LXR linux/arch/m68k/fpsp040/x

   1|
   2|       x_unsupp.sa 3.3 7/1/91
   3|
   4|       fpsp_unsupp --- FPSP handler for unsupported data type exception
   5|
   6| Trap vector #55       (See table 8-1 Mc68030 User's manual).
   7| Invoked when the user program encounters a data format (packed) that
   8| hardware does not support or a data type (denormalized numbers or un-
   9| normalized numbers).
  10| Normalizes denorms and unnorms, unpacks packed numbers then stores
  11| them back into the machine to let the 040 finish the operation.
  12|
  13| Unsupp calls two routines:
  14|       1. get_op -  gets the operand(s)
  15|       2. res_func - restore the function back into the 040 or
  16|                       if fmove.p fpm,<ea> then pack source (fpm)
  17|                       and store in users memory <ea>.
  18|
  19|  Input: Long fsave stack frame
  20|
  21|
  22
  23|               Copyright (C) Motorola, Inc. 1990
  24|                       All Rights Reserved
  25|
  26|       For details on the license for this file, please see the
  27|       file, README, in this same directory.
  28
  29X_UNSUPP:       |idnt    2,1 | Motorola 040 Floating Point Software Package
  30
  31        |section        8
  32
  33#include "fpsp.h"
  34
  35        |xref   get_op
  36        |xref   res_func
  37        |xref   gen_except
  38        |xref   fpsp_fmt_error
  39
  40        .global fpsp_unsupp
  41fpsp_unsupp:
  42|
  43        link            %a6,#-LOCAL_SIZE
  44        fsave           -(%a7)
  45        moveml          %d0-%d1/%a0-%a1,USER_DA(%a6)
  46        fmovemx %fp0-%fp3,USER_FP0(%a6)
  47        fmoveml %fpcr/%fpsr/%fpiar,USER_FPCR(%a6)
  48
  49
  50        moveb           (%a7),VER_TMP(%a6) |save version number
  51        moveb           (%a7),%d0               |test for valid version num
  52        andib           #0xf0,%d0               |test for $4x
  53        cmpib           #VER_4,%d0      |must be $4x or exit
  54        bnel            fpsp_fmt_error
  55
  56        fmovel          #0,%FPSR                |clear all user status bits
  57        fmovel          #0,%FPCR                |clear all user control bits
  58|
  59|       The following lines are used to ensure that the FPSR
  60|       exception byte and condition codes are clear before proceeding,
  61|       except in the case of fmove, which leaves the cc's intact.
  62|
  63unsupp_con:
  64        movel           USER_FPSR(%a6),%d1
  65        btst            #5,CMDREG1B(%a6)        |looking for fmove out
  66        bne             fmove_con
  67        andl            #0xFF00FF,%d1   |clear all but aexcs and qbyte
  68        bras            end_fix
  69fmove_con:
  70        andl            #0x0FFF40FF,%d1 |clear all but cc's, snan bit, aexcs, and qbyte
  71end_fix:
  72        movel           %d1,USER_FPSR(%a6)
  73
  74        st              UFLG_TMP(%a6)   |set flag for unsupp data
  75
  76        bsrl            get_op          |everything okay, go get operand(s)
  77        bsrl            res_func        |fix up stack frame so can restore it
  78        clrl            -(%a7)
  79        moveb           VER_TMP(%a6),(%a7) |move idle fmt word to top of stack
  80        bral            gen_except
  81|
  82        |end
  83