#!/usr/bin/perl
# SPDX-License-Identifier: Apache-2.0
# Copyright 2020 Western Digital Corporation or its affiliates.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

use Getopt::Long;

$helpusage = "placeholder";

GetOptions ('legal'  => \$legal,
            'in=s'   => \$in,
            'out=s'  => \$out,
            'view=s' => \$view ) || die("$helpusage");


if (!defined($in))  { die("must define -in=input"); }
if (!defined($out)) { $out="${in}.out"; }

if ($in eq "decode")       { $view="rv32i";  }
elsif ($in eq "cdecode")   { $view="rv32c";  }
elsif ($in eq "csrdecode") { $view="csr";  }

if (defined($in)) { printf("in=$in\n"); }
if (defined($out)) { printf("out=$out\n"); }
if (defined($view)) { printf("view=$view\n"); }

@in=`cat $in`;

$gather=0;

$TIMEOUT=50;

foreach $line (@in) {

    #printf("$pstate: $line");

    if ($line=~/^\s*\#/) { #printf("skip $line");
                           next; }

    if ($gather==1) {
        if ($line=~/(\S+)/) {
            if ($line=~/}/) { $gather=0; $position=0; next; }
            $label=$1;
            $label=~s/,//g;
            if ($pstate==2) {
                if (defined($INPUT{$CVIEW}{$label})) { die("input $label already defined"); }
                $INPUT{$CVIEW}{$label}=$position++;
                $INPUTLEN{$CVIEW}++;
                $INPUTSTR{$CVIEW}.=" $label";
            }
            elsif ($pstate==3) {
                if (defined($OUTPUT{$CVIEW}{$label})) { die("output $label already defined"); }
                $OUTPUT{$CVIEW}{$label}=$position++;
                $OUTPUTLEN{$CVIEW}++;
                $OUTPUTSTR{$CVIEW}.=" $label";
            }
            else { die("unknown pstate $pstate in gather"); }
        }
    }

    if ($line=~/^.definition/) {
        $pstate=1; next;
    }
     if ($pstate==1) {  # definition
        if ($line!~/^.output/) {
            if ($line=~/(\S+)\s*=\s*(\S+)/) {
                $key=$1; $value=$2;
                $value=~s/\./-/g;
                $value=~s/\[//g;
                $value=~s/\]//g;
                $DEFINITION{$key}=$value;
            }
        }
        else { $pstate=2; next; }
    }

    if ($line=~/^.input/) {
        $pstate=2; next;
    }

    if ($pstate==2) {  # input
        if ($line=~/(\S+)\s*=\s*\{/) {
            $CVIEW=$1; $gather=1; next;
        }
    }

    if ($line=~/^.output/) {
        $pstate=3; next;
    }

    if ($pstate==3) {  # output
        if ($line=~/(\S+)\s*=\s*\{/) {
            $CVIEW=$1; $gather=1; next;
        }
    }

    if ($line=~/^.decode/) {
        $pstate=4; next;
    }

   if ($pstate==4) {  # decode
        if ($line=~/([^\[]+)\[([^\]]+)\]\s*=\s*\{([^\}]+)\}/) {
            $dview=$1; $inst=$2; $body=$3;
            $dview=~s/\s+//g;
            $inst=~s/\s+//g;
            #printf("$dview $inst $body\n");
            if ($inst=~/([^\{]+)\{([^-]+)-([^\}]+)\}/) {
                $base=$1; $lo=$2; $hi=$3;
                $hi++;
                for ($i=0; $i<$TIMEOUT && $lo ne $hi; $i++) {
                    #printf("decode $dview $base$lo\n");

                    $expand=$base.$lo;
                    if (!defined($DEFINITION{$expand})) { die("could not find instruction definition for inst $expand"); }

                    $DECODE{$dview}{$expand}=$body;
                    $lo++;
                }
                if ($i == $TIMEOUT) { die("timeout in decode expansion"); }

            }
            else {
                if (!defined($DEFINITION{$inst})) { die("could not find instruction definition for inst $inst"); }
                $DECODE{$dview}{$inst}=$body;
            }
        }
   }

}


#printf("view $view len %d\n",$OUTPUTLEN{$view});

#printf("$OUTPUTSTR{$view}\n");


# need to switch this somehow based on 16/32
printf(".i %d\n",$INPUTLEN{$view});

if (defined($legal)) {
    printf(".o 1\n");
}
else {
    printf(".o %d\n",$OUTPUTLEN{$view});
}

printf(".ilb %s\n",$INPUTSTR{$view});

if (defined($legal)) {
    printf(".ob legal\n");
}
else {
    printf(".ob %s\n",$OUTPUTSTR{$view});
}

if (defined($legal)) {
    printf(".type fd\n");
}
else {
    printf(".type fr\n");
}

$DEFAULT_TEMPLATE='0'x$OUTPUTLEN{$view};

foreach $inst (sort keys %{ $DECODE{$view} }) {

    $body=$DECODE{$view}{$inst};
    @sigs=split(' ',$body);

    $template=$DEFAULT_TEMPLATE;
    foreach $sig (@sigs) {
        if (!defined($OUTPUT{$view}{$sig})) { die("could not find output definition for sig $sig in view $view"); }
        $position=$OUTPUT{$view}{$sig};
        substr($template,$position,1,1);
    }

#    if (!defined($DEFINITION{$inst})) { die("could not find instruction defintion for inst $inst"); }

    printf("# $inst\n");
    if (defined($legal)) {
        printf("$DEFINITION{$inst} 1\n");
    }
    else {
        printf("$DEFINITION{$inst} $template\n");
    }

}


exit;

foreach $inst (sort keys %DEFINITION) {
    $value=$DEFINITION{$inst};
    printf("%-10s = $value\n",$inst);
}


foreach $sig (sort keys %{ $OUTPUT{$view} }) {
    $position=$OUTPUT{$view}{$sig};
    printf("$sig $position\n");
}