Simulation of computer processor

An instruction emulation system which translates target instructions into emulation instructions, the system comprising:

• a host processor which executes instructions formatted in accordance with a host processor instruction set;
• a target instruction memory in which the target instructions are stored, the target instructions being grouped into a plurality of blocks, at least some of the blocks having both a signal handing target instruction and a non-signal handling target instruction;
• an translation instruction memory, the translation instruction memory having sets of translating instructions for generating emulation instructions for the target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• a jump table memory having stored therein a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• a jump table shadow memory having a plurality of jump table shadow tables, each jump table shadow table being paired with one of the plurality of blocks having a signal handing target instruction, each jump table shadow table having stored therein a copy of a jump table entry associated with the signal handling target instruction included the block with which the jump table entry table is paired;
• wherein, in compiling a designated block of target instructions, the host processor compiles a portion of the jump table which corresponds to the designated block and the jump table shadow table for any other block invoked by a signal generated by the designated block.

An instruction emulation system which translates target instructions into emulation instructions, the system comprising:

• a host processor which executes instructions formatted in accordance with a host processor instruction set;
• a target instruction memory in which the target instructions are stored, the target instructions being grouped into a plurality of blocks;
• an translation instruction memory, the translation instruction memory having sets of translating instructions for generating emulation instructions for each of the target instructions;
• a jump table memory having a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• wherein the jump table memory is partitioned into segments corresponding to the blocks stored in the target instruction memory, and wherein selected ones of the segments of the jump table memory are uncompacted in accordance with a recent utilization criteria and non-selected ones of the segments are compacted.

A method of using a host processor to simulate a target processor, the method comprising:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the fetching, decoding, translating, and executing steps are performed coordinated in pipeline fashion;
• wherein the step of translating the emulating instructions includes storing the emulation instructions in an emulation instruction area of a memory,
• wherein the step of executing the emulation instructions includes obtaining the emulation instructions from the memory, and
• wherein the method further comprises:
• making a determination when more emulation instructions are needed for execution by the host processor, and
• in response to the determination, interrupting the decoding and translating of the target instructions in order to fetch more target instructions.

A method of using a host processor to simulate a target processor, the method comprising:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the fetching, decoding, translating, and executing steps are performed coordinated in pipeline fashion;
• wherein the target instruction memory has target instructions of differing types, the target instructions stored in the target instruction memory having non-uniform instruction length including a shortest target instruction length;
• executing a translation routine to perform the step of translating the target instructions into emulation instructions, the translation routing comprising translation instructions stored in a translation instruction memory, the translation instruction memory having sets of translating instructions for generating emulation instructions for each of the differing types of target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• and
• providing a jump table memory having a plurality of entries, each of the plurality of entries in the jump table having an entry length which is no greater than the shortest target instruction length, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory.

A method of using a host processor to simulate a target processor, the method comprising:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the fetching, decoding, translating, and executing steps are performed coordinated in pipeline fashion;
• grouping the target instructions being grouped into a plurality of blocks, at least some of the blocks having both a signal handing target instruction and a non-signal handling target instruction;
• executing a translation routine to perform the step of translating the target instructions into emulation instructions, the translation routing comprising sets of translation instructions stored in a translation instruction memory for generating emulation instructions for each of the differing types of target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• providing a jump table memory having stored therein a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• providing a jump table shadow memory having a plurality of, jump table shadow tables, each jump table shadow table being paired with one of the plurality of blocks having a signal handing target instruction, each jump table shadow table having stored therein a copy of a jump table entry associated with the signal handling target instruction included the block with which the jump table entry table is paired;
• wherein, in compiling a designated block of target instructions, the host processor compiles a portion of the jump table which corresponds to the designated block and the jump table shadow table for any other block invoked by a signal generated by the designated block.

A method of using a host processor to simulate a target processor, the method comprising:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the fetching, decoding, translating, and executing steps are performed coordinated in pipeline fashion;
• grouping the target instructions being grouped into a plurality of blocks;
• executing a translation routine to perform the step of translating the target instructions into emulation instructions, the translation routing comprising sets of translation instructions stored in a translation instruction memory,
• providing a jump table memory having a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• partitioning the jump table memory into segments corresponding to the blocks stored in the target instruction memory;
• and
• uncompacting selected ones of the segments of the jump table memory are in accordance with a recent utilization criteria with non-selected ones of the segments being compacted.

An instruction emulation system comprising:

• a target instruction memory for storing target instructions coded in accordance with an instruction set of the target processor;
• a host processor which performs the following in coordinated pipeline fashion:
• (1) decoding the target instructions;
• (2) translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• (3) executing the emulation instructions;
• an emulation instruction area of a memory;
• wherein in translating the emulating instructions the host processor stores the emulation instructions in an emulation instruction area of a memory, wherein the executing of the emulation instructions includes obtaining the emulation instructions from the emulation instruction area of memory, and wherein the host processor makes a determination when more emulation instructions are needed for execution by the host processor and, in response to the determination, interrupts the decoding and translating of the target instructions in order to fetch more target instructions.

An instruction emulation system comprising:

• a target instruction memory for storing target instructions coded in accordance with an instruction set of the target processor;
• a host processor which performs the following in coordinated pipeline fashion:
• (1) decoding the target instructions;
• (2) translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• (3) executing the emulation instructions;
• wherein the target instruction memory has target instructions of differing types, the target instructions stored in the target instruction memory having non-uniform instruction length including a shortest target instruction length;
• wherein the host processor executes a translation routine to perform the translating of the target instructions into emulation instructions, the translation routing comprising translation instructions stored in a translation instruction memory, the translation instruction memory having sets of translating instructions for generating emulation instructions for each of the differing types of target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• and
• a jump table memory having a plurality of entries, each of the plurality of entries in the jump table having an entry length which is no greater than the shortest target instruction length, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory.

An instruction emulation system comprising:

• a target instruction memory for storing target instructions coded in accordance with an instruction set of the target processor;
• a host processor which performs the following in coordinated pipeline fashion:
• (1) decoding the target instructions;
• (2) translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• (3) executing the emulation instructions;
• wherein the target instructions are grouped into a plurality of blocks, at least some of the blocks having both a signal handing target instruction and a non-signal handling target instruction;
• wherein the host processor executes a translation routine to perform the translating of the target instructions into emulation instructions, the translation routing comprising sets of translation instructions stored in a translation instruction memory for generating emulation instructions for each of the differing types of target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• a jump table memory having stored therein a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• a jump table shadow memory having a plurality of jump table shadow tables, each jump table shadow table being paired with one of the plurality of blocks having a signal handing target instruction, each jump table shadow table having stored therein a copy of a jump table entry associated with the signal handling target instruction included the block with which the jump table entry table is paired;
• wherein, in compiling a designated block of target instructions, the host processor compiles a portion of the jump table which corresponds to the designated block and the jump table shadow table for any other block invoked by a signal generated by the designated block.

An instruction emulation system comprising:

• a target instruction memory for storing target instructions coded in accordance with an instruction set of the target processor;
• a host processor which performs the following in coordinated pipeline fashion:
• (1) decoding the target instructions;
• (2) translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• (3) executing the emulation instructions;
• wherein the target instructions are grouped in the target instruction memory into a plurality of blocks;
• wherein the host processor executes a translation routine to perform the translating of the target instructions into emulation instructions, the translation routing comprising sets of translation instructions stored in a translation instruction memory;
• a jump table memory having a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• wherein the jump table memory is partitioned into segments corresponding to the blocks stored in the target instruction memory, and wherein selected ones of the segments of the jump table memory are uncompacted in accordance with a recent utilization criteria and non-selected ones of the segments are compacted.

A computer software product including emulation supervisory routine instructions stored in a memory for execution by a host processor to simulate a target processor, the emulation supervisory routine performing the following steps:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the step of translating the emulating instructions includes storing the emulation instructions in an emulation instruction area of a memory;
• wherein the step of executing the emulation instructions includes obtaining the emulation instructions from the memory,
• making a determination when more emulation instructions are needed for execution by the host processor, and
• in response to the determination, interrupting the decoding and translating of the target instructions in order to fetch more target instructions.

A computer software product including emulation supervisory routine instructions stored in a memory for execution by a host processor to simulate a target processor, the emulation supervisory routine performing the following steps:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the target instruction memory has target instructions of differing types, the target instructions stored in the target instruction memory having non-uniform instruction length including a shortest target instruction length;
• executing a translation routine to perform the step of translating the target instructions into emulation instructions, the translation routing comprising translation instructions stored in a translation instruction memory, the translation instruction memory having sets of translating instructions for generating emulation instructions for each of the differing types of target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• and
• administering a jump table memory having a plurality of entries, each of the plurality of entries in the jump table having an entry length which is no greater than the shortest target instruction length, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory.

A computer software product including emulation supervisory routine instructions stored in a memory for execution by a host processor to simulate a target processor, the emulation supervisory routine performing the following steps:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the steps coordinated further comprise:
• grouping the target instructions being grouped into a plurality of blocks, at least some of the blocks having both a signal handing target instruction and a non-signal handling target instruction;
• executing a translation routine to perform the step of translating the target instructions into emulation instructions, the translation routing comprising sets of translation instructions stored in a translation instruction memory for generating emulation instructions for each of the differing types of target instructions, the sets of translating instructions being formatted in accordance with the host processor instruction set, the emulation instructions generated for a particular target instruction being structured to accomplish a same activity as the particular target instruction for which it is generated;
• administering a jump table memory having stored therein a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• administering a jump table shadow memory having a plurality of jump table shadow tables, each jump table shadow table being paired with one of the plurality of blocks having a signal handing target instruction, each jump table shadow table having stored therein a copy of a jump table entry associated with the signal handling target instruction included the block with which the jump table entry table is paired;
• wherein, in compiling a designated block of target instructions, the host processor compiles a portion of the jump table which corresponds to the designated block and the jump table shadow table for any other block invoked by a signal generated by the designated block.

A computer software product including emulation supervisory routine instructions stored in a memory for execution by a host processor to simulate a target processor, the emulation supervisory routine performing the following steps:

• fetching, from a target instruction memory, target instructions coded in accordance with an instruction set of the target processor;
• decoding the target instructions;
• translating the target instructions into emulation instructions, the emulation instructions being formatted in accordance with an instruction set of the host processor;
• executing the emulation instructions using the host processor;
• wherein the steps coordinated further comprise:
• grouping the target instructions being grouped into a plurality of blocks;
• executing a translation routine to perform the step of translating the target instructions into emulation instructions, the translation routing comprising sets of translation instructions stored in a translation instruction memory,
• administering a jump table memory having a plurality of entries, a selected target instruction in the target instruction memory having associated therewith a selected entry in the jump table memory, the selected entry in the jump table memory having stored therein a pointer to a specific one of the sets of translation instructions in the translation instruction memory;
• partitioning the jump table memory into segments corresponding to the blocks stored in the target instruction memory;
• and
• uncompacting selected ones of the segments of the jump table memory are in accordance with a recent utilization criteria with non-selected ones of the segments being compacted.