forked from KolibriOS/kolibrios
91 lines
3.7 KiB
NASM
91 lines
3.7 KiB
NASM
|
;*****************************************************************************
|
||
|
;*
|
||
|
;* 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
|
||
|
|
||
|
modstart i4fd386
|
||
|
|
||
|
xdefp __I4FD
|
||
|
xdefp __U4FD
|
||
|
|
||
|
;[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
|
||
|
;[]
|
||
|
;[] __I4FD convert signed 32-bit integer in EAX into double float
|
||
|
;[] __U4FD convert unsigned 32-bit integer in EAX into double float
|
||
|
;[] Input: EAX - 32-bit integer
|
||
|
;[] Output: EDX:EAX - double precision representation of integer
|
||
|
;[]
|
||
|
;[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
|
||
|
|
||
|
defpe __I4FD
|
||
|
or EAX,EAX ; if number is negative
|
||
|
_if s ; then
|
||
|
neg EAX ; - negate number
|
||
|
mov EDX,00000BFFh ; - set exponent
|
||
|
_else ; else
|
||
|
|
||
|
; convert unsigned 32-bit integer to double
|
||
|
|
||
|
defpe __U4FD
|
||
|
mov EDX,000003FFh ; - set exponent
|
||
|
_endif ; endif
|
||
|
or EAX,EAX ; if number is not zero
|
||
|
_if ne ; then
|
||
|
push ECX ; - save ECX
|
||
|
bsr ECX,EAX ; - find most significant non-zero bit
|
||
|
mov CH,CL ; - save shift count
|
||
|
mov CL,31 ; - calculate # of bits to shift by
|
||
|
sub CL,CH ; - ...
|
||
|
shl EAX,CL ; - shift bits into position
|
||
|
_shl EAX,1 ; - one more to get rid of implied 1 bit
|
||
|
mov CL,CH ; - get shift count
|
||
|
movzx ECX,CH ; - get shift count
|
||
|
add ECX,EDX ; - calculate exponent
|
||
|
mov EDX,EAX ; - get the bits
|
||
|
and EDX,0FFFFF000h ; - keep 20 bits
|
||
|
or EDX,ECX ; - get exponent in there
|
||
|
ror EDX,12 ; - rotate into position
|
||
|
shl EAX,20 ; - get last 12 bits into place
|
||
|
pop ECX ; - restore ECX
|
||
|
ret ; - return
|
||
|
_endif ; endif
|
||
|
sub EDX,EDX ; zero EDX
|
||
|
ret ; return
|
||
|
|
||
|
endproc __U4FD
|
||
|
endproc __I4FD
|
||
|
|
||
|
endmod
|
||
|
end
|