Example #1
0
// Kernel call
static bool
kc(PPCEmuAssembler& a, Instruction instr)
{
   auto id = instr.kcn;
   auto kc = cpu::getKernelCall(id);
   decaf_assert(kc, fmt::format("Encountered invalid Kernel Call ID {}", id));

   // Evict all stored register as a KC might read or modify them.
   a.evictAll();

   // Save NIA back to memory in case KC reads/writes it
   a.mov(a.niaMem, a.genCia + 4);

   // Call the KC
   a.mov(a.sysArgReg[0], asmjit::Ptr(kc->func));
   a.mov(a.sysArgReg[1], asmjit::Ptr(kc->user_data));
   a.call(asmjit::Ptr(&kc_stub));
   a.mov(a.stateReg, asmjit::x86::rax);

   // Check if the KC adjusted nia.  If it has, we need to return
   //  to the dispatcher.  Note that we assume the cache was already
   //  cleared before this instruction since KC requires that anyways.
   auto niaUnchangedLbl = a.newLabel();

   a.cmp(a.niaMem, a.genCia + 4);
   a.je(niaUnchangedLbl);

   a.mov(a.finaleNiaArgReg, a.niaMem);
   a.mov(a.finaleJmpSrcArgReg, 0);
   a.jmp(asmjit::Ptr(gFinaleFn));

   a.bind(niaUnchangedLbl);

   return true;
}