The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 1995
Filed:
Dec. 18, 1992
Jean-Charles D Mourey, Cupertino, CA (US);
Sean R Parent, Morgan Hill, CA (US);
Bruce K Jones, Mountain View, CA (US);
Alan W Lillich, Los Gatos, CA (US);
Erik L Eidt, Campbell, CA (US);
Eric P Traut, Mountain View, CA (US);
Apple Computer, Inc., Cupertino, CA (US);
Abstract
The invention provides a method and apparatus for switching between execution of a plurality of object code types having different conventions for invoking program procedures and performing stack manipulations. The invention may also be used to switch between different calling conventions within a single object code type. Briefly according to the invention, a computer system comprises a routine descriptor, a stack switch frame, a mode switching mechanism for switching from a first processor, code or calling convention type to a second processor, code or calling convention type and means for executing instructions in various code type codes. A routine descriptor describes a program or code segment and its code type and calling conventions. A routine descriptor contains, among other information, a 'mixed mode' field which is set to a specific, predetermined value such as a value indicating an instruction which is not legal in the runtime environment of a first processor, code or calling convention type. When that instruction is encountered, control is transferred to the mode switching mechanism. A routine descriptor also contains a 'procedure information' field which is set to a value indicating the convention for invoking a program segment and performing appropriate stack manipulations. When a routine calls a routine having a different stack model, the mode switching mechanism uses a stack switch frame to provide a transition between the two different stack types.