1 addressing the cam and ram, Figure 11-9, Data format, cam match ram read -6 – Epson ARM.POWERED ARM720T User Manual

Page 190: Figure 11-10, Rd format, write cache victim and lockdown base -6, Figure 11-11, Rd format, write cache victim -6, Table 11-4, Write cache victim and lockdown operations -6

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11: Test Support

11-6

EPSON

ARM720T CORE CPU MANUAL

The CAM match, RAM read format for data is shown in Figure 11-9.

Figure 11-9 Data format, CAM match RAM read

11.4.1

Addressing the CAM and RAM

For the CAM read or write, and RAM read or write operations you must specify the segment,

index, and word (for the RAM operations). The CAM and RAM operations use the value in the

victim pointer for that segment, so you must ensure that the value is written in the victim

pointer before any CAM or RAM operation.
If the MCR write victim and lockdown base is used, then the victim pointer is incremented

after every CAM read or write, and every RAM read or write. If the MCR write victim is used,

then the victim pointer is only incremented after every CAM read or write. This enables

efficient reading or writing of the CAM and RAM for an entire segment. The write cache victim

and lockdown operations are shown in Table 11-4.

The write cache victim and lockdown base format for Rd is shown in Figure 11-10.

Figure 11-10 Rd format, write cache victim and lockdown base

The write cache victim format for Rd is shown in Figure 11-11.

Figure 11-11 Rd format, write cache victim

Another cache test register, C15.C, is written with the current victim of the addressed segment

whenever an MCR CAM read is executed. This is intended for use in debug to establish the

value of the current victim pointer of each segment before reading the values of the CAM and

RAM, so that the value can be restored afterwards.

Table 11-4 Write cache victim and lockdown operations

Operation

Instructions

Write cache victim and lockdown base

MCR p15, 0, <Rd>, c9, c0, 0
MCR p15, 0, <Rd>, c9, c0, 1

Write cache victim

MCR p15, 0, <Rd>, c9, c1, 0
MCR p15, 0, <Rd>, c9, c1, 1

Hit

RAM data word [29:0]

31

29

30

Miss

0

31

0

SBZ

Index

25

26

Seg

31

7 6 5 4

0

SBZ

SBZ

Index

26 25

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