83 lines
3.6 KiB
NASM
83 lines
3.6 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!
|
|
;*
|
|
;*****************************************************************************
|
|
|
|
|
|
;========================================================================
|
|
;== Name: I4FS, U4FS ==
|
|
;== Operation: Convert Integer types to single precision ==
|
|
;== Inputs: EAX, unsigned or signed integer ==
|
|
;== Outputs: EAX single precision floating point ==
|
|
;== Volatile: none ==
|
|
;== ==
|
|
;========================================================================
|
|
include mdef.inc
|
|
include struct.inc
|
|
|
|
modstart i4fs386
|
|
|
|
xdefp __I4FS
|
|
xdefp __U4FS
|
|
|
|
|
|
defpe __U4FS
|
|
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
|
|
neg CL ; - calculate # of bits to rotate by
|
|
add CL,23 ; - ...
|
|
and CL,1fh ; - just keep last 5 bits
|
|
rol EAX,CL ; - shift bits into position
|
|
and EAX,007FFFFFh ; - mask out sign and exponent bits
|
|
mov CL,CH ; - get shift count
|
|
add CL,7Fh ; - calculate exponent
|
|
and ECX,0FFh ; - isolate exponent
|
|
shl ECX,23 ; - shift exponent into position
|
|
or EAX,ECX ; - place into result
|
|
pop ECX ; - restore ECX
|
|
_endif ; endif
|
|
ret ; return
|
|
|
|
endproc __U4FS
|
|
|
|
defpe __I4FS
|
|
or EAX,EAX ; check sign
|
|
jns __U4FS ; if positive, just convert
|
|
neg EAX ; take absolute value of number
|
|
call __U4FS ; convert to FS
|
|
or EAX,80000000h ; set sign bit on
|
|
ret ; and return
|
|
endproc __I4FS
|
|
|
|
endmod
|
|
end
|