0,0 → 1,171 |
;***************************************************************************** |
;* |
;* 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 |