u/Realistic_Extent3487

Hi

i am interested in consoles emulation and low level hardware emulation i know every process but do not know where to start

i was working on mips32 recompiler currently i have made decoder and my IR

IR_TYPE type;

IR_OP operation;

uint32_t mips32_instruction;

union

{

// R templates

struct {IRReg RegA,RegB,RegC;}op_r_r_r;

struct {IRReg RegA,RegB; uint8_t sa;}op_r_r_sa;

struct {IRReg RegA,RegB;}op_r_r;

struct {IRReg RegA,RegB;}op_r_hilo;

struct {IRReg RegA,RegB;}op_hilo_r;

// I templates

struct {IRReg RegA,RegB; int16_t immediate;}op_r_r_imm16;

struct {IRReg RegA,RegB; int16_t offset;}op_r_r_off16;

struct {IRReg RegA,RegB; uint16_t u16;}op_r_r_u16;

};

and there is funcs that set the instructions like this

void make_r_r_r (RegID RegA, RegID RegB ,RegID RegC)

{

this->op_r_r_r.RegA.id = RegA;

this->op_r_r_r.RegB.id = RegB;

this->op_r_r_r.RegC.id = RegC;

}

what should i do next i am poorly know x86 instructions while i need it to build the backend if some has already made jit before and experience in recompilers help me to complete it

for jit compiler you have to write the whole compiler:
1- decoder

2- IR

2- register allocator

3- optimization like eliminate dead code

4- a whole arch backend like x86 or arm with register allocator and optimization again

for llvm just do this :

1- write decoder then for every instruction see what is the equivalent in llvm ir

llvm has it is own reg alloc + heavy optimization that emit incredibly fast code