programming assignment

Schematic Diagram of the Set Up for Programming Simulation ofPRIVATE the ITSIAC.

REGISTER Primary Storage

Decode Table Control Storage

The next page has a description of the register functions:

Register Functions

ACC: Accumulator

A 16-bit register is involved in all arithmetic

operations. One of the operands in each arithmetic

operation must be in the Accumulator; the other must

be in primary storage.

PSIAR: Primary Storage Instruction Address Register

This 8-bit register points to the location in

primary storage of the next machine language

instruction to be executed.

SAR: Storage Address Register

This 8-bit register is involved in all references to

primary storage. It holds the address of the

location in primary storage being read from or

written to.

SDR: Storage Data Register

This 16-bit register is also involved in all

references to primary storage. It holds the data

being written to or receives the data being read

from primary storage at the locations specified in

the SAR.

TMPR: Temporary register

This 16-bit register is used to extract the address

portion (right-most 8-bits) of the machine instruction

in the SDR so that it may be placed in the SAR. (ITSIAC

does not allow direct SDR to SAR transfers.)

CSIAR: Control Storage Instruction Address Register

The register points to the location of the next microinstruction (in control storage) to be executed.

MIR: Microinstruction Register

This register contains the current microinstruction being

executed.

PSIAR

ACC

SDR

TMPR

SAR

Opcode CS Address

[ 1 ] __________

[ 2 ] __________

[ 3 ] __________

[ 4 ] __________

[ 5 ] __________

[ 6 ] __________

[ 7 ] __________

[ 8 ] __________

[ 9 ] __________

CSIAR

MIR