BIP I - VHDL (VHSIC Hardware Description Language)

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██╔══██╗██║██╔══██╗      ███║      ->> Author: André Solano F. R. Maiolini
██████╔╝██║██████╔╝█████╗╚██║      ->> Date: 25/06/2024
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CONTENTS

• This repository contains VHDL code and testbenches using GHDL, GTKWave, and Makefile to the describe a Basic Instruction-set Processor (BIP).
• The CPU can execute basic instructions stored in ROM, using an accumulator (ACC) and an Arithmetic Logic Unit (ALU) for arithmetic and logical operations.
• This CPU adopts the Harvard architecture.

INSTRUCTION-SET

OP CODE	BINARY	INSTRUCTION	DESCRIPTION
0	0000	HLT	Halt
1	0001	STO	(addr) ← ACC
2	0010	LD	ACC ← (addr)
3	0011	LDI	ACC ← const.
4	0100	ADD	ACC ← ACC + (addr)
5	0101	ADDI	ACC ← ACC + const.
6	0110	SUB	ACC ← ACC - (addr)
7	0111	SUBI	ACC ← ACC - const.
8	1000	JUMP	PC ← const.
9	1001	NOP	No operation
A	1010	CMP	Compare ACC with (addr)
B	1011	JNE	PC ← const., if CMP ≠ ACC
C	1100	JL	PC ← const., if CMP < ACC
D	1101	JG	PC ← const., if CMP > ACC
E	1110	IN	ACC ← INPUT(addr)
F	1111	OUT	OUTPUT(addr) ← ACC

REPOSITORY STRUCTURE

├── src/
│   ├── components/
│   |   ├── arithmetic_logic_unit/
|   |   ├── control/
|   |   ├── counter/
|   |   ├── memory/
|   |   ├── register/
|   |   └── timer/
|   └── cpu.vhd
|
├── test/
|   ├── testbench/
|   └── waveform/
|
├── makefile
└── README.md

Dependencies

To run the tests and view the results, you'll need the following tools installed on your system:

• GHDL
• GTKWave
• Make

Usage

Inputs and Outputs

- enable_clk : Enables clock pulses;
- MR         : Master-Reset (active LOW);                 ____________________________
- in_port_1  : Input port 1 (16 bits);                   /                           /\
- in_port_2  : Input port 2 (16 bits);                  /         BIP I            _/ /\
- in_port_3  : Input port 3 (16 bits);                 /        (Harvard)         / \/
- in_port_4  : Input port 4 (16 bits);                /                           /\
- out_port_1 : Output port 1 (16 bits);              /___________________________/ /
- out_port_2 : Output port 2 (16 bits);              \___________________________\/
- out_port_3 : Output port 3 (16 bits);               \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
- out_port_4 : Output port 4 (16 bits).

Makefile

The included Makefile automates the process of compilation, simulation, and result visualization.

1. Navigate to the project directory;
2. Run the testbench and visualize the waveform:

make test

3. View the last generated waveform:

make view;

4. Clean up the generated files:

make clean

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