173
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
Restrictions
The restrictions are:
• use CPS only from privileged software, it has no effect if used in unprivileged software
• CPS cannot be conditional and so must not be used inside an IT block.
Condition Flags
This instruction does not change the condition flags.
Examples
CPSID i
; Disable interrupts and configurable fault handlers (set PRIMASK)
CPSID f
; Disable interrupts and all fault handlers (set FAULTMASK)
CPSIE i
; Enable interrupts and configurable fault handlers (clear PRIMASK)
CPSIE f
; Enable interrupts and fault handlers (clear FAULTMASK)
11.6.11.3
DMB
Data Memory Barrier.
Syntax
DMB{cond}
where:
cond
is an optional condition code, see
Operation
DMB acts as a data memory barrier. It ensures that all explicit memory accesses that appear, in
program order, before the DMB instruction are completed before any explicit memory accesses
that appear, in program order, after the DMB instruction. DMB does not affect the ordering or
execution of instructions that do not access memory.
Condition Flags
This instruction does not change the flags.
Examples
DMB
; Data Memory Barrier
Содержание SAM4S Series
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