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