PM0056 datasheet(102/156 Pages) STMICROELECTRONICS

102 / 156 page

The Cortex-M3 instruction set

PM0056

102/156

DocID15491 Rev 5

When you write to BASEPRI_MAX, the instruction writes to BASEPRI only if either:

•

Rn is non-zero and the current BASEPRI value is 0

•

Rn is non-zero and less than the current BASEPRI value.

See MRS on page 100.

Restrictions

Rn must not be SP and must not be PC.

Condition flags

This instruction updates the flags explicitly based on the value in Rn.

Examples

MSR

CONTROL, R1 ; Read R1 value and write it to the CONTROL register

3.9.8

NOP

No Operation.

Syntax

NOP{cond}

where:

•

‘cond’ is an optional condition code, see Conditional execution on page 57.

Operation

NOP does nothing. NOP is not necessarily a time-consuming NOP. The processor might

remove it from the pipeline before it reaches the execution stage.

Use NOP for padding, for example to place the following instruction on a 64-bit boundary.

Condition flags

This instruction does not change the flags.

Examples

NOP

; No operation

3.9.9

SEV

Send Event.

Syntax

SEV{cond}

where:

•

‘cond’ is an optional condition code, see Conditional execution on page 57.

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