US 6,446,094 B1 · Data structure for emulating virtual memory working spaces

Abstract

In an emulation of a multiprocessor Target computer system on a Host computer system, Host virtual memory addresses are mapped and utilized as Target virtual memory addresses. Target virtual memory control tables are setup accordingly. Virtual-to-real address translation of a Target system effective address to a Host system virtual addresses is performed by identifying a working space for the effective address, selecting a working space base address data structure entry utilizing the corresponding working space number, determining a working space base address from that selected working space base address data structure entry, and then performing a linear translation multiplying the effective address by a constant and adding it to the working space base address to generate the host system virtual address. A corresponding working space limit entry can be utilized to bounds check the addresses generated.

Claims16

Dependent claims

A data structure stored in a Host memory in a Host computer system for use in emulator software executing on the Host computer system emulating a Target computer system supporting a plurality of working spaces for performing virtual-to-real memory address translation of a Target computer system effective address to an address in a Host virtual memory assigned to the emulator software during emulation of a Target instruction for the Target computer system by the emulator software, wherein:

the data structure comprises:
a working space table comprising:
a plurality of working space base address table entries, with each of the plurality of working space base address table entries corresponding to a working space;
a first one of the plurality of working space base address table entries corresponding to a first one of the plurality of working spaces contains a first one of a plurality of Host virtual memory addresses;
a second one of the plurality of working space base address table entries corresponding to a second one of the plurality of working spaces contains a second one of the plurality of Host virtual memory addresses,
each of the plurality of Host virtual memory addresses is a virtual memory address within a contiguous extent of the Host virtual memory assigned to the emulator software;
the first one of the plurality of Host memory virtual addresses identifies a first contiguous subset of the Host virtual memory assigned to the emulator software;
and
the second one of the plurality of Host memory virtual addresses identifies a second contiguous subset of the Host virtual memory assigned to the emulator software.

6 more elements

A machine readable medium containing emulator software for emulating a set of Target code instructions for a Target computer system supporting a plurality of working spaces by executing a plurality of Host instructions on a Host computer system, wherein the emulator software utilizes a data structure for performing virtual-to-real memory address translation of a Target computer system effective address to an address in a Host virtual memory assigned to the emulator software during emulation of a Target instruction for the Target computer system by the emulator software, wherein:

the data structure comprises:
a working space table comprising:
a plurality of working space base address table entries, with each of the plurality of working space base address table entries corresponding to a working space;
a first one of the plurality of working space base address table entries corresponding to a first one of the plurality of working spaces contains a first one of a plurality of Host virtual memory addresses;
a second one of the plurality of working space base address table entries corresponding to a second one of the plurality of working spaces contains a second one of the plurality of Host virtual memory addresses;
each of the plurality of Host virtual memory addresses is a virtual memory address within a contiguous extent of the Host virtual memory assigned to the emulator software,
the first one of the plurality of Host memory virtual addresses identifies a first contiguous subset of the Host virtual memory assigned to the emulator software;
and
the second one of the plurality of Host memory virtual addresses identifies a second contiguous subset of the Host virtual memory assigned to the emulator software.

6 more elements

Dependencies are inferred from the claim text.

Data structure for emulating virtual memory working spaces

Life of this patent

Data structure for emulating virtual memory working spaces

Life of this patent

Abstract

Claims16