gnu-efi/lib/aarch64/math.c

   1 /*
   2  * Copright (C) 2014 Linaro Ltd.
   3  * Author: Ard Biesheuvel <ard.biesheuvel@linaro.org>
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice and this list of conditions, without modification.
  10  * 2. The name of the author may not be used to endorse or promote products
  11  *    derived from this software without specific prior written permission.
  12  *
  13  * Alternatively, this software may be distributed under the terms of the
  14  * GNU General Public License as published by the Free Software Foundation;
  15  * either version 2 of the License, or (at your option) any later version.
  16  */
  17
  18 #include "lib.h"
  19
  20 UINT64
  21 LShiftU64 (
  22     IN UINT64   Operand,
  23     IN UINTN    Count
  24     )
  25 // Left shift 64bit by 32bit and get a 64bit result
  26 {
  27     return Operand << Count;
  28 }
  29
  30 UINT64
  31 RShiftU64 (
  32     IN UINT64   Operand,
  33     IN UINTN    Count
  34     )
  35 // Right shift 64bit by 32bit and get a 64bit result
  36 {
  37     return Operand >> Count;
  38 }
  39
  40
  41 UINT64
  42 MultU64x32 (
  43     IN UINT64   Multiplicand,
  44     IN UINTN    Multiplier
  45     )
  46 // Multiple 64bit by 32bit and get a 64bit result
  47 {
  48     return Multiplicand * Multiplier;
  49 }
  50
  51 UINT64
  52 DivU64x32 (
  53     IN UINT64   Dividend,
  54     IN UINTN    Divisor,
  55     OUT UINTN   *Remainder OPTIONAL
  56     )
  57 // divide 64bit by 32bit and get a 64bit result
  58 // N.B. only works for 31bit divisors!!
  59 {
  60     if (Remainder)
  61         *Remainder = Dividend % Divisor;
  62     return Dividend / Divisor;
  63 }