Method and apparatus for providing test mode access to an instru

Electrical computers and digital processing systems: memory – Storage accessing and control – Hierarchical memories

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

711128, 711144, 711154, G06F 1200, G06F 1300

Patent

active

061015784

ABSTRACT:
A method and apparatus for providing full accessibility to on-chip instruction cache and microcode ROM are described. A dummy tag and a dummy instruction are written into a cache tag array and an instruction array, respectively, during a test mode. The dummy tag is concatenated with a predetermined set number and a predetermined word address to form a dummy address having a dummy tag field, a set field and a word address field. An instruction fetch is invoked using the dummy address. The instruction cache is accessed with the dummy address, and a cache miss is forced to occur. The dummy tag field of the dummy address is written into the tag array at a row specified by the predetermined set number, and the dummy instruction is written into the instruction array at the same row. Execution of the dummy instruction is suppressed. A read operation is performed in a similar manner, except in that case an instruction cache hit is forced to occur to cause data to be read from the instruction cache. Execution of the data read from the cache is suppressed. Microcode ROM is also read by invoking a dummy instruction fetch The dummy instruction fetch causes data to be retrieved from a predetermined address in the ROM. Execution of the retrieved data is suppressed.

REFERENCES:
patent: 4293950 (1981-10-01), Shimizu et al.
patent: 5165029 (1992-11-01), Sawai et al.
patent: 5226009 (1993-07-01), Avimoto
patent: 5249281 (1993-09-01), Fuccio et al.
patent: 5345582 (1994-09-01), Tsuchiya
patent: 5367653 (1994-11-01), Coyle et al.
patent: 5410669 (1995-04-01), Biggs et al.
patent: 5457696 (1995-10-01), Mori
patent: 5493667 (1996-02-01), Huck et al.
patent: 5553264 (1996-09-01), Ozveren et al.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Method and apparatus for providing test mode access to an instru does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method and apparatus for providing test mode access to an instru, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for providing test mode access to an instru will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-1160382

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.