Relocatable read only memory

Details Relocatable read only memory Relocatable read only memory

1980-02-14

1983-02-15

Springborn, Harvey E.

Boots, shoes, and leggings

G06F 1300

Patent

active

043744117

ABSTRACT:
A read only memory apparatus for use in a byte oriented processor (10) includes a data selector (25) which responds to the first memory fetch of a memory reference instruction (40, 28) to provide a selected set of output bits (20) from a read only memory to a particular portion (22) of the processor data bus. The apparatus provides a set of replacement bits (26) to the same portion of the data bus (22) in response to each occurrence of detection (29, 30') of the most significant byte of a such memory reference instruction being provided to the data bus. The replacement bits occur in the most significant byte of the address referred to in the memory reference instruction and prevents the processor's program counter from jumping out of the address space alloted to the read only memory. In the preferred form, the same set of switches (17) used with an address decoder (15) to define the location of the ROM circuit in the address space of the processor's memory also provides replacement bits.

REFERENCES:
patent: 3681757 (1972-08-01), Allen et al.
patent: 3781826 (1973-12-01), Beausoleil
patent: 3959783 (1976-05-01), Fressineau et al.
patent: 3980991 (1976-09-01), Mercurio
patent: 4038645 (1977-07-01), Birney et al.
patent: 4051460 (1977-09-01), Yamada et al.
patent: 4121286 (1978-10-01), Venton et al.
"Kilobaud: Hardware Program Relocation-The Way Biggies Do It", Dr. Michael Wingfield, The Small Computer Magazine, Jan. 1978, Issue No. 13, pp. 60-62.
Computer Dictionary & Handbook, Sippl & Sippl, Howard W. Sams & Co., Inc., Third Edition, 1980, Preface and pp. 136, 340, 278, 279, 336 & 337.

Affiliated with

Also associated with

Rating

Relocatable read only memory does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Relocatable read only memory, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relocatable read only memory will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1804104