Abstract:
Machine instructions, referred to herein as a long Convert from Zoned instruction (CDZT) and extended Convert from Zoned instruction (CXZT), are provided that read EBCDIC or ASCII data from memory, convert it to the appropriate decimal floating point format, and write it to a target floating point register or floating point register pair. Further, machine instructions, referred to herein as a long Convert to Zoned instruction (CZDT) and extended Convert to Zoned instruction (CZXT), are provided that convert a decimal floating point (DFP) operand in a source floating point register or floating point register pair to EBCDIC or ASCII data and store it to a target memory location.
Abstract:
Execution of instructions in a transactional environment is selectively controlled. A TRANSACTION BEGIN instruction initiates a transaction and includes controls that selectively indicate whether certain types of instructions are permitted to execute within the transaction. The controls include one or more of an allow access register modification control and an allow floating point operation control.
Abstract:
A transaction is initiated via a transaction begin instruction. During execution of the transaction, the transaction may abort. If the transaction aborts, a determination is made as to the type of transaction. Based on the transaction being a first type of transaction, resuming execution at the transaction begin instruction, and based on the transaction being a second type, resuming execution at an instruction following the transaction begin instruction. Regardless of transaction type, resuming execution includes restoring one or more registers specified in the transaction begin instruction and discarding transactional stores. For one type of transaction, the nonconstrained transaction, the resuming includes storing information in a transaction diagnostic block.
Abstract:
Program exception conditions cause a transaction to abort and typically result in an interruption in which the operating system obtains control. A program interruption filtering control is provided to selectively present the interrupt. That is, the interrupt from the program exception condition may or may not be presented depending at least on the program interruption filtering control and a transaction class associated with the program exception condition. The program interruption filtering control is provided by a TRANSACTION BEGIN instruction.
Abstract:
Vector exception handling is facilitated. A vector instruction is executed that operates on one or more elements of a vector register. When an exception is encountered during execution of the instruction, a vector exception code is provided that indicates a position within the vector register that caused the exception. The vector exception code also includes a reason for the exception.
Abstract:
Constrained transactional processing is provided. A constrained transaction is initiated by execution of a Transaction Begin constrained instruction. The constrained transaction has a number of restrictions associated therewith. Absent violation of a restriction, the constrained transaction is to complete. If an abort condition is encountered, the transaction is re-executed starting at the Transaction Begin instruction. Violation of a restriction may cause an interrupt.
Abstract:
When an abort of a transaction occurs, a determination is made as to whether diagnostic information is to be stored in one or more transaction diagnostic blocks (TDBs). There are different types of transaction diagnostic blocks to accept diagnostic information depending on the type of abort and other considerations. As examples, there are a program-specified TDB in which information is stored if a valid TDB address is provided in a transaction begin instruction; a program interruption TDB, which is stored into when the program is aborted due to an interruption; and a program interception TDB, which is stored into when an abort results in an interception.
Abstract:
Processing of character data is facilitated. A Find Element Equal instruction is provided that compares data of multiple vectors for equality and provides an indication of equality, if equality exists. An index associated with the equal element is stored in a target vector register. Further, the same instruction, the Find Element Equal instruction, also searches a selected vector for null elements, also referred to as zero elements. A result of the instruction is dependent on whether the null search is provided, or just the compare.
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.