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Instruction Overview
The user-supplied argument for
stack frame.
LINK
frame size is 2 words when the argument is zero. The maximum stack
18
frame size is 2
performs the reciprocal of
UNLINK
moving the current value of
and
from the stack.
FP
RETS
The
instruction typically follows a Pop Multiple instruction that
UNLINK
restores pointer and data registers previously saved to the stack.
The frame values remain on the stack until a subsequent Push, Push Mul-
tiple or
operation overwrites them.
LINK
Of course, FP must not be modified by user code between
to preserve stack integrity.
UNLINK
Neither
nor
LINK
occur while either of these instructions is executing cause the instruction
to abort. For example, a load/store operation might cause a protection vio-
lation while
LINK
original values prior to the execution of this instruction. This measure
ensures that the instruction can be restarted after the exception.
Note that when a
memory may already be changed due to stores that have already completed
before the exception. Likewise, an aborted
and
registers changed because of a load that has already completed
FP
RETS
before the interruption.
The illustrations below show the stack contents after executing a
instruction followed by a Push Multiple instruction.
10-18
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
LINK
always saves
RETS
+ 8 = 262152 bytes in 4-byte increments.
LINK
into
FP
can be interrupted. However, exceptions that
UNLINK
is executing. In that case,
operation aborts due to an exception, the stack
LINK
determines the size of the allocated
and
on the stack, so the minimum
FP
, de-allocating the frame space by
and restoring previous values into
SP
and
SP
FP
operation may leave the
UNLINK
and
LINK
are reset to their
LINK
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