Assembler Simulator

An assembler simulator based on MIPS architecture

The program uses windows form for the user interface part

• With code editor to load an save asm files and add code comments
• Option to run the code, reset the simulator and see output
• View of the program memory and instruction memory
• View of the registers and address that labels refers to
• 32 bits registers implemented
• Address is oriented in byte (8 bits)
• Syscall for output of char, integers and floats
• You can disable the emulator feed (GUI, callbacks, etc) to have max performance

Views

Instructions memory

Labels View

Show the labels poiting addresses

Memory View

Show program memory per byte or char

Registers View

Show registers values

Code and output view

Show the code with options in the top and output

Implemented instructions

List of implementes instructions from MIPS

Arithmetic

Instructions to do arithmetic operations

add reg1 reg2 reg3 ; reg1 = reg2 + reg3
addi reg1 reg2 integer ; reg1 = reg2 + integer
sub reg1 reg2 reg3 ; reg1 = reg2 - reg3
div reg1 reg2 reg3 ; reg1 = reg2 / reg3
mul reg1 reg2 reg3 ; reg1 = reg2 * reg3
muli reg1 reg2 integer ; reg1 = reg2 * integer

addf reg1 reg2 reg3 ; reg1 = reg2 + reg3
addfi reg1 reg2 float ; reg1 = reg2 + float
subf reg1 reg2 reg3 ; reg1 = reg2 - reg3
divf reg1 reg2 reg3 ; reg1 = reg2 / reg3
mulf reg1 reg2 reg3 ; reg1 = reg2 * reg3
mulfi reg1 reg2 float ; reg1 = reg2 * float

se reg1 reg2 reg3 ; set reg1 as one if reg2 equals reg3 content, else set zero
sne reg1 reg2 reg3 ; set reg1 as one if reg2 not equals reg3 content, else set zero

slt reg1 reg2 reg3 ; set reg1 as one if reg2 < reg3 (int comparision) else set zero
sgt reg1 reg2 reg3 ; set reg1 as one if reg2 > reg3 (int comparision) else set zero
slte reg1 reg2 reg3 ; set reg1 as one if reg2 <= reg3 (int comparision) else set zero
sgte reg1 reg2 reg3 ; set reg1 as one if reg2 >= reg3 (int comparision) else set zero

sltf reg1 reg2 reg3 ; set reg1 as one if reg2 < reg3 (float comparision) else set zero
sgtf reg1 reg2 reg3 ; set reg1 as one if reg2 > reg3 (float comparision) else set zero
sltef reg1 reg2 reg3 ; set reg1 as one if reg2 <= reg3 (float comparision) else set zero
sgtef reg1 reg2 reg3 ; set reg1 as one if reg2 >= reg3 (float comparision) else set zero

Logic

Instructios to do logic operations

sfl is shift left and sfr is shift right

and reg1 reg2 reg3 ; reg1 = reg2 & reg3
xor reg1 reg2 reg3 ; reg1 = reg2 ^ reg3
or reg1 reg2 reg3 ; reg1 = reg2 | reg3
sfl reg1 reg2 reg3 ; reg1 = reg2 << reg3
sfr reg1 reg2 reg3 ; reg1 = reg2 >> reg3
not reg1 reg2 ; reg1 = ~reg2

Flow Control

Instructions to control program flow

j label ; go to instruction at address of label
jal label ; go to instruction at address of label, and save previous address+1 at ra
jr register ; go to instruction at address contained in register
beq reg1 reg2 label ; if reg1 and reg2 are same bytes go to address of label
beq reg1 reg2 label ; if reg1 and reg2 are same bytes go to address of label

Memory

Instructions to control program memory

lw reg1 integer reg2 ; reg1 = memory[reg2 + integer]
sw reg1 integer reg2 ; memory[reg2 + integer] = reg1
lb reg1 integer reg2 ; reg1 = memory[reg2 + integer]
sb reg1 integer reg2 ; memory[reg2 + integer] = reg1

lbr reg1 hex_value ; load hex_value into reg1
lcr reg1 char(ASCII) ; load char into reg1
lir reg1 integer ; load integer into reg1
lfr reg1 float ; load float into reg1

move reg1 reg2 ; reg1 = reg2
cfi reg1 reg2 ; reg1 = (float)reg2
cif reg1 reg2 ; reg1 = (int)reg2

Syscall

Syscall for output integer (number 1), float(number2), char(number3)

addi v0 v0 1
move a0 t0
syscall

Registers

register zero

Register that stores the zero value

register one

Register that stores the one value

registers s0 to s7

Registers for saved values

regtisters t0 to t9

Registers for temp values

registers a0 to a3

Arguments registers

regtisters v0 to v1

Returned values registers

register ve

Register that store the rest of some integer division

register vef

Register that store the rest of some float division

register gp and sp

Heap and stack pointer

register ra

Register to hold the return address

register pc

Program counter register

Examples

Fibonnaci

A program that outputs n numbers from fibonnaci sequence

Even number in the stack

ASCII

A program that print some ascii chars

Float

A program that do a float sum and print it

Using the API

Take a look at Program.cs of the AssemblerSimulator project to see the example below

public static void Main()
{
    Emulator emulator = new Emulator(OnMemoryChange, OnRegisterChange, OnSyscall);

    emulator.AddInstruction("lir t0 10"); // Carrega valor 10 em t0
    emulator.AddInstruction("sw t0 0 sp");  // Carrega na pilha o valor 10
    
    // Syscall para printar inteiro
    emulator.AddInstruction("addi v0 v0 1");
    emulator.AddInstruction("move a0 t0");
    emulator.AddInstruction("syscall");

    emulator.ValidateInstructions();
    emulator.ExecuteAll();
}

Output

OnRegisterChange t0 10 0 0 0
OnRegisterChange pc 1 0 0 0
OnMemoryChange 0 10
OnMemoryChange 1 0
OnMemoryChange 2 0
OnMemoryChange 3 0
OnRegisterChange pc 2 0 0 0
OnRegisterChange v0 1 0 0 0
OnRegisterChange pc 3 0 0 0
OnRegisterChange a0 10 0 0 0
OnRegisterChange pc 4 0 0 0
OnSyscall 1 10 0 0 0
OnRegisterChange pc 5 0 0 0