Control store apparatus having dual mode operation handling mechanism
AssigneeHoneywell Information Systems Inc.
InventorsKiyoshi H. Terakawa, Henry F. Hartley
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Abstract
A writeable control store in a data processing system is provided with a dual mode capability. Coupled with the control store in the system is a central processing unit which may provide the next address of the control store's memory dependent upon the mode of the control store. Otherwise, also dependent upon such mode, the control store memory is addressed, dependent upon the results of tests conducted in the central processing unit, by one of at least two alternative addresses. The control words addressed in the writeable control store are used to control the operation of the central processing unit.
Claims15
A microprogram-controlled data processor system wherein a set of system control words is augmented by a plurality of series of user-generated control words, said system comprising:
- a control store for storing and selectively outputting said plurality of series of user-generated control words, each of said stored user-generated control words including an address field and being addressable in said control store in a first control store addressing mode or a second control store addressing mode independent of said first control store addressing mode;
- a central processing unit coupled to said control store for executing said system control words and said user-generated control words outputted by said control store;
- means for selecting said first control store addressing mode of said second control store addressing mode, said selecting means comprising a manually-operated switch;
- first address generating means responsive to the selection of said first control store addressing mode for individually generating the address of the next user-generated control word in said control store to be executed by said central processor unit responsive to the contents of said address field;
- second address generating means responsive to the selection of said second control store addressing mode for selectively generating the addresses of user-generated control words stored in said control store independently of said address fields;
- and
- means for receiving said generated addresses from said first address generating means and said second address generating means, for addressing said user-generated control words stored in said control store in accordance with said received addresses and for transferring said addressed user-generated control words to said central processor unit.
A data processing system for executing a microprogram wherein said microprogram comprises a series of microinstructions, each of said microinstructions being associated with one or more firmware control words, said data processing system comprising:
- a central processor unit for executing firmware control words;
- a control store for addressably storing a series of user-generated firmware control words, each of said user-generated firmware control words including an operand field for storing the designation of an operation to be performed by said central processor unit and a next address field for storing a designation of an address in said control store of the next user-generated firmware control word to be executed;
- a next address generator coupled to said central processor unit for interpreting a said user-generated firmware control word being executed by said central processor unit to generate in a first user-generated firmware control word addressing mode the address in said control store of the next user-generated control word to be executed by said central processor unit responsive to the right address field;
- means for generating in a second user-generated firmware control word addressing mode the address in said control store of the next user-generated firmware control word to be executed by said central processor unit independently of the address field of the user-generated firmware control word being executed by said central processor unit;
- means for selecting said first user-generated firmware control word addressing mode or said second user-generated firmware conrol word addressing mode, said selecting means comprising a manually-operated switch;
- means responsive to said selecting means for addressing said control store to cause said control store to output a said user-generated firmware control word and for transferring said outputted user-generated firmware control word to said central processor unit;
- and
- means for selectively supplying to said addressing and transferring meas either a said address generated by said next address generator or a said address generated by said address generating means.
A data processing system for executing a microprogram wherein said microprogram comprises a series of microinstructions, each of said microinstructions being associated with one or more firmware control words, said data processing system comprising:
- a central processor unit for executing firmware control words;
- a control store for addressably storing a series of user-generated firmware control words, each of said user-generated firmware control words including an operand field for storing the designation of an operation to be performed by said central processor unit and a next address field for storing a designation of an address in said control store of the next user-generated firmware control word to be executed;
- a next address generator coupled to said central processor unit for interpreting a said user-generated firmware control word being executed by said central processor unit to generate in a first user-generated firmware control word addressing mode the address in said control store of the next user-generated control word to be executed by said central processor unit responsive to the next address field;
- means for generating in a second user-generated firmware control word addressing mode the address in said control store of the next user-generated firmware control word to be executed by said central processor unit independently of the address field of the user-generated firmware control word being executed by said central processor unit;
- manual switch means for selecting said first user-generated firmware control word addressing mode or said second user-generated firmware control word addressing mode;
- means responsive to said selecting means for addressing said control store to cause said control store to output a said user-generated firmware control word and for transferring said outputted user-generated firmware control word to said central processor unit;
- and
- means for selectively supplying to said addressing and transferring means either a said address generated by said next address generator or a said address generated by said address generating means.
Dependencies are inferred from the claim text.