sdcc/device/lib/_srslonglong.c

   1 /*-------------------------------------------------------------------------
   2    _srslonglong.c - routine for shift right of 64 bit signed long long
   3
   4    Copyright (C) 2012, Philipp Klaus Krause . philipp@informatik.uni-frankfurt.de
   5
   6    This library is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any
   9    later version.
  10
  11    This library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this library; see the file COPYING. If not, write to the
  18    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19    MA 02110-1301, USA.
  20
  21    As a special exception, if you link this library with other files,
  22    some of which are compiled with SDCC, to produce an executable,
  23    this library does not by itself cause the resulting executable to
  24    be covered by the GNU General Public License. This exception does
  25    not however invalidate any other reasons why the executable file
  26    might be covered by the GNU General Public License.
  27 -------------------------------------------------------------------------*/
  28
  29 #include <stdint.h>
  30
  31 #include <stdbit.h>
  32
  33 #include <sdcc-lib.h>
  34
  35 #ifdef __SDCC_LONGLONG
  36
  37 #if __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_BIG__
  38 long long _srslonglong(long long l, char s) __SDCC_NONBANKED
  39 {
  40      int32_t * const top =    ( int32_t *)((char *)(&l) + 0);
  41     uint32_t * const middle = (uint32_t *)((char *)(&l) + 2);
  42     uint32_t * const bottom = (uint32_t *)((char *)(&l) + 4);
  43     uint16_t * const w =      (uint16_t *)(&l);
  44
  45     for (; s >= 16; s-= 16)
  46     {
  47         w[3] = w[2];
  48         w[2] = w[1];
  49         w[1] = w[0];
  50         w[0] = (w[0] & 0x8000) ? 0xffff : 0x000000;
  51     }
  52
  53     (*bottom) >>= s;
  54     (*middle) |= (((*middle & 0xffff0000ul) >> s) & 0x0000fffful);
  55     (*top) >>= s;
  56
  57     return(l);
  58 }
  59 #elif __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_LITTLE__
  60 long long _srslonglong(long long l, char s) __SDCC_NONBANKED
  61 {
  62     _AUTOMEM  int32_t * const top =    (_AUTOMEM  int32_t *)((_AUTOMEM char *)(&l) + 4);
  63     _AUTOMEM uint32_t * const middle = (_AUTOMEM uint32_t *)((_AUTOMEM char *)(&l) + 2);
  64     _AUTOMEM uint32_t * const bottom = (_AUTOMEM uint32_t *)((_AUTOMEM char *)(&l) + 0);
  65     _AUTOMEM uint16_t * const w =      (_AUTOMEM uint16_t *)(&l);
  66
  67     for (; s >= 16; s-= 16)
  68     {
  69         w[0] = w[1];
  70         w[1] = w[2];
  71         w[2] = w[3];
  72         w[3] = (w[3] & 0x8000) ? 0xffff : 0x000000;
  73     }
  74
  75     (*bottom) >>= s;
  76     (*middle) |= (((*middle & 0xffff0000ul) >> s) & 0x0000fffful);
  77     (*top) >>= s;
  78
  79     return(l);
  80 }
  81 #else
  82 #error Support for mixed endiannness not implemented!
  83 #endif
  84
  85 #endif
  86