;*****************************************************************************
;*
;* 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: FSI4, FSU4, FSI2, FSU2, FSI1, FSU1 ==
;== Operation: Convert single precision to integer ==
;== Inputs: EAX single precision floating point ==
;== Outputs: EAX integer value ==
;== Volatile: none ==
;== ==
;== ==
;== handle -1.0 -> 0xffffffff ==
;========================================================================
include mdef.inc
include struct.inc
modstart fsi4386
xdefp __FSI4
xdefp __FSU4
xdefp __FSI2
xdefp __FSU2
xdefp __FSI1
xdefp __FSU1
defpe __FSI4
push ECX ; save cx
mov cl,7fh+31 ; maximum number 2^31-1
call __FSI ; convert to integer
pop ECX ; restore cx
ret ; return (overflow already handled
endproc __FSI4
defpe __FSU4
push ECX ; save cx
mov cl,7fh+32 ; maximum number 2^32-1
call __FSU ; convert to integer
pop ECX ; restore cx
ret ; return if no overflow
endproc __FSU4
defpe __FSI2
push ECX ; save cx
mov cl,7fh+15 ; maximum number 2^15-1
call __FSI ; convert to integer
pop ECX ; restore cx
ret ; return (overflow already handled
endproc __FSI2
defpe __FSU2
push ECX ; save cx
mov cl,7fh+16 ; maximum number 2^16-1
call __FSU ; convert to integer
pop ECX ; restore cx
ret ; return if no overflow
endproc __FSU2
defpe __FSI1
push ECX ; save cx
mov cl,7fh+7 ; maximum number 2^7-1
call __FSI ; convert to integer
pop ECX ; restore cx
ret ; return (overflow already handled
endproc __FSI1
defpe __FSU1
push ECX ; save cx
mov cl,7fh+8 ; maximum number 2^8-1
call __FSU ; convert to integer
pop ECX ; restore cx
ret ; return if no overflow
endproc __FSU1
__FSI proc near
__FSU:
or EAX,EAX ; check sign bit
jns short __FSAbs ; treat as unsigned if positive
call __FSAbs ; otherwise convert number
neg EAX ; negate the result
ret ; and return
endproc __FSI
; 18-nov-87 AFS (for WATCOM C)
;__FSU proc near
; jmp
; or dx,dx ; check sign bit
; jns __FSAbs ; just convert if positive
; sub ax,ax ; return 0 if negative
; sub dx,dx ; ...
; ret
; endproc __FSU
;========================================================================
;== Name: FSAbs_ ==
;== Inputs: EAX float ==
;== CL maximum exponent excess $7f ==
;== Outputs: EAX integer, absolute value of float ==
;== if exponent >= maximum then 2^max - 1 ==
;== returned ==
;========================================================================
__FSAbs proc near
or EAX,EAX ; check if number 0
je short retzero ; if so, just return it
_shl EAX,1 ; shift mantissa over
rol EAX,8 ; get exponent to bottom
cmp AL,7fh ; quit if number < 1.0 15-apr-91
jb short uflow ; ...
mov CH,AL ; save exponent
stc ; set carry for implied bit
rcr EAX,1 ; put implied '1' bit in
shr EAX,8 ; remove exponent
cmp CH,CL ; check if exponent exceeds maximum
jae short retmax ; return maximum value if so
sub CH,7fh+23 ; calculate amount to shift (+ve -> left)
jae short m_left ; jump if left shift/no shift
xchg CH,CL ; get shift count
neg CL ; make positive
shr EAX,CL ; shift mantissa
ret ; return with number
m_left:
_if ne ; done if exponent exactly 23
mov CL,CH ; - get shift count
shl EAX,CL ; - shift number left
_endif ; endif
ret ; return
retmax: mov EAX,0FFFFFFFFh ; return maximum value
sub CL,7Fh+32 ; subtract bias + 32
neg CL ; get shift count
shr EAX,CL ; compute value
ret ; return
uflow:
retzero:sub EAX,EAX ; ensure entire number 0
ret ; return
endproc __FSAbs
endmod
end