Re: [PATCH 2/2] target/riscv: csr: Remove redundant check in fp csr read/write routines

[Alistair Francis]

On Tue, Mar 30, 2021 at 10:18 PM Bin Meng <bmeng...@gmail.com> wrote:
>
> The following check:
>
>     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
>         return -RISCV_EXCP_ILLEGAL_INST;
>     }
>
> is redundant in fflags/frm/fcsr read/write routines, as the check was
> already done in fs().
>
> Signed-off-by: Bin Meng <bmeng...@gmail.com>

Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>

Alistair

> ---
>
>  target/riscv/csr.c | 24 ------------------------
>  1 file changed, 24 deletions(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 2bad396f64..7c24318f75 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -193,11 +193,6 @@ static int pmp(CPURISCVState *env, int csrno)
>  /* User Floating-Point CSRs */
>  static int read_fflags(CPURISCVState *env, int csrno, target_ulong *val)
>  {
> -#if !defined(CONFIG_USER_ONLY)
> -    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> -        return -RISCV_EXCP_ILLEGAL_INST;
> -    }
> -#endif
>      *val = riscv_cpu_get_fflags(env);
>      return 0;
>  }
> @@ -205,9 +200,6 @@ static int read_fflags(CPURISCVState *env, int csrno, 
> target_ulong *val)
>  static int write_fflags(CPURISCVState *env, int csrno, target_ulong val)
>  {
>  #if !defined(CONFIG_USER_ONLY)
> -    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> -        return -RISCV_EXCP_ILLEGAL_INST;
> -    }
>      env->mstatus |= MSTATUS_FS;
>  #endif
>      riscv_cpu_set_fflags(env, val & (FSR_AEXC >> FSR_AEXC_SHIFT));
> @@ -216,11 +208,6 @@ static int write_fflags(CPURISCVState *env, int csrno, 
> target_ulong val)
>
>  static int read_frm(CPURISCVState *env, int csrno, target_ulong *val)
>  {
> -#if !defined(CONFIG_USER_ONLY)
> -    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> -        return -RISCV_EXCP_ILLEGAL_INST;
> -    }
> -#endif
>      *val = env->frm;
>      return 0;
>  }
> @@ -228,9 +215,6 @@ static int read_frm(CPURISCVState *env, int csrno, 
> target_ulong *val)
>  static int write_frm(CPURISCVState *env, int csrno, target_ulong val)
>  {
>  #if !defined(CONFIG_USER_ONLY)
> -    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> -        return -RISCV_EXCP_ILLEGAL_INST;
> -    }
>      env->mstatus |= MSTATUS_FS;
>  #endif
>      env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
> @@ -239,11 +223,6 @@ static int write_frm(CPURISCVState *env, int csrno, 
> target_ulong val)
>
>  static int read_fcsr(CPURISCVState *env, int csrno, target_ulong *val)
>  {
> -#if !defined(CONFIG_USER_ONLY)
> -    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> -        return -RISCV_EXCP_ILLEGAL_INST;
> -    }
> -#endif
>      *val = (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
>          | (env->frm << FSR_RD_SHIFT);
>      if (vs(env, csrno) >= 0) {
> @@ -256,9 +235,6 @@ static int read_fcsr(CPURISCVState *env, int csrno, 
> target_ulong *val)
>  static int write_fcsr(CPURISCVState *env, int csrno, target_ulong val)
>  {
>  #if !defined(CONFIG_USER_ONLY)
> -    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
> -        return -RISCV_EXCP_ILLEGAL_INST;
> -    }
>      env->mstatus |= MSTATUS_FS;
>  #endif
>      env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
> --
> 2.25.1
>
>