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  1. /*-------------------------------------------------------------------------
  2.    _fsreturnval.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.  
  41.         .globl  fs_round_and_return
  42. fs_round_and_return:
  43. #ifdef FLOAT_FULL_ACCURACY
  44.         // discard the extra 8 bits of precision we kept around in r1
  45.         cjne    r1, #128, 00001$
  46.         mov     a, r2
  47.         rrc     a
  48.         cpl     c
  49. 00001$:
  50.         jc      fs_zerocheck_return
  51.         mov     a, r2
  52.         add     a, #1
  53.         mov     r2, a
  54.         clr     a
  55.         addc    a, r3
  56.         mov     r3, a
  57.         clr     a
  58.         addc    a, r4
  59.         mov     r4, a
  60.         jnc     fs_zerocheck_return
  61.         mov     r4, #0x80
  62.         inc     exp_a
  63. #endif
  64.  
  65.         .globl  fs_zerocheck_return
  66. fs_zerocheck_return:
  67.         // zero output is a special case
  68.         cjne    r4, #0, fs_direct_return
  69.         cjne    r3, #0, fs_direct_return
  70.         cjne    r2, #0, fs_direct_return
  71.  
  72.         .globl  fs_return_zero
  73. fs_return_zero:
  74.         clr     a
  75.         mov     b, a
  76.         mov     dph, a
  77.         mov     dpl, a
  78.         ret
  79.  
  80.         .globl  fs_direct_return
  81. fs_direct_return:
  82.         // collect all pieces and return
  83.         mov     c, sign_a
  84.         mov     a, exp_a
  85.         rrc     a
  86.         mov     b, r4
  87.         mov     b.7, c
  88.         mov     dph, r3
  89.         mov     dpl, r2
  90.         ret
  91.  
  92.         .globl  fs_return_inf
  93. fs_return_inf:
  94.         clr     a
  95.         mov     dph, a
  96.         mov     dpl, a
  97.         mov     b, #0x80
  98.         cpl     a
  99.         mov     c, sign_a
  100.         rrc     a
  101.         ret
  102.  
  103.         .globl  fs_return_nan
  104. fs_return_nan:
  105.         clr     a
  106.         mov     dph, a
  107.         mov     dpl, a
  108.         mov     b, #0xC0
  109.         mov     a, #0x7F
  110.         ret
  111.  
  112.         __endasm;
  113. }
  114.  
  115. #endif
  116.