_On($bit+1) if ($digit & 2);
	    $vec->Bit_On($bit+0) if ($digit & 1);
	}
	return ($vec);
    }
    elsif ($number =~ /\'s?b([0-1]+)$/i) {
	return (Bit::Vector->new_Bin($bits,$1));
    }
    elsif ($number =~ /\'s?d?([0-9]+)$/i
	   || $number =~ /^([0-9]+)$/i) {
	return (Bit::Vector->new_Dec($bits,$1));
    }
    return undef;
}

######################################################################
#### Signal utilities

sub split_bus {
    my $bus = shift;
    if ($bus !~ /\[/) {
	# Fast case: No bussing
	return $bus;
    } elsif ($bus =~ /^([^\[]+\[)([0-9]+):([0-9]+)(\][^\]]*)$/) {
	# Middle speed case: Simple max:min
	my $bit;
	my @vec = ();
	if ($2 >= $3) {
	    for ($bit = $2; $bit >= $3; $bit --) {
		push @vec, $1 . $bit . $4;
	    }
	} else {
	    for ($bit = $2; $bit <= $3; $bit ++) {
		push @vec, $1 . $bit . $4;
	    }
	}
	return @vec;
    } else {
	# Complex case: x:y:z,p,...	etc
	# Do full parsing
	my @pretext = ();	# [brnum]
	my @expanded = ();	# [brnum][bitoccurance]
	my $inbra = 0;
	my $brnum = 0;
	my ($beg,$end,$step);
	foreach (split (/([:\]\[,])/, $bus)) {
	    if (/^\[/) {
		$inbra = 1;
		$pretext[$brnum] .= $_;
	    }
	    if (!$inbra) {
		# Not in bracket, just remember text
		$pretext[$brnum] .= $_;
		next;
	    }
	    if (/[\],]/) {
		if (defined $beg) {
		    # End of bus piece
		    #print "Got seg $beg $end $step\n";
		    my $bit;
		    if ($beg >= $end) {
			for ($bit = $beg; $bit >= $end; $bit -= $step) {
			    push @{$expanded[$brnum]}, $bit;
			}
		    } else {
			for ($bit = $beg; $bit <= $end; $bit += $step) {
			    push @{$expanded[$brnum]}, $bit;
			}
		    }
		}
		$beg = undef;
		# Now what?
		if (/^\]/) {
		    $inbra = 0;
		    $brnum++;
		    $pretext[$brnum] .= $_;
		}
		elsif (/,/) {
		    $inbra = 1;
		}
	    } elsif (/:/) {
		$inbra++;
	    }
	    else {
		if ($inbra == 1) {	# Begin value
		    $beg = $end = number_value($_);  # [2'b11:2'b00] is legal
		    $step = 1;
		} elsif ($inbra == 2) {	# End value
		    $end = number_value($_);  # [2'b11:2'b00] is legal
		} elsif ($inbra == 3) {	# Middle value
		    $step = number_value($_);  # [2'b11:2'b00] is legal
		}
		# Else ignore extra colons
	    }
	}

	# Determine max size of any bracket expansion array
	my $br;
	my $max_size = $#{$expanded[0]};
	for ($br=1; $br<$brnum; $br++) {
	    my $len = $#{$expanded[$br]};
	    if ($len < 0) {
		push @{$expanded[$br]}, "";
		$len = 0;
	    }
	    $max_size = $len if $max_size < $len;
	}

	my $i;
	my @vec = ();
	for ($i=0; $i<=$max_size; $i++) {
	    $bus = "";
	    for ($br=0; $br<$brnum; $br++) {
		#print "i $i  br $br >", $pretext[$br],"<\n";
		$bus .= $pretext[$br] . $expanded[$br][$i % (1+$#{$expanded[$br]})];
	    }
	    $bus .= $pretext[$br];	# Trailing stuff
	    push @vec, $bus;
	}
	return @vec;
    }
}

sub split_bus_nocomma {
    # Faster version of split_bus
    my $bus = shift;
    if ($bus !~ /:/) {
	# Fast case: No bussing
	return $bus;
    } elsif ($bus =~ /^([^\[]+\[)([0-9]+):([0-9]+)(\][^\]]*)$/) {
	# Middle speed case: Simple max:min
	my $bit;
	my @vec = ();
	if ($2 >= $3) {
	    for ($bit = $2; $bit >= $3; $bit --) {
		push @vec, $1 . $bit . $4;
	    }
	} else {
	    for ($bit = $2; $bit <= $3; $bit ++) {
		push @vec, $1 . $bit . $4;
	    }
	}
	return @vec;
    } else {
	# Complex case: x:y	etc
	# Do full parsing
	my @pretext = ();	# [brnum]
	my @expanded = ();	# [brnum][bitoccurance]
	my $inbra = 0;
	my $brnum = 0;
	my ($beg,$end);
	foreach (split (/([:\]\[])/, $bus)) {
	    if (/^\[/) {
		$inbra = 1;
		$pretext[$brnum] .= $_;
	    }
	    if (!$inbra) {
		# Not in bracket, just remember text
		$pretext[$brnum] .= $_;
		next;
	    }
	    if (/[\]]/) {
		if (defined $beg) {
		    # End of bus piece
		    #print "Got seg $beg $end\n";
		    my $bit;
		    if ($beg >= $end) {
			for ($bit = $beg; $bit >= $end; $bit--) {
			    push @{$expanded[$brnum]}, $bit;
			}
		    } else {
			for ($bit = $beg; $bit <= $end; $bit++) {
			    push @{$expanded[$brnum]}, $bit;
			}
		    }
		}
		$beg = undef;
		# Now what?
		if (/^\]/) {
		    $inbra = 0;
		    $brnum++;
		    $pretext[$brnum] .= $_;
		}
	    } elsif (/:/) {
		$inbra++;
	    }
	    else {
		if ($inbra == 1) {	# Begin value
		    $beg = $end = $_;
		} elsif ($inbra == 2) {	# End value
		    $end = $_;
		}
		# Else ignore extra colons
	    }
	}

	# Determine max size of any bracket expansion array
	my $br;
	my $max_size = $#{$expanded[0]};
	for ($br=1; $br<$brnum; $br++) {
	    my $len = $#{$expanded[$br]};
	    if ($len < 0) {
		push @{$expanded[$br]}, "";
		$len = 0;
	    }
	    $max_size = $len if $max_size < $len;
	}

	my $i;
	my @vec = ();
	for ($i=0; $i<=$max_size; $i++) {
	    $bus = "";
	    for ($br=0; $br<$brnum; $br++) {
		#print "i $i  br $br >", $pretext[$br],"<\n";
		$bus .= $pretext[$br] . $expanded[$br][$i % (1+$#{$expanded[$br]})];
	    }
	    $bus .= $pretext[$br];	# Trailing stuff
	    push @vec, $bus;
	}
	return @vec;
    }
}

######################################################################
#### Package return
1;