Multiplex communications – Wide area network – Packet switching
Patent
1993-05-10
1996-11-12
Donaghue, Larry D.
Multiplex communications
Wide area network
Packet switching
395885, 370 99, 3642598, 3642393, 3642568, 3642603, 3642604, 3649613, G06F 1338, G06F 1204, G06F 700
Patent
active
055749232
ABSTRACT:
A method and apparatus for performing bi-endian byte and short accesses in a single endian microprocessor. The present invention is used in a microprocessor or in a microprocessor in a computer system. The present invention provides a single endian microprocessor that promotes sub-word accesses to word accesses with a means for manipulating the two least significant bits of the access address to point to the correct sub-word data returned during an access to bi-endian external memory. The method for manipulating the address bits is also used to allow a single endian data cache to operate with the bi-endian external memory. The two LSBs of the address are manipulated such that the pointer values are A1# and A0# for word promoted byte accesses or cacheable accesses. For word promoted short accesses or cacheable accesses, the pointer values are A1# and A0. The present invention offers increased flexibility in interfacing a single-endian microprocessor with bi-endian systems. The present invention provides easy interfacing without undue or overly complex modifications to existing circuits.
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Heeb Jay
Huck Scott
Shenoy Sunil
Donaghue Larry D.
Intel Corporation
Rinehart Mark H.
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