Vaibhav Shrimali <vaibhav.shrimali@xxxxxxxxx> writes: > I wanted to know : how to set some value at a particular memory > location on the stack. > Suppose I want to set a value stored in a rtx type variable to a > memory location. > Is the following code correct? > I need to read a particular memory location, then XOR it with the hard > frame pointer and then store it back in its place. > will this code work? > Note: Here at (argument pointer - 8) location, I am pushing a copy of > return address earlier and after that the hard_frame_pointer is > pushed. > Now, I want to XOR the duplicate return address with the new > hard_frame_pointer_rtx generated after pushing the frame pointer on > the stack. > I wanted to know that will this code work to do the task? > > arg_ptr = cfun->machine->force_align_arg_pointer; > r = gen_rtx_PLUS (Pmode, arg_ptr, -8); > r = gen_rtx_MEM (Pmode, r); > m = force_reg(Pmode,r); // OR : m = copy_to_mode_reg(Pmode, r); > m1 = simplify_binary_operation(XOR, Pmode, m, hard_frame_pointer_rtx); > > set1 = emit_insn(gen_rtx_SET (Pmode,r, m1)); > RTX_FRAME_RELATED_P (set1) = 1; > > > If not, please guide me with some solution that would allow me to > write a rtx variable value to a particular memory location. I'm guessing that you are doing this after register allocation. At that point in the compilation you can no longer call force_reg, as force_reg will try to create a new pseudo-register which will never get allocated. You have to pick a register to use instead. If you are doing this before register allocation then it looks more or less OK. Does it work? Ian
