mipsevm

mipsevm

Supported 63 instructions:

Category	Instruction	Description
Arithmetic	add	Add.
Arithmetic	addi	Add immediate (with sign-extension).
Arithmetic	addiu	Add immediate unsigned.
Arithmetic	addu	Add unsigned.
Logical	and	Bitwise AND.
Logical	andi	Bitwise AND immediate.
Conditional Branch	beq	Branch on equal.
Conditional Branch	bgez	Branch on greater than or equal to zero.
Conditional Branch	bgtz	Branch on greater than zero.
Conditional Branch	blez	Branch on less than or equal to zero.
Conditional Branch	bltz	Branch on less than zero.
Conditional Branch	bne	Branch on not equal.
Logical	clo	Count leading ones.
Logical	clz	Count leading zeros.
Arithmetic	div	Divide.
Arithmetic	divu	Divide unsigned.
Unconditional Jump	j	Jump.
Unconditional Jump	jal	Jump and link.
Unconditional Jump	jalr	Jump and link register.
Unconditional Jump	jr	Jump register.
Data Transfer	lb	Load byte.
Data Transfer	lbu	Load byte unsigned.
Data Transfer	lh	Load halfword.
Data Transfer	lhu	Load halfword unsigned.
Data Transfer	ll	Load linked word.
Data Transfer	lui	Load upper immediate.
Data Transfer	lw	Load word.
Data Transfer	lwl	Load word left.
Data Transfer	lwr	Load word right.
Data Transfer	mfhi	Move from HI register.
Data Transfer	mflo	Move from LO register.
Data Transfer	movn	Move conditional on not zero.
Data Transfer	movz	Move conditional on zero.
Data Transfer	mthi	Move to HI register.
Data Transfer	mtlo	Move to LO register.
Arithmetic	mul	Multiply (to produce a word result).
Arithmetic	mult	Multiply.
Arithmetic	multu	Multiply unsigned.
Logical	nor	Bitwise NOR.
Logical	or	Bitwise OR.
Logical	ori	Bitwise OR immediate.
Data Transfer	sb	Store byte.
Data Transfer	sc	Store conditional.
Data Transfer	sh	Store halfword.
Logical	sll	Shift left logical.
Logical	sllv	Shift left logical variable.
Comparison	slt	Set on less than (signed).
Comparison	slti	Set on less than immediate.
Comparison	sltiu	Set on less than immediate unsigned.
Comparison	sltu	Set on less than unsigned.
Logical	sra	Shift right arithmetic.
Logical	srav	Shift right arithmetic variable.
Logical	srl	Shift right logical.
Logical	srlv	Shift right logical variable.
Arithmetic	sub	Subtract.
Arithmetic	subu	Subtract unsigned.
Data Transfer	sw	Store word.
Data Transfer	swl	Store word left.
Data Transfer	swr	Store word right.
Serialization	sync	Synchronize shared memory.
System Calls	syscall	System call.
Logical	xor	Bitwise XOR.
Logical	xori	Bitwise XOR immediate.

To run:

1. Load a program into a state, e.g. using LoadELF.
2. Patch the program if necessary: e.g. using PatchGo for Go programs, PatchStack for empty initial stack, etc.
3. Implement the PreimageOracle interface
4. Instrument the emulator with the state, and pre-image oracle, using NewInstrumentedState
5. Step through the instrumented state with Step(proof), where proof==true if witness data should be generated. Steps are faster with proof==false.
6. Optionally repeat the step on-chain by calling MIPS.sol and PreimageOracle.sol, using the above witness data.