The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 18, 1976
Filed:
Jun. 07, 1973
John J Serra, Monroe, CT (US);
Ronald T Prodan, Shelton, CT (US);
Bunker Ramo Corporation, Oak Brook, IL (US);
Abstract
This invention relates to a method and apparatus for determining the address mode of each instruction in a microprogrammed processor, and for utilizing the address mode determination to locate the effective operand of the instruction. A microprogram memory is included which contains microprogram micro-orders for controlling the obtaining of the effective operand for an instruction in each of the address modes. The address being accessed in the microprogram memory at any given time is stored in a microprogram register. There is a decoder which is operative in response to the address mode tag of an instruction for generating the address of the entry point in the microprogram memory for the microprogram micro-orders to be utilized to control the obtaining of the effective operand for the mode indicated by the tag. The address mode tag of each instruction is applied to the decoder and the microprogram entry point address read out from the decoder in response to the tag is stored in the microprogram register. The storing of the entry point address in the microprogram register initiates the execution of the microprogram micro-orders for the indicated mode, the micro-orders controlling the obtaining of the desired effective operand. The decoder means may also be utilized to obtain a starting address for the operation code microprograms, the operation code being applied to the decoder after the address tag and the resulting starting address being stored in a temporary register until execution of the required micro-orders of the address mode microprogram has been completed.