Instruction Set used in SIC/XE

Pre-Requisite: SIC/XE Architecture

SIC/XE (Simplified Instructional Computer Extra Equipment or Extra Expensive). SIC/XE is an advanced version of SIC. Both SIC and SIC/XE are closely related to each other that’s why they are Upward Compatible.

Below mentioned are the instructions that are used in SIC/XE (Simplified Instructional Computer Extra Equipment or Extra Expensive) Architecture. You can view the instructions that are particularly used in SIC Architecture.

Before Proceeding to the table, we will be clear that M stands for Memory R1 and R2 are registers (A, B, S, T).

MNEMONIC	OPERAND	OPCODE	EXPLANATION
ADDR	R1, R2	90	R2 = R2 + R1
CLEAR	R1	04	R1 = 0
COMPR	R1, R2	A0	compares R1 and R2
DIVR	R1, R2	9C	R2 = R2 / R1
LDB	M	68	B = M
LDS	M	6C	S = M
LDT	M	74	T = M
MULR	R1, R2	98	R2 = R2 * R1
RMO	R1, R2	AC	R2 = R1
SHIFTL	R1, n	A4	left shifts R1 n times
SHIFTR	R1, n	A8	right shifts R1 n times
STB	M	78	M = B
STS	M	7C	M = S
STT	M	84	M = T
SUBR	R1, R2	94	R2 = R2 – R1
TIXR	R1	B8	X = X + 1; compares X and R1

FAQs on Instruction Set in SIC/XE

Q.1: What are opcodes in SIC/XE?

Answer:

Opcodes are simply the operation codes that help in representing specific machine instructions in the SIC/XE assembly language.

Q.2: What is working of Immediate Addressing?

Answer:

Immediate Addressing involves a constant value embedded in instruction itself instead of a address.

Q.3: How many types of addressing modes are present in SIC/XE?

Answer:

SIC/XE supports 5 types of addressing modes:

• Simple (S)
• Immediate (I)
• Indirect (N)
• Indexed (X)
• Extended (B)