;*****************************************************************************
;*
;* Open Watcom Project
;*
;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
;*
;* ========================================================================
;*
;* This file contains Original Code and/or Modifications of Original
;* Code as defined in and that are subject to the Sybase Open Watcom
;* Public License version 1.0 (the 'License'). You may not use this file
;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
;* provided with the Original Code and Modifications, and is also
;* available at www.sybase.com/developer/opensource.
;*
;* The Original Code and all software distributed under the License are
;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
;* NON-INFRINGEMENT. Please see the License for the specific language
;* governing rights and limitations under the License.
;*
;* ========================================================================
;*
;* Description: WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
;* DESCRIBE IT HERE!
;*
;*****************************************************************************
include mdef.inc
include struct.inc
.8087
modstart _7fu8386
xdefp __FSU87
xdefp __FDU87
defpe __FSU87
sub esp,12
mov [esp],eax
fld dword ptr [esp]
jmp short convert
defpe __FDU87
sub esp,12
mov [esp],eax
mov 4[esp],edx
fld qword ptr [esp]
; fall through
convert:
push ecx
fstp tbyte ptr 4[esp] ; get number out in memory
mov ax,12[esp] ; pick up sign/exponent
and ax,7fffh ; isolate exponent
sub ax,16383 ; remove bias
jl ret_zero ; if less than .5, return zero
cmp ax,64 ; are we too big?
jae ret_inf ; if so, return infinity
mov cl,63 ; calculate shift count
sub cl,al ; ...
mov eax,4[esp] ; pick up mantissa
mov edx,8[esp] ; ...
je negate ; skip out if no shifting
L2:
shr edx,1 ; shift down one bit
rcr eax,1 ; ...
dec cl ; are we done?
jne L2 ; do it again if not
negate:
test byte ptr 13[esp],80h ; is number negative?
jns done ; if not, we're done
neg edx ; negate number
neg eax ; ...
sbb edx,0 ; ...
done:
pop ecx ; ...
add esp,12 ; outta here
ret ; ...
ret_zero:
xor edx,edx
xor eax,eax
jmp done
ret_inf:
mov edx,0ffffffffh
mov eax,edx
jmp done
endproc __FDU87
endproc __FSU87
endmod
end