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. Based on the origin address, a segment table entry is obtained which contains a format control field and an access validity field. If the format control and access validity are enabled, the segment table entry further contains an access control and fetch protection fields, and a segment-frame absolute address. Store operations to the block of data are permitted only if the access control field matches a program access key provided by either a Program Status Word or an operand of a program instruction being executed. Fetch operations from the desired block of data are permitted only if the program access key associated with the virtual address is equal to the segment access control field.

Abstract: A computer-implemented method for implementing a full space dynamic address translation (“DAT”) structure and a subspace DAT structure is provided. A non-limiting example of the computer-implemented method includes determining, by a processor, that switching between the full space DAT structure and the subspace DAT structure is enabled by examining a bit in a control register. The method determines, by the processor, that there is a new context different from an existing context based on the bit in the control register indicating that switching is enabled, and switches, by the processor, the context of the DAT structures based on determining that the new context is different from the existing context.

Abstract: Aspects include a computer-implemented method includes receiving an instruction at a processor to perform an operation on a memory block having an address and accessing a state indicator by the processor without altering a value of the state indicator. The state indicator is stored in a memory location independent of the memory block, and accessing includes sending a request to an operator to return the value of the state indicator to the processor. The method also includes determining based on the value of the state indicator whether the memory block is in a pre-defined state.

Abstract: Aspects include a computer-implemented method that includes receiving an instruction at a processor to perform an operation on a memory block having an address and accessing a state indicator by the processor without altering a value of the state indicator. The state indicator is stored in a memory location independent of the memory block, and accessing includes sending a request to an operator to return the value of the state indicator to the processor. The method also includes determining based on the value of the state indicator whether the memory block is in a pre-defined state.

Abstract: A computer-implemented method for implementing a full space dynamic address translation (“DAT”) structure and a subspace DAT structure is provided. A non-limiting example of the computer-implemented method includes determining, by a processor, that switching between the full space DAT structure and the subspace DAT structure is enabled by examining a bit in a control register. The method determines, by the processor, that there is a new context different from an existing context based on the bit in the control register indicating that switching is enabled, and switches, by the processor, the context of the DAT structures based on determining that the new context is different from the existing context.

Abstract: Aspects include a computer-implemented method includes receiving an instruction at a processor, the instruction associated with a memory block having an address, and accessing a state indicator by the processor. The state indicator indicates whether the memory block is in a pre-defined state, and the state indicator is accessible by the processor independent of the memory block. The method also includes, based on the state indicator indicating that the memory block is in the pre-defined state, inspecting a subset of data values in the memory block, and identifying the pre-defined state of the memory block based on the subset of data values.

Abstract: Aspects include a computer-implemented method that includes receiving an instruction at a processor, the instruction associated with a memory block having an address, and accessing a state indicator by the processor. The state indicator indicates whether the memory block is in a pre-defined state, and the state indicator is accessible by the processor independent of the memory block. The method also includes, based on the state indicator indicating that the memory block is in the pre-defined state, inspecting a subset of data values in the memory block, and identifying the pre-defined state of the memory block based on the subset of data values.

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. Based on the origin address, a segment table entry is obtained which contains a format control field and an access validity field. If the format control and access validity are enabled, the segment table entry further contains an access control and fetch protection fields, and a segment-frame absolute address. Store operations to the block of data are permitted only if the access control field matches a program access key provided by either a Program Status Word or an operand of a program instruction being executed. Fetch operations from the desired block of data are permitted only 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. Based on the origin address, a segment table entry is obtained which contains a format control field and an access validity field. If the format control and access validity are enabled, the segment table entry further contains an access control and fetch protection fields, and a segment-frame absolute address. Store operations to the block of data are permitted only if the access control field matches a program access key provided by either a Program Status Word or an operand of a program instruction being executed. Fetch operations from the desired block of data are permitted only if the program access key associated with the virtual address is equal to the segment access control field.

Abstract: A method for branch prediction, the method comprising, receiving a branch wrong guess instruction having a branch wrong guess instruction address and data including an opcode and a branch target address, determining whether the branch wrong guess instruction was predicted by a branch prediction mechanism, sending the branch wrong guess instruction to an execution unit responsive to determining that the branch wrong guess instruction was predicted by the branch prediction mechanism, and receiving and decoding instructions at the branch target address.

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 emulated. Fetch operations are permitted if the program access key associated with the virtual address is equal to the segment access control field or the fetch protection field is not enabled.

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. Based on the origin address, a segment table entry is obtained which contains a format control field and an access validity field. If the format control and access validity are enabled, the segment table entry further contains an access control and fetch protection fields, and a segment-frame absolute address. Store operations to the block of data are permitted only if the access control field matches a program access key provided by either a Program Status Word or an operand of a program instruction being executed. Fetch operations from the desired block of data are permitted only if the program access key associated with the virtual address is equal to the segment access control field.

Abstract: Aspects include a computer-implemented method includes receiving an instruction at a processor, the instruction associated with a memory block having an address, and accessing a state indicator by the processor. The state indicator indicates whether the memory block is in a pre-defined state, and the state indicator is accessible by the processor independent of the memory block. The method also includes, based on the state indicator indicating that the memory block is in the pre-defined state, inspecting a subset of data values in the memory block, and identifying the pre-defined state of the memory block based on the subset of data values.

Abstract: Aspects include a computer-implemented method that includes receiving an instruction at a processor, the instruction associated with a memory block having an address, and accessing a state indicator by the processor. The state indicator indicates whether the memory block is in a pre-defined state, and the state indicator is accessible by the processor independent of the memory block. The method also includes, based on the state indicator indicating that the memory block is in the pre-defined state, inspecting a subset of data values in the memory block, and identifying the pre-defined state of the memory block based on the subset of data values.

Abstract: Aspects include a computer-implemented method that includes receiving an instruction at a processor to perform an operation on a memory block having an address and accessing a state indicator by the processor without altering a value of the state indicator. The state indicator is stored in a memory location independent of the memory block, and accessing includes sending a request to an operator to return the value of the state indicator to the processor. The method also includes determining based on the value of the state indicator whether the memory block is in a pre-defined state.

Abstract: Aspects include a computer-implemented method includes receiving an instruction at a processor to perform an operation on a memory block having an address and accessing a state indicator by the processor without altering a value of the state indicator. The state indicator is stored in a memory location independent of the memory block, and accessing includes sending a request to an operator to return the value of the state indicator to the processor. The method also includes determining based on the value of the state indicator whether the memory block is in a pre-defined state.

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 emulated. Fetch operations are permitted if the program access key associated with the virtual address is equal to the segment access control field or the fetch protection field is not enabled.

Abstract: Data operand fetching control includes a computer processor that includes a control unit for determining memory access operations. The control unit is configured to perform a method. The method includes calculating a summation weight value for each instruction in a pipeline, the summation weight value calculated as a function of branch uncertainty and a pendency in which the instruction resides in the pipeline relative to other instructions in the pipeline. The method also includes mapping the summation weight value of a selected instruction that is attempting to access system memory to a memory access control, each memory access control specifying a manner of handling data fetching operations. The method further includes performing a memory access operation for the selected instruction based upon the mapping.

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 emulated. Fetch operations are permitted if the program access key associated with the virtual address is equal to the segment access control field or the fetch protection field is not enabled.

Abstract: Data operand fetching control includes calculating a summation weight value for each instruction in a pipeline, the summation weight value calculated as a function of branch uncertainty and a pendency in which the instruction resides in the pipeline relative to other instructions in the pipeline. The data operand fetching control also includes mapping the summation weight value of a selected instruction that is attempting to access system memory to a memory access control. Each memory access control specifies a manner of handling data fetching operations. The data operand fetching control further includes performing a memory access operation for the selected instruction based upon the mapping.