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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [m68k/] [fpsp040/] [x_fline.S] - Blame information for rev 1777

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Line No. Rev Author Line
1 1623 jcastillo
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|       x_fline.sa 3.3 1/10/91
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|
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|       fpsp_fline --- FPSP handler for fline exception
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|
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|       First determine if the exception is one of the unimplemented
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|       floating point instructions.  If so, let fpsp_unimp handle it.
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|       Next, determine if the instruction is an fmovecr with a non-zero
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|        field.  If so, handle here and return.  Otherwise, it
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|       must be a real F-line exception.
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|
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|               Copyright (C) Motorola, Inc. 1990
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|                       All Rights Reserved
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|
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|       THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
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|       The copyright notice above does not evidence any
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|       actual or intended publication of such source code.
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X_FLINE:        |idnt    2,1 | Motorola 040 Floating Point Software Package
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        |section        8
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        .include "fpsp.h"
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        |xref   real_fline
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        |xref   fpsp_unimp
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        |xref   uni_2
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        |xref   mem_read
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        |xref   fpsp_fmt_error
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        .global fpsp_fline
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fpsp_fline:
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|
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|       check for unimplemented vector first.  Use EXC_VEC-4 because
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|       the equate is valid only after a 'link a6' has pushed one more
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|       long onto the stack.
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        cmpw    #UNIMP_VEC,EXC_VEC-4(%a7)
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        beql    fpsp_unimp
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|
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|       fmovecr with non-zero  handling here
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        subl    #4,%a7          |4 accounts for 2-word difference
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|                               ;between six word frame (unimp) and
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|                               ;four word frame
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        link    %a6,#-LOCAL_SIZE
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        fsave   -(%a7)
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        moveml  %d0-%d1/%a0-%a1,USER_DA(%a6)
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        moveal  EXC_PC+4(%a6),%a0       |get address of fline instruction
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        leal    L_SCR1(%a6),%a1 |use L_SCR1 as scratch
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        movel   #4,%d0
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        addl    #4,%a6          |to offset the sub.l #4,a7 above so that
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|                               ;a6 can point correctly to the stack frame
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|                               ;before branching to mem_read
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        bsrl    mem_read
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        subl    #4,%a6
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        movel   L_SCR1(%a6),%d0 |d0 contains the fline and command word
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        bfextu  %d0{#4:#3},%d1  |extract coprocessor id
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        cmpib   #1,%d1          |check if cpid=1
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        bne     not_mvcr        |exit if not
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        bfextu  %d0{#16:#6},%d1
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        cmpib   #0x17,%d1               |check if it is an FMOVECR encoding
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        bne     not_mvcr
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|                               ;if an FMOVECR instruction, fix stack
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|                               ;and go to FPSP_UNIMP
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fix_stack:
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        cmpib   #VER_40,(%a7)   |test for orig unimp frame
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        bnes    ck_rev
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        subl    #UNIMP_40_SIZE-4,%a7 |emulate an orig fsave
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        moveb   #VER_40,(%a7)
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        moveb   #UNIMP_40_SIZE-4,1(%a7)
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        clrw    2(%a7)
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        bras    fix_con
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ck_rev:
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        cmpib   #VER_41,(%a7)   |test for rev unimp frame
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        bnel    fpsp_fmt_error  |if not $40 or $41, exit with error
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        subl    #UNIMP_41_SIZE-4,%a7 |emulate a rev fsave
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        moveb   #VER_41,(%a7)
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        moveb   #UNIMP_41_SIZE-4,1(%a7)
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        clrw    2(%a7)
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fix_con:
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        movew   EXC_SR+4(%a6),EXC_SR(%a6) |move stacked sr to new position
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        movel   EXC_PC+4(%a6),EXC_PC(%a6) |move stacked pc to new position
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        fmovel  EXC_PC(%a6),%FPIAR |point FPIAR to fline inst
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        movel   #4,%d1
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        addl    %d1,EXC_PC(%a6) |increment stacked pc value to next inst
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        movew   #0x202c,EXC_VEC(%a6) |reformat vector to unimp
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        clrl    EXC_EA(%a6)     |clear the EXC_EA field
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        movew   %d0,CMDREG1B(%a6) |move the lower word into CMDREG1B
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        clrl    E_BYTE(%a6)
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        bsetb   #UFLAG,T_BYTE(%a6)
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        moveml  USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
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        bral    uni_2
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not_mvcr:
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        moveml  USER_DA(%a6),%d0-%d1/%a0-%a1 |restore data registers
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        frestore (%a7)+
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        unlk    %a6
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        addl    #4,%a7
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        bral    real_fline
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        |end

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