Analog Devices VisualDSP++ 3.5 Manual page 219

Memory Overlays and Advanced LDF Commands
OVERLAY_INPUT
{
ALGORITHM (ALL_FIT)
OVERLAY_OUTPUT (fft_two.ovl)
INPUT_SECTIONS ( Fft_mid.doj(program) )
} > ovl_code
The two defined overlays (
segment
ovl_code
tion . All instruction and data defined in the
program
segment within the
overlay. All instructions and data defined in
are part of overlay
Fft_mid.doj
within each overlay.
The first and the last called functions are in overlay
middle functions are in overlay
( ) is referenced during code execution,
fft_one
to internal memory. When the second function (
overlay id=2
(in overlay
fft_two
already in internal memory and an overlay transfer does not occur.
To verify whether an overlay is in internal memory, place the overlay ID
of this overlay into a register (for example,
compare this value to the overlay ID of each overlay already loaded by
loading these overlay values into a register (for example,
CC = p0 == p1;
if CC jump skipped_DMA_setup;
Finally, when the last function (
again transferred to internal memory for execution.
VisualDSP++ 3.5 Linker and Utilities Manual
for 16-Bit Processors
// Overlay to live in section ovl_c
fft_one.ovl
(defined by the
Fft_1st_last.doj
fft_two.ovl
fft_two
is transferred to internal memory. When the third function
) is referenced, the overlay manager recognizes that it is
/* Is overlay already in internal memory? */
/* If so, do not transfer it in. */
fft_one
and
fft_two.ovl
command), and run in sec-
MEMORY{}
file are part of the
program
. The result is two functions
fft_one
. When the first function
overlay id=1
fft_two
in Blackfin processors) and
P0
) is referenced,
) live in memory
memory
program
fft_one.ovl
within the file
. The two
is transferred
) is referenced,
).
R1
is
overlay id=1
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