Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kernel/timeconst.pl
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
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1 #!/usr/bin/perl 2 # ----------------------------------------------------------------------- 3 # 4 # Copyright 2007-2008 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, 23 125,3, 24 '0xc49ba5e4','0x1fbe76c8b4',37, 25 3,125, 26 '0xa2c2aaab','0xaaaa',16, 27 125000,3, 28 '0xc9539b89','0x7fffbce4217d',47, 29 3,125000, 30 ], 32 => [ 31 '0xfa000000','0x6000000',27, 32 125,4, 33 '0x83126e98','0xfdf3b645a',36, 34 4,125, 35 '0xf4240000','0x0',17, 36 31250,1, 37 '0x8637bd06','0x3fff79c842fa',46, 38 1,31250, 39 ], 48 => [ 40 '0xa6aaaaab','0x6aaaaaa',27, 41 125,6, 42 '0xc49ba5e4','0xfdf3b645a',36, 43 6,125, 44 '0xa2c2aaab','0x15555',17, 45 62500,3, 46 '0xc9539b89','0x3fffbce4217d',46, 47 3,62500, 48 ], 64 => [ 49 '0xfa000000','0xe000000',28, 50 125,8, 51 '0x83126e98','0x7ef9db22d',35, 52 8,125, 53 '0xf4240000','0x0',18, 54 15625,1, 55 '0x8637bd06','0x1fff79c842fa',45, 56 1,15625, 57 ], 100 => [ 58 '0xa0000000','0x0',28, 59 10,1, 60 '0xcccccccd','0x733333333',35, 61 1,10, 62 '0x9c400000','0x0',18, 63 10000,1, 64 '0xd1b71759','0x1fff2e48e8a7',45, 65 1,10000, 66 ], 122 => [ 67 '0x8325c53f','0xfbcda3a',28, 68 500,61, 69 '0xf9db22d1','0x7fbe76c8b',35, 70 61,500, 71 '0x8012e2a0','0x3ef36',18, 72 500000,61, 73 '0xffda4053','0x1ffffbce4217',45, 74 61,500000, 75 ], 128 => [ 76 '0xfa000000','0x1e000000',29, 77 125,16, 78 '0x83126e98','0x3f7ced916',34, 79 16,125, 80 '0xf4240000','0x40000',19, 81 15625,2, 82 '0x8637bd06','0xfffbce4217d',44, 83 2,15625, 84 ], 200 => [ 85 '0xa0000000','0x0',29, 86 5,1, 87 '0xcccccccd','0x333333333',34, 88 1,5, 89 '0x9c400000','0x0',19, 90 5000,1, 91 '0xd1b71759','0xfff2e48e8a7',44, 92 1,5000, 93 ], 250 => [ 94 '0x80000000','0x0',29, 95 4,1, 96 '0x80000000','0x180000000',33, 97 1,4, 98 '0xfa000000','0x0',20, 99 4000,1, 100 '0x83126e98','0x7ff7ced9168',43, 101 1,4000, 102 ], 256 => [ 103 '0xfa000000','0x3e000000',30, 104 125,32, 105 '0x83126e98','0x1fbe76c8b',33, 106 32,125, 107 '0xf4240000','0xc0000',20, 108 15625,4, 109 '0x8637bd06','0x7ffde7210be',43, 110 4,15625, 111 ], 300 => [ 112 '0xd5555556','0x2aaaaaaa',30, 113 10,3, 114 '0x9999999a','0x1cccccccc',33, 115 3,10, 116 '0xd0555556','0xaaaaa',20, 117 10000,3, 118 '0x9d495183','0x7ffcb923a29',43, 119 3,10000, 120 ], 512 => [ 121 '0xfa000000','0x7e000000',31, 122 125,64, 123 '0x83126e98','0xfdf3b645',32, 124 64,125, 125 '0xf4240000','0x1c0000',21, 126 15625,8, 127 '0x8637bd06','0x3ffef39085f',42, 128 8,15625, 129 ], 1000 => [ 130 '0x80000000','0x0',31, 131 1,1, 132 '0x80000000','0x0',31, 133 1,1, 134 '0xfa000000','0x0',22, 135 1000,1, 136 '0x83126e98','0x1ff7ced9168',41, 137 1,1000, 138 ], 1024 => [ 139 '0xfa000000','0xfe000000',32, 140 125,128, 141 '0x83126e98','0x7ef9db22',31, 142 128,125, 143 '0xf4240000','0x3c0000',22, 144 15625,16, 145 '0x8637bd06','0x1fff79c842f',41, 146 16,15625, 147 ], 1200 => [ 148 '0xd5555556','0xd5555555',32, 149 5,6, 150 '0x9999999a','0x66666666',31, 151 6,5, 152 '0xd0555556','0x2aaaaa',22, 153 2500,3, 154 '0x9d495183','0x1ffcb923a29',41, 155 3,2500, 156 ] 157 ); 158 159 $has_bigint = eval 'use Math::BigInt qw(bgcd); 1;'; 160 161 sub bint($) 162 { 163 my($x) = @_; 164 return Math::BigInt->new($x); 165 } 166 167 # 168 # Constants for division by reciprocal multiplication. 169 # (bits, numerator, denominator) 170 # 171 sub fmul($$$) 172 { 173 my ($b,$n,$d) = @_; 174 175 $n = bint($n); 176 $d = bint($d); 177 178 return scalar (($n << $b)+$d-bint(1))/$d; 179 } 180 181 sub fadj($$$) 182 { 183 my($b,$n,$d) = @_; 184 185 $n = bint($n); 186 $d = bint($d); 187 188 $d = $d/bgcd($n, $d); 189 return scalar (($d-bint(1)) << $b)/$d; 190 } 191 192 sub fmuls($$$) { 193 my($b,$n,$d) = @_; 194 my($s,$m); 195 my($thres) = bint(1) << ($b-1); 196 197 $n = bint($n); 198 $d = bint($d); 199 200 for ($s = 0; 1; $s++) { 201 $m = fmul($s,$n,$d); 202 return $s if ($m >= $thres); 203 } 204 return 0; 205 } 206 207 # Generate a hex value if the result fits in 64 bits; 208 # otherwise skip. 209 sub bignum_hex($) { 210 my($x) = @_; 211 my $s = $x->as_hex(); 212 213 return (length($s) > 18) ? undef : $s; 214 } 215 216 # Provides mul, adj, and shr factors for a specific 217 # (bit, time, hz) combination 218 sub muladj($$$) { 219 my($b, $t, $hz) = @_; 220 my $s = fmuls($b, $t, $hz); 221 my $m = fmul($s, $t, $hz); 222 my $a = fadj($s, $t, $hz); 223 return (bignum_hex($m), bignum_hex($a), $s); 224 } 225 226 # Provides numerator, denominator values 227 sub numden($$) { 228 my($n, $d) = @_; 229 my $g = bgcd($n, $d); 230 return ($n/$g, $d/$g); 231 } 232 233 # All values for a specific (time, hz) combo 234 sub conversions($$) { 235 my ($t, $hz) = @_; 236 my @val = (); 237 238 # HZ_TO_xx 239 push(@val, muladj(32, $t, $hz)); 240 push(@val, numden($t, $hz)); 241 242 # xx_TO_HZ 243 push(@val, muladj(32, $hz, $t)); 244 push(@val, numden($hz, $t)); 245 246 return @val; 247 } 248 249 sub compute_values($) { 250 my($hz) = @_; 251 my @val = (); 252 my $s, $m, $a, $g; 253 254 if (!$has_bigint) { 255 die "$0: HZ == $hz not canned and ". 256 "Math::BigInt not available\n"; 257 } 258 259 # MSEC conversions 260 push(@val, conversions(1000, $hz)); 261 262 # USEC conversions 263 push(@val, conversions(1000000, $hz)); 264 265 return @val; 266 } 267 268 sub outputval($$) 269 { 270 my($name, $val) = @_; 271 my $csuf; 272 273 if (defined($val)) { 274 if ($name !~ /SHR/) { 275 $val = "U64_C($val)"; 276 } 277 printf "#define %-23s %s\n", $name.$csuf, $val.$csuf; 278 } 279 } 280 281 sub output($@) 282 { 283 my($hz, @val) = @_; 284 my $pfx, $bit, $suf, $s, $m, $a; 285 286 print "/* Automatically generated by kernel/timeconst.pl */\n"; 287 print "/* Conversion constants for HZ == $hz */\n"; 288 print "\n"; 289 print "#ifndef KERNEL_TIMECONST_H\n"; 290 print "#define KERNEL_TIMECONST_H\n"; 291 print "\n"; 292 293 print "#include <linux/param.h>\n"; 294 print "#include <linux/types.h>\n"; 295 296 print "\n"; 297 print "#if HZ != $hz\n"; 298 print "#error \"kernel/timeconst.h has the wrong HZ value!\"\n"; 299 print "#endif\n"; 300 print "\n"; 301 302 foreach $pfx ('HZ_TO_MSEC','MSEC_TO_HZ', 303 'HZ_TO_USEC','USEC_TO_HZ') { 304 foreach $bit (32) { 305 foreach $suf ('MUL', 'ADJ', 'SHR') { 306 outputval("${pfx}_$suf$bit", shift(@val)); 307 } 308 } 309 foreach $suf ('NUM', 'DEN') { 310 outputval("${pfx}_$suf", shift(@val)); 311 } 312 } 313 314 print "\n"; 315 print "#endif /* KERNEL_TIMECONST_H */\n"; 316 } 317 318 # Pretty-print Perl values 319 sub perlvals(@) { 320 my $v; 321 my @l = (); 322 323 foreach $v (@_) { 324 if (!defined($v)) { 325 push(@l, 'undef'); 326 } elsif ($v =~ /^0x/) { 327 push(@l, "\'".$v."\'"); 328 } else { 329 push(@l, $v.''); 330 } 331 } 332 return join(',', @l); 333 } 334 335 ($hz) = @ARGV; 336 337 # Use this to generate the %canned_values structure 338 if ($hz eq '--can') { 339 shift(@ARGV); 340 @hzlist = sort {$a <=> $b} (@ARGV); 341 342 print "# Precomputed values for systems without Math::BigInt\n"; 343 print "# Generated by:\n"; 344 print "# timeconst.pl --can ", join(' ', @hzlist), "\n"; 345 print "\%canned_values = (\n"; 346 my $pf = "\t"; 347 foreach $hz (@hzlist) { 348 my @values = compute_values($hz); 349 print "$pf$hz => [\n"; 350 while (scalar(@values)) { 351 my $bit; 352 foreach $bit (32) { 353 my $m = shift(@values); 354 my $a = shift(@values); 355 my $s = shift(@values); 356 print "\t\t", perlvals($m,$a,$s), ",\n"; 357 } 358 my $n = shift(@values); 359 my $d = shift(@values); 360 print "\t\t", perlvals($n,$d), ",\n"; 361 } 362 print "\t]"; 363 $pf = ', '; 364 } 365 print "\n);\n"; 366 } else { 367 $hz += 0; # Force to number 368 if ($hz < 1) { 369 die "Usage: $0 HZ\n"; 370 } 371 372 @val = @{$canned_values{$hz}}; 373 if (!defined(@val)) { 374 @val = compute_values($hz); 375 } 376 output($hz, @val); 377 } 378 exit 0;
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