3 ms·
> One would simply specify that for any instruction used by a binary outside some core set, a fallback must be offered. That is exactly what RVA23 does. It spe
by brucehoult 2y ago
> One would simply specify that for any instruction used by a binary outside some core set, a fallback must be offered.
That is exactly what RVA23 does. It specifies what must work. It doesn't specify the performance of any instruction -- that is between a hardware vendor and their customers as to which ones are fast.
> If you execute unknown instruction 0x80 then code at the fallback pointer+0x80 will be executed instead.
RISC-V instructions are 4 bytes long (i.e. 2^32 of them), not 1 byte. Using that simple technique, with just a pointer to the actual handler included in the table, the table will be 32 GB in size.