reactos/lib/sdk/crt/math/i386/allshl_asm.s

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS kernel
   4  * PURPOSE:           Run-Time Library
   5  * FILE:              lib/rtl/i386/allshl.S
   6  * PROGRAMER:         Alex Ionescu (alex@relsoft.net)
   7  *
   8  * Copyright (C) 2002 Michael Ringgaard.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  *
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. Neither the name of the project nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES// LOSS OF USE, DATA, OR PROFITS// OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 .globl __allshl
  38
  39 .intel_syntax noprefix
  40
  41 /* FUNCTIONS ***************************************************************/
  42
  43 //
  44 // llshl - long shift left
  45 //
  46 // Purpose:
  47 //       Does a Long Shift Left (signed and unsigned are identical)
  48 //       Shifts a long left any number of bits.
  49 //
  50 // Entry:
  51 //       EDX:EAX - long value to be shifted
  52 //       CL      - number of bits to shift by
  53 //
  54 // Exit:
  55 //       EDX:EAX - shifted value
  56 //
  57 // Uses:
  58 //       CL is destroyed.
  59 //
  60
  61 __allshl:
  62
  63 //
  64 // Handle shifts of 64 or more bits (all get 0)
  65 //
  66         cmp     cl, 64
  67         jae     short RETZERO
  68
  69 //
  70 // Handle shifts of between 0 and 31 bits
  71 //
  72         cmp     cl, 32
  73         jae     short MORE32
  74         shld    edx,eax,cl
  75         shl     eax,cl
  76         ret
  77
  78 //
  79 // Handle shifts of between 32 and 63 bits
  80 //
  81 MORE32:
  82         mov     edx,eax
  83         xor     eax,eax
  84         and     cl,31
  85         shl     edx,cl
  86         ret
  87
  88 //
  89 // return 0 in edx:eax
  90 //
  91 RETZERO:
  92         xor     eax,eax
  93         xor     edx,edx
  94         ret