[Libre-soc-dev] v3.1B prefix

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon Dec 21 18:19:48 GMT 2020

ahh, i have an idea.  given that the bitmarking worked so well, why not try
the same trick with svp64?

* svp64 prefix is established (RM=NNN)
* one major opcode (all of it) is allocated
 to "bitfield"
* any subsequent *32 bit* instructions with
 a 1 are considered "prefixed" by RM=NNN

actually it would even be possible to do this more than once... *with
different prefixes*.

thus an overlap occurs where some instructions used for some purposes are
marked with one RM pattern, others with another, interleaved together.

ahhh this is even how we could do 2-operand swizzle.

this is going to need some analysis though to see if it would be
worthwhile.  and we haven't got an assembler let alone disassembler yet.


crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

More information about the Libre-soc-dev mailing list