70 lines
2.2 KiB
OCaml
70 lines
2.2 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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open Arch
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open Mach
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(* The Digital Unix assembler does scheduling better than us.
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However, the Linux-Alpha assembler does not do scheduling, so we do
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a feeble attempt here. *)
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class scheduler = object (self)
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inherit Schedgen.scheduler_generic as super
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(* Latencies (in cycles). Based on the 21064, with some poetic license. *)
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method oper_latency = function
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Ireload -> 3
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| Iload(_, _) -> 3
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| Iconst_symbol _ -> 3 (* turned into a load *)
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| Iconst_float _ -> 3 (* ends up in a load *)
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| Iintop(Imul) -> 23
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| Iintop_imm(Imul, _) -> 23
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| Iaddf -> 6
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| Isubf -> 6
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| Imulf -> 6
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| Idivf -> 63
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| _ -> 2
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(* Most arithmetic instructions can be executed back-to-back in 1 cycle.
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However, some combinations (arith; load or arith; store) require 2
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cycles. Also, by claiming 2 cycles instead of 1, we might favor
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dual issue. *)
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(* Issue cycles. Rough approximations. *)
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method oper_issue_cycles = function
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Iconst_float _ -> 4 (* load from $gp, then load *)
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| Ialloc _ -> 4
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| Iintop(Icheckbound) -> 2
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| Iintop_imm(Idiv, _) -> 3
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| Iintop_imm(Imod, _) -> 5
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| Iintop_imm(Icheckbound, _) -> 2
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| Ifloatofint -> 10
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| Iintoffloat -> 10
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| _ -> 1
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(* Say that reloadgp is not part of a basic block (prevents moving it
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past an operation that uses $gp) *)
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method oper_in_basic_block = function
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Ispecific(Ireloadgp _) -> false
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| op -> super#oper_in_basic_block op
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end
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let fundecl =
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if digital_asm
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then (fun f -> f)
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else (new scheduler)#schedule_fundecl
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