Amiga-Request@cs.odu.edu (Amiga Sources/Binaries Moderator) (07/16/90)
Submitted-by: bryce@cbmvax.commodore.com (Bryce Nesbitt)
Posting-number: Volume 90, Issue 219
Archive-name: util/decigel020/part01
[ uuencoded executable enclosed ...tad ]
Decigel020 - The functionality of the famous "decigel" program, but
working on the 68020/68030 processors.
The old Decigel would correctly patch the instruction on the 68020,
but chances are the old (bad) instruction was still in the instruction
cache. This code flushes the cache after modifying memory.
This code may not function under future revisions of the operating
system. This code is safe on the 68000/68010/68020 and 68030.
This code is not expected to function on the 68040.
If the instruction was MOVE SR,<ea> it is converted to MOVE CCR,<ea>.
The instruction cache is flushed, then the instruction is re-executed.
#!/bin/sh
# This is a shell archive. Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file". To overwrite existing
# files, type "sh file -c". You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g.. If this archive is complete, you
# will see the following message at the end:
# "End of archive 1 (of 1)."
# Contents: decigel020.asm decigel020.uu
# Wrapped by tadguy@xanth on Sun Jul 15 20:28:30 1990
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'decigel020.asm' -a "${1}" != "-c" ; then
echo shar: Will not clobber existing file \"'decigel020.asm'\"
else
echo shar: Extracting \"'decigel020.asm'\" \(3135 characters\)
sed "s/^X//" >'decigel020.asm' <<'END_OF_FILE'
X**
X**
X** Decigel020 - The functionality of the famous "decigel" program, but
X** working on the 68020/68030 processors.
X**
X** The old Decigel would correctly patch the instruction on the 68020,
X** but chances are the old (bad) instruction was still in the instruction
X** cache. This code flushes the cache after modifying memory.
X**
X** This code may not function under future revisions of the operating
X** system. This code is safe on the 68000/68010/68020 and 68030.
X** This code is not expected to function on the 68040.
X**
X**
X** Written Tuesday 03-Apr-90 21:21:47 -Bryce Nesbitt
X**
X**
X INCLUDE "exec/types.i"
X INCLUDE "exec/memory.i"
X INCLUDE "exec/ables.i"
X INCLUDE "exec/execbase.i"
X INCLUDE "libraries/dosextens.i"
X
X INT_ABLES
X
X XREF _LVOFindTask
X XREF _LVOSupervisor
X
XABSEXECBASE EQU 4
XPrivTrapVector EQU $20
X
X
X
X
X;-------------- install patch then detach -----------------------------------
X
X move.l ABSEXECBASE,a6
X
X
X ;
X ; Contents of the old vector are used to self-modify our
X ; code. The new vector replaces the old.
X ;
X DISABLE
X move.l PrivTrapVector,ModifyCode+2
X bsr.s FlushCache
X move.l #NewPrivTrap,PrivTrapVector
X ENABLE
X
X
X ;
X ; Detach our code from the CLI
X ;
X suba.l a1,a1
X jsr _LVOFindTask(a6)
X move.l d0,a0
X move.l pr_CLI(a0),a0
X add.l a0,a0
X add.l a0,a0
X move.l a0,d0
X beq.s not_cli
X clr.l cli_Module(a0)
Xnot_cli: moveq #0,d0
X rts
X
X
X
X
X*
X* Flush the instruction cache
X*
XFlushCache: movem.l a5/a6,-(sp)
X move.l ABSEXECBASE,a6
X btst.b #AFB_68020,AttnFlags+1(a6) ;>=68020 includes cache
X beq.s fc_nocache
X
X lea.l FlushTrap(pc),a5
X jsr _LVOSupervisor(a6)
X
Xfc_nocache: movem.l (sp)+,a5/a6
X rts
X;
X;
XFlushTrap: dc.w $4e7a,$0002 ;movec.l CACR,d0
X bset #3,d0 ;Set "Clear instruction cache" bit
X dc.w $4e7b,$0002 ;movec.l d0,CACR
X rte
X
X
X
X
X
X*****************************************************************************
X** **
X** **
X** The trap handler wedged into the privilege violation vector. **
X** **
X** If the instruction was MOVE SR,<ea> it is converted to MOVE CCR,<ea>. **
X** The instruction cache is flushed, then the instruction is re-executed. **
X** **
X** **
X*****************************************************************************
X
XSTKOFFSET EQU 4*3
X
X;
X; New privilege violation vector
X;
XNewPrivTrap: movem.l d0/a0/a6,-(sp)
X move.l STKOFFSET+2(sp),a0
X move.w (a0),d0 ; Examine opcode
X andi.w #~%111111,d0 ; Mask out EA field
X cmpi.w #$40C0,d0 ; A MOVE SR,<ea>?
X beq.s GotOne
X movem.l (sp)+,d0/a0/a6
XModifyCode: jmp $01234567 ; To previous handler... (exit)
X
X;
X; Code executed if the instruction was MOVE SR,<ea>
X;
XGotOne: move.l ABSEXECBASE,a6
X
X
X DISABLE
X bset #1,(a0) ; Convert to MOVE CCR,<ea>
X btst.b #AFB_68020,AttnFlags+1(a6) ;>=68020 includes cache
X beq.s no_cache
X
X dc.w $4e7b,$8802 ; movec.l a0,CAAR
X dc.w $4e7a,$0002 ; movec.l CACR,d0
X bset #2,d0 ; Set "Clear entry in instruction cache"
X dc.w $4e7b,$0002 ; movec.l d0,CACR
Xno_cache: ENABLE
X
X
X movem.l (sp)+,d0/a0/a6
X rte ; Rerun new opcode... (exit)
X
X END
END_OF_FILE
if test 3135 -ne `wc -c <'decigel020.asm'`; then
echo shar: \"'decigel020.asm'\" unpacked with wrong size!
fi
# end of 'decigel020.asm'
fi
if test -f 'decigel020.uu' -a "${1}" != "-c" ; then
echo shar: Will not clobber existing file \"'decigel020.uu'\"
else
echo shar: Extracting \"'decigel020.uu'\" \(745 characters\)
sed "s/^X//" >'decigel020.uu' <<'END_OF_FILE'
Xbegin 644 decigel020
XM```#\P`````````#``````````(````V``````````````/I````-BQX``0SN
XM_$```-_PFE(N`28C^``@````DF$R(?P```!X`"!3+@$F;`@S_,```-_PFI/)Q
XM3J[^VB!`(&@`K-'(T<@@"&<$0J@`/'``3G5(YP`&+'@`!`@N``$!*6<(2_H`X
XM#$ZN_^),WV``3G5.>@`"",```TY[``).<TCG@((@;P`.,!`"0/_`#$!`P&<*D
XM3-]!`4[Y`2-%9RQX``0S_$```-_PFE(N`28(T``!""X``0$I9Q!.>X@"3GH`W
XM`@C```).>P`"4RX!)FP(,_S```#?\)I,WT$!3G,``````^P````"````````J
XM`!0````<`````````_`````#14Y!0DQ%+C`U-@``````T`````-%3D%"3$4N^
XM,#4U```````P`````TUO9&EF>4-O9&4``````)`````#3F5W4')I=E1R87``E
XM````>`````-F8U]N;V-A8VAE``````!D`````T9L=7-H0V%C:&4``````$P`]
XM```";F]?8V%C:&4```#"`````D=O=$]N90``````E@````-&;'5S:%1R87``T
XM``````!J`````FYO=%]C;&D`````2`````````/R```#Z0````````/R```#U
X)Z@````````/R?
X``
Xend
Xsize 504
END_OF_FILE
if test 745 -ne `wc -c <'decigel020.uu'`; then
echo shar: \"'decigel020.uu'\" unpacked with wrong size!
fi
# end of 'decigel020.uu'
fi
echo shar: End of archive 1 \(of 1\).
cp /dev/null ark1isdone
MISSING=""
for I in 1 ; do
if test ! -f ark${I}isdone ; then
MISSING="${MISSING} ${I}"
fi
done
if test "${MISSING}" = "" ; then
echo You have the archive.
rm -f ark[1-9]isdone
else
echo You still need to unpack the following archives:
echo " " ${MISSING}
fi
## End of shell archive.
exit 0
--
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