ARM64 Code Examples

The simulator was developed for teaching 64-bit ARM Instruction set in CSC 220 and CSC 446 at CUNY College of Staten Island by Prof. Shuqun Zhang. It is based on the the Unicorn CPU emulator framework for JavaScript by Alexandro Sanchez (https://github.com/AlexAltea/unicorn.js).

2. Plantz, Robert G., Introduction to Computer Organization: ARM Assembly Language Using the Raspberry Pi 2017.

3. THINK IN GEEK, Exploring AArch64 assembler https://thinkingeek.com/categories/aarch64/

4. A Guide to ARM64 / AArch64 Assembly on Linux with Shellcodes and Cryptography, https://modexp.wordpress.com/2018/10/30/arm64-assembly/

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Some ARM64 examples for testing

1. first program: arithmetic instructions
	mov x0, #2
	mov x1, #-3
	add x2, x0, x1   // 2+(-3)
    sub x3, x0, x1  // 2-(3)
    mul x4, x0, x1  // 2*(-3)
    udiv x5, x1, x0  // 2/(-3)
	sdiv x6, x1, x0  // 2/(-3)
	
2. multiply: 9*7 - 5*3

mov x1, #9  //x0 <- 9
	mov x2, #7 //x1 <- 7
	mul x0, x1, x2 //x0 <- x1 * x2
	mov x2, #5 // x1 <- 5
	mov x3, #3 // x2 <- 3
	mul x1, x2, x3 // x1 <- x2 * x3
	sub x0, x0, x1 // x0 <- x0 - x1

3. logic instructions
	mov x0, #6
	mov x1, #10
	and x2, x0, x1
	orr x3, x0, x1
	eor x4, x0, x1
	
4. shift instructions (show equivlance of shift to multiplication/division)
    mov x0, #8
    lsl x5, x0, #3 // x0*8
	lsr x6, x0, #2 // x0/4
	asr x7, x0, #3 // x0/8
	ror x8, x0, #1 
	
5. memory access: load/store data in data segment: 
first store 5 and 3 into data segment (starting address 0x800) and then load and add them together

mov x0, #5
	adr x1, #0x800  //can't use mov because of 16-bit imm limit for mov
	str x0, [x1]    
	ldr x4, [x1]   
	
	mov x0, #3
	add x1, x1, #8  
	str x0, [x1]    
	ldr x5, [x1]   
	
	add x6, x4, x5

6. load/store data in stack using stack pointer sp
    mov     w0, #19 
	str     w0, [sp, #12]
	ldr     w0, [sp, #12]
	add     w0, w0, #02
	add     sp, sp, #0x10

7. simple loop: a=0; for (i=0; i<3) a=a+2;

mov x0, #0  //a 
    mov x1,#0  //i
	mov x2, #2
loop: add x1, x1, #1
    add x0,x0,x2
    cmp x1,#3
    b.ne loop

8. Branch instructions: if (a == 3) b=a-2; else b=a+2;

mov x0, #2
    mov x1, #3  //a
	cmp x1, #3
    b.eq equal
    add x2, x0, x1
    b end 
equal: sub x2, x0, x1
end:

9. find the largest and put in x0

main:
    mov x1, #34
    mov x2, #54
    mov x3, #91
    mov x0, x1     /* start with x1 */

cmp x0, x2
    b.ge test_r3
    mov x0, x2

test_r3:
    cmp x0, x3
    b.ge end
    mov x0, x3

end:

10. function call: main() { a=0; adder2(a);},  int adder2(int a) { return a + 2;}

main: mov w0, #0
	bl adder2
	ret     //important, inifinity loop without it

adder2: sub     sp, sp, #0x10
	str     w0, [sp, #12]
	ldr     w0, [sp, #12]
	add     w0, w0, #0x2
	add     sp, sp, #0x10
	ret

11. computer fibonacci sequence:

main:	
	mov x0, 0 //answer
	mov x1, 9  // find 9th number
	mov x2, 0   //first number
	mov x3, 1  //second number
	mov x4, 0  //i=0

loop:
	add x4, x4, 1  
	cmp x1, x4 
	b.le exit
	mov x5, x0
	add x0, x2, x3
	mov x2, x0
	mov x3, x5
	b.al loop
exit:

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Features:

Assembler directives
1. .text / .code
2. .data
3. .byte
4. .short
5. .word
6. .asciiz
7. .space
Debugging
1. Breakpoints
2. Stepping
3. Highlighting machine code being executed
4. Printing output
5. Printing generated assembly code
6. Registers values reflect current state
7. Condition flags values reflect current state
8. Memory values reflect current state
Syntax highlighting for ARM assembly
Change theme of code-editor
Importing/Exporting Machine/Assembly Code and Sample Code
Creating user account
1. Saving projects
2. Making them private or public
Convertors
1. Converting machine code into different formats
2. Convertor in the bottom of the page for convenience

ARM64 Online Simulator