mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-29 01:39:41 +03:00
103 lines
4.2 KiB
NASM
103 lines
4.2 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 i8fs386
|
|
|
|
xref __I8LS
|
|
xref __I8RS
|
|
|
|
; Convert signed 64-bit integer to single precision float
|
|
; Input: [EDX, EAX] = 64-bit integer
|
|
; Output: [EAX] = 32-bit float
|
|
|
|
xdefp __I8FS
|
|
defp __I8FS
|
|
or EDX,EDX ; check sign
|
|
jns __U8FS ; if positive, just convert
|
|
neg EDX ;
|
|
neg EAX ; take absolute value of number
|
|
sbb EDX,0 ;
|
|
call __U8FS ; convert to FS
|
|
or EAX,80000000h ; set sign bit on
|
|
ret ; return
|
|
endproc __I8FS
|
|
|
|
; Convert unsigned 64-bit integer to single precision float
|
|
; Input: [EDX, EAX] = 64-bit integer
|
|
; Output: [EAX] = 32-bit float
|
|
|
|
xdefp __U8FS
|
|
defp __U8FS
|
|
or EAX,EAX ; if lo is zero
|
|
_if e ;
|
|
or EDX,EDX ; and if hi is zero
|
|
_if e ;
|
|
ret ; - return
|
|
_endif
|
|
_endif ; endif
|
|
push ECX ; save ECX
|
|
push EBX ; save EBX
|
|
bsr ECX,EDX ; find most significant non-zero bit in hi
|
|
_if e ; if all zero bits
|
|
bsr ECX,EAX ; - find most significant non-zero bit in lo
|
|
_else ; else
|
|
add CL,32 ; - adjust shift count since hi was not 0
|
|
_endif ; endif
|
|
push ECX ; save shift count
|
|
neg CL ; calculate # of bits to shift by
|
|
add CL,63-8 ; ...
|
|
mov EBX,ECX ; set up for call
|
|
or CL,CL ; if mantissa should move left
|
|
_if ge ; then
|
|
call __I8LS ; - shift left
|
|
_else ; else
|
|
neg BL ; - make positive
|
|
call __I8RS ; - shift right
|
|
_endif ; endif
|
|
pop ECX ; restore shift count
|
|
and EDX,007FFFFFh ; mask out sign and exponent bits
|
|
add CL,127 ; calculate exponent (excess 127)
|
|
; and ECX,0FFh ; isolate exponent (not required)
|
|
shl ECX,23 ; shift exponent into position
|
|
or EDX,ECX ; place into result
|
|
mov EAX,EDX ; single precision is only 32 bits
|
|
pop EBX ; restore EBX
|
|
pop ECX ; restore ECX
|
|
ret ; return
|
|
endproc __U8FS
|
|
|
|
endmod
|
|
end
|