SimLab

Best on desktop

This simulator works on phones, but the memory tables and code stepping are much easier on a PC.

SIM LAB

SimLab 8051

Assemble, inspect, and step through 8051 or 8085 code with a cleaner workflow.

Device

🤖 8051 AI Assistant (Groq)

Free AI Learning! Uses Groq API

Explain 8051 code
Step-by-step guidance
Answer questions

Code Editor

Memory & Storage

Tip: click any memory cell to edit.

RAM (0X00-0X00FF)
	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0x000	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x001	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x002	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x003	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x004	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x005	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x006	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x007	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x008	00	07	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x009	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00a	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00b	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00c	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00d	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00e	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00f	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00

ROM (0X0000-0X0FFF)
	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0x000	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x001	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x002	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x003	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x004	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x005	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x006	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x007	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x008	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x009	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00a	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00b	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00c	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00d	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00e	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00
0x00f	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00	00

Registers & State

Register	Value
A/PSW	0x00 0x00
B	0x00
SP	0x07
PC	0x0000
DPTR	0x0000

Flag	Value
P
_UD
OV
RS0
RS1
F0
AC
CY

Register banks
	00	01	10	11
R0	00	00	00	00
R1	00	00	00	00
R2	00	00	00	00
R3	00	00	00	00
R4	00	00	00	00
R5	00	00	00	00
R6	00	00	00	00
R7	00	00	00	00

Supported Opcodes (8051)

ADD AJMP ANL CJNE CLR CPL DA DEC DIV DJNZ INC JB JBC JC JMP JNB JNC JNZ JZ LJMP MOV MOVX MUL ORG ORL POP PUSH RL RLC RR RRC SETB SJMP SUBB SWAP