Oc Address Array; Figure 4.9 Memory-Mapped Ic Data Array - Hitachi SH7751 Hardware Manual

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2. IC data array write
The longword data specified in the data field is written for the data specified by the longword
specification bits in the address field in the IC entry corresponding to the entry set in the
address field.
31
Address field
1 1 1 1 0 0 0 1
31
Data field
L
: Longword specification bits
: Reserved bits (0 write value, undefined read value)
4.5.3

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 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, and the
entry is specified by bits [13:5]. CCR.OIX and CCR.ORA have no effect on this entry
specification. 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
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
24
23

Figure 4.9 Memory-Mapped IC Data Array

13
12
Longword data
Rev. 3.0, 04/02, page 105 of 1064
5 4
2 1 0
Entry
L
0

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