kernel/timeconst.pl - linux - Git at Google

 #!/usr/bin/perl
 # -----------------------------------------------------------------------
 #
 #   Copyright 2007-2008 rPath, Inc. - All Rights Reserved
 #
 #   This file is part of the Linux kernel, and is made available under
 #   the terms of the GNU General Public License version 2 or (at your
 #   option) any later version; incorporated herein by reference.
 #
 # -----------------------------------------------------------------------
 #

 #
 # Usage: timeconst.pl HZ > timeconst.h
 #

 # Precomputed values for systems without Math::BigInt
 # Generated by:
 # timeconst.pl --can 24 32 48 64 100 122 128 200 250 256 300 512 1000 1024 1200
 %canned_values = (
 	24 => [
 		'0xa6aaaaab','0x2aaaaaa',26,
 		125,3,
 		'0xc49ba5e4','0x1fbe76c8b4',37,
 		3,125,
 		'0xa2c2aaab','0xaaaa',16,
 		125000,3,
 		'0xc9539b89','0x7fffbce4217d',47,
 		3,125000,
 	], 32 => [
 		'0xfa000000','0x6000000',27,
 		125,4,
 		'0x83126e98','0xfdf3b645a',36,
 		4,125,
 		'0xf4240000','0x0',17,
 		31250,1,
 		'0x8637bd06','0x3fff79c842fa',46,
 		1,31250,
 	], 48 => [
 		'0xa6aaaaab','0x6aaaaaa',27,
 		125,6,
 		'0xc49ba5e4','0xfdf3b645a',36,
 		6,125,
 		'0xa2c2aaab','0x15555',17,
 		62500,3,
 		'0xc9539b89','0x3fffbce4217d',46,
 		3,62500,
 	], 64 => [
 		'0xfa000000','0xe000000',28,
 		125,8,
 		'0x83126e98','0x7ef9db22d',35,
 		8,125,
 		'0xf4240000','0x0',18,
 		15625,1,
 		'0x8637bd06','0x1fff79c842fa',45,
 		1,15625,
 	], 100 => [
 		'0xa0000000','0x0',28,
 		10,1,
 		'0xcccccccd','0x733333333',35,
 		1,10,
 		'0x9c400000','0x0',18,
 		10000,1,
 		'0xd1b71759','0x1fff2e48e8a7',45,
 		1,10000,
 	], 122 => [
 		'0x8325c53f','0xfbcda3a',28,
 		500,61,
 		'0xf9db22d1','0x7fbe76c8b',35,
 		61,500,
 		'0x8012e2a0','0x3ef36',18,
 		500000,61,
 		'0xffda4053','0x1ffffbce4217',45,
 		61,500000,
 	], 128 => [
 		'0xfa000000','0x1e000000',29,
 		125,16,
 		'0x83126e98','0x3f7ced916',34,
 		16,125,
 		'0xf4240000','0x40000',19,
 		15625,2,
 		'0x8637bd06','0xfffbce4217d',44,
 		2,15625,
 	], 200 => [
 		'0xa0000000','0x0',29,
 		5,1,
 		'0xcccccccd','0x333333333',34,
 		1,5,
 		'0x9c400000','0x0',19,
 		5000,1,
 		'0xd1b71759','0xfff2e48e8a7',44,
 		1,5000,
 	], 250 => [
 		'0x80000000','0x0',29,
 		4,1,
 		'0x80000000','0x180000000',33,
 		1,4,
 		'0xfa000000','0x0',20,
 		4000,1,
 		'0x83126e98','0x7ff7ced9168',43,
 		1,4000,
 	], 256 => [
 		'0xfa000000','0x3e000000',30,
 		125,32,
 		'0x83126e98','0x1fbe76c8b',33,
 		32,125,
 		'0xf4240000','0xc0000',20,
 		15625,4,
 		'0x8637bd06','0x7ffde7210be',43,
 		4,15625,
 	], 300 => [
 		'0xd5555556','0x2aaaaaaa',30,
 		10,3,
 		'0x9999999a','0x1cccccccc',33,
 		3,10,
 		'0xd0555556','0xaaaaa',20,
 		10000,3,
 		'0x9d495183','0x7ffcb923a29',43,
 		3,10000,
 	], 512 => [
 		'0xfa000000','0x7e000000',31,
 		125,64,
 		'0x83126e98','0xfdf3b645',32,
 		64,125,
 		'0xf4240000','0x1c0000',21,
 		15625,8,
 		'0x8637bd06','0x3ffef39085f',42,
 		8,15625,
 	], 1000 => [
 		'0x80000000','0x0',31,
 		1,1,
 		'0x80000000','0x0',31,
 		1,1,
 		'0xfa000000','0x0',22,
 		1000,1,
 		'0x83126e98','0x1ff7ced9168',41,
 		1,1000,
 	], 1024 => [
 		'0xfa000000','0xfe000000',32,
 		125,128,
 		'0x83126e98','0x7ef9db22',31,
 		128,125,
 		'0xf4240000','0x3c0000',22,
 		15625,16,
 		'0x8637bd06','0x1fff79c842f',41,
 		16,15625,
 	], 1200 => [
 		'0xd5555556','0xd5555555',32,
 		5,6,
 		'0x9999999a','0x66666666',31,
 		6,5,
 		'0xd0555556','0x2aaaaa',22,
 		2500,3,
 		'0x9d495183','0x1ffcb923a29',41,
 		3,2500,
 	]
 );

 $has_bigint = eval 'use Math::BigInt qw(bgcd); 1;';

 sub bint($)
 {
 	my($x) = @_;
 	return Math::BigInt->new($x);
 }

 #
 # Constants for division by reciprocal multiplication.
 # (bits, numerator, denominator)
 #
 sub fmul($$$)
 {
 	my ($b,$n,$d) = @_;

 	$n = bint($n);
 	$d = bint($d);

 	return scalar (($n << $b)+$d-bint(1))/$d;
 }

 sub fadj($$$)
 {
 	my($b,$n,$d) = @_;

 	$n = bint($n);
 	$d = bint($d);

 	$d = $d/bgcd($n, $d);
 	return scalar (($d-bint(1)) << $b)/$d;
 }

 sub fmuls($$$) {
 	my($b,$n,$d) = @_;
 	my($s,$m);
 	my($thres) = bint(1) << ($b-1);

 	$n = bint($n);
 	$d = bint($d);

 	for ($s = 0; 1; $s++) {
 		$m = fmul($s,$n,$d);
 		return $s if ($m >= $thres);
 	}
 	return 0;
 }

 # Generate a hex value if the result fits in 64 bits;
 # otherwise skip.
 sub bignum_hex($) {
 	my($x) = @_;
 	my $s = $x->as_hex();

 	return (length($s) > 18) ? undef : $s;
 }

 # Provides mul, adj, and shr factors for a specific
 # (bit, time, hz) combination
 sub muladj($$$) {
 	my($b, $t, $hz) = @_;
 	my $s = fmuls($b, $t, $hz);
 	my $m = fmul($s, $t, $hz);
 	my $a = fadj($s, $t, $hz);
 	return (bignum_hex($m), bignum_hex($a), $s);
 }

 # Provides numerator, denominator values
 sub numden($$) {
 	my($n, $d) = @_;
 	my $g = bgcd($n, $d);
 	return ($n/$g, $d/$g);
 }

 # All values for a specific (time, hz) combo
 sub conversions($$) {
 	my ($t, $hz) = @_;
 	my @val = ();

 	# HZ_TO_xx
 	push(@val, muladj(32, $t, $hz));
 	push(@val, numden($t, $hz));

 	# xx_TO_HZ
 	push(@val, muladj(32, $hz, $t));
 	push(@val, numden($hz, $t));

 	return @val;
 }

 sub compute_values($) {
 	my($hz) = @_;
 	my @val = ();
 	my $s, $m, $a, $g;

 	if (!$has_bigint) {
 		die "$0: HZ == $hz not canned and ".
 		    "Math::BigInt not available\n";
 	}

 	# MSEC conversions
 	push(@val, conversions(1000, $hz));

 	# USEC conversions
 	push(@val, conversions(1000000, $hz));

 	return @val;
 }

 sub outputval($$)
 {
 	my($name, $val) = @_;
 	my $csuf;

 	if (defined($val)) {
 	    if ($name !~ /SHR/) {
 		$val = "U64_C($val)";
 	    }
 	    printf "#define %-23s %s\n", $name.$csuf, $val.$csuf;
 	}
 }

 sub output($@)
 {
 	my($hz, @val) = @_;
 	my $pfx, $bit, $suf, $s, $m, $a;

 	print "/* Automatically generated by kernel/timeconst.pl */\n";
 	print "/* Conversion constants for HZ == $hz */\n";
 	print "\n";
 	print "#ifndef KERNEL_TIMECONST_H\n";
 	print "#define KERNEL_TIMECONST_H\n";
 	print "\n";

 	print "#include <linux/param.h>\n";
 	print "#include <linux/types.h>\n";

 	print "\n";
 	print "#if HZ != $hz\n";
 	print "#error \"kernel/timeconst.h has the wrong HZ value!\"\n";
 	print "#endif\n";
 	print "\n";

 	foreach $pfx ('HZ_TO_MSEC','MSEC_TO_HZ',
 		      'HZ_TO_USEC','USEC_TO_HZ') {
 		foreach $bit (32) {
 			foreach $suf ('MUL', 'ADJ', 'SHR') {
 				outputval("${pfx}_$suf$bit", shift(@val));
 			}
 		}
 		foreach $suf ('NUM', 'DEN') {
 			outputval("${pfx}_$suf", shift(@val));
 		}
 	}

 	print "\n";
 	print "#endif /* KERNEL_TIMECONST_H */\n";
 }

 # Pretty-print Perl values
 sub perlvals(@) {
 	my $v;
 	my @l = ();

 	foreach $v (@_) {
 		if (!defined($v)) {
 			push(@l, 'undef');
 		} elsif ($v =~ /^0x/) {
 			push(@l, "\'".$v."\'");
 		} else {
 			push(@l, $v.'');
 		}
 	}
 	return join(',', @l);
 }

 ($hz) = @ARGV;

 # Use this to generate the %canned_values structure
 if ($hz eq '--can') {
 	shift(@ARGV);
 	@hzlist = sort {$a <=> $b} (@ARGV);

 	print "# Precomputed values for systems without Math::BigInt\n";
 	print "# Generated by:\n";
 	print "# timeconst.pl --can ", join(' ', @hzlist), "\n";
 	print "\%canned_values = (\n";
 	my $pf = "\t";
 	foreach $hz (@hzlist) {
 		my @values = compute_values($hz);
 		print "$pf$hz => [\n";
 		while (scalar(@values)) {
 			my $bit;
 			foreach $bit (32) {
 				my $m = shift(@values);
 				my $a = shift(@values);
 				my $s = shift(@values);
 				print "\t\t", perlvals($m,$a,$s), ",\n";
 			}
 			my $n = shift(@values);
 			my $d = shift(@values);
 			print "\t\t", perlvals($n,$d), ",\n";
 		}
 		print "\t]";
 		$pf = ', ';
 	}
 	print "\n);\n";
 } else {
 	$hz += 0;			# Force to number
 	if ($hz < 1) {
 		die "Usage: $0 HZ\n";
 	}

 	$cv = $canned_values{$hz};
 	@val = defined($cv) ? @$cv : compute_values($hz);
 	output($hz, @val);
 }
 exit 0;
	#!/usr/bin/perl
	# -----------------------------------------------------------------------
	#
	# Copyright 2007-2008 rPath, Inc. - All Rights Reserved
	#
	# This file is part of the Linux kernel, and is made available under
	# the terms of the GNU General Public License version 2 or (at your
	# option) any later version; incorporated herein by reference.
	#
	# -----------------------------------------------------------------------
	#

	#
	# Usage: timeconst.pl HZ > timeconst.h
	#

	# Precomputed values for systems without Math::BigInt
	# Generated by:
	# timeconst.pl --can 24 32 48 64 100 122 128 200 250 256 300 512 1000 1024 1200
	%canned_values = (
	24 => [
	'0xa6aaaaab','0x2aaaaaa',26,
	125,3,
	'0xc49ba5e4','0x1fbe76c8b4',37,
	3,125,
	'0xa2c2aaab','0xaaaa',16,
	125000,3,
	'0xc9539b89','0x7fffbce4217d',47,
	3,125000,
	], 32 => [
	'0xfa000000','0x6000000',27,
	125,4,
	'0x83126e98','0xfdf3b645a',36,
	4,125,
	'0xf4240000','0x0',17,
	31250,1,
	'0x8637bd06','0x3fff79c842fa',46,
	1,31250,
	], 48 => [
	'0xa6aaaaab','0x6aaaaaa',27,
	125,6,
	'0xc49ba5e4','0xfdf3b645a',36,
	6,125,
	'0xa2c2aaab','0x15555',17,
	62500,3,
	'0xc9539b89','0x3fffbce4217d',46,
	3,62500,
	], 64 => [
	'0xfa000000','0xe000000',28,
	125,8,
	'0x83126e98','0x7ef9db22d',35,
	8,125,
	'0xf4240000','0x0',18,
	15625,1,
	'0x8637bd06','0x1fff79c842fa',45,
	1,15625,
	], 100 => [
	'0xa0000000','0x0',28,
	10,1,
	'0xcccccccd','0x733333333',35,
	1,10,
	'0x9c400000','0x0',18,
	10000,1,
	'0xd1b71759','0x1fff2e48e8a7',45,
	1,10000,
	], 122 => [
	'0x8325c53f','0xfbcda3a',28,
	500,61,
	'0xf9db22d1','0x7fbe76c8b',35,
	61,500,
	'0x8012e2a0','0x3ef36',18,
	500000,61,
	'0xffda4053','0x1ffffbce4217',45,
	61,500000,
	], 128 => [
	'0xfa000000','0x1e000000',29,
	125,16,
	'0x83126e98','0x3f7ced916',34,
	16,125,
	'0xf4240000','0x40000',19,
	15625,2,
	'0x8637bd06','0xfffbce4217d',44,
	2,15625,
	], 200 => [
	'0xa0000000','0x0',29,
	5,1,
	'0xcccccccd','0x333333333',34,
	1,5,
	'0x9c400000','0x0',19,
	5000,1,
	'0xd1b71759','0xfff2e48e8a7',44,
	1,5000,
	], 250 => [
	'0x80000000','0x0',29,
	4,1,
	'0x80000000','0x180000000',33,
	1,4,
	'0xfa000000','0x0',20,
	4000,1,
	'0x83126e98','0x7ff7ced9168',43,
	1,4000,
	], 256 => [
	'0xfa000000','0x3e000000',30,
	125,32,
	'0x83126e98','0x1fbe76c8b',33,
	32,125,
	'0xf4240000','0xc0000',20,
	15625,4,
	'0x8637bd06','0x7ffde7210be',43,
	4,15625,
	], 300 => [
	'0xd5555556','0x2aaaaaaa',30,
	10,3,
	'0x9999999a','0x1cccccccc',33,
	3,10,
	'0xd0555556','0xaaaaa',20,
	10000,3,
	'0x9d495183','0x7ffcb923a29',43,
	3,10000,
	], 512 => [
	'0xfa000000','0x7e000000',31,
	125,64,
	'0x83126e98','0xfdf3b645',32,
	64,125,
	'0xf4240000','0x1c0000',21,
	15625,8,
	'0x8637bd06','0x3ffef39085f',42,
	8,15625,
	], 1000 => [
	'0x80000000','0x0',31,
	1,1,
	'0x80000000','0x0',31,
	1,1,
	'0xfa000000','0x0',22,
	1000,1,
	'0x83126e98','0x1ff7ced9168',41,
	1,1000,
	], 1024 => [
	'0xfa000000','0xfe000000',32,
	125,128,
	'0x83126e98','0x7ef9db22',31,
	128,125,
	'0xf4240000','0x3c0000',22,
	15625,16,
	'0x8637bd06','0x1fff79c842f',41,
	16,15625,
	], 1200 => [
	'0xd5555556','0xd5555555',32,
	5,6,
	'0x9999999a','0x66666666',31,
	6,5,
	'0xd0555556','0x2aaaaa',22,
	2500,3,
	'0x9d495183','0x1ffcb923a29',41,
	3,2500,
	]
	);

	$has_bigint = eval 'use Math::BigInt qw(bgcd); 1;';

	sub bint($)
	{
	my($x) = @_;
	return Math::BigInt->new($x);
	}

	#
	# Constants for division by reciprocal multiplication.
	# (bits, numerator, denominator)
	#
	sub fmul($$$)
	{
	my ($b,$n,$d) = @_;

	$n = bint($n);
	$d = bint($d);

	return scalar (($n << $b)+$d-bint(1))/$d;
	}

	sub fadj($$$)
	{
	my($b,$n,$d) = @_;

	$n = bint($n);
	$d = bint($d);

	$d = $d/bgcd($n, $d);
	return scalar (($d-bint(1)) << $b)/$d;
	}

	sub fmuls($$$) {
	my($b,$n,$d) = @_;
	my($s,$m);
	my($thres) = bint(1) << ($b-1);

	$n = bint($n);
	$d = bint($d);

	for ($s = 0; 1; $s++) {
	$m = fmul($s,$n,$d);
	return $s if ($m >= $thres);
	}
	return 0;
	}

	# Generate a hex value if the result fits in 64 bits;
	# otherwise skip.
	sub bignum_hex($) {
	my($x) = @_;
	my $s = $x->as_hex();

	return (length($s) > 18) ? undef : $s;
	}

	# Provides mul, adj, and shr factors for a specific
	# (bit, time, hz) combination
	sub muladj($$$) {
	my($b, $t, $hz) = @_;
	my $s = fmuls($b, $t, $hz);
	my $m = fmul($s, $t, $hz);
	my $a = fadj($s, $t, $hz);
	return (bignum_hex($m), bignum_hex($a), $s);
	}

	# Provides numerator, denominator values
	sub numden($$) {
	my($n, $d) = @_;
	my $g = bgcd($n, $d);
	return ($n/$g, $d/$g);
	}

	# All values for a specific (time, hz) combo
	sub conversions($$) {
	my ($t, $hz) = @_;
	my @val = ();

	# HZ_TO_xx
	push(@val, muladj(32, $t, $hz));
	push(@val, numden($t, $hz));

	# xx_TO_HZ
	push(@val, muladj(32, $hz, $t));
	push(@val, numden($hz, $t));

	return @val;
	}

	sub compute_values($) {
	my($hz) = @_;
	my @val = ();
	my $s, $m, $a, $g;

	if (!$has_bigint) {
	die "$0: HZ == $hz not canned and ".
	"Math::BigInt not available\n";
	}

	# MSEC conversions
	push(@val, conversions(1000, $hz));

	# USEC conversions
	push(@val, conversions(1000000, $hz));

	return @val;
	}

	sub outputval($$)
	{
	my($name, $val) = @_;
	my $csuf;

	if (defined($val)) {
	if ($name !~ /SHR/) {
	$val = "U64_C($val)";
	}
	printf "#define %-23s %s\n", $name.$csuf, $val.$csuf;
	}
	}

	sub output($@)
	{
	my($hz, @val) = @_;
	my $pfx, $bit, $suf, $s, $m, $a;

	print "/* Automatically generated by kernel/timeconst.pl */\n";
	print "/* Conversion constants for HZ == $hz */\n";
	print "\n";
	print "#ifndef KERNEL_TIMECONST_H\n";
	print "#define KERNEL_TIMECONST_H\n";
	print "\n";

	print "#include <linux/param.h>\n";
	print "#include <linux/types.h>\n";

	print "\n";
	print "#if HZ != $hz\n";
	print "#error \"kernel/timeconst.h has the wrong HZ value!\"\n";
	print "#endif\n";
	print "\n";

	foreach $pfx ('HZ_TO_MSEC','MSEC_TO_HZ',
	'HZ_TO_USEC','USEC_TO_HZ') {
	foreach $bit (32) {
	foreach $suf ('MUL', 'ADJ', 'SHR') {
	outputval("${pfx}_$suf$bit", shift(@val));
	}
	}
	foreach $suf ('NUM', 'DEN') {
	outputval("${pfx}_$suf", shift(@val));
	}
	}

	print "\n";
	print "#endif /* KERNEL_TIMECONST_H */\n";
	}

	# Pretty-print Perl values
	sub perlvals(@) {
	my $v;
	my @l = ();

	foreach $v (@_) {
	if (!defined($v)) {
	push(@l, 'undef');
	} elsif ($v =~ /^0x/) {
	push(@l, "\'".$v."\'");
	} else {
	push(@l, $v.'');
	}
	}
	return join(',', @l);
	}

	($hz) = @ARGV;

	# Use this to generate the %canned_values structure
	if ($hz eq '--can') {
	shift(@ARGV);
	@hzlist = sort {$a <=> $b} (@ARGV);

	print "# Precomputed values for systems without Math::BigInt\n";
	print "# Generated by:\n";
	print "# timeconst.pl --can ", join(' ', @hzlist), "\n";
	print "\%canned_values = (\n";
	my $pf = "\t";
	foreach $hz (@hzlist) {
	my @values = compute_values($hz);
	print "$pf$hz => [\n";
	while (scalar(@values)) {
	my $bit;
	foreach $bit (32) {
	my $m = shift(@values);
	my $a = shift(@values);
	my $s = shift(@values);
	print "\t\t", perlvals($m,$a,$s), ",\n";
	}
	my $n = shift(@values);
	my $d = shift(@values);
	print "\t\t", perlvals($n,$d), ",\n";
	}
	print "\t]";
	$pf = ', ';
	}
	print "\n);\n";
	} else {
	$hz += 0; # Force to number
	if ($hz < 1) {
	die "Usage: $0 HZ\n";
	}

	$cv = $canned_values{$hz};
	@val = defined($cv) ? @$cv : compute_values($hz);
	output($hz, @val);
	}
	exit 0;