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From: frank.chang@sifive.com
To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>,
	Frank Chang <frank.chang@sifive.com>,
	Bastian Koppelmann <kbastian@mail.uni-paderborn.de>,
	Richard Henderson <richard.henderson@linaro.org>,
	Alistair Francis <Alistair.Francis@wdc.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	LIU Zhiwei <zhiwei_liu@c-sky.com>
Subject: [PATCH v7 25/75] target/riscv: rvv-1.0: take fractional LMUL into vector max elements calculation
Date: Fri, 26 Feb 2021 11:18:09 +0800	[thread overview]
Message-ID: <20210226031902.23656-26-frank.chang@sifive.com> (raw)
In-Reply-To: <20210226031902.23656-1-frank.chang@sifive.com>

From: Frank Chang <frank.chang@sifive.com>

Update vext_get_vlmax() and MAXSZ() to take fractional LMUL into
calculation for RVV 1.0.

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu.h                      | 43 ++++++++++++++++++-------
 target/riscv/insn_trans/trans_rvv.c.inc | 12 ++++++-
 2 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index ad79669a2ce..367b182735f 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -395,18 +395,27 @@ FIELD(TB_FLAGS, HLSX, 15, 1)
 bool riscv_cpu_is_32bit(CPURISCVState *env);
 
 /*
- * 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);
 }
 
@@ -419,12 +428,22 @@ static inline 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 367fb28186f..72d0bc109b0 100644
--- a/target/riscv/insn_trans/trans_rvv.c.inc
+++ b/target/riscv/insn_trans/trans_rvv.c.inc
@@ -1268,7 +1268,17 @@ GEN_VEXT_AMO_TRANS(vamomaxuei64_v, MO_64, 35, rwdvm, amo_op, amo_check)
 /*
  *** 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)
 {
-- 
2.17.1



  parent reply	other threads:[~2021-02-26  3:36 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-26  3:17 [PATCH v7 00/75] support vector extension v1.0 frank.chang
2021-02-26  3:17 ` [PATCH v7 01/75] target/riscv: drop vector 0.7.1 and add 1.0 support frank.chang
2021-02-26  3:17 ` [PATCH v7 02/75] target/riscv: Use FIELD_EX32() to extract wd field frank.chang
2021-02-26  3:17 ` [PATCH v7 03/75] target/riscv: rvv-1.0: add mstatus VS field frank.chang
2021-02-26  3:17 ` [PATCH v7 04/75] target/riscv: rvv-1.0: add sstatus " frank.chang
2021-02-26  3:17 ` [PATCH v7 05/75] target/riscv: rvv-1.0: introduce writable misa.v field frank.chang
2021-02-26  3:17 ` [PATCH v7 06/75] target/riscv: rvv-1.0: add translation-time vector context status frank.chang
2021-02-26  3:17 ` [PATCH v7 07/75] target/riscv: rvv-1.0: remove rvv related codes from fcsr registers frank.chang
2021-02-26  3:17 ` [PATCH v7 08/75] target/riscv: rvv-1.0: add vcsr register frank.chang
2021-02-26  3:17 ` [PATCH v7 09/75] target/riscv: rvv-1.0: add vlenb register frank.chang
2021-02-26  3:17 ` [PATCH v7 10/75] target/riscv: rvv-1.0: check MSTATUS_VS when accessing vector csr registers frank.chang
2021-02-26  3:17 ` [PATCH v7 11/75] target/riscv: rvv-1.0: remove MLEN calculations frank.chang
2021-02-26  3:17 ` [PATCH v7 12/75] target/riscv: rvv-1.0: add fractional LMUL frank.chang
2021-02-26  3:17 ` [PATCH v7 13/75] target/riscv: rvv-1.0: add VMA and VTA frank.chang
2021-02-26  3:17 ` [PATCH v7 14/75] target/riscv: rvv-1.0: update check functions frank.chang
2021-02-26  3:17 ` [PATCH v7 15/75] target/riscv: introduce more imm value modes in translator functions frank.chang
2021-02-26  3:18 ` [PATCH v7 16/75] target/riscv: rvv:1.0: add translation-time nan-box helper function frank.chang
2021-02-26  3:18 ` [PATCH v7 17/75] target/riscv: rvv-1.0: configure instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 18/75] target/riscv: rvv-1.0: stride load and store instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 19/75] target/riscv: rvv-1.0: index " frank.chang
2021-02-26  3:18 ` [PATCH v7 20/75] target/riscv: rvv-1.0: fix address index overflow bug of indexed load/store insns frank.chang
2021-02-26  3:18 ` [PATCH v7 21/75] target/riscv: rvv-1.0: fault-only-first unit stride load frank.chang
2021-02-26  3:18 ` [PATCH v7 22/75] target/riscv: rvv-1.0: amo operations frank.chang
2021-02-26  3:18 ` [PATCH v7 23/75] target/riscv: rvv-1.0: load/store whole register instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 24/75] target/riscv: rvv-1.0: update vext_max_elems() for load/store insns frank.chang
2021-02-26  3:18 ` frank.chang [this message]
2021-02-26  3:18 ` [PATCH v7 26/75] target/riscv: rvv-1.0: floating-point square-root instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 27/75] target/riscv: rvv-1.0: floating-point classify instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 28/75] target/riscv: rvv-1.0: mask population count instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 29/75] target/riscv: rvv-1.0: find-first-set mask bit instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 30/75] target/riscv: rvv-1.0: set-X-first mask bit instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 31/75] target/riscv: rvv-1.0: iota instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 32/75] target/riscv: rvv-1.0: element index instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 33/75] target/riscv: rvv-1.0: allow load element with sign-extended frank.chang
2021-02-26  3:18 ` [PATCH v7 34/75] target/riscv: rvv-1.0: register gather instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 35/75] target/riscv: rvv-1.0: integer scalar move instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 36/75] target/riscv: rvv-1.0: floating-point move instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 37/75] target/riscv: rvv-1.0: floating-point scalar move instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 38/75] target/riscv: rvv-1.0: whole register " frank.chang
2021-02-26  3:18 ` [PATCH v7 39/75] target/riscv: rvv-1.0: integer extension instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 40/75] target/riscv: rvv-1.0: single-width averaging add and subtract instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 41/75] target/riscv: rvv-1.0: single-width bit shift instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 42/75] target/riscv: rvv-1.0: integer add-with-carry/subtract-with-borrow frank.chang
2021-02-26  3:18 ` [PATCH v7 43/75] target/riscv: rvv-1.0: narrowing integer right shift instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 44/75] target/riscv: rvv-1.0: widening integer multiply-add instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 45/75] target/riscv: rvv-1.0: single-width saturating add and subtract instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 46/75] target/riscv: rvv-1.0: integer comparison instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 47/75] target/riscv: rvv-1.0: floating-point compare instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 48/75] target/riscv: rvv-1.0: mask-register logical instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 49/75] target/riscv: rvv-1.0: slide instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 50/75] target/riscv: rvv-1.0: floating-point " frank.chang
2021-02-26  3:18 ` [PATCH v7 51/75] target/riscv: rvv-1.0: narrowing fixed-point clip instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 52/75] target/riscv: rvv-1.0: single-width floating-point reduction frank.chang
2021-02-26  3:18 ` [PATCH v7 53/75] target/riscv: rvv-1.0: widening floating-point reduction instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 54/75] target/riscv: rvv-1.0: single-width scaling shift instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 55/75] target/riscv: rvv-1.0: remove widening saturating scaled multiply-add frank.chang
2021-02-26  3:18 ` [PATCH v7 56/75] target/riscv: rvv-1.0: remove vmford.vv and vmford.vf frank.chang
2021-02-26  3:18 ` [PATCH v7 57/75] target/riscv: rvv-1.0: remove integer extract instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 58/75] target/riscv: rvv-1.0: floating-point min/max instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 59/75] target/riscv: introduce floating-point rounding mode enum frank.chang
2021-02-26  3:18 ` [PATCH v7 60/75] target/riscv: rvv-1.0: floating-point/integer type-convert instructions frank.chang
2021-02-26  3:18 ` [PATCH v7 61/75] target/riscv: rvv-1.0: widening floating-point/integer type-convert frank.chang
2021-02-26  3:18 ` [PATCH v7 62/75] target/riscv: add "set round to odd" rounding mode helper function frank.chang
2021-02-26  3:18 ` [PATCH v7 63/75] target/riscv: rvv-1.0: narrowing floating-point/integer type-convert frank.chang
2021-02-26  3:18 ` [PATCH v7 64/75] target/riscv: rvv-1.0: relax RV_VLEN_MAX to 1024-bits frank.chang
2021-02-26  3:18 ` [PATCH v7 65/75] target/riscv: rvv-1.0: implement vstart CSR frank.chang
2021-02-26  3:18 ` [PATCH v7 66/75] target/riscv: rvv-1.0: trigger illegal instruction exception if frm is not valid frank.chang
2021-02-26  3:18 ` [PATCH v7 67/75] target/riscv: rvv-1.0: set mstatus.SD bit when writing vector CSRs frank.chang
2021-02-26  3:18 ` [PATCH v7 68/75] target/riscv: gdb: support vector registers for rv64 & rv32 frank.chang
2021-02-26  3:18 ` [PATCH v7 69/75] target/riscv: rvv-1.0: floating-point reciprocal square-root estimate instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 70/75] target/riscv: rvv-1.0: floating-point reciprocal " frank.chang
2021-02-26  3:18 ` [PATCH v7 71/75] target/riscv: set mstatus.SD bit when writing fp CSRs frank.chang
2021-02-26  3:18 ` [PATCH v7 72/75] target/riscv: rvv-1.0: rename r2_zimm to r2_zimm11 frank.chang
2021-02-26  3:18 ` [PATCH v7 73/75] target/riscv: rvv-1.0: add vsetivli instruction frank.chang
2021-02-26  3:18 ` [PATCH v7 74/75] target/riscv: rvv-1.0: add evl parameter to vext_ldst_us() frank.chang
2021-02-26  3:18 ` [PATCH v7 75/75] target/riscv: rvv-1.0: add vector unit-stride mask load/store insns frank.chang

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