arch/m68k/fpsp040/x_fline.S

   1 |
   2 |       x_fline.sa 3.3 1/10/91
   3 |
   4 |       fpsp_fline --- FPSP handler for fline exception
   5 |
   6 |       First determine if the exception is one of the unimplemented
   7 |       floating point instructions.  If so, let fpsp_unimp handle it.
   8 |       Next, determine if the instruction is an fmovecr with a non-zero
   9 |       <ea> field.  If so, handle here and return.  Otherwise, it
  10 |       must be a real F-line exception.
  11 |
  12
  13 |               Copyright (C) Motorola, Inc. 1990
  14 |                       All Rights Reserved
  15 |
  16 |       For details on the license for this file, please see the
  17 |       file, README, in this same directory.
  18
  19 X_FLINE:        |idnt    2,1 | Motorola 040 Floating Point Software Package
  20
  21         |section        8
  22
  23 #include "fpsp.h"
  24
  25         |xref   real_fline
  26         |xref   fpsp_unimp
  27         |xref   uni_2
  28         |xref   mem_read
  29         |xref   fpsp_fmt_error
  30
  31         .global fpsp_fline
  32 fpsp_fline:
  33 |
  34 |       check for unimplemented vector first.  Use EXC_VEC-4 because
  35 |       the equate is valid only after a 'link a6' has pushed one more
  36 |       long onto the stack.
  37 |
  38         cmpw    #UNIMP_VEC,EXC_VEC-4(%a7)
  39         beql    fpsp_unimp
  40
  41 |
  42 |       fmovecr with non-zero <ea> handling here
  43 |
  44         subl    #4,%a7          |4 accounts for 2-word difference
  45 |                               ;between six word frame (unimp) and
  46 |                               ;four word frame
  47         link    %a6,#-LOCAL_SIZE
  48         fsave   -(%a7)
  49         moveml  %d0-%d1/%a0-%a1,USER_DA(%a6)
  50         moveal  EXC_PC+4(%a6),%a0       |get address of fline instruction
  51         leal    L_SCR1(%a6),%a1 |use L_SCR1 as scratch
  52         movel   #4,%d0
  53         addl    #4,%a6          |to offset the sub.l #4,a7 above so that
  54 |                               ;a6 can point correctly to the stack frame
  55 |                               ;before branching to mem_read
  56         bsrl    mem_read
  57         subl    #4,%a6
  58         movel   L_SCR1(%a6),%d0 |d0 contains the fline and command word
  59         bfextu  %d0{#4:#3},%d1  |extract coprocessor id
  60         cmpib   #1,%d1          |check if cpid=1
  61         bne     not_mvcr        |exit if not
  62         bfextu  %d0{#16:#6},%d1
  63         cmpib   #0x17,%d1               |check if it is an FMOVECR encoding
  64         bne     not_mvcr
  65 |                               ;if an FMOVECR instruction, fix stack
  66 |                               ;and go to FPSP_UNIMP
  67 fix_stack:
  68         cmpib   #VER_40,(%a7)   |test for orig unimp frame
  69         bnes    ck_rev
  70         subl    #UNIMP_40_SIZE-4,%a7 |emulate an orig fsave
  71         moveb   #VER_40,(%a7)
  72         moveb   #UNIMP_40_SIZE-4,1(%a7)
  73         clrw    2(%a7)
  74         bras    fix_con
  75 ck_rev:
  76         cmpib   #VER_41,(%a7)   |test for rev unimp frame
  77         bnel    fpsp_fmt_error  |if not $40 or $41, exit with error
  78         subl    #UNIMP_41_SIZE-4,%a7 |emulate a rev fsave
  79         moveb   #VER_41,(%a7)
  80         moveb   #UNIMP_41_SIZE-4,1(%a7)
  81         clrw    2(%a7)
  82 fix_con:
  83         movew   EXC_SR+4(%a6),EXC_SR(%a6) |move stacked sr to new position
  84         movel   EXC_PC+4(%a6),EXC_PC(%a6) |move stacked pc to new position
  85         fmovel  EXC_PC(%a6),%FPIAR |point FPIAR to fline inst
  86         movel   #4,%d1
  87         addl    %d1,EXC_PC(%a6) |increment stacked pc value to next inst
  88         movew   #0x202c,EXC_VEC(%a6) |reformat vector to unimp
  89         clrl    EXC_EA(%a6)     |clear the EXC_EA field
  90         movew   %d0,CMDREG1B(%a6) |move the lower word into CMDREG1B
  91         clrl    E_BYTE(%a6)
  92         bsetb   #UFLAG,T_BYTE(%a6)
  93         moveml  USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
  94         bral    uni_2
  95
  96 not_mvcr:
  97         moveml  USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
  98         frestore (%a7)+
  99         unlk    %a6
 100         addl    #4,%a7
 101         bral    real_fline
 102
 103         |end