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;; Machine description for RISC-V atomic operations.
;; Copyright (C) 2011-2019 Free Software Foundation, Inc.
;; Contributed by Andrew Waterman (andrew@sifive.com).
;; Based on MIPS target for GNU compiler.
;; 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_c_enum "unspec" [
UNSPEC_COMPARE_AND_SWAP
UNSPEC_SYNC_OLD_OP
UNSPEC_SYNC_EXCHANGE
UNSPEC_ATOMIC_STORE
UNSPEC_MEMORY_BARRIER
])
(define_code_iterator any_atomic [plus ior xor and])
(define_code_attr atomic_optab
[(plus "add") (ior "or") (xor "xor") (and "and")])
;; Memory barriers.
(define_expand "mem_thread_fence"
[(match_operand:SI 0 "const_int_operand" "")] ;; model
""
{
if (INTVAL (operands[0]) != MEMMODEL_RELAXED)
{
rtx mem = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
MEM_VOLATILE_P (mem) = 1;
emit_insn (gen_mem_thread_fence_1 (mem, operands[0]));
}
DONE;
})
;; Until the RISC-V memory model (hence its mapping from C++) is finalized,
;; conservatively emit a full FENCE.
(define_insn "mem_thread_fence_1"
[(set (match_operand:BLK 0 "" "")
(unspec:BLK [(match_dup 0)] UNSPEC_MEMORY_BARRIER))
(match_operand:SI 1 "const_int_operand" "")] ;; model
""
"fence\tiorw,iorw")
;; Atomic memory operations.
;; Implement atomic stores with amoswap. Fall back to fences for atomic loads.
(define_insn "atomic_store<mode>"
[(set (match_operand:GPR 0 "memory_operand" "=A")
(unspec_volatile:GPR
[(match_operand:GPR 1 "reg_or_0_operand" "rJ")
(match_operand:SI 2 "const_int_operand")] ;; model
UNSPEC_ATOMIC_STORE))]
"TARGET_ATOMIC"
"%F2amoswap.<amo>%A2 zero,%z1,%0"
[(set (attr "length") (const_int 8))])
(define_insn "atomic_<atomic_optab><mode>"
[(set (match_operand:GPR 0 "memory_operand" "+A")
(unspec_volatile:GPR
[(any_atomic:GPR (match_dup 0)
(match_operand:GPR 1 "reg_or_0_operand" "rJ"))
(match_operand:SI 2 "const_int_operand")] ;; model
UNSPEC_SYNC_OLD_OP))]
"TARGET_ATOMIC"
"%F2amo<insn>.<amo>%A2 zero,%z1,%0"
[(set (attr "length") (const_int 8))])
(define_insn "atomic_fetch_<atomic_optab><mode>"
[(set (match_operand:GPR 0 "register_operand" "=&r")
(match_operand:GPR 1 "memory_operand" "+A"))
(set (match_dup 1)
(unspec_volatile:GPR
[(any_atomic:GPR (match_dup 1)
(match_operand:GPR 2 "reg_or_0_operand" "rJ"))
(match_operand:SI 3 "const_int_operand")] ;; model
UNSPEC_SYNC_OLD_OP))]
"TARGET_ATOMIC"
"%F3amo<insn>.<amo>%A3 %0,%z2,%1"
[(set (attr "length") (const_int 8))])
(define_insn "atomic_exchange<mode>"
[(set (match_operand:GPR 0 "register_operand" "=&r")
(unspec_volatile:GPR
[(match_operand:GPR 1 "memory_operand" "+A")
(match_operand:SI 3 "const_int_operand")] ;; model
UNSPEC_SYNC_EXCHANGE))
(set (match_dup 1)
(match_operand:GPR 2 "register_operand" "0"))]
"TARGET_ATOMIC"
"%F3amoswap.<amo>%A3 %0,%z2,%1"
[(set (attr "length") (const_int 8))])
(define_insn "atomic_cas_value_strong<mode>"
[(set (match_operand:GPR 0 "register_operand" "=&r")
(match_operand:GPR 1 "memory_operand" "+A"))
(set (match_dup 1)
(unspec_volatile:GPR [(match_operand:GPR 2 "reg_or_0_operand" "rJ")
(match_operand:GPR 3 "reg_or_0_operand" "rJ")
(match_operand:SI 4 "const_int_operand") ;; mod_s
(match_operand:SI 5 "const_int_operand")] ;; mod_f
UNSPEC_COMPARE_AND_SWAP))
(clobber (match_scratch:GPR 6 "=&r"))]
"TARGET_ATOMIC"
"%F5 1: lr.<amo>%A5 %0,%1; bne %0,%z2,1f; sc.<amo>%A4 %6,%z3,%1; bnez %6,1b; 1:"
[(set (attr "length") (const_int 20))])
(define_expand "atomic_compare_and_swap<mode>"
[(match_operand:SI 0 "register_operand" "") ;; bool output
(match_operand:GPR 1 "register_operand" "") ;; val output
(match_operand:GPR 2 "memory_operand" "") ;; memory
(match_operand:GPR 3 "reg_or_0_operand" "") ;; expected value
(match_operand:GPR 4 "reg_or_0_operand" "") ;; desired value
(match_operand:SI 5 "const_int_operand" "") ;; is_weak
(match_operand:SI 6 "const_int_operand" "") ;; mod_s
(match_operand:SI 7 "const_int_operand" "")] ;; mod_f
"TARGET_ATOMIC"
{
emit_insn (gen_atomic_cas_value_strong<mode> (operands[1], operands[2],
operands[3], operands[4],
operands[6], operands[7]));
rtx compare = operands[1];
if (operands[3] != const0_rtx)
{
rtx difference = gen_rtx_MINUS (<MODE>mode, operands[1], operands[3]);
compare = gen_reg_rtx (<MODE>mode);
emit_insn (gen_rtx_SET (compare, difference));
}
if (word_mode != <MODE>mode)
{
rtx reg = gen_reg_rtx (word_mode);
emit_insn (gen_rtx_SET (reg, gen_rtx_SIGN_EXTEND (word_mode, compare)));
compare = reg;
}
emit_insn (gen_rtx_SET (operands[0], gen_rtx_EQ (SImode, compare, const0_rtx)));
DONE;
})
(define_expand "atomic_test_and_set"
[(match_operand:QI 0 "register_operand" "") ;; bool output
(match_operand:QI 1 "memory_operand" "+A") ;; memory
(match_operand:SI 2 "const_int_operand" "")] ;; model
"TARGET_ATOMIC"
{
/* We have no QImode atomics, so use the address LSBs to form a mask,
then use an aligned SImode atomic. */
rtx result = operands[0];
rtx mem = operands[1];
rtx model = operands[2];
rtx addr = force_reg (Pmode, XEXP (mem, 0));
rtx aligned_addr = gen_reg_rtx (Pmode);
emit_move_insn (aligned_addr, gen_rtx_AND (Pmode, addr, GEN_INT (-4)));
rtx aligned_mem = change_address (mem, SImode, aligned_addr);
set_mem_alias_set (aligned_mem, 0);
rtx offset = gen_reg_rtx (SImode);
emit_move_insn (offset, gen_rtx_AND (SImode, gen_lowpart (SImode, addr),
GEN_INT (3)));
rtx tmp = gen_reg_rtx (SImode);
emit_move_insn (tmp, GEN_INT (1));
rtx shmt = gen_reg_rtx (SImode);
emit_move_insn (shmt, gen_rtx_ASHIFT (SImode, offset, GEN_INT (3)));
rtx word = gen_reg_rtx (SImode);
emit_move_insn (word, gen_rtx_ASHIFT (SImode, tmp,
gen_lowpart (QImode, shmt)));
tmp = gen_reg_rtx (SImode);
emit_insn (gen_atomic_fetch_orsi (tmp, aligned_mem, word, model));
emit_move_insn (gen_lowpart (SImode, result),
gen_rtx_LSHIFTRT (SImode, tmp,
gen_lowpart (QImode, shmt)));
DONE;
})
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