kernel/timeconst.pl

   1 #!/usr/bin/perl
   2 # -----------------------------------------------------------------------
   3 #
   4 #   Copyright 2007 rPath, Inc. - All Rights Reserved
   5 #
   6 #   This file is part of the Linux kernel, and is made available under
   7 #   the terms of the GNU General Public License version 2 or (at your
   8 #   option) any later version; incorporated herein by reference.
   9 #
  10 # -----------------------------------------------------------------------
  11 #
  12
  13 #
  14 # Usage: timeconst.pl HZ > timeconst.h
  15 #
  16
  17 # Precomputed values for systems without Math::BigInt
  18 # Generated by:
  19 # timeconst.pl --can 24 32 48 64 100 122 128 200 250 256 300 512 1000 1024 1200
  20 %canned_values = (
  21         24 => [
  22                 '0xa6aaaaab','0x2aaaaaa',26,
  23                 '0xa6aaaaaaaaaaaaab','0x2aaaaaaaaaaaaaa',58,
  24                 125,3,
  25                 '0xc49ba5e4','0x1fbe76c8b4',37,
  26                 '0xc49ba5e353f7ceda','0x1fbe76c8b439581062',69,
  27                 3,125,
  28                 '0xa2c2aaab','0xaaaa',16,
  29                 '0xa2c2aaaaaaaaaaab','0xaaaaaaaaaaaa',48,
  30                 125000,3,
  31                 '0xc9539b89','0x7fffbce4217d',47,
  32                 '0xc9539b8887229e91','0x7fffbce4217d2849cb25',79,
  33                 3,125000,
  34         ], 32 => [
  35                 '0xfa000000','0x6000000',27,
  36                 '0xfa00000000000000','0x600000000000000',59,
  37                 125,4,
  38                 '0x83126e98','0xfdf3b645a',36,
  39                 '0x83126e978d4fdf3c','0xfdf3b645a1cac0831',68,
  40                 4,125,
  41                 '0xf4240000','0x0',17,
  42                 '0xf424000000000000','0x0',49,
  43                 31250,1,
  44                 '0x8637bd06','0x3fff79c842fa',46,
  45                 '0x8637bd05af6c69b6','0x3fff79c842fa5093964a',78,
  46                 1,31250,
  47         ], 48 => [
  48                 '0xa6aaaaab','0x6aaaaaa',27,
  49                 '0xa6aaaaaaaaaaaaab','0x6aaaaaaaaaaaaaa',59,
  50                 125,6,
  51                 '0xc49ba5e4','0xfdf3b645a',36,
  52                 '0xc49ba5e353f7ceda','0xfdf3b645a1cac0831',68,
  53                 6,125,
  54                 '0xa2c2aaab','0x15555',17,
  55                 '0xa2c2aaaaaaaaaaab','0x1555555555555',49,
  56                 62500,3,
  57                 '0xc9539b89','0x3fffbce4217d',46,
  58                 '0xc9539b8887229e91','0x3fffbce4217d2849cb25',78,
  59                 3,62500,
  60         ], 64 => [
  61                 '0xfa000000','0xe000000',28,
  62                 '0xfa00000000000000','0xe00000000000000',60,
  63                 125,8,
  64                 '0x83126e98','0x7ef9db22d',35,
  65                 '0x83126e978d4fdf3c','0x7ef9db22d0e560418',67,
  66                 8,125,
  67                 '0xf4240000','0x0',18,
  68                 '0xf424000000000000','0x0',50,
  69                 15625,1,
  70                 '0x8637bd06','0x1fff79c842fa',45,
  71                 '0x8637bd05af6c69b6','0x1fff79c842fa5093964a',77,
  72                 1,15625,
  73         ], 100 => [
  74                 '0xa0000000','0x0',28,
  75                 '0xa000000000000000','0x0',60,
  76                 10,1,
  77                 '0xcccccccd','0x733333333',35,
  78                 '0xcccccccccccccccd','0x73333333333333333',67,
  79                 1,10,
  80                 '0x9c400000','0x0',18,
  81                 '0x9c40000000000000','0x0',50,
  82                 10000,1,
  83                 '0xd1b71759','0x1fff2e48e8a7',45,
  84                 '0xd1b71758e219652c','0x1fff2e48e8a71de69ad4',77,
  85                 1,10000,
  86         ], 122 => [
  87                 '0x8325c53f','0xfbcda3a',28,
  88                 '0x8325c53ef368eb05','0xfbcda3ac10c9714',60,
  89                 500,61,
  90                 '0xf9db22d1','0x7fbe76c8b',35,
  91                 '0xf9db22d0e560418a','0x7fbe76c8b43958106',67,
  92                 61,500,
  93                 '0x8012e2a0','0x3ef36',18,
  94                 '0x8012e29f79b47583','0x3ef368eb04325',50,
  95                 500000,61,
  96                 '0xffda4053','0x1ffffbce4217',45,
  97                 '0xffda4052d666a983','0x1ffffbce4217d2849cb2',77,
  98                 61,500000,
  99         ], 128 => [
 100                 '0xfa000000','0x1e000000',29,
 101                 '0xfa00000000000000','0x1e00000000000000',61,
 102                 125,16,
 103                 '0x83126e98','0x3f7ced916',34,
 104                 '0x83126e978d4fdf3c','0x3f7ced916872b020c',66,
 105                 16,125,
 106                 '0xf4240000','0x40000',19,
 107                 '0xf424000000000000','0x4000000000000',51,
 108                 15625,2,
 109                 '0x8637bd06','0xfffbce4217d',44,
 110                 '0x8637bd05af6c69b6','0xfffbce4217d2849cb25',76,
 111                 2,15625,
 112         ], 200 => [
 113                 '0xa0000000','0x0',29,
 114                 '0xa000000000000000','0x0',61,
 115                 5,1,
 116                 '0xcccccccd','0x333333333',34,
 117                 '0xcccccccccccccccd','0x33333333333333333',66,
 118                 1,5,
 119                 '0x9c400000','0x0',19,
 120                 '0x9c40000000000000','0x0',51,
 121                 5000,1,
 122                 '0xd1b71759','0xfff2e48e8a7',44,
 123                 '0xd1b71758e219652c','0xfff2e48e8a71de69ad4',76,
 124                 1,5000,
 125         ], 250 => [
 126                 '0x80000000','0x0',29,
 127                 '0x8000000000000000','0x0',61,
 128                 4,1,
 129                 '0x80000000','0x180000000',33,
 130                 '0x8000000000000000','0x18000000000000000',65,
 131                 1,4,
 132                 '0xfa000000','0x0',20,
 133                 '0xfa00000000000000','0x0',52,
 134                 4000,1,
 135                 '0x83126e98','0x7ff7ced9168',43,
 136                 '0x83126e978d4fdf3c','0x7ff7ced916872b020c4',75,
 137                 1,4000,
 138         ], 256 => [
 139                 '0xfa000000','0x3e000000',30,
 140                 '0xfa00000000000000','0x3e00000000000000',62,
 141                 125,32,
 142                 '0x83126e98','0x1fbe76c8b',33,
 143                 '0x83126e978d4fdf3c','0x1fbe76c8b43958106',65,
 144                 32,125,
 145                 '0xf4240000','0xc0000',20,
 146                 '0xf424000000000000','0xc000000000000',52,
 147                 15625,4,
 148                 '0x8637bd06','0x7ffde7210be',43,
 149                 '0x8637bd05af6c69b6','0x7ffde7210be9424e592',75,
 150                 4,15625,
 151         ], 300 => [
 152                 '0xd5555556','0x2aaaaaaa',30,
 153                 '0xd555555555555556','0x2aaaaaaaaaaaaaaa',62,
 154                 10,3,
 155                 '0x9999999a','0x1cccccccc',33,
 156                 '0x999999999999999a','0x1cccccccccccccccc',65,
 157                 3,10,
 158                 '0xd0555556','0xaaaaa',20,
 159                 '0xd055555555555556','0xaaaaaaaaaaaaa',52,
 160                 10000,3,
 161                 '0x9d495183','0x7ffcb923a29',43,
 162                 '0x9d495182a9930be1','0x7ffcb923a29c779a6b5',75,
 163                 3,10000,
 164         ], 512 => [
 165                 '0xfa000000','0x7e000000',31,
 166                 '0xfa00000000000000','0x7e00000000000000',63,
 167                 125,64,
 168                 '0x83126e98','0xfdf3b645',32,
 169                 '0x83126e978d4fdf3c','0xfdf3b645a1cac083',64,
 170                 64,125,
 171                 '0xf4240000','0x1c0000',21,
 172                 '0xf424000000000000','0x1c000000000000',53,
 173                 15625,8,
 174                 '0x8637bd06','0x3ffef39085f',42,
 175                 '0x8637bd05af6c69b6','0x3ffef39085f4a1272c9',74,
 176                 8,15625,
 177         ], 1000 => [
 178                 '0x80000000','0x0',31,
 179                 '0x8000000000000000','0x0',63,
 180                 1,1,
 181                 '0x80000000','0x0',31,
 182                 '0x8000000000000000','0x0',63,
 183                 1,1,
 184                 '0xfa000000','0x0',22,
 185                 '0xfa00000000000000','0x0',54,
 186                 1000,1,
 187                 '0x83126e98','0x1ff7ced9168',41,
 188                 '0x83126e978d4fdf3c','0x1ff7ced916872b020c4',73,
 189                 1,1000,
 190         ], 1024 => [
 191                 '0xfa000000','0xfe000000',32,
 192                 '0xfa00000000000000','0xfe00000000000000',64,
 193                 125,128,
 194                 '0x83126e98','0x7ef9db22',31,
 195                 '0x83126e978d4fdf3c','0x7ef9db22d0e56041',63,
 196                 128,125,
 197                 '0xf4240000','0x3c0000',22,
 198                 '0xf424000000000000','0x3c000000000000',54,
 199                 15625,16,
 200                 '0x8637bd06','0x1fff79c842f',41,
 201                 '0x8637bd05af6c69b6','0x1fff79c842fa5093964',73,
 202                 16,15625,
 203         ], 1200 => [
 204                 '0xd5555556','0xd5555555',32,
 205                 '0xd555555555555556','0xd555555555555555',64,
 206                 5,6,
 207                 '0x9999999a','0x66666666',31,
 208                 '0x999999999999999a','0x6666666666666666',63,
 209                 6,5,
 210                 '0xd0555556','0x2aaaaa',22,
 211                 '0xd055555555555556','0x2aaaaaaaaaaaaa',54,
 212                 2500,3,
 213                 '0x9d495183','0x1ffcb923a29',41,
 214                 '0x9d495182a9930be1','0x1ffcb923a29c779a6b5',73,
 215                 3,2500,
 216         ]
 217 );
 218
 219 $has_bigint = eval 'use Math::BigInt qw(bgcd); 1;';
 220
 221 sub bint($)
 222 {
 223         my($x) = @_;
 224         return Math::BigInt->new($x);
 225 }
 226
 227 #
 228 # Constants for division by reciprocal multiplication.
 229 # (bits, numerator, denominator)
 230 #
 231 sub fmul($$$)
 232 {
 233         my ($b,$n,$d) = @_;
 234
 235         $n = bint($n);
 236         $d = bint($d);
 237
 238         return scalar (($n << $b)+$d-bint(1))/$d;
 239 }
 240
 241 sub fadj($$$)
 242 {
 243         my($b,$n,$d) = @_;
 244
 245         $n = bint($n);
 246         $d = bint($d);
 247
 248         $d = $d/bgcd($n, $d);
 249         return scalar (($d-bint(1)) << $b)/$d;
 250 }
 251
 252 sub fmuls($$$) {
 253         my($b,$n,$d) = @_;
 254         my($s,$m);
 255         my($thres) = bint(1) << ($b-1);
 256
 257         $n = bint($n);
 258         $d = bint($d);
 259
 260         for ($s = 0; 1; $s++) {
 261                 $m = fmul($s,$n,$d);
 262                 return $s if ($m >= $thres);
 263         }
 264         return 0;
 265 }
 266
 267 # Provides mul, adj, and shr factors for a specific
 268 # (bit, time, hz) combination
 269 sub muladj($$$) {
 270         my($b, $t, $hz) = @_;
 271         my $s = fmuls($b, $t, $hz);
 272         my $m = fmul($s, $t, $hz);
 273         my $a = fadj($s, $t, $hz);
 274         return ($m->as_hex(), $a->as_hex(), $s);
 275 }
 276
 277 # Provides numerator, denominator values
 278 sub numden($$) {
 279         my($n, $d) = @_;
 280         my $g = bgcd($n, $d);
 281         return ($n/$g, $d/$g);
 282 }
 283
 284 # All values for a specific (time, hz) combo
 285 sub conversions($$) {
 286         my ($t, $hz) = @_;
 287         my @val = ();
 288
 289         # HZ_TO_xx
 290         push(@val, muladj(32, $t, $hz));
 291         push(@val, muladj(64, $t, $hz));
 292         push(@val, numden($t, $hz));
 293
 294         # xx_TO_HZ
 295         push(@val, muladj(32, $hz, $t));
 296         push(@val, muladj(64, $hz, $t));
 297         push(@val, numden($hz, $t));
 298
 299         return @val;
 300 }
 301
 302 sub compute_values($) {
 303         my($hz) = @_;
 304         my @val = ();
 305         my $s, $m, $a, $g;
 306
 307         if (!$has_bigint) {
 308                 die "$0: HZ == $hz not canned and ".
 309                     "Math::BigInt not available\n";
 310         }
 311
 312         # MSEC conversions
 313         push(@val, conversions(1000, $hz));
 314
 315         # USEC conversions
 316         push(@val, conversions(1000000, $hz));
 317
 318         return @val;
 319 }
 320
 321 sub output($@)
 322 {
 323         my($hz, @val) = @_;
 324         my $pfx, $bit, $suf, $s, $m, $a;
 325
 326         print "/* Automatically generated by kernel/timeconst.pl */\n";
 327         print "/* Conversion constants for HZ == $hz */\n";
 328         print "\n";
 329         print "#ifndef KERNEL_TIMECONST_H\n";
 330         print "#define KERNEL_TIMECONST_H\n";
 331         print "\n";
 332
 333         print "#include <linux/param.h>\n";
 334
 335         print "\n";
 336         print "#if HZ != $hz\n";
 337         print "#error \"kernel/timeconst.h has the wrong HZ value!\"\n";
 338         print "#endif\n";
 339         print "\n";
 340
 341         foreach $pfx ('HZ_TO_MSEC','MSEC_TO_HZ',
 342                       'USEC_TO_HZ','HZ_TO_USEC') {
 343                 foreach $bit (32, 64) {
 344                         foreach $suf ('MUL', 'ADJ', 'SHR') {
 345                                 printf "#define %-23s %s\n",
 346                                         "${pfx}_$suf$bit", shift(@val);
 347                         }
 348                 }
 349                 foreach $suf ('NUM', 'DEN') {
 350                         printf "#define %-23s %s\n",
 351                                 "${pfx}_$suf", shift(@val);
 352                 }
 353         }
 354
 355         print "\n";
 356         print "#endif /* KERNEL_TIMECONST_H */\n";
 357 }
 358
 359 ($hz) = @ARGV;
 360
 361 # Use this to generate the %canned_values structure
 362 if ($hz eq '--can') {
 363         shift(@ARGV);
 364         @hzlist = sort {$a <=> $b} (@ARGV);
 365
 366         print "# Precomputed values for systems without Math::BigInt\n";
 367         print "# Generated by:\n";
 368         print "# timeconst.pl --can ", join(' ', @hzlist), "\n";
 369         print "\%canned_values = (\n";
 370         my $pf = "\t";
 371         foreach $hz (@hzlist) {
 372                 my @values = compute_values($hz);
 373                 print "$pf$hz => [\n";
 374                 while (scalar(@values)) {
 375                         my $bit;
 376                         foreach $bit (32, 64) {
 377                                 my $m = shift(@values);
 378                                 my $a = shift(@values);
 379                                 my $s = shift(@values);
 380                                 print "\t\t\'",$m,"\',\'",$a,"\',",$s,",\n";
 381                         }
 382                         my $n = shift(@values);
 383                         my $d = shift(@values);
 384                         print "\t\t",$n,',',$d,",\n";
 385                 }
 386                 print "\t]";
 387                 $pf = ', ';
 388         }
 389         print "\n);\n";
 390 } else {
 391         $hz += 0;                       # Force to number
 392         if ($hz < 1) {
 393                 die "Usage: $0 HZ\n";
 394         }
 395
 396         @val = @{$canned_values{$hz}};
 397         if (!defined(@val)) {
 398                 @val = compute_values($hz);
 399         }
 400         output($hz, @val);
 401 }
 402 exit 0;