1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- U I N T P -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2012, Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- Support for universal integer arithmetic 33 34-- WARNING: There is a C version of this package. Any changes to this 35-- source file must be properly reflected in the C header file uintp.h 36 37with Alloc; 38with Table; 39pragma Elaborate_All (Table); 40with Types; use Types; 41 42package Uintp is 43 44 ------------------------------------------------- 45 -- Basic Types and Constants for Uintp Package -- 46 ------------------------------------------------- 47 48 type Uint is private; 49 -- The basic universal integer type 50 51 No_Uint : constant Uint; 52 -- A constant value indicating a missing or unset Uint value 53 54 Uint_0 : constant Uint; 55 Uint_1 : constant Uint; 56 Uint_2 : constant Uint; 57 Uint_3 : constant Uint; 58 Uint_4 : constant Uint; 59 Uint_5 : constant Uint; 60 Uint_6 : constant Uint; 61 Uint_7 : constant Uint; 62 Uint_8 : constant Uint; 63 Uint_9 : constant Uint; 64 Uint_10 : constant Uint; 65 Uint_11 : constant Uint; 66 Uint_12 : constant Uint; 67 Uint_13 : constant Uint; 68 Uint_14 : constant Uint; 69 Uint_15 : constant Uint; 70 Uint_16 : constant Uint; 71 Uint_24 : constant Uint; 72 Uint_32 : constant Uint; 73 Uint_63 : constant Uint; 74 Uint_64 : constant Uint; 75 Uint_80 : constant Uint; 76 Uint_128 : constant Uint; 77 78 Uint_Minus_1 : constant Uint; 79 Uint_Minus_2 : constant Uint; 80 Uint_Minus_3 : constant Uint; 81 Uint_Minus_4 : constant Uint; 82 Uint_Minus_5 : constant Uint; 83 Uint_Minus_6 : constant Uint; 84 Uint_Minus_7 : constant Uint; 85 Uint_Minus_8 : constant Uint; 86 Uint_Minus_9 : constant Uint; 87 Uint_Minus_12 : constant Uint; 88 Uint_Minus_36 : constant Uint; 89 Uint_Minus_63 : constant Uint; 90 Uint_Minus_80 : constant Uint; 91 Uint_Minus_128 : constant Uint; 92 93 type UI_Vector is array (Pos range <>) of Int; 94 -- Vector containing the integer values of a Uint value 95 96 -- Note: An earlier version of this package used pointers of arrays of Ints 97 -- (dynamically allocated) for the Uint type. The change leads to a few 98 -- less natural idioms used throughout this code, but eliminates all uses 99 -- of the heap except for the table package itself. For example, Uint 100 -- parameters are often converted to UI_Vectors for internal manipulation. 101 -- This is done by creating the local UI_Vector using the function N_Digits 102 -- on the Uint to find the size needed for the vector, and then calling 103 -- Init_Operand to copy the values out of the table into the vector. 104 105 ----------------- 106 -- Subprograms -- 107 ----------------- 108 109 procedure Initialize; 110 -- Initialize Uint tables. Note that Initialize must not be called if 111 -- Tree_Read is used. Note also that there is no lock routine in this 112 -- unit, these are among the few tables that can be expanded during 113 -- gigi processing. 114 115 procedure Tree_Read; 116 -- Initializes internal tables from current tree file using the relevant 117 -- Table.Tree_Read routines. Note that Initialize should not be called if 118 -- Tree_Read is used. Tree_Read includes all necessary initialization. 119 120 procedure Tree_Write; 121 -- Writes out internal tables to current tree file using the relevant 122 -- Table.Tree_Write routines. 123 124 function UI_Abs (Right : Uint) return Uint; 125 pragma Inline (UI_Abs); 126 -- Returns abs function of universal integer 127 128 function UI_Add (Left : Uint; Right : Uint) return Uint; 129 function UI_Add (Left : Int; Right : Uint) return Uint; 130 function UI_Add (Left : Uint; Right : Int) return Uint; 131 -- Returns sum of two integer values 132 133 function UI_Decimal_Digits_Hi (U : Uint) return Nat; 134 -- Returns an estimate of the number of decimal digits required to 135 -- represent the absolute value of U. This estimate is correct or high, 136 -- i.e. it never returns a value that is too low. The accuracy of the 137 -- estimate affects only the effectiveness of comparison optimizations 138 -- in Urealp. 139 140 function UI_Decimal_Digits_Lo (U : Uint) return Nat; 141 -- Returns an estimate of the number of decimal digits required to 142 -- represent the absolute value of U. This estimate is correct or low, 143 -- i.e. it never returns a value that is too high. The accuracy of the 144 -- estimate affects only the effectiveness of comparison optimizations 145 -- in Urealp. 146 147 function UI_Div (Left : Uint; Right : Uint) return Uint; 148 function UI_Div (Left : Int; Right : Uint) return Uint; 149 function UI_Div (Left : Uint; Right : Int) return Uint; 150 -- Returns quotient of two integer values. Fatal error if Right = 0 151 152 function UI_Eq (Left : Uint; Right : Uint) return Boolean; 153 function UI_Eq (Left : Int; Right : Uint) return Boolean; 154 function UI_Eq (Left : Uint; Right : Int) return Boolean; 155 pragma Inline (UI_Eq); 156 -- Compares integer values for equality 157 158 function UI_Expon (Left : Uint; Right : Uint) return Uint; 159 function UI_Expon (Left : Int; Right : Uint) return Uint; 160 function UI_Expon (Left : Uint; Right : Int) return Uint; 161 function UI_Expon (Left : Int; Right : Int) return Uint; 162 -- Returns result of exponentiating two integer values. 163 -- Fatal error if Right is negative. 164 165 function UI_GCD (Uin, Vin : Uint) return Uint; 166 -- Computes GCD of input values. Assumes Uin >= Vin >= 0 167 168 function UI_Ge (Left : Uint; Right : Uint) return Boolean; 169 function UI_Ge (Left : Int; Right : Uint) return Boolean; 170 function UI_Ge (Left : Uint; Right : Int) return Boolean; 171 pragma Inline (UI_Ge); 172 -- Compares integer values for greater than or equal 173 174 function UI_Gt (Left : Uint; Right : Uint) return Boolean; 175 function UI_Gt (Left : Int; Right : Uint) return Boolean; 176 function UI_Gt (Left : Uint; Right : Int) return Boolean; 177 pragma Inline (UI_Gt); 178 -- Compares integer values for greater than 179 180 function UI_Is_In_Int_Range (Input : Uint) return Boolean; 181 pragma Inline (UI_Is_In_Int_Range); 182 -- Determines if universal integer is in Int range 183 184 function UI_Le (Left : Uint; Right : Uint) return Boolean; 185 function UI_Le (Left : Int; Right : Uint) return Boolean; 186 function UI_Le (Left : Uint; Right : Int) return Boolean; 187 pragma Inline (UI_Le); 188 -- Compares integer values for less than or equal 189 190 function UI_Lt (Left : Uint; Right : Uint) return Boolean; 191 function UI_Lt (Left : Int; Right : Uint) return Boolean; 192 function UI_Lt (Left : Uint; Right : Int) return Boolean; 193 -- Compares integer values for less than 194 195 function UI_Max (Left : Uint; Right : Uint) return Uint; 196 function UI_Max (Left : Int; Right : Uint) return Uint; 197 function UI_Max (Left : Uint; Right : Int) return Uint; 198 -- Returns maximum of two integer values 199 200 function UI_Min (Left : Uint; Right : Uint) return Uint; 201 function UI_Min (Left : Int; Right : Uint) return Uint; 202 function UI_Min (Left : Uint; Right : Int) return Uint; 203 -- Returns minimum of two integer values 204 205 function UI_Mod (Left : Uint; Right : Uint) return Uint; 206 function UI_Mod (Left : Int; Right : Uint) return Uint; 207 function UI_Mod (Left : Uint; Right : Int) return Uint; 208 pragma Inline (UI_Mod); 209 -- Returns mod function of two integer values 210 211 function UI_Mul (Left : Uint; Right : Uint) return Uint; 212 function UI_Mul (Left : Int; Right : Uint) return Uint; 213 function UI_Mul (Left : Uint; Right : Int) return Uint; 214 -- Returns product of two integer values 215 216 function UI_Ne (Left : Uint; Right : Uint) return Boolean; 217 function UI_Ne (Left : Int; Right : Uint) return Boolean; 218 function UI_Ne (Left : Uint; Right : Int) return Boolean; 219 pragma Inline (UI_Ne); 220 -- Compares integer values for inequality 221 222 function UI_Negate (Right : Uint) return Uint; 223 pragma Inline (UI_Negate); 224 -- Returns negative of universal integer 225 226 function UI_Rem (Left : Uint; Right : Uint) return Uint; 227 function UI_Rem (Left : Int; Right : Uint) return Uint; 228 function UI_Rem (Left : Uint; Right : Int) return Uint; 229 -- Returns rem of two integer values 230 231 function UI_Sub (Left : Uint; Right : Uint) return Uint; 232 function UI_Sub (Left : Int; Right : Uint) return Uint; 233 function UI_Sub (Left : Uint; Right : Int) return Uint; 234 pragma Inline (UI_Sub); 235 -- Returns difference of two integer values 236 237 function UI_Modular_Exponentiation 238 (B : Uint; 239 E : Uint; 240 Modulo : Uint) return Uint; 241 -- Efficiently compute (B ** E) rem Modulo 242 243 function UI_Modular_Inverse (N : Uint; Modulo : Uint) return Uint; 244 -- Compute the multiplicative inverse of N in modular arithmetics with the 245 -- given Modulo (uses Euclid's algorithm). Note: the call is considered 246 -- to be erroneous (and the behavior is undefined) if n is not invertible. 247 248 function UI_From_Int (Input : Int) return Uint; 249 -- Converts Int value to universal integer form 250 251 function UI_From_CC (Input : Char_Code) return Uint; 252 -- Converts Char_Code value to universal integer form 253 254 function UI_To_Int (Input : Uint) return Int; 255 -- Converts universal integer value to Int. Fatal error if value is not in 256 -- appropriate range. 257 258 function UI_To_CC (Input : Uint) return Char_Code; 259 -- Converts universal integer value to Char_Code. Fatal error if value is 260 -- not in Char_Code range. 261 262 function Num_Bits (Input : Uint) return Nat; 263 -- Approximate number of binary bits in given universal integer. This 264 -- function is used for capacity checks, and it can be one bit off 265 -- without affecting its usage. 266 267 function Vector_To_Uint 268 (In_Vec : UI_Vector; 269 Negative : Boolean) return Uint; 270 -- Functions that calculate values in UI_Vectors, call this function to 271 -- create and return the Uint value. In_Vec contains the multiple precision 272 -- (Base) representation of a non-negative value. Leading zeroes are 273 -- permitted. Negative is set if the desired result is the negative of the 274 -- given value. The result will be either the appropriate directly 275 -- represented value, or a table entry in the proper canonical format is 276 -- created and returned. 277 -- 278 -- Note that Init_Operand puts a signed value in the result vector, but 279 -- Vector_To_Uint is always presented with a non-negative value. The 280 -- processing of signs is something that is done by the caller before 281 -- calling Vector_To_Uint. 282 283 --------------------- 284 -- Output Routines -- 285 --------------------- 286 287 type UI_Format is (Hex, Decimal, Auto); 288 -- Used to determine whether UI_Image/UI_Write output is in hexadecimal 289 -- or decimal format. Auto, the default setting, lets the routine make a 290 -- decision based on the value. 291 292 UI_Image_Max : constant := 48; -- Enough for a 128-bit number 293 UI_Image_Buffer : String (1 .. UI_Image_Max); 294 UI_Image_Length : Natural; 295 -- Buffer used for UI_Image as described below 296 297 procedure UI_Image (Input : Uint; Format : UI_Format := Auto); 298 -- Places a representation of Uint, consisting of a possible minus sign, 299 -- followed by the value in UI_Image_Buffer. The form of the value is an 300 -- integer literal in either decimal (no base) or hexadecimal (base 16) 301 -- format. If Hex is True on entry, then hex mode is forced, otherwise 302 -- UI_Image makes a guess at which output format is more convenient. 303 -- The value must fit in UI_Image_Buffer. If necessary, the result is an 304 -- approximation of the proper value, using an exponential format. The 305 -- image of No_Uint is output as a single question mark. 306 307 procedure UI_Write (Input : Uint; Format : UI_Format := Auto); 308 -- Writes a representation of Uint, consisting of a possible minus sign, 309 -- followed by the value to the output file. The form of the value is an 310 -- integer literal in either decimal (no base) or hexadecimal (base 16) 311 -- format as appropriate. UI_Format shows which format to use. Auto, the 312 -- default, asks UI_Write to make a guess at which output format will be 313 -- more convenient to read. 314 315 procedure pid (Input : Uint); 316 pragma Export (Ada, pid); 317 -- Writes representation of Uint in decimal with a terminating line 318 -- return. This is intended for use from the debugger. 319 320 procedure pih (Input : Uint); 321 pragma Export (Ada, pih); 322 -- Writes representation of Uint in hex with a terminating line return. 323 -- This is intended for use from the debugger. 324 325 ------------------------ 326 -- Operator Renamings -- 327 ------------------------ 328 329 function "+" (Left : Uint; Right : Uint) return Uint renames UI_Add; 330 function "+" (Left : Int; Right : Uint) return Uint renames UI_Add; 331 function "+" (Left : Uint; Right : Int) return Uint renames UI_Add; 332 333 function "/" (Left : Uint; Right : Uint) return Uint renames UI_Div; 334 function "/" (Left : Int; Right : Uint) return Uint renames UI_Div; 335 function "/" (Left : Uint; Right : Int) return Uint renames UI_Div; 336 337 function "*" (Left : Uint; Right : Uint) return Uint renames UI_Mul; 338 function "*" (Left : Int; Right : Uint) return Uint renames UI_Mul; 339 function "*" (Left : Uint; Right : Int) return Uint renames UI_Mul; 340 341 function "-" (Left : Uint; Right : Uint) return Uint renames UI_Sub; 342 function "-" (Left : Int; Right : Uint) return Uint renames UI_Sub; 343 function "-" (Left : Uint; Right : Int) return Uint renames UI_Sub; 344 345 function "**" (Left : Uint; Right : Uint) return Uint renames UI_Expon; 346 function "**" (Left : Uint; Right : Int) return Uint renames UI_Expon; 347 function "**" (Left : Int; Right : Uint) return Uint renames UI_Expon; 348 function "**" (Left : Int; Right : Int) return Uint renames UI_Expon; 349 350 function "abs" (Real : Uint) return Uint renames UI_Abs; 351 352 function "mod" (Left : Uint; Right : Uint) return Uint renames UI_Mod; 353 function "mod" (Left : Int; Right : Uint) return Uint renames UI_Mod; 354 function "mod" (Left : Uint; Right : Int) return Uint renames UI_Mod; 355 356 function "rem" (Left : Uint; Right : Uint) return Uint renames UI_Rem; 357 function "rem" (Left : Int; Right : Uint) return Uint renames UI_Rem; 358 function "rem" (Left : Uint; Right : Int) return Uint renames UI_Rem; 359 360 function "-" (Real : Uint) return Uint renames UI_Negate; 361 362 function "=" (Left : Uint; Right : Uint) return Boolean renames UI_Eq; 363 function "=" (Left : Int; Right : Uint) return Boolean renames UI_Eq; 364 function "=" (Left : Uint; Right : Int) return Boolean renames UI_Eq; 365 366 function ">=" (Left : Uint; Right : Uint) return Boolean renames UI_Ge; 367 function ">=" (Left : Int; Right : Uint) return Boolean renames UI_Ge; 368 function ">=" (Left : Uint; Right : Int) return Boolean renames UI_Ge; 369 370 function ">" (Left : Uint; Right : Uint) return Boolean renames UI_Gt; 371 function ">" (Left : Int; Right : Uint) return Boolean renames UI_Gt; 372 function ">" (Left : Uint; Right : Int) return Boolean renames UI_Gt; 373 374 function "<=" (Left : Uint; Right : Uint) return Boolean renames UI_Le; 375 function "<=" (Left : Int; Right : Uint) return Boolean renames UI_Le; 376 function "<=" (Left : Uint; Right : Int) return Boolean renames UI_Le; 377 378 function "<" (Left : Uint; Right : Uint) return Boolean renames UI_Lt; 379 function "<" (Left : Int; Right : Uint) return Boolean renames UI_Lt; 380 function "<" (Left : Uint; Right : Int) return Boolean renames UI_Lt; 381 382 ----------------------------- 383 -- Mark/Release Processing -- 384 ----------------------------- 385 386 -- The space used by Uint data is not automatically reclaimed. However, a 387 -- mark-release regime is implemented which allows storage to be released 388 -- back to a previously noted mark. This is used for example when doing 389 -- comparisons, where only intermediate results get stored that do not 390 -- need to be saved for future use. 391 392 type Save_Mark is private; 393 394 function Mark return Save_Mark; 395 -- Note mark point for future release 396 397 procedure Release (M : Save_Mark); 398 -- Release storage allocated since mark was noted 399 400 procedure Release_And_Save (M : Save_Mark; UI : in out Uint); 401 -- Like Release, except that the given Uint value (which is typically among 402 -- the data being released) is recopied after the release, so that it is 403 -- the most recent item, and UI is updated to point to its copied location. 404 405 procedure Release_And_Save (M : Save_Mark; UI1, UI2 : in out Uint); 406 -- Like Release, except that the given Uint values (which are typically 407 -- among the data being released) are recopied after the release, so that 408 -- they are the most recent items, and UI1 and UI2 are updated if necessary 409 -- to point to the copied locations. This routine is careful to do things 410 -- in the right order, so that the values do not clobber one another. 411 412 ----------------------------------- 413 -- Representation of Uint Values -- 414 ----------------------------------- 415 416private 417 418 type Uint is new Int range Uint_Low_Bound .. Uint_High_Bound; 419 for Uint'Size use 32; 420 421 No_Uint : constant Uint := Uint (Uint_Low_Bound); 422 423 -- Uint values are represented as multiple precision integers stored in 424 -- a multi-digit format using Base as the base. This value is chosen so 425 -- that the product Base*Base is within the range of allowed Int values. 426 427 -- Base is defined to allow efficient execution of the primitive operations 428 -- (a0, b0, c0) defined in the section "The Classical Algorithms" 429 -- (sec. 4.3.1) of Donald Knuth's "The Art of Computer Programming", 430 -- Vol. 2. These algorithms are used in this package. In particular, 431 -- the product of two single digits in this base fits in a 32-bit integer. 432 433 Base_Bits : constant := 15; 434 -- Number of bits in base value 435 436 Base : constant Int := 2 ** Base_Bits; 437 438 -- Values in the range -(Base-1) .. Max_Direct are encoded directly as 439 -- Uint values by adding a bias value. The value of Max_Direct is chosen 440 -- so that a directly represented number always fits in two digits when 441 -- represented in base format. 442 443 Min_Direct : constant Int := -(Base - 1); 444 Max_Direct : constant Int := (Base - 1) * (Base - 1); 445 446 -- The following values define the bias used to store Uint values which 447 -- are in this range, as well as the biased values for the first and last 448 -- values in this range. We use a new derived type for these constants to 449 -- avoid accidental use of Uint arithmetic on these values, which is never 450 -- correct. 451 452 type Ctrl is range Int'First .. Int'Last; 453 454 Uint_Direct_Bias : constant Ctrl := Ctrl (Uint_Low_Bound) + Ctrl (Base); 455 Uint_Direct_First : constant Ctrl := Uint_Direct_Bias + Ctrl (Min_Direct); 456 Uint_Direct_Last : constant Ctrl := Uint_Direct_Bias + Ctrl (Max_Direct); 457 458 Uint_0 : constant Uint := Uint (Uint_Direct_Bias); 459 Uint_1 : constant Uint := Uint (Uint_Direct_Bias + 1); 460 Uint_2 : constant Uint := Uint (Uint_Direct_Bias + 2); 461 Uint_3 : constant Uint := Uint (Uint_Direct_Bias + 3); 462 Uint_4 : constant Uint := Uint (Uint_Direct_Bias + 4); 463 Uint_5 : constant Uint := Uint (Uint_Direct_Bias + 5); 464 Uint_6 : constant Uint := Uint (Uint_Direct_Bias + 6); 465 Uint_7 : constant Uint := Uint (Uint_Direct_Bias + 7); 466 Uint_8 : constant Uint := Uint (Uint_Direct_Bias + 8); 467 Uint_9 : constant Uint := Uint (Uint_Direct_Bias + 9); 468 Uint_10 : constant Uint := Uint (Uint_Direct_Bias + 10); 469 Uint_11 : constant Uint := Uint (Uint_Direct_Bias + 11); 470 Uint_12 : constant Uint := Uint (Uint_Direct_Bias + 12); 471 Uint_13 : constant Uint := Uint (Uint_Direct_Bias + 13); 472 Uint_14 : constant Uint := Uint (Uint_Direct_Bias + 14); 473 Uint_15 : constant Uint := Uint (Uint_Direct_Bias + 15); 474 Uint_16 : constant Uint := Uint (Uint_Direct_Bias + 16); 475 Uint_24 : constant Uint := Uint (Uint_Direct_Bias + 24); 476 Uint_32 : constant Uint := Uint (Uint_Direct_Bias + 32); 477 Uint_63 : constant Uint := Uint (Uint_Direct_Bias + 63); 478 Uint_64 : constant Uint := Uint (Uint_Direct_Bias + 64); 479 Uint_80 : constant Uint := Uint (Uint_Direct_Bias + 80); 480 Uint_128 : constant Uint := Uint (Uint_Direct_Bias + 128); 481 482 Uint_Minus_1 : constant Uint := Uint (Uint_Direct_Bias - 1); 483 Uint_Minus_2 : constant Uint := Uint (Uint_Direct_Bias - 2); 484 Uint_Minus_3 : constant Uint := Uint (Uint_Direct_Bias - 3); 485 Uint_Minus_4 : constant Uint := Uint (Uint_Direct_Bias - 4); 486 Uint_Minus_5 : constant Uint := Uint (Uint_Direct_Bias - 5); 487 Uint_Minus_6 : constant Uint := Uint (Uint_Direct_Bias - 6); 488 Uint_Minus_7 : constant Uint := Uint (Uint_Direct_Bias - 7); 489 Uint_Minus_8 : constant Uint := Uint (Uint_Direct_Bias - 8); 490 Uint_Minus_9 : constant Uint := Uint (Uint_Direct_Bias - 9); 491 Uint_Minus_12 : constant Uint := Uint (Uint_Direct_Bias - 12); 492 Uint_Minus_36 : constant Uint := Uint (Uint_Direct_Bias - 36); 493 Uint_Minus_63 : constant Uint := Uint (Uint_Direct_Bias - 63); 494 Uint_Minus_80 : constant Uint := Uint (Uint_Direct_Bias - 80); 495 Uint_Minus_128 : constant Uint := Uint (Uint_Direct_Bias - 128); 496 497 Uint_Max_Simple_Mul : constant := Uint_Direct_Bias + 2 ** 15; 498 -- If two values are directly represented and less than or equal to this 499 -- value, then we know the product fits in a 32-bit integer. This allows 500 -- UI_Mul to efficiently compute the product in this case. 501 502 type Save_Mark is record 503 Save_Uint : Uint; 504 Save_Udigit : Int; 505 end record; 506 507 -- Values outside the range that is represented directly are stored using 508 -- two tables. The secondary table Udigits contains sequences of Int values 509 -- consisting of the digits of the number in a radix Base system. The 510 -- digits are stored from most significant to least significant with the 511 -- first digit only carrying the sign. 512 513 -- There is one entry in the primary Uints table for each distinct Uint 514 -- value. This table entry contains the length (number of digits) and 515 -- a starting offset of the value in the Udigits table. 516 517 Uint_First_Entry : constant Uint := Uint (Uint_Table_Start); 518 519 -- Some subprograms defined in this package manipulate the Udigits table 520 -- directly, while for others it is more convenient to work with locally 521 -- defined arrays of the digits of the Universal Integers. The type 522 -- UI_Vector is defined for this purpose and some internal subprograms 523 -- used for converting from one to the other are defined. 524 525 type Uint_Entry is record 526 Length : Pos; 527 -- Length of entry in Udigits table in digits (i.e. in words) 528 529 Loc : Int; 530 -- Starting location in Udigits table of this Uint value 531 end record; 532 533 package Uints is new Table.Table ( 534 Table_Component_Type => Uint_Entry, 535 Table_Index_Type => Uint'Base, 536 Table_Low_Bound => Uint_First_Entry, 537 Table_Initial => Alloc.Uints_Initial, 538 Table_Increment => Alloc.Uints_Increment, 539 Table_Name => "Uints"); 540 541 package Udigits is new Table.Table ( 542 Table_Component_Type => Int, 543 Table_Index_Type => Int, 544 Table_Low_Bound => 0, 545 Table_Initial => Alloc.Udigits_Initial, 546 Table_Increment => Alloc.Udigits_Increment, 547 Table_Name => "Udigits"); 548 549 -- Note: the reason these tables are defined here in the private part of 550 -- the spec, rather than in the body, is that they are referenced directly 551 -- by gigi. 552 553end Uintp; 554