Command Evaluation And Setup - Analog Devices VisualDSP++ 3.5 Manual

Memory Overlays and Advanced LDF Commands
PLIT{
plit_commands
instruction
= PLIT_SYMBOL_OVERLAYID [
symbol
= PLIT_SYMBOL_ADDRESS
symbol
Figure 5-9. Syntax Tree of the PLIT{} Command
Parts of the
PLIT{}
•
instruction
The instructions may occur in any reasonable order in the com-
mand structure and may precede or follow symbols. The following
two constants contain information about symbol and the overlay in
which it occurs. You must supply instructions to handle that
information.
•
PLIT_SYMBOL_OVERLAYID
•
PLIT_SYMBOL_ADDRESS
resolved symbol in run-time memory

Command Evaluation and Setup

The linker first evaluates the sequence of assembly code in each
. Each line is passed to a processor-specific assembler, which
plit_command
supplies values for the symbols and expressions. After evaluation, the
linker places the returned bytes into the
addressing in that output section.
To help you write an overlay manager, the linker generates PLIT constants
for each symbol in an overlay. Data can be overlaid, just like code. If an
overlay-resident function calls for additional data overlays, include an
instruction for finding them.
VisualDSP++ 3.5 Linker and Utilities Manual
for 16-Bit Processors
}
command are:
– None, one, or multiple assembly instructions.
– Returns the overlay ID
– Returns the absolute address of the
]
symbol
output section and manages
.PLIT
5-35