EP1103890A2
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EP
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Method for the direct call of a function by a software module by means of a processor with a memory-management-unit (MMU)
Assignee: National Instruments Ireland Resources Ltd
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Filing: 2000-11-03
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Granted: —
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Expires: 2020-11-03
Abstract
Abstract A method for the direct call of a target function by a start function by means of a processor with a memory management unit (MMU) in a computer operated by an operating system. In today's multitasking operating systems, the call of a function of a first task by a second task is executed and managed by the task scheduler of the operating system. The time of the execution of the called function is uncertain and is dependent on the operating system as well as the tasks managed at every point in time by the operating system. One object of the invention is to disclose a method which enables a time-determined call of a function and which is executed immediately in connection with the call. This object is achieved in that the start function is a component of a first task with a first memory context and in that the first task performs a context switch from the first memory context into the other memory context and this memory switch is reversed after the execution of the target function.
Inventors
- 👤 Stefan Klemens Müller
- 👤 Rudolf Nacken
- 👤 Clemens Bierwisch
- 👤 Ulrich Dieterle
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:28
CPC Classifications
G; G06; G06F; G06F9/00; G06F9/06; G06F9/46; G06F9/54
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
92 words
Method for the direct call of a target function by means of a start
function through a processor with a memory management unit (MMU) in a
computer operated by an operating system, characterized in that the start function is
a component of a first task with a first memory context and the target function is in
another memory context and in that the first task performs a context switch from the
first memory context into the other memory context and this context switch is
reversed after the execution of the target function.
Claim 2
Dependent Claim
40 words
Method according to Claim 1, characterized in that in order to
perform the context switch, the physical address of the memory context of the task
containing the target function is written into the MMU control register by the first
task.
Claim 3
Dependent Claim
43 words
Method according to Claim 1, characterized in that parts of the first
task as well as parts of the second task containing the target function are copied into
a new memory context and the context switch is performed into this new memory
context.
Claim 4
Dependent Claim
77 words
Method according to Claim 3, wherein the computer features
working memory (RAM) and mass storage, e.g., a hard disk, and wherein the
operating system swaps out parts of the working memory to the mass storage as
required, characterized in that the memory region of the copied memory context is
locked at least during the runtime of the target function called by the start function
in order to avoid swapping out this memory region from the working memory.
Claim 5
Dependent Claim
41 words
Method according to any one of the preceding claims, characterized
in that the start function avoids task switching by the operating system during the
runtime of the target function by deactivating the interrupt handling by means of a
processor control register.
Claim 6
Dependent Claim
26 words
Method according to any one of the preceding claims, characterized
in that the target function includes no program steps containing a call of the
operating system.
Claim 7
Dependent Claim
40 words
Method according to any one of the preceding claims, characterized
in that during the call to the target function by the start function, a new call to the
target function by a function outside of the target function is blocked.
Claim 8
Dependent Claim
41 words
Method according to any one of the preceding claims, characterized
in that the task containing the target function only executes accesses that are
performed entirely within a processing cycle to data that could be used or changed
by the target function.
Claim 9
Dependent Claim
38 words
Method according to any one of the preceding claims, characterized
in that the task containing the target function only executes accesses that are
protected by flags to data that could be used or changed by the target function.
Claim 10
Dependent Claim
49 words
Software program to be loaded into the working memory of a
computer operated by an operating system with a processor with a memory
management unit (MMU), characterized in that it includes a task with a start
function for performing a method according to any one of the preceding claims.
Claim 11
Dependent Claim
30 words
Software program according to Claim 10, characterized in that it
includes a second task with a target function for performing a method according to
any one of the preceding claims.
Claim 12
Dependent Claim
13 words
Machine-readable data carrier with a software program according to
claim 10 or 11.
Claim 13
Independent Claim
107 words
A method for the direct call of a target function by means of a start
function in a computer system comprising a processor with a memory management
unit (MMU), wherein the computer system includes an operating system, wherein
the start function is a component of a first task with a first memory context and the
target function is in another memory context, the method comprising: the first task performing a context switch from the first memory context into
the other memory context; executing the target function in the other memory context; reversing said context switch to return to the first memory context after
executing the target function.
Claim 14
Dependent Claim
43 words
The method according to Claim 13, wherein the CPU includes a
MMU control register; wherein the first task performing the context switch includes the first task
writing the physical address of the memory context containing the target function
into the MMU control register.
Claim 15
Dependent Claim
60 words
The method according to Claim 13, further comprising
copying parts of the memory context of the first task as well as parts of the
memory context of the second task containing the target function into a new
memory context; wherein the first task performing the context switch comprises the first task
performing the context switch into the new memory context.
References Cited (Backward Citations)
No citation records indexed.
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