sdcc/device/lib/_fsget2args.c

   1 /*-------------------------------------------------------------------------
   2    _fsget2args.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         // arg1: passed in a,b,dph,dpl
  40         // arg2: passed on stack
  41         __asm
  42         .globl  fsgetargs
  43 fsgetargs:
  44         // extract the two inputs, placing them into:
  45         //      sign     exponent   mantissa
  46         //      ----     --------   --------
  47         //  a:  sign_a   exp_a      r4/r3/r2
  48         //  b:  sign_b   exp_b      r7/r6/r5
  49         //
  50         mov     r2, dpl
  51         mov     r3, dph
  52         mov     c, b.7
  53         rlc     a
  54         mov     sign_a, c
  55         mov     exp_a, a
  56         jz      00001$
  57         setb    b.7
  58 00001$:
  59         mov     r4, b
  60         // now extract the 2nd parameter from the stack
  61         mov     a, sp
  62         add     a, #249
  63         mov     r0, a
  64         mov     a, @r0
  65         mov     r5, a
  66         inc     r0
  67         mov     a, @r0
  68         mov     r6, a
  69         inc     r0
  70         mov     b, @r0
  71         inc     r0
  72         mov     a, @r0
  73         mov     c, b.7
  74         rlc     a
  75         mov     sign_b, c
  76         mov     exp_b, a
  77         jz      00002$
  78         setb    b.7
  79 00002$:
  80         mov     r7, b
  81         ret
  82         __endasm;
  83 }
  84
  85 #endif