ARM Cortex-M3 Guía de usuario descargar pdf (Pagina 51)

Programmers Model

ID072410 Non-Confidential

This means that software must not use load-multiple or store-multiple instructions to access a

device or access a memory region that is read-sensitive or sensitive to repeated writes. The

software must not use these instructions in any case where repeated reads or writes might cause

inconsistent results or unwanted side-effects.

Base register update in LDM and STM operations

There are cases when an

LDM

STM

updates the base register:

• When the instruction specifies base register write-back, the base register changes to the

updated address. An abort restores the original base value.

• When the base register is in the register list of an

LDM

, and is not the last register in the list,

the base register changes to the loaded value.

LDM

STM

is restarted rather than continued if:

• the instruction faults

• the instruction is inside an

If an

LDM

has completed a base load, it is continued from before the base load.

1 2 ... 46 47 48 49 50 51 52 53 54 55 56 ... 136 137

Sin comentarios

ARM Cortex-M3 Guía de usuario Pagina 51