Epson ARM720T Manuel D’Utilisation

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

Figure 11-9  Data format, CAM match RAM read 

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

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