CPUProject

CPU project is one of the projects designed in department of computer engineering at TTU as a lab project. The main aims of this project are:

• Developing a generic CPU without any fancy feature
• Writing a compiler for it
• Compiling GCC for this architecture
• Booting a light linux on it

CPU Design

Functionality Requirements

The CPU is supposed to be able to perform the following operations:

• Addition/Subtraction
• Increment/Decrement
• Arithmetic and Logical Shift
• Bitwise AND, OR, XOR and NOT
• Negation
• Load/Store
• Unconditional Branch (jump)
• Branch if zero / Branch if Overflow / Branch if Carry
• Clear Registers/Flags
• PUSH / POP
• NOP/HALT

Instruction Set Architecture (ISA)

The following instrcutions designed for the CPU:

Instruction	Description	OpCode	DPU Command	Data To DPU	MemAddress	Next PC
Add_A_B	A <-- A + B	Example	Example	Example	Example	Example
Add_A_Mem	Example	Example	Example	Example	Example	Example
Add_A_Dir	Example	Example	Example	Example	Example	Example
Sub_A_B	Example	Example	Example	Example	Example	Example
Sub_A_Mem	Example	Example	Example	Example	Example	Example
Sub_A_Dir	Example	Example	Example	Example	Example	Example
IncA	Example	Example	Example	Example	Example	Example
DecA	Example	Example	Example	Example	Example	Example
And_A_B	Example	Example	Example	Example	Example	Example
OR_A_B	Example	Example	Example	Example	Example	Example
XOR_A_B	Example	Example	Example	Example	Example	Example
FlipA	Example	Example	Example	Example	Example	Example
NegA	Example	Example	Example	Example	Example	Example
Jmp	Example	Example	Example	Example	Example	Example
JmpZ	Example	Example	Example	Example	Example	Example
JmpOV	Example	Example	Example	Example	Example	Example
Jmp_rel	Example	Example	Example	Example	Example	Example
JMPEQ	Example	Example	Example	Example	Example	Example
ClearZ	Example	Example	Example	Example	Example	Example
ClearOV	Example	Example	Example	Example	Example	Example
LoadPC	Example	Example	Example	Example	Example	Example
SavePC	Example	Example	Example	Example	Example	Example
ShiftArithR	Example	Example	Example	Example	Example	Example
ShiftArithL	Example	Example	Example	Example	Example	Example
ShiftA_R	Example	Example	Example	Example	Example	Example
ShiftA_L	Example	Example	Example	Example	Example	Example
Load_A_Mem	Example	Example	Example	Example	Example	Example
Store_A_Mem	Example	Example	Example	Example	Example	Example
Load_B_Dir	Example	Example	Example	Example	Example	Example
Load_B_Mem	Example	Example	Example	Example	Example	Example
JmpC	Example	Example	Example	Example	Example	Example
ClearC	Example	Example	Example	Example	Example	Example
ClearACC	Example	Example	Example	Example	Example	Example
RRC	Example	Example	Example	Example	Example	Example
PUSH	Example	Example	Example	Example	Example	Example
POP	Example	Example	Example	Example	Example	Example
RLC	Example	Example	Example	Example	Example	Example
NOP	Example	Example	Example	Example	Example	Example
HALT	Example	Example	Example	Example	Example	Example

Other instructions implementation

the follwoing instructions can be also implemented with the ones in IS:

• Call "function_name":

PUSH
SavePC
Push
Jmp "function address"
POP  

• Return:

POP
Add_A_Dir 4
LoadPC