MIPSsembler

A tiny MIPS assembler written in Rust.

MIPS(Microprocessor without Interlocked Pipeline Stages)

Basic instruction formats

R (Register)

and $17, $17, $0

+-----------+-------+-------+-------+----------+----------+
| opcode(6) | rs(5) | rt(5) | rd(5) | shamt(5) | funct(6) |
+-----------+-------+-------+-------+----------+----------+
| 000000    | 10001 | 00000 | 10001 | 00000    | 100100   |
+-----------+-------+-------+-------+----------+----------+

I (Immediate)

addiu $17, $17, 0x1

+-----------+-------+-------+-----------------------------+
| opcode(6) | rs(5) | rt(5) | immediate(16)               |
+-----------+-------+-------+-----------------------------+
| 001001    | 10001 | 10001 | 0000000000000001            |
+-----------+-------+-------+-----------------------------+

J (Jump)

j lab1

+-----------+---------------------------------------------+
| opcode(6) | address(26)                                 |
+-----------+---------------------------------------------+
| 000010    | 00000100000000000000000110                  |
+-----------+---------------------------------------------+

Memory allocation

$sp +---------------+ 0x7ffffffc
    | Stack         | 
    +-------+-------+
    |       |       |
    |       v       |
    |               |
    |       ^       |
    |       |       |
    +-------+-------+
    | Heap          |
$gp +---------------+ 0x10008000
    | Static(Data)  |
    +---------------+ 0x10000000
    | Text(Code)    |
 PC +---------------+ 0x00400000
    | Reserved      |
    +---------------+ 0x00000000

Example

$ mipssembler input.s output.o

input.s

	.data
data1:	.word	100
data2:	.word	200
data3:	.word	0x12345678
	.text
main:
	and	$17, $17, $0
	and	$18, $18, $0
	la	$8, data1
	la	$9, data2
	and	$10, $10, $0
lab1:
	and	$11, $11, $0
lab2:
	addiu	$17, $17, 0x1
	addiu	$11, $11, 0x1
	or	$9, $9, $0
	bne	$11, $8, lab2
lab3:
	addiu	$18, $18, 0x2
	addiu	$11, $11, 1
	sll	$18, $17, 1
	srl	$17, $18, 1
	and	$19, $17, $18
	bne	$11, $9, lab3
lab4:
	addu	$5, $5, $31
	nor	$16, $17, $18
	beq	$10, $8, lab5
	j	lab1
lab5:
	ori	$16, $16, 0xf0f0

output.o

00000000000000000000000001011000
00000000000000000000000000001100
00000010001000001000100000100100
00000010010000001001000000100100
00111100000010000001000000000000
00111100000010010001000000000000
00110101001010010000000000000100
00000001010000000101000000100100
00000001011000000101100000100100
00100110001100010000000000000001
00100101011010110000000000000001
00000001001000000100100000100101
00010101011010001111111111111100
00100110010100100000000000000010
00100101011010110000000000000001
00000000000100011001000001000000
00000000000100101000100001000010
00000010001100101001100000100100
00010101011010011111111111111010
00000000101111110010100000100001
00000010001100101000000000100111
00010001010010000000000000000001
00001000000100000000000000000110
00110110000100001111000011110000
00000000000000000000000001100100
00000000000000000000000011001000
00010010001101000101011001111000

License

This project is licensed under the MIT License - see the LICENSE file for details.