摘要:
In an enhanced dynamic address translation facility a virtual address to be translated and an initial origin address of a translation table of the hierarchy of translation tables are used to access a segment table entry containing a format control field and an access validity field. If the format control field is enabled, the segment table entry further contains an access control field and a fetch protection field and a segment-frame absolute address. Fetch operations from the desired block of data are permitted if the program access key associated with the virtual address is equal to the segment access control field.
摘要:
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.
摘要:
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.
摘要:
What is disclosed is a frame management function defined for a machine architecture of a computer system. In one embodiment, a machine instruction is obtained containing an opcode for a frame management instruction identifying a first and second general register. Clear frame information is obtained from the first general register having a frame size field indicating whether a storage frame is a small or large block of data. The second general register contains an operand address of a storage frame. If the storage frame is a small block, all bytes of the small block of data are set to zero. If the storage frame is a large block of data, an operand address of an initial first block of data within the large block is obtained from the second general register. All data of all blocks within the large block are cleared starting from the initial first block.
摘要:
What is disclosed is a set key and clear frame management function defined for a machine architecture of a computer system. In one embodiment, a machine instruction is obtained which identifies a first and second general register. Obtained from the first general register is a frame size field indicating whether a storage frame is one of a small block or a large block of data. Obtained from the second general register is an operand address of a storage frame upon which the instruction is to be performed. If the storage frame is a small block, the instruction is performed only on the small block. If the indicated storage frame is a large block of data, an operand address of an initial first block of data within the large block of data is obtained from the second general register. The frame management instruction is performed on all blocks starting from the initial first block.
摘要:
What is disclosed is a set key and clear frame management function defined for a machine architecture of a computer system. In one embodiment, a machine instruction is obtained which identifies a first and second general register. Obtained from the first general register is a frame size field indicating whether a storage frame is one of a small block or a large block of data. Obtained from the second general register is an operand address of a storage frame upon which the instruction is to be performed. If the storage frame is a small block, the instruction is performed only on the small block. If the indicated storage frame is a large block of data, an operand address of an initial first block of data within the large block of data is obtained from the second general register. The frame management instruction is performed on all blocks starting from the initial first block.
摘要:
What is disclosed is a frame management function defined for a machine architecture of a computer system. In one embodiment, a frame management instruction is obtained which identifies a first and second general register. The first general register contains a frame management field having a key field with access-protection bits and a block-size indication. If the block-size indication indicates a large block then an operand address of a large block of data is obtained from the second general register. The large block of data has a plurality of small blocks each of which is associated with a corresponding storage key having a plurality of storage key access-protection bits. If the block size indication indicates a large block, the storage key access-protection bits of each corresponding storage key of each small block within the large block is set with the access-protection bits of the key field.
摘要:
What is disclosed is a frame management function defined for a machine architecture of a computer system. In one embodiment, a frame management instruction is obtained which identifies a first and second general register. The first general register contains a frame management field having a key field with access-protection bits and a block-size indication. If the block-size indication indicates a large block then an operand address of a large block of data is obtained from the second general register. The large block of data has a plurality of small blocks each of which is associated with a corresponding storage key having a plurality of storage key access-protection bits. If the block size indication indicates a large block, the storage key access-protection bits of each corresponding storage key of each small block within the large block is set with the access-protection bits of the key field.
摘要:
A translation table entry contains a change recording override field for controlling whether a change bit is to be set on a store or not. Each 4K byte block of main storage has an associated storage key comprising a change bit. The change recording override field controls whether the change bit of the storage key associated with the desired 4K byte block of main storage is set to 1 for a store operation.
摘要:
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.