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List Searching Procedure

IP.com Disclosure Number: IPCOM000092739D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 35K

Publishing Venue

IBM

Related People

Blaauw, GA: AUTHOR [+2]

Abstract

The insertion of binary data in addressable general registers of a data processing system provides a flexible arrangement by which a list searching instruction, as shown, can be executed.

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List Searching Procedure

The insertion of binary data in addressable general registers of a data processing system provides a flexible arrangement by which a list searching instruction, as shown, can be executed.

The drawing depicts a number, of elements within a list of elements wherein each element is comprised of data, a key or attribute byte, and a chain address. The latter is the address of the next element in the list to be searched. The instruction to be executed includes an operation portion which identifies the list searching instruction SLT, an M1 field specifying a type of test to be conducted, a length field L2 specifying the number of bytes of data to be tested, designation of one of the general registers B2 specifying the beginning address of the list of elements, and a number or binary bits representing a displacement D2. The latter is added to the element address to obtain a chain address which specifies the address of the next element to be searched.

Various binary data is inserted in addressable general registers to be utilized during the execution of the instruction. In register O, there is inserted a mask and a count. The mask is binary data which is compared with key data in an element. The count field specifies the number of elements in the list to be searched during the execution of the instruction. Register 1 contains the binary predecessor address of the element searched previous to the current element. Register 2 contains the address of the current element address being searched.

Register 3 contains the data comparand. This is compared with the data in the element during the search. Register 4 is a binary representation of the data offset. This is added to the current element address to obtain the beginning address of the data field to be compared with the data comparand in register 3. Register 5 contains the key offset. The latter is added to the current element address to obtain the location of the key data which is tested by the mask contained in register 0. Register B2 specifies the base address of the list of elements to be searched. The D2 portion of the instruction, which is a displacement val...