ISA: add definition and/or reference for big/little endian

[dthaler]

John Scudder comments:

Thanks for this.

Although one would hope that “big-endian” and “little-endian” are widely
understood, it might not be a bad idea to supply definitions and/or a reference.

[dthaler]

Paul Wouters comments:

Can the headers in the tables such as in Section 3 be extended so it is
more clear how many bits are in the various fields ? eg the IETF style is:

                     1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|    opcode     |     regs      |            offset             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                              imm                              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Why "host vs big" endian instead of "host order vs network order" or
"little vs big endian" ? I understand not all hosts are "host endian",
I am just a little confused why to fixup two common sets into a new set.

NITS:

boilerplate got rendered badly

[dthaler]

The appropriate reference for endianness is IEN 137

[dthaler]

Proposed patch posted at https://mailarchive.ietf.org/arch/msg/bpf/G0yjlzZ4GazyQC2gN0jW8YjqGkk/
(Boilerplate fix will be done as part of #160)

[dthaler]

Fixed in draft -04