private void markReserved(int ropReg, int category) {
    reservedRopRegs.set(ropReg, ropReg + category, true);
  }
Marks a range of rop registers as "reserved for a local variable."

@param ropReg {@code >= 0;} rop register to reserve
@param category {@code > 0;} width to reserve
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/back/FirstFitLocalCombiningAllocator.java