Instruction Set Main Topics Instruction Operation code Operand

Instruction Set �������

Main Topics • Instruction – Operation code – Operand – Instruction Representation – Number of Addresses – Types of Operation • Data Transfer • Transfer of Control • Register

Instruction Set Architecture (ISA) • ISA ��� component ��� operation ��������������������� – Memory organization • address space ����� location ���������� ? • addressibility ������� location ? – Register set • ������ ? �������������� ? – instruction set

What is an Instruction – operation �������������������� • ����������� Instruction Set Architecture (ISA)

Elements of an Instruction • instruction ��������� • Operation code ���� operation ��������� ADD ���������� opcode • Source operand reference ������� operand ������� 1 operand ������ (operand ��� input ��� operation) • Result operand reference ����������� operation

Instruction Types – Data storage: memory instruction • ���������� CPU ������������������� – Data movement: I/O instruction • ������������������� – Control: Test and branch instruction

Number of Addresses • 4 addresses – Instruction ������ address 4 addresses ��� operand 2 ������� 1 ��������� 1 ��� – ��������� address ���������� program counter ����

Example • Y=(A-B)/(C+D*E) SUB MPY ADD DIV Y, A, B T, D, E T, T, C Y, Y, T Y=A-B T=D*E T=T+C Y=Y/T MOV SUB MOV MPY ADD DIV Y, A Y, B T, D T, C Y, T 6 instructions 4 instructions Y=A Y=Y-B T=D T=T*D T=T+C Y=Y/T LOAD MPY ADD STOR LOAD SUB DIV STOR D E C Y A B Y Y 8 instructions AC=D AC=AC*E AC=AC+C Y=AC AC=AC-B AC=AC/Y Y=AC

Types of Operand • Addresses • Numbers – Integer/floating point – Decimal • Characters – ASCII etc – Logical Data • Bits or flags

Types of Operation • • Data Transfer Arithmetic Logical Conversion I/O System Control Transfer of Control

Transfer of Control

����� • William Stalling, Computer Organization and Architecture, USA • Yale N. Patt, Sanjay J. Patel, Introduction to Computing Systems: From Bits and Gates to C and Beyond, USA