Quake-III-Arena

Quake III Arena GPL Source Release
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ftol.nasm (2949B)

      1 ;===========================================================================
      2 ;Copyright (C) 1999-2005 Id Software, Inc.
      3 ;
      4 ;This file is part of Quake III Arena source code.
      5 ;
      6 ;Quake III Arena source code is free software; you can redistribute it
      7 ;and/or modify it under the terms of the GNU General Public License as
      8 ;published by the Free Software Foundation; either version 2 of the License,
      9 ;or (at your option) any later version.
     10 ;
     11 ;Quake III Arena source code is distributed in the hope that it will be
     12 ;useful, 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 Foobar; if not, write to the Free Software
     18 ;Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
     19 ;===========================================================================
     20 
     21 ;
     22 ; qftol -- fast floating point to long conversion.
     23 ;
     24 
     25 segment .data
     26 
     27 temp    dd 0.0
     28 fpucw   dd 0
     29 
     30 ; Precision Control Field , 2 bits / 0x0300 
     31 ; PC24 0x0000   Single precision (24 bits). 
     32 ; PC53 0x0200   Double precision (53 bits). 
     33 ; PC64 0x0300   Extended precision (64 bits).
     34 
     35 ; Rounding Control Field, 2 bits / 0x0C00
     36 ; RCN  0x0000   Rounding to nearest (even). 
     37 ; RCD  0x0400   Rounding down (directed, minus). 
     38 ; RCU  0x0800   Rounding up (directed plus).
     39 ; RC0  0x0C00   Rounding towards zero (chop mode).
     40 
     41 
     42 ; rounding towards nearest (even)
     43 cw027F  dd 0x027F ; double precision
     44 cw037F  dd 0x037F ; extended precision
     45 
     46 ; rounding towards zero (chop mode)
     47 cw0E7F  dd 0x0E7F ; double precision
     48 cw0F7F  dd 0x0F7F ; extended precision
     49 
     50 
     51 segment .text
     52 
     53 ;
     54 ; int qftol( void ) - default control word
     55 ;
     56 
     57 global qftol
     58 
     59 qftol: 
     60         fistp dword [temp]
     61         mov eax, [temp]
     62         ret
     63 
     64 
     65 ;
     66 ; int qftol027F( void ) - DirectX FPU 
     67 ;
     68 
     69 global qftol027F
     70 
     71 qftol027F:
     72 	fnstcw [fpucw]
     73 	fldcw  [cw027F]  
     74         fistp dword [temp]
     75 	fldcw  [fpucw]
     76         mov eax, [temp]
     77         ret
     78 
     79 ;
     80 ; int qftol037F( void ) - Linux FPU 
     81 ;
     82 
     83 global qftol037F
     84 
     85 qftol037F:
     86 	fnstcw [fpucw]
     87 	fldcw  [cw037F]  
     88         fistp dword [temp]
     89 	fldcw  [fpucw]
     90         mov eax, [temp]
     91         ret
     92 
     93 
     94 ;
     95 ; int qftol0F7F( void ) - ANSI
     96 ;
     97 
     98 global qftol0F7F
     99 
    100 qftol0F7F:
    101 	fnstcw [fpucw]
    102 	fldcw  [cw0F7F]  
    103         fistp dword [temp]
    104 	fldcw  [fpucw]
    105         mov eax, [temp]
    106         ret
    107 
    108 ;
    109 ; int qftol0E7F( void ) 
    110 ;
    111 
    112 global qftol0E7F
    113 
    114 qftol0E7F:
    115 	fnstcw [fpucw]
    116 	fldcw  [cw0E7F]  
    117         fistp dword [temp]
    118 	fldcw  [fpucw]
    119         mov eax, [temp]
    120         ret
    121 
    122 
    123 
    124 ;
    125 ; long Q_ftol( float q )
    126 ;
    127 
    128 global Q_ftol
    129 
    130 Q_ftol:
    131         fld dword [esp+4]  
    132         fistp dword [temp]
    133         mov eax, [temp]
    134         ret
    135 
    136 
    137 ;
    138 ; long qftol0F7F( float q ) - Linux FPU 
    139 ;
    140 
    141 global Q_ftol0F7F
    142 
    143 Q_ftol0F7F:
    144 	fnstcw [fpucw]
    145 	fld dword [esp+4]  
    146 	fldcw  [cw0F7F]  
    147         fistp dword [temp]
    148 	fldcw  [fpucw]
    149         mov eax, [temp]
    150         ret
    151