List of Abbreviations and Terms
Term
Definition
BHT
Branch History Table
BTB
Branch Target Buffer
RAS
Return-Address Stack
CLINT
Core Local Interruptor. Generates per-hart software interrupts and timer
interrupts.
hart
HARdware Thread
DTIM
Data Tightly Integrated Memory
ITIM
Instruction Tightly Integrated Memory
JTAG
Joint Test Action Group
LIM
Loosely Integrated Memory. Used to describe memory space delivered in
a SiFive Core Complex but not tightly integrated to a CPU core.
PMP
Physical Memory Protection
PLIC
Platform-Level Interrupt Controller. The global interrupt controller in a
RISC-V system.
TileLink
A free and open interconnect standard originally developed at UC Berke-
ley.
RO
Used to describe a Read Only register field.
RW
Used to describe a Read/Write register field.
WO
Used to describe a Write Only registers field.
WARL
Write-Any Read-Legal field. A register field that can be written with any
value, but returns only supported values when read.
WIRI
Writes-Ignored, Reads-Ignore field. A read-only register field reserved for
future use. Writes to the field are ignored, and reads should ignore the
value returned.
WLRL
Write-Legal, Read-Legal field. A register field that should only be written
with legal values and that only returns legal value if last written with a
legal value.
WPRI
Writes-Preserve Reads-Ignore field. A register field that might contain
unknown information. Reads should ignore the value returned, but writes
to the whole register should preserve the original value.
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