1 ;; Scheduling description for GR6.
2 ;; Copyright (C) 2013-2018 Free Software Foundation, Inc.
4 ;; This file is part of GCC.
6 ;; GCC is free software; you can redistribute it and/or modify
7 ;; it under the terms of the GNU General Public License as published by
8 ;; the Free Software Foundation; either version 3, or (at your option)
11 ;; GCC is distributed in the hope that it will be useful,
12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 ;; GNU General Public License for more details.
16 ;; You should have received a copy of the GNU General Public License
17 ;; along with GCC; see the file COPYING3. If not see
18 ;; <http://www.gnu.org/licenses/>.
20 ;; GR6 is a dual-issue, superscalar, out-of-order processor.
22 ;; The GR6 pipeline has 3 major components:
23 ;; 1. The FETCH/DECODE/DISPATCH stages, an in-order front-end,
24 ;; 2. The PROCESS stage, which is the out-of-order core,
25 ;; 3. The STORE stage, an in-order register storage stage.
27 ;; The front-end and the back-end (PROCESS + STORE) are connected through a set
28 ;; of reservation stations which, among other things, serve as buffers for the
29 ;; decoded instructions. The reservation stations are attached to a specific
30 ;; execution unit of the PROCESS stage and the DISPATCH stage is responsible
31 ;; for dispatching the decoded instructions to the appropriate stations. Most
32 ;; execution units have multiple reservation stations, thus making it possible
33 ;; to dispatch two instructions per unit on a given cycle, but only one of them
34 ;; can be executed on the next cycle.
36 ;; Since the core executes the instructions out of order, the most important
37 ;; consideration for performance tuning is to make sure that enough decoded
38 ;; instructions are ready for execution in the PROCESS stage while not stalling
39 ;; the front-end, i.e while not trying to dispatch a decoded instruction to an
40 ;; execution unit whose reservation stations are full. Therefore, we do not
41 ;; model the reservation stations (which is equivalent to pretending that there
42 ;; is only one of them for each execution unit) but only the execution unit,
43 ;; thus preserving some margin in case the unit itself stalls unexpectedly.
45 ;; CPU execution units:
47 ;; inst[1|2] The front-end: 2 instructions can be issued on a given
48 ;; cycle by the FETCH/DECODE/DISPATCH stages, except for
49 ;; the Block Move instructions.
51 ;; mov Move Execution Unit: immediate moves into registers.
53 ;; alu[1|2] The 2 Arithmetic and Logic Units: other instructions
54 ;; operating on the registers.
56 ;; bru Branch Resolution Unit: all branches.
58 ;; mem_wr Memory Write Unit: all writes to memory.
60 ;; mem_rd Memory Read Unit: all reads from memory.
62 ;; mem_eam EAM interface: reads and writes from and to the EAM
63 ;; and reads from the FP registers.
65 ;; eam Extended Arithmetic Module: multiply, divide and
68 ;; fpcu Floating-Point Compare Unit: FP comparisons.
70 ;; fpu[1|2|3|4] The 4 Floating-Point Units: all other instructions
71 ;; operating on the FP registers.
73 (define_automaton "gr6,gr6_fpu")
75 (define_cpu_unit "gr6_inst1, gr6_inst2" "gr6")
76 (define_cpu_unit "gr6_mov" "gr6")
77 (define_cpu_unit "gr6_alu1,gr6_alu2" "gr6")
78 (define_cpu_unit "gr6_bru" "gr6")
79 (define_cpu_unit "gr6_mem_wr,gr6_mem_rd,gr6_mem_eam" "gr6")
80 (define_cpu_unit "gr6_eam" "gr6")
81 (define_cpu_unit "gr6_fpcu" "gr6")
82 (define_cpu_unit "gr6_fpu1,gr6_fpu2,gr6_fpu3,gr6_fpu4" "gr6_fpu")
84 (define_reservation "gr6_issue" "(gr6_inst1 | gr6_inst2)")
85 (define_reservation "gr6_single_issue" "gr6_inst1 + gr6_inst2")
87 (define_insn_reservation "gr6_immediate" 1
88 (and (eq_attr "cpu" "gr6")
89 (eq_attr "type" "imm_reg"))
90 "gr6_issue + gr6_mov")
92 (define_insn_reservation "gr6_alu" 1
93 (and (eq_attr "cpu" "gr6")
94 (eq_attr "type" "arith,arith2,logic,cmp"))
95 "gr6_issue + (gr6_alu1 | gr6_alu2)")
97 (define_insn_reservation "gr6_branch" 1
98 (and (eq_attr "cpu" "gr6")
99 (eq_attr "type" "abs_branch,branch,call,ret,rfi"))
100 "gr6_issue + gr6_bru")
102 (define_insn_reservation "gr6_block_move" 16
103 (and (eq_attr "cpu" "gr6")
104 (eq_attr "type" "bmi"))
105 "gr6_single_issue*16")
107 (define_insn_reservation "gr6_cpu_other" 1
108 (and (eq_attr "cpu" "gr6")
109 (eq_attr "type" "dsi,nop"))
112 (define_insn_reservation "gr6_write_mem" 1
113 (and (eq_attr "cpu" "gr6")
114 (eq_attr "type" "reg_mem"))
115 "gr6_issue + gr6_mem_wr")
117 (define_insn_reservation "gr6_read_mem" 6
118 (and (eq_attr "cpu" "gr6")
119 (eq_attr "type" "mem_reg"))
120 "gr6_issue + gr6_mem_rd, nothing*5")
124 (define_insn_reservation "gr6_write_eam" 2
125 (and (eq_attr "cpu" "gr6")
126 (eq_attr "type" "reg_eam"))
127 "gr6_issue + gr6_mem_eam, nothing")
129 (define_reservation "gr6_issue_eam" "gr6_issue + gr6_mem_eam + gr6_eam")
131 (define_insn_reservation "gr6_read_eam" 2
132 (and (eq_attr "cpu" "gr6")
133 (eq_attr "type" "eam_reg"))
134 "gr6_issue_eam, nothing")
136 (define_insn_reservation "gr6_shiftdi" 2
137 (and (eq_attr "cpu" "gr6")
138 (eq_attr "type" "shiftdi"))
139 "gr6_issue_eam, gr6_eam")
141 (define_insn_reservation "gr6_mul" 3
142 (and (eq_attr "cpu" "gr6")
143 (eq_attr "type" "mul"))
144 "gr6_issue_eam, gr6_eam*2")
146 (define_insn_reservation "gr6_div" 34
147 (and (eq_attr "cpu" "gr6")
148 (eq_attr "type" "div"))
149 "gr6_issue_eam, gr6_eam*33")
151 (define_insn_reservation "gr6_divd" 66
152 (and (eq_attr "cpu" "gr6")
153 (eq_attr "type" "divd"))
154 "gr6_issue_eam, gr6_eam*65")
158 (define_insn_reservation "gr6_read_fp" 2
159 (and (eq_attr "cpu" "gr6")
160 (eq_attr "type" "fp_reg"))
161 "gr6_issue + gr6_mem_eam, nothing")
163 (define_insn_reservation "gr6_cmp_fp" 1
164 (and (eq_attr "cpu" "gr6")
165 (eq_attr "type" "fcmp"))
166 "gr6_issue + gr6_fpcu")
168 (define_insn_reservation "gr6_fp_1cycle" 1
169 (and (eq_attr "cpu" "gr6")
170 (eq_attr "type" "fmove,ftoi,itof"))
171 "gr6_issue + gr6_fpu1")
173 (define_insn_reservation "gr6_fp_3cycle" 3
174 (and (eq_attr "cpu" "gr6")
175 (eq_attr "type" "fp"))
176 "gr6_issue + gr6_fpu2, nothing*2")
178 (define_insn_reservation "gr6_fp_17cycle" 17
179 (and (eq_attr "cpu" "gr6")
180 (eq_attr "type" "fdiv,fsqrt"))
181 "gr6_issue + gr6_fpu3, gr6_fpu3*14, nothing*2")
183 (define_insn_reservation "gr6_write_fp" 1
184 (and (eq_attr "cpu" "gr6")
185 (eq_attr "type" "reg_fp"))
186 "gr6_issue + gr6_fpu4")