Database set condition test instruction

Claim 1

In an internally programmed data processing apparatus having a memory comprised of a plurality of segments of addressable space each segment having a segment number, each of said segments delineated by upper and lower variable bounds, with predetermined ones of said segments storing a plurality of files of database records grouped in sets of database records, each set having at least one owner database record, each of said database records having at least one pointer address for linking predetermined ones of said database records to predetermined others of said database records and to predetermined ones of said sets, each of said database records also being associated with one each of a record descriptor for describing said associated database record, said record descriptors being stored in predetermined sections of said segments; said data processing apparatus also having an arithmetic and logic unit (ALU) for performing arithmetic and logic operations on any data or address of said segments, database records, and descriptors, said data processing apparatus further having a system base from which absolute addresses of said segments, database records and descriptors are referenced, said data processing apparatus having a plurality of base registers, each base register for storing signals for referencing said segments; instruction hardware responsive to a test-set instruction for determining whether or not a selected one of said database records is linked to predetermined others of said database records, said test-set instruction having a first base register address (BR) for identifying a first of said plurality of base registers storing signals indicative of a first segmented address of a first of said database records and said test-set instruction further including a first address syllable for identifying a second one of said base registers storing signals for referencing the set descriptor associated with said first of said database records, said instruction hardware comprising: first means responsive to signals corresponding to said first address syllable identifying said second base register to convert said signals of said second base register into an absolute address for fetching the associated set descriptor of said selected one of said database records from one of said predetermined sections of said segments; b. second means coupled to said first means and responsive to signals indicative of the displacement address in said set descriptor for generating an absolute address for fetching said pointer address of said pointers in said first of said database records; c. third means coupled to said first and second means and responsive to said first and second means for storing signals representative of said pointer address fetched from one of said segments; and d. fourth means coupled to said third means and responsive to said signals from said third means for determining whether or not said selected one of said database records is linked to selected others of said database records.