#!/usr/bin/perl -w
# usage   ../make-clocks [<input-file> ...] -Dmclock=khz -Dsclock=khz

use strict qw(vars);
use POSIX;

sub p ($) { print $_[0] or die $!; }

our (%defs);

p("; autogenerated - do not edit\n");
p("; $0 @ARGV\n");
while ($ARGV[$#ARGV] =~ m/^\-/) {
    $_ = pop @ARGV;
    last if m/^\-\-$/;
    die unless m/^\-D(\w+)\=(\w+)$/;
    $defs{$1}= $2;
}

our ($name,$ms,$interval,$msclock);
# $interval is in seconds
# mclock or sclock is in kHz
# ourtimerclock is mclock or sclock * 250 (for Fosc/4)
# call 250 foscscale
# basically interval = cycles / clock
# adjusted for units  interval = cycles * prescale / (foscscale * msclock)
#                 ie  cycles = interval * foscscale * msclock / prescale
#                 or  msclock = cycles * prescale / (foscscale * interval)

sub scaleable ($$$$$$) {
    my ($width, $foscscale, $scalebitnums, $scales,
	$deadcycles, $overflowp) = @_;
    my ($maxcycles, $scalespec, $scalebits);
    my ($cycles, $cyequ, @scalebits);
    my ($prescale);
    $maxcycles = (1 << $width) - $deadcycles;
    foreach $scalespec (@$scales) {
	$scalespec =~ m/^0*(\d+)\-([01]+)$/;
	($prescale,$scalebits) = ($1,$2);
	length($scalebits) == @$scalebitnums
	    or die "$scalespec @$scalebitnums";

	$cycles= $interval * $foscscale * $msclock / $prescale;
	next if $cycles > $maxcycles;

	if (length($scalebits)) {
	    p("${name}scale equ ");
	    @scalebits = (map { "(1<<$_)" }
			  grep { $scalebits =~ s/^.// or die; $&; }
			  @$scalebitnums);
	    push @scalebits, '0' unless @scalebits;
	    p(join '|', @scalebits);
	    p("; $prescale:1\n");
	}

	$cyequ= "${name}cycles";
	p(sprintf "%s equ %d\n", $cyequ, $cycles);
	if ($overflowp) {
	    p("${name}init equ ".(1<<$width)." - $cyequ\n");
	    if ($width == 16) {
		p("${name}inith equ ${name}init / 256\n");
		p("${name}initl equ ${name}init & 255\n");
	    }
	}
	return;
    }
    warn "clock speed too high for $name\n";
}

sub do_T2period {
    my (@scales, $pre, $prex, $prebits, $posti, $this);
    for $pre (qw(1-00 4-01 16-10)) {
	$pre =~ m/^(\d+)\-([01]+)$/;
	($prex,$prebits) = ($1,$2);
	for ($posti=0; $posti<15; $posti++) {
	    $this= sprintf "%03d-%s%04b", $prex * ($posti+1), $prebits, $posti;
	    push @scales, $this;
	}
    }
    local ($name) = "${name}_t2";
    scaleable(8, 250.0, [qw(T2CKPS1 T2CKPS0 TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0)],
	      [ sort @scales ], 0, 0);
}

sub do_T13ov ($) {
    my ($n) = @_;
    local ($name) = "${name}_t${n}";
    scaleable(16, 250.0, ["T${n}CKPS1","T${n}CKPS0"],
	      [qw(1-00 2-01 4-10 8-11)], 1, 1);
}

sub do_T0ov ($) {
    my ($w) = @_;
    local ($name) = "${name}_t0";
    scaleable($w, 250.0, ["PSA","T0PS2","T0PS1","T0PS0"],
	      [qw(1-1000 2-0000 4-0001 8-0010 16-0011
		32-0100 64-0101 128-0110 256-0111)], 1, 1);
}

sub do_T0ov8  { do_T0ov(8);  }
sub do_T0ov16 { do_T0ov(16); }
sub do_T1ov { do_T13ov(1); }
sub do_T3ov { do_T13ov(3); }

sub provide_interval ($$$$) {
    my ($iname, $thisval, $unitname, $unitval) = @_;
    my ($inthisunit, $inthisunitint);
    $inthisunit= $thisval / $unitval;
    return if $inthisunit > 256000000.0;
    $inthisunitint= sprintf "%d", $inthisunit;
    return if abs(($inthisunitint - $inthisunit) / $inthisunit) > 0.001;
    p("${iname}_${unitname} equ $inthisunitint\n");
}

sub doline () {
    my ($orgname,$mswant,$specd,$unit,$cy,$how,$baseinterval);
    chomp;
    s/\s*[;\#].*//;
    return unless m/^\S/;
    die "$_ ?" unless
	m/^(\w+)\s+([MST]+)\s+(\w+)\s+([0-9.]+)(s|ms|us|ns|Hz|kHz|MHz)((?:[-+][0-9.]+cy)?)$/;
    ($orgname,$mswant,$how,$baseinterval,$unit,$cy) = ($1,$2,$3,$4,$5,$6,$7);
    $specd= $baseinterval.$unit.$cy;
    if ($unit =~ m/M/) { $baseinterval *= 1.e6; }
    if ($unit =~ m/k/) { $baseinterval *= 1.e3; }
    if ($unit =~ m/m/) { $baseinterval *= 1.e-3; }
    if ($unit =~ m/u/) { $baseinterval *= 1.e-6; }
    if ($unit =~ m/n/) { $baseinterval *= 1.e-9; }
    if ($unit =~ s/Hz//) { $baseinterval = 1.0 / $baseinterval; }
    if ($cy =~ s/cy$//) { $cy *= 4.0; }
    elsif ($cy = m//) { $cy = 0.0; }
    else { die "$cy ?"; }
    p("\n");
    p(";========== $orgname ($specd: ${baseinterval}s, ${cy}cy) ==========\n");
    if ($mswant =~ m/T/) {
	provide_interval($orgname, $baseinterval, 'us', 1.e-6);
	provide_interval($orgname, $baseinterval, 'ms', 1.e-3);
	provide_interval($orgname, $baseinterval, 's', 1.0);
    }
    foreach $ms (qw(m s)) {
	next unless $mswant =~ m/$ms/i;
	$msclock= "${ms}clock";
	die $msclock unless exists $defs{$msclock};
	$msclock= $defs{$msclock};
	$interval= $baseinterval + $cy / ($msclock * 1000.0);
	p(";---------- $orgname, ${interval}s, ${msclock}kHz ----------\n");
	$name = $orgname.'_'.($ms eq 'm' ? 'master' : 'slave');
	&{ "do_$how" };
    }
}

while (<>) {
    doline();
}