Intel IXC1100, IXP42X Example 10. Locking Data into Data Cache

Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
September 2006 DM
Order Number: 252480-006US 69
Intel XScale® Processor—Intel® IXP42X product line and IXC1100 control plane processors
Example 10. Locking Data into Data Cache
; R1 contains the virtual address of a region of memory to lock,
; configured with C=1 and B=1
; R0 is the number of 32-byte lines to lock into the data cache. In this
; example 16 lines of data are locked into the cache.
; MMU and data cache are enabled prior to this code.
MACRO DRAIN
MCR P15, 0, R0, C7, C10, 4 ; drain pending loads and stores
ENDM
DRAIN
MOV R2, #0x1
MCR P15,0,R2,C9,C2,0 ; Put the data cache in lock mode
CPWAIT
MOV R0, #16
LOOP1:
MCR P15,0,R1,C7,C10,1 ; Write back the line if it’s dirty in the cache
MCR P15,0,R1, C7,C6,1 ; Flush/Invalidate the line from the cache
LDR R2, [R1], #32 ; Load and lock 32 bytes of data located at [R1]
; into the data cache. Post-increment the address
; in R1 to the next cache line.
SUBS R0, R0, #1; Decrement loop count
BNE LOOP1
; Turn off data cache locking
MOV R2, #0x0
MCR P15,0,R2,C9,C2,0 ; Take the data cache out of lock mode.
CPWAIT