busytable: moved out of rename

support simulating larger ram by using mmap

Opt mem timing

Read image from .gz file

RS：divide rs to ctrl and data

use concatenation for ubtb target generation

Add --max-instr option for emu

modify Emulator::execute function argument list from (uint64_t n) to (uint64_t max_cycle, uint64_t max_instr)

To optimize timing, move redirect logic later

Add assert to freelist

* MMIO inst will run correctly

ubtb: use lower bits for tag(not fully tagged so will get false hit on wide instruction distribution