Subject:
|
Pattern in RCX opcodes.
|
Newsgroups:
|
lugnet.robotics
|
Date:
|
Sun, 20 Dec 1998 16:20:05 GMT
|
Original-From:
|
Vadim Strizhevsky <vadim@optonline.netNOSPAM>
|
Viewed:
|
1330 times
|
| |
|
|
Did anyone notice that the last hex digit of the RCX opcodes uniquely (well
almost) identifies number of bytes that the opcode takes as arguments?
0,6 -> void
1,7 -> 1 byte
2 -> 2 bytes.
3 -> 3 bytes.
4 -> 4 bytes.
5 -> 5 bytes
I think the only exceptions are 0x95 and 0x45, but I might have missed
something.
This is probably from the ream of neat-but-useless information, but being a
number theory fan I couldn't help but notice it. It definately looks "by
design", so I wonder if this is somehow used in firmware or ROM?
-Vadim
|
|
Message has 1 Reply:
 | | Re: Pattern in RCX opcodes.
|
| (...) This is certainly used by the ROM. I believe Paul Haas was the first to notice this, see the comment on my web page, (URL) notes Paul Haas was right about messages being grouped and parsed by lower 3 bits And lower, in the RXI handler: receive (...) (26 years ago, 20-Dec-98, to lugnet.robotics)
|
2 Messages in This Thread:
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
