#21 Decoder fail

[André Luiz Cardoso]

Hi!

I'm modeling the Freescale's ColdFire processor and it
has the following instructions:

EXTB.L:

Format:

ac_format Type_SHIFT = "%op:4 %count:3 %dir:3 %type:3
%reg53:3";

Decoder:

extbL.set_decoder(op=0x04, count=0x04, dir=0x07,
type=0x00);

LEA.L:

Format:

ac_format Type_ADD = "%op:4 %reg23:3 %opmode33:3 %ea:6";

Decoder:

leaL.set_decoder(op=0x04, opmode33=0x07);

My cross compiler generated the following:

11c: 49c0 extbl %d0

and my model does:

DBG: ----- PC=0x11c ----- 11
DBG: LEA.L <%ea>, %Ax 0 4 begin
DBG: <%ea> --> A4
DBG: Effective Address = 0
DBG: A4 = -1208643616
DBG: A4 = 0
DBG: LEA.L <%ea>, %Ax 0 4 end

The problem is that the decoder only recognizes the
LEA.L instruction because the begining (2 first bytes)
of the instructions is the same.
I already faced this problem with other two
instructions and resolved it by changing the
instruction format of one of those, but in this case, a
change like this take off all the semantics envolved on
the format...it will make my model harden to understand.

[Alexandro]

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user_id=1489337

Hello Andre,

Which 'set_decoder' is specified first in your model: extbL
ou leaL ? You should declare extbL first because the order
in which 'set_decoder's are specified matters in the
decoding process. If you put leaL before extbL, the decoder
will always accuse the instruction leaL.

Regards,
Alexandro.

[André Luiz Cardoso]

Logged In: YES
user_id=1491895

Hi Alexandro,

In my original coldfire_isa.ac file, the leaL was specified
first. I tried to put the extbl first, in fact I changed it
to be the first instruction declared, but the problem persists.
Do you have any suggestions to solve this?
I think that the order of declaration shouldnt matter in
this case...

Thanks.
Sorry about my english...