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;; ARM Cortex-A8 scheduling description.
;; Copyright (C) 2007, 2010 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. 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.
(define_reservation "cortex_a8_load_store_2"
"cortex_a8_alu0+cortex_a8_alu1+cortex_a8_issue_ls,\
cortex_a8_alu0+cortex_a8_issue_ls")
;; 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 (and (eq_attr "type" "alu")
(eq_attr "neon_type" "none"))
(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")
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