From bf3c1bd265917cfcfd93215d5eebfa9d154816da Mon Sep 17 00:00:00 2001 From: Frank Chang Date: Fri, 14 Aug 2020 17:31:34 +0800 Subject: [PATCH 033/107] target/riscv: rvv-1.0: take fractional LMUL into vector max elements calculation 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 | 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 3835d22ca1..f773bae96b 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -404,18 +404,27 @@ 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); } @@ -428,12 +437,22 @@ 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 a992bd170d..71f2343d4d 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) { -- 2.33.1