diff gcc/config/arm/cortex-a8.md @ 0:a06113de4d67

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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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+;; ARM Cortex-A8 scheduling description.
+;; Copyright (C) 2007 Free Software Foundation, Inc.
+;; Contributed by CodeSourcery.
+
+;; This file is part of GCC.
+
+;; GCC is free software; you can redistribute it and/or modify it
+;; under the terms of the GNU General Public License as published
+;; by the Free Software Foundation; either version 3, or (at your
+;; option) any later version.
+
+;; GCC is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+;; or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+;; License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GCC; see the file COPYING3.  If not see
+;; <http://www.gnu.org/licenses/>.
+
+(define_automaton "cortex_a8")
+
+;; Only one load/store instruction can be issued per cycle
+;; (although reservation of this unit is only required for single
+;; loads and stores -- see below).
+(define_cpu_unit "cortex_a8_issue_ls" "cortex_a8")
+
+;; Only one branch instruction can be issued per cycle.
+(define_cpu_unit "cortex_a8_issue_branch" "cortex_a8")
+
+;; The two ALU pipelines.
+(define_cpu_unit "cortex_a8_alu0" "cortex_a8")
+(define_cpu_unit "cortex_a8_alu1" "cortex_a8")
+
+;; The usual flow of an instruction through the pipelines.
+(define_reservation "cortex_a8_default"
+                    "cortex_a8_alu0|cortex_a8_alu1")
+
+;; The flow of a branch instruction through the pipelines.
+(define_reservation "cortex_a8_branch"
+                    "(cortex_a8_alu0+cortex_a8_issue_branch)|\
+                     (cortex_a8_alu1+cortex_a8_issue_branch)")
+
+;; The flow of a load or store instruction through the pipeline in
+;; the case where that instruction consists of only one micro-op...
+(define_reservation "cortex_a8_load_store_1"
+                    "(cortex_a8_alu0+cortex_a8_issue_ls)|\
+                     (cortex_a8_alu1+cortex_a8_issue_ls)")
+
+;; ...and in the case of two micro-ops.  We don't need to reserve
+;; cortex_a8_issue_ls here because dual issue is altogether forbidden
+;; during the issue cycle of the first micro-op.  (Instead of modelling
+;; a separate issue unit, we instead reserve alu0 and alu1 to
+;; prevent any other instructions from being issued upon that first cycle.)
+;; Even though the load/store pipeline is usually available in either
+;; ALU pipe, multi-cycle instructions always issue in pipeline 0.  This
+;; reservation is therefore the same as cortex_a8_multiply_2 below.
+(define_reservation "cortex_a8_load_store_2"
+                    "cortex_a8_alu0+cortex_a8_alu1,\
+                     cortex_a8_alu0")
+
+;; The flow of a single-cycle multiplication.
+(define_reservation "cortex_a8_multiply"
+                    "cortex_a8_alu0")
+
+;; The flow of a multiplication instruction that gets decomposed into
+;; two micro-ops.  The two micro-ops will be issued to pipeline 0 on
+;; successive cycles.  Dual issue cannot happen at the same time as the
+;; first of the micro-ops.
+(define_reservation "cortex_a8_multiply_2"
+                    "cortex_a8_alu0+cortex_a8_alu1,\
+                     cortex_a8_alu0")
+
+;; Similarly, the flow of a multiplication instruction that gets
+;; decomposed into three micro-ops.  Dual issue cannot occur except on
+;; the cycle upon which the third micro-op is issued.
+(define_reservation "cortex_a8_multiply_3"
+                    "cortex_a8_alu0+cortex_a8_alu1,\
+                     cortex_a8_alu0+cortex_a8_alu1,\
+                     cortex_a8_alu0")
+
+;; The model given here assumes that all instructions are unconditional.
+
+;; Data processing instructions, but not move instructions.
+
+;; We include CLZ with these since it has the same execution pattern
+;; (source read in E2 and destination available at the end of that cycle).
+(define_insn_reservation "cortex_a8_alu" 2
+  (and (eq_attr "tune" "cortexa8")
+       (ior (and (eq_attr "type" "alu")
+                (not (eq_attr "insn" "mov,mvn")))
+            (eq_attr "insn" "clz")))
+  "cortex_a8_default")
+
+(define_insn_reservation "cortex_a8_alu_shift" 2
+  (and (eq_attr "tune" "cortexa8")
+       (and (eq_attr "type" "alu_shift")
+            (not (eq_attr "insn" "mov,mvn"))))
+  "cortex_a8_default")
+
+(define_insn_reservation "cortex_a8_alu_shift_reg" 2
+  (and (eq_attr "tune" "cortexa8")
+       (and (eq_attr "type" "alu_shift_reg")
+            (not (eq_attr "insn" "mov,mvn"))))
+  "cortex_a8_default")
+
+;; Move instructions.
+
+(define_insn_reservation "cortex_a8_mov" 1
+  (and (eq_attr "tune" "cortexa8")
+       (and (eq_attr "type" "alu,alu_shift,alu_shift_reg")
+            (eq_attr "insn" "mov,mvn")))
+  "cortex_a8_default")
+
+;; Exceptions to the default latencies for data processing instructions.
+
+;; A move followed by an ALU instruction with no early dep.
+;; (Such a pair can be issued in parallel, hence latency zero.)
+(define_bypass 0 "cortex_a8_mov" "cortex_a8_alu")
+(define_bypass 0 "cortex_a8_mov" "cortex_a8_alu_shift"
+               "arm_no_early_alu_shift_dep")
+(define_bypass 0 "cortex_a8_mov" "cortex_a8_alu_shift_reg"
+               "arm_no_early_alu_shift_value_dep")
+
+;; An ALU instruction followed by an ALU instruction with no early dep.
+(define_bypass 1 "cortex_a8_alu,cortex_a8_alu_shift,cortex_a8_alu_shift_reg"
+               "cortex_a8_alu")
+(define_bypass 1 "cortex_a8_alu,cortex_a8_alu_shift,cortex_a8_alu_shift_reg"
+               "cortex_a8_alu_shift"
+               "arm_no_early_alu_shift_dep")
+(define_bypass 1 "cortex_a8_alu,cortex_a8_alu_shift,cortex_a8_alu_shift_reg"
+               "cortex_a8_alu_shift_reg"
+               "arm_no_early_alu_shift_value_dep")
+
+;; Multiplication instructions.  These are categorized according to their
+;; reservation behavior and the need below to distinguish certain
+;; varieties for bypasses.  Results are available at the E5 stage
+;; (but some of these are multi-cycle instructions which explains the
+;; latencies below).
+
+(define_insn_reservation "cortex_a8_mul" 6
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "insn" "mul,smulxy,smmul"))
+  "cortex_a8_multiply_2")
+
+(define_insn_reservation "cortex_a8_mla" 6
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "insn" "mla,smlaxy,smlawy,smmla,smlad,smlsd"))
+  "cortex_a8_multiply_2")
+
+(define_insn_reservation "cortex_a8_mull" 7
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "insn" "smull,umull,smlal,umlal,umaal,smlalxy"))
+  "cortex_a8_multiply_3")
+
+(define_insn_reservation "cortex_a8_smulwy" 5
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "insn" "smulwy,smuad,smusd"))
+  "cortex_a8_multiply")
+
+;; smlald and smlsld are multiply-accumulate instructions but do not
+;; received bypassed data from other multiplication results; thus, they
+;; cannot go in cortex_a8_mla above.  (See below for bypass details.)
+(define_insn_reservation "cortex_a8_smlald" 6
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "insn" "smlald,smlsld"))
+  "cortex_a8_multiply_2")
+
+;; A multiply with a single-register result or an MLA, followed by an
+;; MLA with an accumulator dependency, has its result forwarded so two
+;; such instructions can issue back-to-back.
+(define_bypass 1 "cortex_a8_mul,cortex_a8_mla,cortex_a8_smulwy"
+               "cortex_a8_mla"
+               "arm_mac_accumulator_is_mul_result")
+
+;; A multiply followed by an ALU instruction needing the multiply
+;; result only at E2 has lower latency than one needing it at E1.
+(define_bypass 4 "cortex_a8_mul,cortex_a8_mla,cortex_a8_mull,\
+                  cortex_a8_smulwy,cortex_a8_smlald"
+               "cortex_a8_alu")
+(define_bypass 4 "cortex_a8_mul,cortex_a8_mla,cortex_a8_mull,\
+                  cortex_a8_smulwy,cortex_a8_smlald"
+               "cortex_a8_alu_shift"
+               "arm_no_early_alu_shift_dep")
+(define_bypass 4 "cortex_a8_mul,cortex_a8_mla,cortex_a8_mull,\
+                  cortex_a8_smulwy,cortex_a8_smlald"
+               "cortex_a8_alu_shift_reg"
+               "arm_no_early_alu_shift_value_dep")
+
+;; Load instructions.
+;; The presence of any register writeback is ignored here.
+
+;; A load result has latency 3 unless the dependent instruction has
+;; no early dep, in which case it is only latency two.
+;; We assume 64-bit alignment for doubleword loads.
+(define_insn_reservation "cortex_a8_load1_2" 3
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "type" "load1,load2,load_byte"))
+  "cortex_a8_load_store_1")
+
+(define_bypass 2 "cortex_a8_load1_2"
+               "cortex_a8_alu")
+(define_bypass 2 "cortex_a8_load1_2"
+               "cortex_a8_alu_shift"
+               "arm_no_early_alu_shift_dep")
+(define_bypass 2 "cortex_a8_load1_2"
+               "cortex_a8_alu_shift_reg"
+               "arm_no_early_alu_shift_value_dep")
+
+;; We do not currently model the fact that loads with scaled register
+;; offsets that are not LSL #2 have an extra cycle latency (they issue
+;; as two micro-ops).
+
+;; A load multiple of three registers is usually issued as two micro-ops.
+;; The first register will be available at E3 of the first iteration,
+;; the second at E3 of the second iteration, and the third at E4 of
+;; the second iteration.  A load multiple of four registers is usually
+;; issued as two micro-ops.
+(define_insn_reservation "cortex_a8_load3_4" 5
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "type" "load3,load4"))
+  "cortex_a8_load_store_2")
+
+(define_bypass 4 "cortex_a8_load3_4"
+               "cortex_a8_alu")
+(define_bypass 4 "cortex_a8_load3_4"
+               "cortex_a8_alu_shift"
+               "arm_no_early_alu_shift_dep")
+(define_bypass 4 "cortex_a8_load3_4"
+               "cortex_a8_alu_shift_reg"
+               "arm_no_early_alu_shift_value_dep")
+
+;; Store instructions.
+;; Writeback is again ignored.
+
+(define_insn_reservation "cortex_a8_store1_2" 0
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "type" "store1,store2"))
+  "cortex_a8_load_store_1")
+
+(define_insn_reservation "cortex_a8_store3_4" 0
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "type" "store3,store4"))
+  "cortex_a8_load_store_2")
+
+;; An ALU instruction acting as a producer for a store instruction
+;; that only uses the result as the value to be stored (as opposed to
+;; using it to calculate the address) has latency zero; the store
+;; reads the value to be stored at the start of E3 and the ALU insn
+;; writes it at the end of E2.  Move instructions actually produce the
+;; result at the end of E1, but since we don't have delay slots, the
+;; scheduling behavior will be the same.
+(define_bypass 0 "cortex_a8_alu,cortex_a8_alu_shift,\
+                  cortex_a8_alu_shift_reg,cortex_a8_mov"
+               "cortex_a8_store1_2,cortex_a8_store3_4"
+               "arm_no_early_store_addr_dep")
+
+;; Branch instructions
+
+(define_insn_reservation "cortex_a8_branch" 0
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "type" "branch"))
+  "cortex_a8_branch")
+
+;; Call latencies are not predictable.  A semi-arbitrary very large
+;; number is used as "positive infinity" so that everything should be
+;; finished by the time of return.
+(define_insn_reservation "cortex_a8_call" 32
+  (and (eq_attr "tune" "cortexa8")
+       (eq_attr "type" "call"))
+  "cortex_a8_issue_branch")
+
+;; NEON (including VFP) instructions.
+
+(include "cortex-a8-neon.md")
+