SH7763 Datasheet, PDF (275/2026 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 7 Caches
7.6.3 OC Address Array
The OC address array is allocated to addresses H'F400 0000 to H'F4FF FFFF in the P4 area. An
address array access requires a 32-bit address field specification (when reading or writing) and a
32-bit data field specification. The way and entry to be accessed are specified in the address field,
and the write tag, U bit, and V bit are specified in the data field.
In the address field, bits [31:24] have the value H'F4 indicating the OC address array, and the way
is specified by bits [14:13] and the entry by bits [12:5]. The association bit (A bit) [3] in the
address field specifies whether or not association is performed when writing to the OC address
array. As only longword access is used, 0 should be specified for address field bits [1:0].
In the data field, the tag is indicated by bits [31:10], the U bit by bit [1], and the V bit by bit [0].
As the OC address array tag is 19 bits in length, data field bits [31:29] are not used in the case of a
write in which association is not performed. Data field bits [31:29] are used for the virtual address
specification only in the case of a write in which association is performed.
The following three kinds of operation can be used on the OC address array:
1. OC address array read
The tag, U bit, and V bit are read into the data field from the OC entry corresponding to the
way and entry set in the address field. In a read, associative operation is not performed
regardless of whether the association bit specified in the address field is 1 or 0.
2. OC address array write (non-associative)
The tag, U bit, and V bit specified in the data field are written to the OC entry corresponding to
the way and entry set in the address field. The A bit in the address field should be cleared to 0.
When a write is performed to a cache line for which the U bit and V bit are both 1, after write-
back of that cache line, the tag, U bit, and V bit specified in the data field are written.
Rev. 1.00 Oct. 01, 2007 Page 209 of 1956
REJ09B0256-0100