sdcc/device/lib/_fsget1arg.c

   1 /*-------------------------------------------------------------------------
   2    _fsget1arg.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 #define __SDCC_FLOAT_LIB
  31 #include <float.h>
  32
  33
  34 #ifdef FLOAT_ASM_MCS51
  35
  36 static void dummy(void) __naked
  37 {
  38         // input passed in a,b,dph,dpl
  39         __asm
  40         .globl  fsgetarg
  41 fsgetarg:
  42         // extract the input, placing it into:
  43         //      sign     exponent   mantissa
  44         //      ----     --------   --------
  45         //  a:  sign_a   exp_a      r4/r3/r2
  46         //
  47         mov     r2, dpl
  48         mov     r3, dph
  49         mov     c, b.7
  50         rlc     a
  51         mov     sign_a, c
  52         mov     exp_a, a
  53         jz      00001$
  54         setb    b.7
  55 00001$:
  56         mov     r4, b
  57         ret
  58         __endasm;
  59 }
  60
  61 #endif