arch/m68k/fpsp040/x

/* */
   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  16 |       THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 
  17 |       The copyright notice above does not evidence any  
  18 |       actual or intended publication of such source code.
  19 
  20 X_FLINE:        |idnt    2,1 | Motorola 040 Floating Point Software Package
  21 
  22         |section        8
  23 
  24         .include "fpsp.h"
  25 
  26         |xref   real_fline
  27         |xref   fpsp_unimp
  28         |xref   uni_2
  29         |xref   mem_read
  30         |xref   fpsp_fmt_error
  31 
  32         .global fpsp_fline
  33 fpsp_fline:
  34 |
  35 |       check for unimplemented vector first.  Use EXC_VEC-4 because
  36 |       the equate is valid only after a 'link a6' has pushed one more
  37 |       long onto the stack.
  38 |
  39         cmpw    #UNIMP_VEC,EXC_VEC-4(%a7)
  40         beql    fpsp_unimp
  41 
  42 |
  43 |       fmovecr with non-zero <ea> handling here
  44 |
  45         subl    #4,%a7          |4 accounts for 2-word difference
  46 |                               ;between six word frame (unimp) and
  47 |                               ;four word frame
  48         link    %a6,#-LOCAL_SIZE
  49         fsave   -(%a7)
  50         moveml  %d0-%d1/%a0-%a1,USER_DA(%a6)
  51         moveal  EXC_PC+4(%a6),%a0       |get address of fline instruction
  52         leal    L_SCR1(%a6),%a1 |use L_SCR1 as scratch
  53         movel   #4,%d0
  54         addl    #4,%a6          |to offset the sub.l #4,a7 above so that
  55 |                               ;a6 can point correctly to the stack frame 
  56 |                               ;before branching to mem_read
  57         bsrl    mem_read
  58         subl    #4,%a6
  59         movel   L_SCR1(%a6),%d0 |d0 contains the fline and command word
  60         bfextu  %d0{#4:#3},%d1  |extract coprocessor id
  61         cmpib   #1,%d1          |check if cpid=1
  62         bne     not_mvcr        |exit if not
  63         bfextu  %d0{#16:#6},%d1
  64         cmpib   #0x17,%d1               |check if it is an FMOVECR encoding
  65         bne     not_mvcr        
  66 |                               ;if an FMOVECR instruction, fix stack
  67 |                               ;and go to FPSP_UNIMP
  68 fix_stack:
  69         cmpib   #VER_40,(%a7)   |test for orig unimp frame
  70         bnes    ck_rev
  71         subl    #UNIMP_40_SIZE-4,%a7 |emulate an orig fsave
  72         moveb   #VER_40,(%a7)
  73         moveb   #UNIMP_40_SIZE-4,1(%a7)
  74         clrw    2(%a7)
  75         bras    fix_con
  76 ck_rev:
  77         cmpib   #VER_41,(%a7)   |test for rev unimp frame
  78         bnel    fpsp_fmt_error  |if not $40 or $41, exit with error
  79         subl    #UNIMP_41_SIZE-4,%a7 |emulate a rev fsave
  80         moveb   #VER_41,(%a7)
  81         moveb   #UNIMP_41_SIZE-4,1(%a7)
  82         clrw    2(%a7)
  83 fix_con:
  84         movew   EXC_SR+4(%a6),EXC_SR(%a6) |move stacked sr to new position
  85         movel   EXC_PC+4(%a6),EXC_PC(%a6) |move stacked pc to new position
  86         fmovel  EXC_PC(%a6),%FPIAR |point FPIAR to fline inst
  87         movel   #4,%d1
  88         addl    %d1,EXC_PC(%a6) |increment stacked pc value to next inst
  89         movew   #0x202c,EXC_VEC(%a6) |reformat vector to unimp
  90         clrl    EXC_EA(%a6)     |clear the EXC_EA field
  91         movew   %d0,CMDREG1B(%a6) |move the lower word into CMDREG1B
  92         clrl    E_BYTE(%a6)
  93         bsetb   #UFLAG,T_BYTE(%a6)
  94         moveml  USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
  95         bral    uni_2
  96 
  97 not_mvcr:
  98         moveml  USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
  99         frestore (%a7)+
 100         unlk    %a6
 101         addl    #4,%a7
 102         bral    real_fline
 103 
 104         |end
/* */
root/arch/m68k/fpsp040/x_fline.S
