Browse Prior Art Database

Dynamic Fast-Path Transfer of Control

IP.com Disclosure Number: IPCOM000102133D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 36K

Publishing Venue

IBM

Related People

Pruul, EA: AUTHOR

Abstract

When a computer program executes another program it requests the operating system to return the address of the target program and then transfer control to that address. This style of interface is very fast. However, it is limiting in that the operating system is locked into one method of transfer. Dynamic "fast-path" transfer of control to another program can utilize operating system enhancements by immediately branching to an executable control block which acts as a front-end, or prolog, for the target program. Conversational Monitoring System (CMS), used in IBM's Virtual Machine/System Product (VM/SP), the operating system for 370 processors and 370 Enterprise System Architecture (ESA) processors, provides dynamic loading capability in SP Release 6, with a dynamic fast-path "branch-type" transfer mechanism.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 95% of the total text.

Dynamic Fast-Path Transfer of Control

       When a computer program executes another program it
requests the operating system to return the address of the target
program and then transfer control to that address.  This style of
interface is very fast.  However, it is limiting in that the
operating system is locked into one method of transfer.  Dynamic
"fast-path" transfer of control to another program can utilize
operating system enhancements by immediately branching to an
executable control block which acts as a front-end, or prolog, for
the target program. Conversational Monitoring System (CMS), used in
IBM's Virtual Machine/System Product (VM/SP), the operating system
for 370 processors and 370 Enterprise System Architecture (ESA)
processors, provides dynamic loading capability in SP Release 6, with
a dynamic fast-path "branch-type" transfer mechanism.  If user
requirements (such as security) place the target program into another
address space, the simple branch interface would not work.  A method
that allows programs operating in different address spaces to
transfer control, without loss of system enhancements, is
accomplished in the following.

      The fast-path linkage previously mentioned is a branch to an
executable control block.  This control block is called a prolog.
Various versions of the operating system can create a prolog tailored
to whatever transfer mechanism is appropriate, such as a program call
instruction across address spaces, which...