Abstract: In one embodiment, after translating a plurality of target instructions from a target memory location into a plurality of host instructions, a write operation to a target memory portion which includes said target memory location is detected. In response to the detecting, a copy of the target instructions is stored in a host memory. In response to an attempt to execute the host instructions, the copy is compared with a plurality of current target instructions presently stored in the target memory location. Further, in response to a mismatch based on the comparison, the host instructions are disabled.

Abstract: In one embodiment, after translating a plurality of target instructions from a target memory location into a plurality of host instructions, a write operation to a target memory portion which includes said target memory location is detected. In response to the detecting, a copy of the target instructions is stored in a host memory. In response to an attempt to execute the host instructions, the copy is compared with a plurality of current target instructions presently stored in the target memory location. Further, in response to a mismatch based on the comparison, the host instructions are disabled.

Abstract: A method and system of instruction modification. A first machine language instruction, which may comprise a plurality of discrete instructions, is fetched. Responsive to a trigger pattern in the first machine language instruction, a segment of the first machine language instruction is modified. Information can be substituted into the segment based on specifics outlined in the trigger pattern. Alternatively, information can be combined with the segment via logical and/or arithmetic operations. Modification of the segment produces a second machine language instruction that is executed by units of the processor. In one embodiment, information may be taken from a queue and used to replace data from the segment. How information is taken from the queue and how the information so taken is used to replace fields of the segment are defined by the trigger pattern.

Abstract: A method and system of instruction modification. A first machine language instruction, which may comprise a plurality of discrete instructions, is fetched. Responsive to a trigger pattern in the first machine language instruction, a segment of the first machine language instruction is modified. Information can be substituted into the segment based on specifics outlined in the trigger pattern. Alternatively, information can be combined with the segment via logical and/or arithmetic operations. Modification of the segment produces a second machine language instruction that is executed by units of the processor. In one embodiment, information may be taken from a queue and used to replace data from the segment. How information is taken from the queue and how the information so taken is used to replace fields of the segment are defined by the trigger pattern.

Abstract: In one embodiment, after translating a plurality of target instructions from a target memory location into a plurality of host instructions, a write operation to a target memory portion which includes said target memory location is detected. In response to the detecting, a copy of the target instructions is stored in a host memory. In response to an attempt to execute the host instructions, the copy is compared with a plurality of current target instructions presently stored in the target memory location. Further, in response to a mismatch based on the comparison, the host instructions are disabled.

Abstract: A method and system of instruction modification. A first machine language instruction, which may comprise a plurality of discrete instructions, is fetched. Responsive to a trigger pattern in the first machine language instruction, a segment of the first machine language instruction is modified. Information can be substituted into the segment based on specifics outlined in the trigger pattern. Alternatively, information can be combined with the segment via logical and/or arithmetic operations. Modification of the segment produces a second machine language instruction that is executed by units of the processor. In one embodiment, information may be taken from a queue and used to replace data from the segment. How information is taken from the queue and how the information so taken is used to replace fields of the segment are defined by the trigger pattern.

Abstract: A method and apparatus for storing and retrieving data in an N-way set associative cache with N data array banks is disclosed. On a cache fill corresponding to a particular way, a portion of each cache line (called a chunk) is placed in each data array bank. On a processor load seeking a requested chunk, a candidate chunk is retrieved from each data array bank and the requested chunk is selected from among the candidates.

Abstract: Dynamic translation of indirect branch instructions of a target application by a host processor is enhanced by including a cache to provide access to the addresses of the most frequently used translations of a host computer, minimizing the need to access the translation buffer. Entries in the cache have a host instruction address and tags that may include a logical address of the instruction of the target application, the physical address of that instruction, the code segment limit to the instruction, and the context value of the host processor associated with that instruction. The cache may be a software cache apportioned by software from the main processor memory or a hardware cache separate from main memory.

Abstract: In a computer which translates instructions from a target instruction set to a host instruction set, a method for determining validity of a translation of a target instruction linked to an earlier translation including the steps of testing a memory address of a target instruction to be executed against a copy of the memory address of the target instruction from which a translation of the target instruction was made, executing the translation if the addresses compare, and generating an exception if the addresses do not compare.

Abstract: A method of translating instructions from a target instruction set to a host instruction set. In one embodiment, a plurality of first target instructions is translated into a plurality of first host instructions. After the translation, it is determined whether the plurality of first target instructions has changed. A copy of a second plurality of target instructions is stored and compared with the plurality of first target instructions if the determining slows the operation of the computer system. After comparing, the plurality of first host instructions is invalidated if there is a mismatch. According to one embodiment, the storing, the comparing and the invaliding is initiated when the determining indicates that a page contains at least one change to the plurality of first target instructions. In one embodiment, the determining is by examining a bit indicator associated with a memory location of the plurality of first target instructions.

Abstract: A method of translating instructions from a target instruction set to a host instruction set. In one embodiment, a plurality of first target instructions is translated into a plurality of first host instructions. After the translation, it is determined whether the plurality of first target instructions has changed. A copy of a second plurality of target instructions is stored and compared with the plurality of first target instructions if the determining slows the operation of the computer system. After comparing, the plurality of first host instructions is invalidated if there is a mismatch. According to one embodiment, the storing, the comparing and the invaliding is initiated when the determining indicates that a page contains at least one change to the plurality of first target instructions. In one embodiment, the determining is by examining a bit indicator associated with a memory location of the plurality of first target instructions.

Abstract: An instruction memory for storing a plurality of instruction bits. A first portion of the instruction memory is for storing a first subset of bits of the plurality of instruction bits. A second portion of the instruction memory is for storing a second subset of bits of the plurality of instruction bits, wherein the second subset of bits is operable to be accessed by an instruction extractor during an instruction extraction earlier than the first subset of bits.

Abstract: Dynamic translation of indirect branch instructions of a target application by a host processor is enhanced by including a cache to provide access to the addresses of the most frequently used translations of a host computer, minimizing the need to access the translation buffer. Entries in the cache have a host instruction address and tags that may include a logical address of the instruction of the target application, the physical address of that instruction, the code segment limit to the instruction, and the context value of the host processor associated with that instruction. The cache may be a software cache apportioned by software from the main processor memory or a hardware cache separate from main memory.

Abstract: In a computer system that translates target instructions from a target instruction set into host instructions from a host instruction set, a method for checking a sequence of target instructions for changes. The method includes testing whether the target instructions at a memory location have changed subsequent to the translating by examining a bit indicator associated with the memory location and determining whether the testing is slowing the operation of the computer system. If the testing is slowing the operation of the computer system, a checking process initiated, which includes storing a copy of the sequence of target instructions and comparing the copy with the sequence of target instructions.

Abstract: In a computer which translates instructions from a target instruction set to a host instruction set, a method for determining validity of a translation of a target instruction linked to an earlier translation including the steps of testing a memory address of a target instruction to be executed against a copy of the memory address of the target instruction from which a translation of the target instruction was made, executing the translation if the addresses compare, and generating an exception if the addresses do not compare.

Abstract: The speed of processing of a sequence of indirect branch instructions in a pipelined processor is increased by overlapping the latencies in the sequence of indirect branch instructions. The architecture of a digital processor is modified to include a link pipe system that allows the sequence of branch addresses required by the indirect branches to be written to a single location within the processor, and to be read from a single location in the processor. The link pipe system contains a plurality of registers (3, 5 & 7) for storage of respective branch target addresses. Each WRITE of a branch address is automatically directed (9) to individual registers within the link pipe system for storing the respective branch addresses; and each READ of a branch address is automatically directed (11) to the register containing the earliest WRITE of an address that was not previously read by the processor, whereby branch target addresses are retrieved on a “first in, first out” basis.

Abstract: Dynamic translation of indirect branch instructions of a target application by a host processor is enhanced by including a cache to provide access to the addresses of the most frequently used translations of a host computer, minimizing the need to access the translation buffer. Each entry in the cache includes a host instruction address, a logical address of the instruction of the target application, the physical address of that instruction, the code segment limit to the instruction, and the context value of the host processor associated with that instruction, the last four named components constituting tags to the host instruction address, and a valid-invalid bit. In a basic embodiment, the cache is a software cache apportioned by software from the main processor memory chips.

Abstract: A method for maintaining consistency between translated host instructions and target instructions from which the host instructions have been translated including the steps of maintaining a copy of a target instruction for which a translated host instruction have been made, comparing the copy of the target instruction with a target instruction at a memory address at which the target instruction from which the copy was made was stored when translated, disabling the translated host instruction if the copy of the target instruction is not the same as the target instruction at the memory address, and executing the translated host instruction if the copy of the target instruction is the same as the target instruction at the memory address.

Abstract: A method for determining if writes to a memory page are directed to target instructions which have been translated to host instructions in a computer which translates instructions from a target instruction set to a host instruction set, including the steps of detecting a write to a memory page storing target instructions which have been translated to host instructions, detecting whether a sub-area of the memory page to which the write is addressed stores target instructions which have been translated, and invalidating host instructions translated from addressed target instructions.