Honeywell G.m.b.h.

Robert J Handly

Robert H Douglas

Troy K Wilson

An improved means and method for accomplishing floating point calculations in computational apparatus includes a primary microprocessor and a secondary microprocessor, each with its own control ROM. The normal or fixed point calculations are handled by the primary microprocessor under the control of a first segment of the associated control ROM. When a floating point calculation is called for, a second segment of that ROM is addressed. The addressing of the second segment of the first ROM also effects the coincident addressing of the ROM of the secondary microprocessor. For floating point calculations, the exponent portion of the numbers being manipulated is handled by the primary microprocessor. Simultaneously therewith, the mantissa portion of the numbers being manipulated is handled by the secondary microprocessor under the control of its associated control ROM. The resultant calculations are recombined in the primary microprocessor to produce a complete solution for the floating point calculation. In executing a division operation, the mantissas are preconditioned to be normalized, the most significant bit being a logical '1'. The divide routine shifts and subtracts repeatedly until the most significant bit in an accumulating register is also a logical '1', thus eliminating the need for a preset counter and the associated control functions.

Floating point division control

An improved means and method for accomplishing floating point calculations in computational apparatus includes a primary microprocessor and a secondary microprocessor each with its own control ROM. The normal or fixed point calculations are handled by the primary microprocessor under the control of a first segment of the associated control ROM. When a floating point calculation is called for, a second segment of that ROM is addressed. The addressing of the second segment of the first ROM also effects the coincident addressing of the ROM of the secondary microprocessor. For floating point calculations, the exponent portion of the numbers being manipulated is handled in the primary microprocessor. Simultaneously therewith, the mantissa portion of the numbers being manipulated are handled in the secondary microprocessor under the control of its associated control ROM. The resultant calculations are recombined in the primary microprocessor to produce a complete solution for the floating point calculation.

Floating point arithmetic control

A computer system features a processor unit which includes its own microprogram control unit. The microprogram control unit includes a storage means for operational instructions for the processor unit and means to issue those instructions in a desired sequence. A communication Bus provides communication channels between the processor unit and either data storage means or other processor units served by the Bus. The processor unit includes a number of clock controlled functional components as well as means for requesting access to the Bus. A clock signal generating means is controlled by signals from the microprogram control unit. When a request has been made for access to the Bus, the processor continues to operate until a point is reached when access to the Bus must be accomplished before continuing. The microprogram control unit issues a control signal which effectively stops the operation of the clock signal generating means until the Bus access routine has been accomplished. The clock signal generating means resumes operation when the access routine has been completed.

Microcomputer apparatus

A computer apparatus includes means for comparing the address stored in an address register with a preset address. When the stored address matches the preset address the comparison means issues an alarm signal which may be used to effect an immediate halt in the execution of a routine, trigger suitable annunciators or, selectively, to enable the injection into the routine of an overriding preset instruction.

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Phoenix, AZ, United States of America

Robert J Handly