sdcc/device/lib/_fsswapargs.c

   1 /*-------------------------------------------------------------------------
   2    _fsswapargs.c - Floating point library in optimized assembly for 8051
   3
   4    Copyright (c) 2004, Paul Stoffregen, paul@pjrc.com
   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
  30
  31 #define __SDCC_FLOAT_LIB
  32 #include <float.h>
  33
  34
  35 #ifdef FLOAT_ASM_MCS51
  36
  37 static void dummy(void) __naked
  38 {
  39         __asm
  40         .globl  fs_swap_a_b
  41 fs_swap_a_b:
  42         mov     a, exp_a
  43         xch     a, exp_b
  44         mov     exp_a, a
  45         // is there a faster way to swap these 2 bits???
  46         // this trick with psw can play havoc with the resiter bank setting
  47         // mov  a, psw
  48         // swap a               // depends on sign bits in psw.1 & psw.5
  49         // mov  psw, a
  50         mov     c, sign_a
  51         rlc     a
  52         mov     c, sign_b
  53         mov     sign_a, c
  54         rrc     a
  55         mov     sign_b, c
  56         mov     a, r4
  57         xch     a, r7
  58         mov     r4, a
  59         mov     a, r3
  60         xch     a, r6
  61         mov     r3, a
  62         mov     a, r2
  63         xch     a, r5
  64         mov     r2, a
  65         ret
  66         __endasm;
  67 }
  68
  69 #endif