Prerequisite - Simplified Instructional Computer (SIC)
These are the instructions used in programming the Simplified Instructional Computer(SIC).
Here,
A stands for Accumulator
M stands for Memory
CC stands for Condition Code
PC stands for Program Counter
RMB stands for Right Most Byte
L stands for Linkage Register
| MNEMONIC | OPERAND | OPCODE | EXPLANATION |
|---|---|---|---|
| ADD | M | 18 | A = A + M |
| AND | M | 40 | A = A AND M |
| COMP | M | 28 | compares A and M |
| DIV | M | 24 | A = A / M |
| J | M | 3C | PC = M |
| JEQ | M | 30 | if CC set to =, PC = M |
| JGT | M | 34 | if CC set to >, PC = M |
| JLT | M | 38 | if CC set to <, PC = M |
| JSUB | M | 48 | L = PC ; PC = M |
| LDA | M | 00 | A = M |
| LDCH | M | 50 | A[RMB] = M[RMB] |
| LDL | M | 08 | L = M |
| LDX | M | 04 | X = M |
| MUL | M | 20 | A = A * M |
| OR | M | 44 | A = A OR M |
| RD | M | D8 | A[RMB] = data specified by M[RMB] |
| RSUB | 4C | PC = L | |
| STA | M | 0C | M = A |
| STCH | M | 54 | M[RMB] = A[RMB] |
| STL | M | 14 | M = L |
| STSW | M | E8 | M = SW |
| STX | M | 10 | M = X |
| SUB | M | 1C | A = A - M |
| TD | M | E0 | test device specified by M |
| TIX | M | 2C | X = X + 1 ; compare X with M |
| WD | M | DC | device specified by M[RMB] = A[RMB] |