@@ -2531,6 +2534,36 @@ Here's a list of all control commands and a description, what they do:
+.INTERRUPTOR
+
+ Export a symbol and mark it as an interruptor. This may be used together
+ with the linker to build a table of interruptor subroutines that are called
+ in an interrupt.
+
+ Note: The linker has a feature to build a table of marked routines, but it
+ is your code that must call these routines, so just declaring a symbol as
+ interruptor does nothing by itself.
+
+ An interruptor is always exported as an absolute (16 bit) symbol. You don't
+ need to use an additional
+ .interruptor IrqHandler
+ .interruptor Handler, 16
+
+
+ See the command and the separate
+ section [ explaining
+ the feature in more detail.
+
+
].LINECONT
Switch on or off line continuations using the backslash character
@@ -3713,14 +3746,16 @@ below uses examples from the C libraries. However, the feature may also be
useful for assembler programs.
-Module overview
+Overview
-Using the and keywords it it possible to export
-functions in a special way. The linker is able to generate tables with all
-functions of a specific type. Such a table will only include symbols
-from object files that are linked into a specific executable. This may be used
-to add initialization and cleanup code for library modules.
+Using the , and keywords it it possible to export functions in a
+special way. The linker is able to generate tables with all functions of a
+specific type. Such a table will only include symbols from object
+files that are linked into a specific executable. This may be used to add
+initialization and cleanup code for library modules, or a table of interrupt
+handler functions.
The C heap functions are an example where module initialization code is used.
All heap functions (malloc , free , ...) work with a few
@@ -3761,36 +3796,35 @@ two bytes in the table (a pointer to the function).
Calling order
-Both, constructors and destructors are sorted in increasing priority order by
-the linker when using one of the builtin linker configurations, so the
-functions with lower priorities come first and are followed by those with
-higher priorities. The C library runtime subroutine that walks over the
-constructor and destructor tables calls the functions starting from the top of
-the table - which means that functions with a high priority are called first.
+The symbols are sorted in increasing priority order by the linker when using
+one of the builtin linker configurations, so the functions with lower
+priorities come first and are followed by those with higher priorities. The C
+library runtime subroutine that walks over the function tables calls the
+functions starting from the top of the table - which means that functions with
+a high priority are called first.
-So when using the C runtime, both constructors and destructors are called with
-high priority functions first, followed by low priority functions.
+So when using the C runtime, functions are called with high priority functions
+first, followed by low priority functions.
Pitfalls
-When creating and using module constructors and destructors, please take care
-of the following:
+When using these special symbols, please take care of the following:
--
+
-
The linker will only generate function tables, it will not generate code to
call these functions. If you're using the feature in some other than the
existing C environments, you have to write code to call all functions in a
-linker generated table yourself. See the
condes module in the C
-runtime for an example on how to do this.
+linker generated table yourself. See the /condes/ and
The linker will only add addresses of functions that are in modules linked to
the executable. This means that you have to be careful where to place the
-condes functions. If initialization is needed for a group of functions, be
-sure to place the initialization function into a module that is linked in
+condes functions. If initialization or an irq handler is needed for a group of
+functions, be sure to place the function into a module that is linked in
regardless of which function is called by the user.
-
@@ -3805,11 +3839,12 @@ does depend on other initialization or cleanup code, you have to choose the
priority for the functions accordingly.
-
-Besides the
and statements, there is also a more
-generic command: . This allows to
-specify an additional type. Predefined types are 0 (constructor) and 1
-(destructor). The linker generates a separate table for each type on request.
+Besides the , and statements, there is also a more generic command:
+ . This allows to specify an
+additional type. Predefined types are 0 (constructor), 1 (destructor) and 2
+(interruptor). The linker generates a separate table for each type on request.