Datasheet

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SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
EXC_RETURN is the value loaded into the LR on exception entry. The exception mechanism relies on this value
to detect when the processor has completed an exception handler. The lowest five bits of this value provide
information on the return stack and processor mode. Table 12-10 shows the EXC_RETURN values with a
description of the exception return behavior.
All EXC_RETURN values have bits[31:5] set to one. When this value is loaded into the PC, it indicates to the
processor that the exception is complete, and the processor initiates the appropriate exception return sequence.
Table 12-10. Exception Return Behavior
EXC_RETURN[31:0] Description
0xFFFFFFF1
Return to Handler mode, exception return uses non-floating-point state
from the MSP and execution uses MSP after return.
0xFFFFFFF9
Return to Thread mode, exception return uses state from MSP and
execution uses MSP after return.
0xFFFFFFFD
Return to Thread mode, exception return uses state from the PSP and
execution uses PSP after return.
0xFFFFFFE1
Return to Handler mode, exception return uses floating-point-state from
MSP and execution uses MSP after return.
0xFFFFFFE9
Return to Thread mode, exception return uses floating-point state from
MSP and execution uses MSP after return.
0xFFFFFFED
Return to Thread mode, exception return uses floating-point state from PSP
and execution uses PSP after return.