Re: [Qemu-devel] [RFC PATCH v3 02/46] target/i386: Push rex_w into DisasContext

[Aleksandar Markovic]

15.08.2019. 04.13, "Jan Bobek" <address@hidden> је написао/ла:
>
> From: Richard Henderson <address@hidden>
>
> Treat this the same as we already do for other rex bits.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target/i386/translate.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/target/i386/translate.c b/target/i386/translate.c
> index d74dbfd585..c0866c2797 100644
> --- a/target/i386/translate.c
> +++ b/target/i386/translate.c
> @@ -44,11 +44,13 @@
>  #define REX_X(s) ((s)->rex_x)
>  #define REX_B(s) ((s)->rex_b)
>  #define REX_R(s) ((s)->rex_r)
> +#define REX_W(s) ((s)->rex_w)
>  #else
>  #define CODE64(s) 0
>  #define REX_X(s) 0
>  #define REX_B(s) 0
>  #define REX_R(s) 0
> +#define REX_W(s) -1

The commit message says "treat rex_w the same as other rex bits". Why is
then REX_W() treated differently here?

Yours,
Aleksandar

>  #endif
>
>  #ifdef TARGET_X86_64
> @@ -100,7 +102,7 @@ typedef struct DisasContext {
>  #ifdef TARGET_X86_64
>      int lma;    /* long mode active */
>      int code64; /* 64 bit code segment */
> -    int rex_x, rex_b, rex_r;
> +    int rex_x, rex_b, rex_r, rex_w;
>  #endif
>      int vex_l;  /* vex vector length */
>      int vex_v;  /* vex vvvv register, without 1's complement.  */
> @@ -4495,7 +4497,6 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>      int modrm, reg, rm, mod, op, opreg, val;
>      target_ulong next_eip, tval;
>      target_ulong pc_start = s->base.pc_next;
> -    int rex_w;
>
>      s->pc_start = s->pc = pc_start;
>      s->override = -1;
> @@ -4503,6 +4504,7 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>      s->rex_x = 0;
>      s->rex_b = 0;
>      s->rex_r = 0;
> +    s->rex_w = -1;
>      s->x86_64_hregs = false;
>  #endif
>      s->rip_offset = 0; /* for relative ip address */
> @@ -4514,7 +4516,6 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>      }
>
>      prefixes = 0;
> -    rex_w = -1;
>
>   next_byte:
>      b = x86_ldub_code(env, s);
> @@ -4557,7 +4558,7 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>      case 0x40 ... 0x4f:
>          if (CODE64(s)) {
>              /* REX prefix */
> -            rex_w = (b >> 3) & 1;
> +            s->rex_w = (b >> 3) & 1;
>              s->rex_r = (b & 0x4) << 1;
>              s->rex_x = (b & 0x2) << 2;
>              s->rex_b = (b & 0x1) << 3;
> @@ -4606,7 +4607,9 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>                  s->rex_b = (~vex2 >> 2) & 8;
>  #endif
>                  vex3 = x86_ldub_code(env, s);
> -                rex_w = (vex3 >> 7) & 1;
> +#ifdef TARGET_X86_64
> +                s->rex_w = (vex3 >> 7) & 1;
> +#endif
>                  switch (vex2 & 0x1f) {
>                  case 0x01: /* Implied 0f leading opcode bytes.  */
>                      b = x86_ldub_code(env, s) | 0x100;
> @@ -4631,9 +4634,9 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>      /* Post-process prefixes.  */
>      if (CODE64(s)) {
>          /* In 64-bit mode, the default data size is 32-bit.  Select
64-bit
> -           data with rex_w, and 16-bit data with 0x66; rex_w takes
precedence
> +           data with REX_W, and 16-bit data with 0x66; REX_W takes
precedence
>             over 0x66 if both are present.  */
> -        dflag = (rex_w > 0 ? MO_64 : prefixes & PREFIX_DATA ? MO_16 :
MO_32);
> +        dflag = (REX_W(s) > 0 ? MO_64 : prefixes & PREFIX_DATA ? MO_16 :
MO_32);
>          /* In 64-bit mode, 0x67 selects 32-bit addressing.  */
>          aflag = (prefixes & PREFIX_ADR ? MO_32 : MO_64);
>      } else {
> @@ -5029,7 +5032,7 @@ static target_ulong disas_insn(DisasContext *s,
CPUState *cpu)
>                  /* operand size for jumps is 64 bit */
>                  ot = MO_64;
>              } else if (op == 3 || op == 5) {
> -                ot = dflag != MO_16 ? MO_32 + (rex_w == 1) : MO_16;
> +                ot = dflag != MO_16 ? MO_32 + (REX_W(s) == 1) : MO_16;
>              } else if (op == 6) {
>                  /* default push size is 64 bit */
>                  ot = mo_pushpop(s, dflag);
> --
> 2.20.1
>
>