sys7.1-doc-wip/OS/FPUEmulation/XUnSupp.a
2019-07-27 22:37:48 +08:00

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;
; File: XUnSupp.a
;
; Contains: Routines to handle the unsupported data type/format exception
;
; Originally Written by: Motorola Inc.
; Adapted to Apple/MPW: Jon Okada
;
; Copyright: © 1990, 1991 by Apple Computer, Inc., all rights reserved.
;
; This file is used in these builds: Mac32
;
; Change History (most recent first):
;
; <2> 3/30/91 BG Rolling in Jon Okada's latest changes.
; <1> 12/14/90 BG First checked into TERROR/BBS.
; xunsupp.a
; Based upon Motorola file 'x_unsupp.sa'.
; CHANGE LOG:
; 09 Jan 91 JPO Inserted label "unsupp" at start of code. Renamed
; label "end_fix" to "usend_fix".
;
*
* x_unsupp.sa 3.1 12/10/90
*
* fpsp_unsupp --- FPSP handler for unsupported data type exception
*
* Trap vector #55 (See table 8-1 Mc68030 User's manual).
* Invoked when the user program encounters a data format (packed) that
* hardware does not support or a data type (denormalized numbers or un-
* normalized numbers).
* Normalizes denorms and unnorms, unpacks packed numbers then stores
* them back into the machine to let the 040 finish the operation.
*
* Unsupp calls two routines:
* 1. get_op - gets the operand(s)
* 2. res_func - restore the function back into the 040 or
* if fmove.p fpm,<ea> then pack source (fpm)
* and store in users memory <ea>.
*
* Input: Long fsave stack frame
*
*
* Copyright (C) Motorola, Inc. 1990
* All Rights Reserved
*
* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
* The copyright notice above does not evidence any
* actual or intended publication of such source code.
* X_UNSUPP IDNT 2,1 Motorola 040 Floating Point Software Package
unsupp: ; label inserted <1/9/91, JPO>
fpsp_unsupp:
*
link a6,#-LOCAL_SIZE
fsave -(a7)
movem.l d0-d1/a0-a1,USER_DA(a6)
fmovem.x fp0-fp3,USER_FP0(a6)
fmovem.l fpcr/fpsr/fpiar,USER_FPCR(a6)
move.b (a7),VER_TMP(a6) ;save version number
move.b (a7),d0 ;test for valid version num
andi.b #$f0,d0 ;test for $4x
cmpi.b #VER_4,d0 ;must be $4x or exit
bne fpsp_fmt_error
fmove.l #0,FPSR ;clear all user status bits
fmove.l #0,FPCR ;clear all user control bits
*
* The following lines are used to ensure that the FPSR
* exception byte and condition codes are clear before proceeding,
* except in the case of fmove, which leaves the cc's intact.
*
unsupp_con:
move.l USER_FPSR(a6),d1
btst #5,CMDREG1B(a6) ;looking for fmove out
bne.b fmove_con
and.l #$FF00FF,d1 ;clear all but aexcs and qbyte
bra.b usend_fix ; label RENAMED <1/9/91, JPO>
fmove_con:
and.l #$0FFF40FF,d1 ;clear all but cc's, snan bit, aexcs, and qbyte
usend_fix: ; label RENAMED <1/9/91, JPO>
move.l d1,USER_FPSR(a6)
st UFLG_TMP(a6) ;set flag for unsupp data
bsr get_op ;everything okay, go get operand(s)
bsr res_func ;fix up stack frame so can restore it
clr.l -(a7)
move.b VER_TMP(a6),(a7) ;move idle fmt word to top of stack
bra gen_except
*