Here is a "first draft" of a working s-record parser using pack and unpack. (Sorry for the delay. Life got more chaotic and I forgot.)

I am just storing the data in @data. While not efficient, Perl arrays are "sparse", so not eating huge volumes of memory. Also, because the "keys" are numbers (addresses in memory), look up is slightly faster than using a hash (which has to handle any characters in keys).

#!perl -w

use warnings;
use strict; 

my @data;

sub srecParse
{
    my $sr = $_[0];

    # extract record type (as single digit) and data (as pairs of hex 
+digits)
    $sr =~ /^S([0-9])((?:[0-9A-Fa-f][0-9A-Fa-f])+)/;
    (defined($1) and defined($2)) or return warn("Bad format: $_[0]");
    my $rt = $1;
    my $hd = $2;

    my $bd = pack('H*', $hd); # convert the hexidecimal string to a by
+te stream

    my $cs = unpack('%8C*', $bd); # calculate byte-wise checksum, incl
+uding the checksum byte
    
    # final result should be 0xFF because checksum byte is 1s compleme
+nt of sum of preceding.
    ($cs == 0xFF) or return warn("Failed checksum: $_[0]");

    my ($cnt, $adr, $adrh, $data);
    if ($rt eq '0') # Text data. Extract like an S1, then display text
+.
    {
        ($cnt, $adr, $data) = unpack('C n X3 C /a', $bd); # C:count, n
+:adr16, /a:data
        return print STDERR "# " . substr($data, 2, -1) . "\n";
    }
    elsif (($rt eq '1') or ($rt eq '9')) # Data with 16 bit address
    {
        ($cnt, $adr, $data) = unpack('C n X3 C /a', $bd); # C:count, n
+:adr16, /a:data
        $cnt -= 2; # adjust byte count, then trim address from in fron
+t of the data.
        $data = substr($data, 2, -1);
    }
    elsif (($rt eq '2') or ($rt eq '8')) # Data with 24 bit address
    {
        # Because there is no code for a 24 bit integer, unpack 24 bit
+ address as high byte and low word.
        ($cnt, $adrh, $adr, $data) = unpack('C C n X4 C /a', $bd); # C
+:count, C:adr8 (MSB), n:adr16 (LSW), /a:data
        $cnt -= 3;                    # adjust byte count
        $adr += $adrh * 256;          # prepend high byte of address t
+o low word
        $data = substr($data, 3, -1); # trim address from in front of 
+the data.
    }
    elsif (($rt eq '3') or ($rt eq '7')) # Data with 32 bit address
    {
        ($cnt, $adr, $data) = unpack('C N X5 C /a', $bd); # C:count, N
+:adr32, /a:data
        $cnt -= 4; # adjust byte count, then trim address from in fron
+t of the data.
        $data = substr($data, 4, -1);
    }
    else
    {
        return warn("Unsupported record type: $_[0]");
    }
    
    printf STDERR "c:%d a:%0X d:%s\n", $cnt, $adr, unpack('H*', $data)
+;

    if (($rt >= 1) and ($rt <= 3))
    {
        for my $i (0 .. ($cnt - 1))
        {
            $data[$adr + $i] = substr($data, $i, 1);
        }
    }
    elsif (($rt >= 7) and ($rt <= 9))
    {
        printf STDERR "Start address: 0x%0X\n", $adr;
    }
}

my $curFile = '';

while (<>)
{
    print STDERR "Reading $ARGV\n" unless ($ARGV eq $curFile);
    $curFile = $ARGV;
    chomp; chomp;
    srecParse($_);
} continue
{
        close ARGV if eof;  # Not eof()!
}
[download]