Le 12/08/2015 19:05, Richard Henderson a écrit :
> On 08/09/2015 01:13 PM, Laurent Vivier wrote:
>> Signed-off-by: Laurent Vivier <laur...@vivier.eu>
>> ---
>> target-m68k/translate.c | 34 +++++++++++++++++++++++++++++++++-
>> 1 file changed, 33 insertions(+), 1 deletion(-)
>>
>> diff --git a/target-m68k/translate.c b/target-m68k/translate.c
>> index adf4521..b7d15e9 100644
>> --- a/target-m68k/translate.c
>> +++ b/target-m68k/translate.c
>> @@ -2035,10 +2035,42 @@ DISAS_INSN(and)
>> TCGv dest;
>> TCGv addr;
>> int opsize;
>> + int exg_mode;
>>
>> + dest = tcg_temp_new();
>> +
>> + /* exg */
>> +
>> + exg_mode = insn & 0x1f8;
>
> Likewise, surely we can decode EXG separately from AND, and avoid doing so for
> coldfire.
I agree for CMPM, not for EXG.
Let's have a look to instructions encoding :)
AND 1100dddooommmrrr
ddd data register number
ooo opmode, invalid: 011, 111
mmmrrr ea mode, if ooo = { 000, 001, 010} invalid: 001000 .. 001111
if ooo = { 100, 101, 110} invalid; 000000 .. 001111
EXG 1100xxx1oooooyyy
xxx register
ooooo valid: 01000, 01001, 10001
yyy register
So, EXG is an AND with
ooo 101, 110
mmm 000, 001
which are invalid combinations for AND.
IMHO, EXG looks like a wart on the AND and should be decoded like that...
I don't know how to add this easily in the table... except by adding 3
entries to decode 1 instruction. Is it acceptable ?
Laurent
