From: Richard Henderson <richard.henderson@linaro.org> To: Alistair Francis <alistair.francis@wdc.com>, qemu-devel@nongnu.org, qemu-riscv@nongnu.org Cc: alistair23@gmail.com, bmeng.cn@gmail.com, palmer@dabbelt.com Subject: Re: [PATCH v2 8/9] target/riscv: Consolidate RV32/64 32-bit instructions Date: Tue, 13 Apr 2021 20:42:51 -0700 [thread overview] Message-ID: <77d3d314-a03e-e081-04c0-a22447fd2658@linaro.org> (raw) In-Reply-To: <058e2779f8bcd25816bc2338a44ab6f1b2d549db.1618356725.git.alistair.francis@wdc.com> On 4/13/21 4:34 PM, Alistair Francis wrote: > -#ifndef CONFIG_USER_ONLY > -# ifdef TARGET_RISCV32 > -# define is_32bit(ctx) true > -# else > +#ifdef TARGET_RISCV32 > +# define is_32bit(ctx) true > +#else > static inline bool is_32bit(DisasContext *ctx) > { > - return !(ctx->misa & RV64); > + return (ctx->misa & RV32) == RV32; Why the change here? Also note the previous comment about fixing this to false for TARGET_RISCV64 && CONFIG_USER_ONLY. > static bool trans_fcvt_l_d(DisasContext *ctx, arg_fcvt_l_d *a) > { > REQUIRE_FPU; > REQUIRE_EXT(ctx, RVD); > + REQUIRE_64BIT(ctx); I think you should always put the 64-bit check first. That way, on TARGET_RISCV32, the entire function folds away. > > - TCGv t0 = tcg_temp_new(); > + TCGv_i64 t0 = tcg_temp_new_i64(); > gen_set_rm(ctx, a->rm); > gen_helper_fcvt_l_d(t0, cpu_env, cpu_fpr[a->rs1]); > - gen_set_gpr(a->rd, t0); > - tcg_temp_free(t0); > + gen_set_gpr(a->rd, (TCGv) t0); So... I really don't like the cast. This is fixable one of two ways. (1) Change the real helper to use target_ulong. (2) Use the gen_helper_* stubs that I talked about in reply to v1. > @@ -390,8 +390,9 @@ static bool trans_fmv_x_d(DisasContext *ctx, arg_fmv_x_d *a) > { > REQUIRE_FPU; > REQUIRE_EXT(ctx, RVD); > + REQUIRE_64BIT(ctx); > > - gen_set_gpr(a->rd, cpu_fpr[a->rs1]); > + gen_set_gpr(a->rd, (TCGv) cpu_fpr[a->rs1]); This one's different, and might be worth #ifdef TARGET_RISCV64 gen_set_gpr #else qemu_build_not_reached #endif > +++ b/target/riscv/insn_trans/trans_rvf.c.inc > @@ -303,11 +303,11 @@ static bool trans_fmv_x_w(DisasContext *ctx, arg_fmv_x_w *a) > > TCGv t0 = tcg_temp_new(); > > -#if defined(TARGET_RISCV64) > - tcg_gen_ext32s_tl(t0, cpu_fpr[a->rs1]); > -#else > - tcg_gen_extrl_i64_i32(t0, cpu_fpr[a->rs1]); > -#endif > + if (!is_32bit(ctx)) { > + tcg_gen_ext32s_tl((TCGv) t0, (TCGv) cpu_fpr[a->rs1]); > + } else { > + tcg_gen_extrl_i64_i32((TCGv_i32) t0, cpu_fpr[a->rs1]); > + } I think you should leave this ifdef alone. The ifdef has determined the size of target_ulong and thus the size of TCGv, and thus the correct move to use. If TARGET_RISCV64 and is_32bit, the high bits are ignored; the fact that they happen to be copies of the sign bit is irrelevant. r~
WARNING: multiple messages have this Message-ID (diff)
From: Richard Henderson <richard.henderson@linaro.org> To: Alistair Francis <alistair.francis@wdc.com>, qemu-devel@nongnu.org, qemu-riscv@nongnu.org Cc: bmeng.cn@gmail.com, palmer@dabbelt.com, alistair23@gmail.com Subject: Re: [PATCH v2 8/9] target/riscv: Consolidate RV32/64 32-bit instructions Date: Tue, 13 Apr 2021 20:42:51 -0700 [thread overview] Message-ID: <77d3d314-a03e-e081-04c0-a22447fd2658@linaro.org> (raw) In-Reply-To: <058e2779f8bcd25816bc2338a44ab6f1b2d549db.1618356725.git.alistair.francis@wdc.com> On 4/13/21 4:34 PM, Alistair Francis wrote: > -#ifndef CONFIG_USER_ONLY > -# ifdef TARGET_RISCV32 > -# define is_32bit(ctx) true > -# else > +#ifdef TARGET_RISCV32 > +# define is_32bit(ctx) true > +#else > static inline bool is_32bit(DisasContext *ctx) > { > - return !(ctx->misa & RV64); > + return (ctx->misa & RV32) == RV32; Why the change here? Also note the previous comment about fixing this to false for TARGET_RISCV64 && CONFIG_USER_ONLY. > static bool trans_fcvt_l_d(DisasContext *ctx, arg_fcvt_l_d *a) > { > REQUIRE_FPU; > REQUIRE_EXT(ctx, RVD); > + REQUIRE_64BIT(ctx); I think you should always put the 64-bit check first. That way, on TARGET_RISCV32, the entire function folds away. > > - TCGv t0 = tcg_temp_new(); > + TCGv_i64 t0 = tcg_temp_new_i64(); > gen_set_rm(ctx, a->rm); > gen_helper_fcvt_l_d(t0, cpu_env, cpu_fpr[a->rs1]); > - gen_set_gpr(a->rd, t0); > - tcg_temp_free(t0); > + gen_set_gpr(a->rd, (TCGv) t0); So... I really don't like the cast. This is fixable one of two ways. (1) Change the real helper to use target_ulong. (2) Use the gen_helper_* stubs that I talked about in reply to v1. > @@ -390,8 +390,9 @@ static bool trans_fmv_x_d(DisasContext *ctx, arg_fmv_x_d *a) > { > REQUIRE_FPU; > REQUIRE_EXT(ctx, RVD); > + REQUIRE_64BIT(ctx); > > - gen_set_gpr(a->rd, cpu_fpr[a->rs1]); > + gen_set_gpr(a->rd, (TCGv) cpu_fpr[a->rs1]); This one's different, and might be worth #ifdef TARGET_RISCV64 gen_set_gpr #else qemu_build_not_reached #endif > +++ b/target/riscv/insn_trans/trans_rvf.c.inc > @@ -303,11 +303,11 @@ static bool trans_fmv_x_w(DisasContext *ctx, arg_fmv_x_w *a) > > TCGv t0 = tcg_temp_new(); > > -#if defined(TARGET_RISCV64) > - tcg_gen_ext32s_tl(t0, cpu_fpr[a->rs1]); > -#else > - tcg_gen_extrl_i64_i32(t0, cpu_fpr[a->rs1]); > -#endif > + if (!is_32bit(ctx)) { > + tcg_gen_ext32s_tl((TCGv) t0, (TCGv) cpu_fpr[a->rs1]); > + } else { > + tcg_gen_extrl_i64_i32((TCGv_i32) t0, cpu_fpr[a->rs1]); > + } I think you should leave this ifdef alone. The ifdef has determined the size of target_ulong and thus the size of TCGv, and thus the correct move to use. If TARGET_RISCV64 and is_32bit, the high bits are ignored; the fact that they happen to be copies of the sign bit is irrelevant. r~
next prev parent reply other threads:[~2021-04-14 3:44 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-13 23:32 [PATCH v2 0/9] RISC-V: Steps towards running 32-bit guests on Alistair Francis 2021-04-13 23:32 ` Alistair Francis 2021-04-13 23:33 ` [PATCH v2 1/9] target/riscv: Remove the hardcoded RVXLEN macro Alistair Francis 2021-04-13 23:33 ` Alistair Francis 2021-04-14 7:59 ` Bin Meng 2021-04-14 7:59 ` Bin Meng 2021-04-13 23:33 ` [PATCH v2 2/9] target/riscv: Remove the hardcoded SSTATUS_SD macro Alistair Francis 2021-04-13 23:33 ` Alistair Francis 2021-04-14 7:59 ` Bin Meng 2021-04-14 7:59 ` Bin Meng 2021-04-13 23:33 ` [PATCH v2 3/9] target/riscv: Remove the hardcoded HGATP_MODE macro Alistair Francis 2021-04-13 23:33 ` Alistair Francis 2021-04-14 7:59 ` Bin Meng 2021-04-14 7:59 ` Bin Meng 2021-04-13 23:33 ` [PATCH v2 4/9] target/riscv: Remove the hardcoded MSTATUS_SD macro Alistair Francis 2021-04-13 23:33 ` Alistair Francis 2021-04-14 3:13 ` Richard Henderson 2021-04-14 3:13 ` Richard Henderson 2021-04-13 23:34 ` [PATCH v2 5/9] target/riscv: Remove the hardcoded SATP_MODE macro Alistair Francis 2021-04-13 23:34 ` Alistair Francis 2021-04-14 3:14 ` Richard Henderson 2021-04-14 3:14 ` Richard Henderson 2021-04-14 8:00 ` Bin Meng 2021-04-14 8:00 ` Bin Meng 2021-04-13 23:34 ` [PATCH v2 6/9] target/riscv: Remove the unused HSTATUS_WPRI macro Alistair Francis 2021-04-13 23:34 ` Alistair Francis 2021-04-14 8:00 ` Bin Meng 2021-04-14 8:00 ` Bin Meng 2021-04-13 23:34 ` [PATCH v2 7/9] target/riscv: Remove an unused CASE_OP_32_64 macro Alistair Francis 2021-04-13 23:34 ` Alistair Francis 2021-04-14 8:00 ` Bin Meng 2021-04-14 8:00 ` Bin Meng 2021-04-13 23:34 ` [PATCH v2 8/9] target/riscv: Consolidate RV32/64 32-bit instructions Alistair Francis 2021-04-13 23:34 ` Alistair Francis 2021-04-14 3:42 ` Richard Henderson [this message] 2021-04-14 3:42 ` Richard Henderson 2021-04-22 2:01 ` Alistair Francis 2021-04-22 2:01 ` Alistair Francis 2021-04-13 23:34 ` [PATCH v2 9/9] target/riscv: Consolidate RV32/64 16-bit instructions Alistair Francis 2021-04-13 23:34 ` Alistair Francis 2021-04-14 3:57 ` Richard Henderson 2021-04-14 3:57 ` Richard Henderson
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