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[59.124.168.89]) by smtp.gmail.com with ESMTPSA id f4sm2087955pfg.34.2021.12.09.23.58.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Dec 2021 23:58:39 -0800 (PST) From: frank.chang@sifive.com To: qemu-devel@nongnu.org Subject: [PATCH v11 26/77] target/riscv: rvv-1.0: take fractional LMUL into vector max elements calculation Date: Fri, 10 Dec 2021 15:56:12 +0800 Message-Id: <20211210075704.23951-27-frank.chang@sifive.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211210075704.23951-1-frank.chang@sifive.com> References: <20211210075704.23951-1-frank.chang@sifive.com> MIME-Version: 1.0 X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::634 (failed) Received-SPF: pass client-ip=2607:f8b0:4864:20::634; envelope-from=frank.chang@sifive.com; helo=mail-pl1-x634.google.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-riscv@nongnu.org, Frank Chang , Bin Meng , Richard Henderson , Alistair Francis , Palmer Dabbelt , LIU Zhiwei Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Frank Chang Update vext_get_vlmax() and MAXSZ() to take fractional LMUL into calculation for RVV 1.0. Signed-off-by: Frank Chang Reviewed-by: Richard Henderson Reviewed-by: Alistair Francis --- target/riscv/cpu.h | 27 ++++++++++++++++--------- target/riscv/cpu_helper.c | 16 ++++++++++++--- target/riscv/insn_trans/trans_rvv.c.inc | 12 ++++++++++- 3 files changed, 42 insertions(+), 13 deletions(-) diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 709b7c3abb..11a0f41b27 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -430,18 +430,27 @@ static inline RISCVMXL riscv_cpu_mxl(CPURISCVState *env) #endif /* - * A simplification for VLMAX - * = (1 << LMUL) * VLEN / (8 * (1 << SEW)) - * = (VLEN << LMUL) / (8 << SEW) - * = (VLEN << LMUL) >> (SEW + 3) - * = VLEN >> (SEW + 3 - LMUL) + * Encode LMUL to lmul as follows: + * LMUL vlmul lmul + * 1 000 0 + * 2 001 1 + * 4 010 2 + * 8 011 3 + * - 100 - + * 1/8 101 -3 + * 1/4 110 -2 + * 1/2 111 -1 + * + * then, we can calculate VLMAX = vlen >> (vsew + 3 - lmul) + * e.g. vlen = 256 bits, SEW = 16, LMUL = 1/8 + * => VLMAX = vlen >> (1 + 3 - (-3)) + * = 256 >> 7 + * = 2 */ static inline uint32_t vext_get_vlmax(RISCVCPU *cpu, target_ulong vtype) { - uint8_t sew, lmul; - - sew = FIELD_EX64(vtype, VTYPE, VSEW); - lmul = FIELD_EX64(vtype, VTYPE, VLMUL); + uint8_t sew = FIELD_EX64(vtype, VTYPE, VSEW); + int8_t lmul = sextract32(FIELD_EX64(vtype, VTYPE, VLMUL), 0, 3); return cpu->cfg.vlen >> (sew + 3 - lmul); } diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 1b31d0ad47..10f3baba53 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -75,12 +75,22 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc, *cs_base = 0; if (riscv_has_ext(env, RVV)) { + /* + * If env->vl equals to VLMAX, we can use generic vector operation + * expanders (GVEC) to accerlate the vector operations. + * However, as LMUL could be a fractional number. The maximum + * vector size can be operated might be less than 8 bytes, + * which is not supported by GVEC. So we set vl_eq_vlmax flag to true + * only when maxsz >= 8 bytes. + */ uint32_t vlmax = vext_get_vlmax(env_archcpu(env), env->vtype); - bool vl_eq_vlmax = (env->vstart == 0) && (vlmax == env->vl); + uint32_t sew = FIELD_EX64(env->vtype, VTYPE, VSEW); + uint32_t maxsz = vlmax << sew; + bool vl_eq_vlmax = (env->vstart == 0) && (vlmax == env->vl) && + (maxsz >= 8); flags = FIELD_DP32(flags, TB_FLAGS, VILL, FIELD_EX64(env->vtype, VTYPE, VILL)); - flags = FIELD_DP32(flags, TB_FLAGS, SEW, - FIELD_EX64(env->vtype, VTYPE, VSEW)); + flags = FIELD_DP32(flags, TB_FLAGS, SEW, sew); flags = FIELD_DP32(flags, TB_FLAGS, LMUL, FIELD_EX64(env->vtype, VTYPE, VLMUL)); flags = FIELD_DP32(flags, TB_FLAGS, VL_EQ_VLMAX, vl_eq_vlmax); diff --git a/target/riscv/insn_trans/trans_rvv.c.inc b/target/riscv/insn_trans/trans_rvv.c.inc index e12db9aae8..5c04ac90da 100644 --- a/target/riscv/insn_trans/trans_rvv.c.inc +++ b/target/riscv/insn_trans/trans_rvv.c.inc @@ -1049,7 +1049,17 @@ GEN_LDST_WHOLE_TRANS(vs8r_v, 8, true) /* *** Vector Integer Arithmetic Instructions */ -#define MAXSZ(s) (s->vlen >> (3 - s->lmul)) + +/* + * MAXSZ returns the maximum vector size can be operated in bytes, + * which is used in GVEC IR when vl_eq_vlmax flag is set to true + * to accerlate vector operation. + */ +static inline uint32_t MAXSZ(DisasContext *s) +{ + int scale = s->lmul - 3; + return scale < 0 ? s->vlen >> -scale : s->vlen << scale; +} static bool opivv_check(DisasContext *s, arg_rmrr *a) {