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|
|       x_unsupp.sa 3.3 7/1/91
|
|       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|       THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 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

        |section        8

        .include "fpsp.h"

        |xref   get_op
        |xref   res_func
        |xref   gen_except
        |xref   fpsp_fmt_error

        .global fpsp_unsupp
fpsp_unsupp:
|
        link            %a6,#-LOCAL_SIZE
        fsave           -(%a7)
        moveml          %d0-%d1/%a0-%a1,USER_DA(%a6)
        fmovemx %fp0-%fp3,USER_FP0(%a6)
        fmoveml %fpcr/%fpsr/%fpiar,USER_FPCR(%a6)


        moveb           (%a7),VER_TMP(%a6) |save version number
        moveb           (%a7),%d0               |test for valid version num
        andib           #0xf0,%d0               |test for $4x
        cmpib           #VER_4,%d0      |must be $4x or exit
        bnel            fpsp_fmt_error

        fmovel          #0,%FPSR                |clear all user status bits
        fmovel          #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:
        movel           USER_FPSR(%a6),%d1
        btst            #5,CMDREG1B(%a6)        |looking for fmove out
        bne             fmove_con
        andl            #0xFF00FF,%d1   |clear all but aexcs and qbyte
        bras            end_fix
fmove_con:
        andl            #0x0FFF40FF,%d1 |clear all but cc's, snan bit, aexcs, and qbyte
end_fix:
        movel           %d1,USER_FPSR(%a6)

        st              UFLG_TMP(%a6)   |set flag for unsupp data

        bsrl            get_op          |everything okay, go get operand(s)
        bsrl            res_func        |fix up stack frame so can restore it
        clrl            -(%a7)
        moveb           VER_TMP(%a6),(%a7) |move idle fmt word to top of stack
        bral            gen_except
|
        |end