User`s guide

Register Field Notation
Register figures and tabulated descriptions have a mnemonic that indicates the
bit or field as described in Table 1.
Table 1 Register Field Type Notation
Notation Description
RW A read/write bit or field. The value may be read and written by
software, microcode, or hardware.
RO A read-only bit or field. The value may be read by software, microcode,
or hardware. It is written by hardware; software or microcode write
transactions are ignored.
WO A write-only bit or field. The value may be written by software and
microcode. It is read by hardware. Read transactions by software or
microcode return an UNPREDICTABLE result.
WZ A write-only bit or field. The value may be written by software or
microcode. It is read by hardware, and read transactions by software or
microcode return a zero.
WC A write-to-clear bit or field. The value may be read by software or
microcode. Software or microcode write transactions of a 1 cause the bit
to be cleared by hardware. Software or microcode write transactions of
a 0 do not modify the state of the bit.
RC A read-to-clear bit or field. The value is written by hardware and
remains unchanged until read. The value may be read by software or
microcode, at which point hardware may write a new value into the
field.
RW1C A read/write one-to-clear bit or field. The value may be read. Software,
microcode, or hardware writes a 1 to clear the bit or field.
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