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(*
* This is a default description for architectures without *any* delay slots.
* By using this dummy module the architecture can use the spanDep.sml
* module for span dependency resolution.
*
* -- Allen
*)
functor NoDelaySlots(I : INSTRUCTIONS) : DELAY_SLOT_PROPERTIES =
struct
structure I = I
datatype delay_slot =
D_NONE (* no delay slot *)
| D_ERROR (* an error *)
| D_ALWAYS (* one delay slot *)
| D_TAKEN (* delay slot is only active when branch is taken *)
| D_FALLTHRU (* delay slot is only active when branch is not taken *)
(* size of delay slot in bytes *)
val delaySlotSize = 0
(* Return the delay slot properties of an instruction *)
fun delaySlot{instr,backward} =
{ n = false, (* is the nullified bit on? *)
nOn = D_ERROR, (* delay type when nullified *)
nOff= D_NONE, (* delay type when not nullified *)
nop = false (* is there a nop padded? *)
}
(* Change the delay slot properties of an instruction *)
fun enableDelaySlot{instr,n,nop} = instr
(* is there any dependency conflict? *)
fun conflict{src,dst} = true
(* can delaySlot fit within the delay slot of jmp? *)
fun delaySlotCandidate{jmp, delaySlot} = false
(* change the branch target of an instruction *)
fun setTarget(instr,label) = instr
end
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