Abstract: A system, method and computer program product for providing a shared memory translation facility. The method includes receiving a request for access to a memory address from a requestor at a configuration, the receiving at a shared memory translation mechanism. It is determined if the memory address refers to a shared memory object (SMO), the SMO accessible by a plurality of configurations. In response to determining that the memory address refers to the SMO, it is determined if the configuration has access to the SMO. In response to determining that the configuration has access to the SMO, the requestor is provided a system absolute address for the SMO and access to the SMO. In this manner direct interchange of data between the plurality of configurations is allowed.

Abstract: A system, method, and computer program product for handling shared cache lines to allow forward progress among processors in a multi-processor environment is provided. A counter and a threshold are provided a processor of the multi-processor environment, such that the counter is incremented for every exclusive cross interrogate (XI) reject that is followed by an instruction completion, and reset on an exclusive XI acknowledgement. If the XI reject counter reaches a preset threshold value, the processor's pipeline is drained by blocking instruction issue and prefetching attempts, creating a window for an exclusive XI from another processor to be honored, after which normal instruction processing is resumed. Configuring the preset threshold value as a programmable value allows for fine-tuning of system performance.

Abstract: A method, system and computer program product for providing filtering of level two guest (G2) quiesce requests. The method includes receiving a G2 quiesce interruption request at a processor currently or previously executing a G2 running under a level two hypervisor in a logical partition. The G2 includes a current zone and G2 virtual machine (VM) identifier. The quiesce interruption request specifies an initiating zone and an initiating G2 VM identifier. It is determined if the G2 quiesce interruption request can be filtered by the processor. The determining is responsive to the current G2 VM identifier, the current zone, the initiating zone and the initiating G2 VM identifier. The G2 quiesce interruption request is filtered at the processor in response to determining that the G2 quiesce interruption request can be filtered. Thus, filtering between G2 virtual machines running in the logical partition is provided.

Abstract: A system, method and computer program product for translations in a computer system. The system includes a general purpose register containing a base address of an address translation table. The system also includes a millicode accessible special displacement register configured to receive a plurality of elements to be translated. The system further includes a multiplexer for selecting a particular one of the plurality of elements from the millicode accessible special displacement register and for generating a displacement or offset value. The system further includes an address generator for creating a combined address containing the base address from the general purpose register and the generated displacement or offset value.

Abstract: A method, system and computer program product for performing an implicit predicted return from a predicted subroutine are provided. The system includes a branch history table/branch target buffer (BHT/BTB) to hold branch information, including a target address of a predicted subroutine and a branch type. The system also includes instruction buffers, and instruction fetch controls to perform a method including fetching a branch instruction at a branch address and a return-point instruction. The method also includes receiving the target address and the branch type, and fetching a fixed number of instructions in response to the branch type. The method further includes referencing the return-point instruction within the instruction buffers such that the return-point instruction is available upon completing the fetching of the fixed number of instructions absent a re-fetch of the return-point instruction.

Abstract: A microprocessor equipped to provide hardware initiated prefetching, includes at least one architecture for performing: issuance of a prefetch instruction; writing of a prefetch address into a prefetch fetch address register (PFAR); attempting a prefetch according to the address; detecting one of a cache miss and a cache hit; and if there is a cache miss, then sending a miss request to a next cache level and attempting cache access in a non-busy cycle; and if there is a cache hit, then incrementing the address in the PFAR and completing the prefetch. A method and a computer program product are provided.

Abstract: A system and method for avoiding deadlocks when performing storage updates in a multi-processor environment. The system includes a processor having a local cache, a store queue having a temporary buffer with capability to reject exclusive cross-interrogates (XI) while an interrogated cache line is owned exclusive and is to be stored, and a mechanism for performing a method. The method includes setting the processor into a slow mode. A current instruction that includes a data store having one or more target lines is received. The current instruction is executed, with the executing including storing results associated with the data store into the temporary buffer. The store queue is prevented from rejecting an exclusive XI corresponding to the target lines of the current instruction. Each target line is acquired with a status of exclusive ownership, and the contents from the temporary buffer are written to each target line after instruction completion.

Abstract: An extended DRAIN instruction is used to stall processing within a computing environment. The instruction includes an indication of the one or more processing stages at which processing is to be stalled. It also includes a control that allows processing to be stalled for additional cycles, as desired.

Abstract: What is provided is an enhanced dynamic address translation facility. In one embodiment, a virtual address to be translated and an initial origin address of any one of a region first table, a region second table, a region third table, or a segment table are obtained. Based on the obtained initial origin address, a segment table entry is obtained which contains a format control and DAT protection fields. If the format control field is enabled, obtaining from the translation table entry a segment-frame absolute address of a large block of data in main storage. The segment-frame absolute address is combined with a page index portion and a byte index portion of the virtual address to form a translated address of the desired block of data. If the DAT protection field is not enabled, fetches and stores are permitted to the desired block of data addressed by the translated virtual address.

Abstract: What is provided is an enhanced dynamic address translation facility. In one embodiment, a virtual address to be translated and an initial origin address of a translation table of the hierarchy of translation tables are obtained. A segment table entry obtained from a segment table contains a format control field. If the format control field is enabled, a segment-frame absolute address of a large block of data in main storage is obtained from the segment table entry. Each 4K byte block of data within the large block has an associated storage key. Store operations associated with the virtual address are performed to the desired block of data. If the change recording override field is disabled, the change bit of the storage key associated with the desired 4K byte block is set to 1. An indication is then provided that the desired 4K byte block has been modified.

Abstract: What is provided is an enhanced dynamic address translation facility. In one embodiment, a virtual address to be translated is first obtained and an initial origin address of a translation table of the hierarchy of translation tables is obtained. Based on the obtained initial origin, a segment table entry is obtained. The segment table entry is configured to contain a format control and access validity fields. If the format control and access validity fields are enabled, the segment table entry further contains an access control field, a fetch protection field, and a segment-frame absolute address. Store operations are permitted only if the access control field matches a program access key provided by any one of a Program Status Word or an operand of a program instruction being executed. Fetch operations are permitted if the program access key associated with the virtual address is equal to the segment access control field.

Abstract: What is provided is an enhanced dynamic address translation facility. In one embodiment, a virtual address to be translated and an initial origin address of a translation table of the hierarchy of translation tables are obtained. An index portion of the virtual address is used to reference an entry in the translation table. If a format control field contained in the translation table entry is enabled, the table entry contains a frame address of a large block of data of at least 1M byte in size. The frame address is then combined with an offset portion of the virtual address to form the translated address of a small 4K byte block of data in main storage or memory.

Abstract: What is provided is an enhanced dynamic address translation facility. In one embodiment, a virtual address to be translated and an initial origin address of a translation table of the hierarchy of translation tables are obtained. An index portion of the virtual address is used to reference an entry in the translation table. If the format control field is enabled, a frame address of a large block of data in main storage is obtained from the translation table entry. The large block of data is a block of at least 1M byte in size. The frame address is then combined with an offset portion of the virtual address to form the translated address of a desired block of data within the large block of data in main storage. The desired large block of data addressed by the translated address is then accessed.

Abstract: The setting of interruption initiatives is directly initiated by external adapters. An adapter external to the processors at which the initiative is to be made pending sends a request directly to a system controller coupled to the adapter and the processors. The system controller then broadcasts a command to the processors instructing the processors to set the interruption initiative.

Abstract: The setting of interruption initiatives is directly initiated by external adapters. An adapter external to the processors at which the initiative is to be made pending sends a request directly to a system controller coupled to the adapter and the processors. The system controller then broadcasts a command to the processors instructing the processors to set the interruption initiative.

Abstract: Complex floating point instructions are executed under millicode control when it is not cost effective to implement its function in hardware. One of the disadvantages to executing complex instructions using millicode routines is that determining and accessing the instructions operands are costly for millicode performance. To determine what the source and target location are, the instruction text is parsed. Furthermore the millicode instruction stream must be modified to access the operand data from and write the result to the program registers specified by the complex floating point instruction. The invention overcomes these disadvantages by providing millicode with register indirect access to the program floating point registers.

Abstract: A computer system with the means to identify based on the instruction being decoded that the operand data that this instruction will access by its nature will not have locality of access and should be installed in the cache in such a way that each successive line brought into the data cache that hits the same congruence class should be placed in the same set as to not disturb the locality of the data that resided in the cache prior to the execution of the instruction that accessed the data that will not have locality of access.

Abstract: An exemplary embodiment of the invention is a method for holding up recovery unit (R-unit) operands for a minimum number of cycles, until all prior updates have completed, by comparing addresses in at least one queue and interlocking valid R-unit register address matches. The method includes receiving a plurality of R-unit register addresses and storing these R-unit register addresses in at least one queue. This method includes a write queue, a read queue, and a pre-write queue. Further, this method requires accessing these queues and comparing the R-unit register addresses therein. After the addresses are compared, the method determines whether there is a valid match between the R-unit register addresses and if so, implementing one of more interlocks.

Abstract: A method of supporting programs that include instructions that modify subsequent instructions in a multi-processor system with a central processing unit including an execution unit, and instruction unit and a plurality of caches including a separate instruction and operand cache.

Abstract: Cryptographic functions are implemented in execution unit hardware on the CPU of a computer system. This implementation enables a lower latency for calling and executing cryptographic operations and increases the efficiency. This decreased latency greatly enhances the capability of general purpose processors in systems that frequently do many cryptographic operations, particularly when only small amounts of data are involved. This allows an implementation that can significantly accelerate the processes involved in doing secure online transactions.