SH7750_08 Datasheet, PDF (223/1162 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

Section 4 Caches
31
24 23
Address field _{1 1 1 1 0 0 0 1}
31
Data field
13 12
Way
Longword data
Entry
54 210
L
0
Legend:
L: Longword specification bits
: Reserved bits (0 write value, undefined read value)
Figure 4.13 Memory-Mapped IC Data Array
4.6.3 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 is 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, the way is
specified by bit [14], and the entry by bits [13:5]. CCR.OIX has no effect on this entry
specification. In RAM mode (CCR.ORA = 1), the OC's address arrays are only accessible in the
memory-mapped cache area, and bit [13] is used to specify the way. For details about address
mapping, see section 4.6.5, Summary of the Memory-Mapping of the OC. The address array bit
[3] association bit (A bit) 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 the 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.
Rev.7.00 Oct. 10, 2008 Page 139 of 1074
REJ09B0366-0700