CHARIS

Charis is a CHARISA assembler/disassembler written in Python

CHARISA stands for CHAnia Reduced Instruction Set Architecture and it's the instruction set of a MIPS like CPU for the Project of the Computer Organization Course (ACE312) at the Technical University of Crete.

Usage:

python charis.py [-a] OR [-d] file

CPU Architecture:

• R0 is a 32-bit Register Hardwired to 0
• 31 32-bit General Purpose Registers R1-R31
• 2 Types of Instructions (R/I Type)
• Instructions Always 32 bits in length
• ALU Operations include: add, sub, nand, not, or, sra, sll, srl, ror, rol, li, addi, nandi, ori
• 3 Types of Branching Instructions: b, bne, beq
• 4 L/S Instructions: lw, sw, lb, sb
• Byte addressable memory

Instruction Synthesis

R Type:

6-bits	5-bits	5-bits	5-bits	5-bits	6-bits
OpCode	Rs	Rd	Rt	Unused	func

I Type:

6-bits	5-bits	5-bits	16-bits
OpCode	Rs	Rd	Immed

Example Assembly

li r1, 0xa
addi r2, 100
or r4, r0, r1
sw r1, 0x2(r2)
lw r1, 5(r8)
b 0x1
beq r0, r0, 0x4

Check example.asm for all instructions.

RTL notation for each instruction