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WORKING WITH THE CPU
R7:Cache Operations register
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Cache operation
functions
This table lists the cache operation functions and associated data and instruction
formats for R7.
Drain write buffer Acts as an explicit memory barrier. This instruction drains
the contents of the write buffers of all memory stores
occurring in program order before the instruction is
completed. No instructions occurring in program order
after this instruction are executed until the instruction
completes.
Use this instruction when timing of specific stores to the
level two memory system has to be controlled (for
example, when a store to an interrupt acknowledge
location has to complete before interrupts are enabled).
Wait for interrupt Drains the contents of the write buffers, puts the processor
into low-power state, and stops the processor from
executing further instructions until an interrupt (or debug
request) occurs. When an interrupt does occur, the
MCR
instruction completes, and the IRQ or FIRQ handler is
entered as normal.
The return link in
R14_irq or R14_fiq contains the address
of the
MCR instruction plus eight, so the typical instruction
used for interrupt return
(SUBS PC,R14,#4) returns to the
instruction following the
MCR.
Function Description
Function/operation Data format Instruction
Invalidate ICache and DCache SBZ
MCR p15, 0, Rd, c7, c7, 0
Invalidate ICache SBZ
MCR p15, 0, Rd, c7, c5, 0
Invalidate ICache single entry (MVA) MVA
MCR p15, 0, Rd, c7, c5, 1
Invalidate ICache single entry (set/way) Set/Way
MCR p15, 0, Rd, c7, c5, 2
Prefetch ICache line (MVA) MVA
MCR p15, 0, Rd, c7, c13, 1
Invalidate DCache SBZ
MCR p15, 0, Rd, c7, c6, 0
Invalidate DCache single entry (MVA) MVA
MCR p15, 0, Rd, c7, c6, 1
Invalidate DCache single entry (set/way) Set/Way
MCR p15, 0, Rd, c7, c6, 2
Clean DCache single entry (MVA) MVA
MCR p15, 0, Rd, c7, c10, 1
Clean DCache single entry (set/way) Set/Way
MCR p15, 0, Rd, c7, C10, 2
Test and clean DCache N/A
MRC p15, 0, Rd, c7, c10, 3
Clean and invalidate DCache entry (MVA) MVA
MCR p15, 0, Rd, c7, c14, 1
Clean and invalidate DCache entry (set/way) Set/Way
MCR p15, 0, Rd, c7, c14, 2
Test, clean, and invalidate DCache N/A
MRC p15, 0, Rd, c7, c14, 3