先决条件–简化教学计算机(SIC)中使用的指令集
由于SIC / XE相对于SIC向上兼容，因此SIC / XE中也使用了SIC中的所有指令。 SIC / XE特有的说明是：
| 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 |
这里，
M代表记忆
R1和R2是寄存器(A，B，S，T)