🖥CPU emulator, it's own assembly commands and compiler.💾

▶Run Project

Prerequisites

• Java 8+
• Terminal - curl command support
• Maven - optional

For Maven users:

1. Clone repository

git clone https://github.com/MKhiriev/AssemblyEmulator.git

2. Create executable JAR file

cd AssemblyEmulator
mvn package

3. Launch project

mvn exec:java

For non-Maven users:

1. Download recent JAR

• From Releases section
• Using command line (specific version):

curl -L -O https://github.com/MKhiriev/AssemblyEmulator/releases/download/v1.0.1-SNAPSHOT/AssemblyEmulator-v1.0.1-SNAPSHOT.jar

2. Launch project

java -jar AssemblyEmulator-v1.0.1-SNAPSHOT.jar

💻CPU architecture

Explanation of inner structure of processor.

• Bit depth: 16 bit
• Architecture type: Von Neumann architecture
• Commands: 1 address
• Implemented program: Convolution of two arrays

Convolution of two arrays:

Arrays have the same lengths, consist of numbers

• a - first array
• b - second array
• i - index of array
• n - length of array

array_convolution = (a[0] * b[0]) + (a[1] * b[1]) + ... + (a[n] * b[n])

Registers

Register	Register Address	Depth, bit	Description
AX	0	16	Stores the result of operations
BX	1	16	-
CX	2	16	Loop counter
DX	3	16	Stores data memory addresses, values
DH	4	8	Stores the address of the element of the 1st array
DL	5	8	Stores the address of the element of the 2nd array

Command format

Name	Bits	Abbreviation	Description
cmdtype	0-7	C	Assembly command
op1	8-15	O	First operand

16 bit command representation:

Range	15-8	7-0
Bits	OOOOOOOO	CCCCCCCC

📑Assembly language

CmdType	Assembly Command	Arguments	Description
0	RET	-	Program completion command
1	LDA1 ch1	ch1 - data memory address	Loads into the AX register the value from the data memory at the address.
2	MRA reg	reg - processor register	Copies the value of the AX register to the specified register.
3	LDA2 op1	op1 - integer	Loads the specified integer into register AX.
4	ADD reg	reg - processor register	Adds the numbers from the AX register and the numbers from the memory, the address of which is written in the specified register. The result is stored in AH.
5	INC reg	reg – processor register	The value of the specified register is incremented.
6	LOOP op1	op1 - instruction memory address	Decreases the value in the CX register in real mode. If the value in CX is non-zero, then the LOOP instruction jumps to the instruction specified as an argument.
7	DEC reg	reg – processor register	The value of the specified register is decremented.
8	MUL reg	reg - processor register	We multiply the number in AX by the number from the data memory at the address written in the specified register. The result is recorded in AH.
9	ADC reg	reg – processor register	Addition with carry.
10	ADD2 ch1	ch1 – data memory address	Adding the number in AX and the number from the data memory at the specified address. The result is stored at the specified address in MEMORY!
11	LDA3 reg	reg - processor register	Copies the value from the specified register to the AX register.
12	LDA4 reg	reg - processor register	Copy the value from the specified register to the AX register

How does it work?

Assembly commands consist of 2 parts:

1. Command
2. Operand

When receiving an assembler text instruction, it breaks down into two parts: the type of the command and the operand.

Table of comparisons is used to translate the command type and operand into machine code. Assembler String is being converted to binary number.

When command type and operand are converted to binary the resulting binary instruction is obtained by placing cmdType bits in the upper 8 bits (15-8) and the operand bits in the lower 8 bits (7-0). For convenient reading the resulting command is presented in hexadecimal system.

There is also an integrated development environment. IDE can run compiler on assembly commands and run code on a processor emulator.

IDE element	Description
Text field	Allows you to write programs without the use of third-party text editors.
“Compile” button	Translates assembler instructions into machine code. The result of the work is displayed in the console.
“Run” button	Translates assembler commands and transfers the machine code to the emulator processor for execution.
Line count field	Allows you to see the size of the resulting program.