;; DFA scheduling description for ST40-300. ;; Copyright (C) 2004-2021 Free Software Foundation, Inc.

;; 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/.

;; Load and store instructions save a cycle if they are aligned on a ;; four byte boundary. Using a function unit for stores encourages ;; gcc to separate load and store instructions by one instruction, ;; which makes it more likely that the linker will be able to word ;; align them when relaxing.

;; The following description models the ST40-300 pipeline using the DFA based ;; scheduler.

;; Two automata are defined to reduce number of states ;; which a single large automaton will have. (Factoring)

(define_automaton “sh4_300_inst_pipeline,sh4_300_fpu_pipe”)

;; This unit is basically the decode unit of the processor. ;; Since SH4 is a dual issue machine,it is as if there are two ;; units so that any insn can be processed by either one ;; of the decoding unit. (define_cpu_unit “sh4_300_pipe_01,sh4_300_pipe_02” “sh4_300_inst_pipeline”)

;; The floating point units. (define_cpu_unit “sh4_300_fpt,sh4_300_fpu,sh4_300_fds” “sh4_300_fpu_pipe”)

;; integer multiplier unit (define_cpu_unit “sh4_300_mul” “sh4_300_inst_pipeline”)

;; LS unit (define_cpu_unit “sh4_300_ls” “sh4_300_inst_pipeline”)

;; The address calculator used for branch instructions. ;; This will be reserved after “issue” of branch instructions ;; and this is to make sure that no two branch instructions ;; can be issued in parallel. (define_cpu_unit “sh4_300_br” “sh4_300_inst_pipeline”)

;; ---------------------------------------------------- ;; This reservation is to simplify the dual issue description.

(define_reservation “sh4_300_issue” “sh4_300_pipe_01|sh4_300_pipe_02”)

(define_reservation “all” “sh4_300_pipe_01+sh4_300_pipe_02”)

;;(define_insn_reservation “nil” 0 (eq_attr “type” “nil”) “nothing”)

;; MOV RM,RN / MOV #imm8,RN / STS PR,RN (define_insn_reservation “sh4_300_mov” 0 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “move,movi8,prget”)) “sh4_300_issue”)

;; Fixed STS from MACL / MACH (define_insn_reservation “sh4_300_mac_gp” 0 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “mac_gp”)) “sh4_300_issue+sh4_300_mul”)

;; Fixed LDS to MACL / MACH (define_insn_reservation “sh4_300_gp_mac” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “gp_mac”)) “sh4_300_issue+sh4_300_mul”)

;; Instructions without specific resource requirements with latency 1. (define_insn_reservation “sh4_300_simple_arith” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “mt_group,arith,dyn_shift,prset”)) “sh4_300_issue”)

;; Load and store instructions have no alignment peculiarities for the ST40-300, ;; but they use the load-store unit, which they share with the fmove type ;; insns (fldi[01]; fmov frn,frm; flds; fsts; fabs; fneg) . ;; Loads have a latency of three.

;; Load Store instructions. (define_insn_reservation “sh4_300_load” 3 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “load,pcload,load_si,pcload_si,pload”)) “sh4_300_issue+sh4_300_ls”)

(define_insn_reservation “sh4_300_mac_load” 3 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “mem_mac”)) “sh4_300_issue+sh4_300_ls+sh4_300_mul”)

(define_insn_reservation “sh4_300_fload” 4 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fload,pcfload”)) “sh4_300_issue+sh4_300_ls+sh4_300_fpt”)

;; sh_adjust_cost describes the reduced latency of the feeding insns of a store. ;; The latency of an auto-increment register is 1; the latency of the memory ;; output is not actually considered here anyway. (define_insn_reservation “sh4_300_store” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “store,pstore”)) “sh4_300_issue+sh4_300_ls”)

(define_insn_reservation “sh4_300_fstore” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fstore”)) “sh4_300_issue+sh4_300_ls+sh4_300_fpt”)

;; Fixed STS.L from MACL / MACH (define_insn_reservation “sh4_300_mac_store” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “mac_mem”)) “sh4_300_issue+sh4_300_mul+sh4_300_ls”)

(define_insn_reservation “sh4_300_gp_fpul” 2 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “gp_fpul”)) “sh4_300_issue+sh4_300_fpt”)

(define_insn_reservation “sh4_300_fpul_gp” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fpul_gp”)) “sh4_300_issue+sh4_300_fpt”)

;; Branch (BF,BF/S,BT,BT/S,BRA) ;; Branch Far (JMP,RTS,BRAF) ;; Group: BR ;; When displacement is 0 for BF / BT, we have effectively conditional ;; execution of one instruction, without pipeline disruption. ;; Otherwise, the latency depends on prediction success. ;; We can't really do much with the latency, even if we could express it, ;; but the pairing restrictions are useful to take into account. ;; ??? If the branch is likely, and not paired with a preceding insn, ;; or likely and likely not predicted, we might want to fill the delay slot. ;; However, there appears to be no machinery to make the compiler ;; recognize these scenarios. (define_insn_reservation “sh4_300_branch” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “cbranch,jump,return,jump_ind”)) “sh4_300_issue+sh4_300_br”)

;; RTE (define_insn_reservation “sh4_300_return_from_exp” 9 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “rte”)) “sh4_300_pipe_01+sh4_300_pipe_02*9”)

;; OCBP, OCBWB ;; Group: CO ;; Latency: 1-5 ;; Issue Rate: 1 ;; cwb is used for the sequence ;; ocbwb @%0 ;; extu.w %0,%2 ;; or %1,%2 ;; mov.l %0,@%2 ;; This description is likely inexact, but this pattern should not actually ;; appear when compiling for sh4-300; we should use isbi instead. ;; If a -mtune option is added later, we should use the icache array ;; dispatch method instead. (define_insn_reservation “sh4_300_ocbwb” 3 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “cwb”)) “all*3”)

;; JSR,BSR,BSRF ;; Calls have a mandatory delay slot, which we‘d like to fill with an insn ;; that can be paired with the call itself. ;; Scheduling runs before reorg, so we approximate this by saying that we ;; want the call to be paired with a preceding insn. ;; In most cases, the insn that loads the address of the call should have ;; a nonzero latency (mov rn,rm doesn’t make sense since we could use rn ;; for the address then). Thus, a preceding insn that can be paired with ;; a call should be eligible for the delay slot. ;; ;; calls introduce a longisch delay that is likely to flush the pipelines ;; of the caller's instructions. Ordinary functions tend to end with a ;; load to restore a register (in the delay slot of rts), while sfuncs ;; tend to end with an EX or MT insn. But that is not actually relevant, ;; since there are no instructions that contend for memory access early. ;; We could, of course, provide exact scheduling information for specific ;; sfuncs, if that should prove useful. (define_insn_reservation “sh4_300_call” 16 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “call,sfunc”)) “sh4_300_issue+sh4_300_br,all*15”)

;; FMOV.S / FMOV.D (define_insn_reservation “sh4_300_fmov” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fmove”)) “sh4_300_issue+sh4_300_fpt”)

;; LDS to FPSCR (define_insn_reservation “sh4_300_fpscr_load” 8 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “gp_fpscr”)) “sh4_300_issue+sh4_300_fpu+sh4_300_fpt”)

;; LDS.L to FPSCR (define_insn_reservation “sh4_300_fpscr_load_mem” 8 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “mem_fpscr”)) “sh4_300_issue+sh4_300_fpu+sh4_300_fpt+sh4_300_ls”)

;; Fixed point multiplication (DMULS.L DMULU.L MUL.L MULS.W,MULU.W) (define_insn_reservation “multi” 2 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “smpy,dmpy”)) “sh4_300_issue+sh4_300_mul”)

;; FPCHG, FRCHG, FSCHG (define_insn_reservation “fpscr_toggle” 1 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fpscr_toggle”)) “sh4_300_issue+sh4_300_fpu+sh4_300_fpt”)

;; FCMP/EQ, FCMP/GT (define_insn_reservation “fp_cmp” 3 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fp_cmp,dfp_cmp”)) “sh4_300_issue+sh4_300_fpu”)

;; Single precision floating point (FADD,FLOAT,FMAC,FMUL,FSUB,FTRC) ;; Double-precision floating-point (FADD,FCNVDS,FCNVSD,FLOAT,FSUB,FTRC) (define_insn_reservation “fp_arith” 6 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fp,ftrc_s,dfp_arith,dfp_conv”)) “sh4_300_issue+sh4_300_fpu”)

;; Single Precision FDIV/SQRT (define_insn_reservation “fp_div” 19 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “fdiv”)) “sh4_300_issue+sh4_300_fpu+sh4_300_fds,sh4_300_fds*15”)

;; Double-precision floating-point FMUL (define_insn_reservation “dfp_mul” 9 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “dfp_mul”)) “sh4_300_issue+sh4_300_fpu,sh4_300_fpu*3”)

;; Double precision FDIV/SQRT (define_insn_reservation “dp_div” 35 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “dfdiv”)) “sh4_300_issue+sh4_300_fpu+sh4_300_fds,sh4_300_fds*31”)

;; ??? We don't really want these for sh4-300. ;; this pattern itself is likely to finish in 3 cycles, but also ;; to disrupt branch prediction for taken branches for the following ;; condbranch. (define_insn_reservation “sh4_300_arith3” 5 (and (eq_attr “pipe_model” “sh4_300”) (eq_attr “type” “arith3”)) “sh4_300_issue,all*4”)

;; arith3b insns without brach redirection make use of the 0-offset 0-latency ;; branch feature, and thus schedule the same no matter if the branch is taken ;; or not. If the branch is redirected, the taken branch might take longer, ;; but then, we don't have to take the next branch. ;; ??? should we suppress branch redirection for sh4-300 to improve branch ;; target hit rates? (define_insn_reservation “arith3b” 2 (and (eq_attr “pipe_model” “sh4”) (eq_attr “type” “arith3”)) “issue,all”)