Re: [Qemu-devel] [PATCH 22/22] tcg-i386: Tidy data16 prefixes.

[Aurelien Jarno <aurelien@aurel32.net>]

On Wed, Apr 28, 2010 at 11:23:19AM -0700, Richard Henderson wrote:
> Include it in the opcode as an extension, as with P_EXT
> or the REX bits in the x86-64 port.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>

Acked-by: Aurelien Jarno <aurelien@aurel32.net>

> ---
>  tcg/i386/tcg-target.c |   21 +++++++++++++--------
>  1 files changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
> index 646a7b6..2f096fa 100644
> --- a/tcg/i386/tcg-target.c
> +++ b/tcg/i386/tcg-target.c
> @@ -161,7 +161,8 @@ static inline int tcg_target_const_match(tcg_target_long val,
>          return 0;
>  }
>  
> -#define P_EXT   0x100 /* 0x0f opcode prefix */
> +#define P_EXT		0x100		/* 0x0f opcode prefix */
> +#define P_DATA16	0x200		/* 0x66 opcode prefix */
>  
>  #define OPC_ARITH_EvIz	(0x81)
>  #define OPC_ARITH_EvIb	(0x83)
> @@ -267,8 +268,12 @@ static const uint8_t tcg_cond_to_jcc[10] = {
>  
>  static inline void tcg_out_opc(TCGContext *s, int opc)
>  {
> -    if (opc & P_EXT)
> +    if (opc & P_DATA16) {
> +        tcg_out8(s, 0x66);
> +    }
> +    if (opc & P_EXT) {
>          tcg_out8(s, 0x0f);
> +    }
>      tcg_out8(s, opc);
>  }
>  
> @@ -460,8 +465,8 @@ static inline void tcg_out_bswap32(TCGContext *s, int reg)
>  
>  static inline void tcg_out_rolw_8(TCGContext *s, int reg)
>  {
> -    tcg_out8(s, 0x66); 
> -    tcg_out_shifti(s, SHIFT_ROL, reg, 8);
> +    tcg_out_modrm(s, OPC_SHIFT_Ib | P_DATA16, SHIFT_ROL, reg);
> +    tcg_out8(s, 8); 
>  }
>  
>  static inline void tgen_arithi(TCGContext *s, int c, int r0,
> @@ -1074,8 +1079,8 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
>              data_reg = r1;
>          }
>          /* movw */
> -        tcg_out8(s, 0x66);
> -        tcg_out_modrm_offset(s, OPC_MOVL_EvGv, data_reg, r0, GUEST_BASE);
> +        tcg_out_modrm_offset(s, OPC_MOVL_EvGv | P_DATA16,
> +                             data_reg, r0, GUEST_BASE);
>          break;
>      case 2:
>          if (bswap) {
> @@ -1180,8 +1185,8 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
>          break;
>      case INDEX_op_st16_i32:
>          /* movw */
> -        tcg_out8(s, 0x66);
> -        tcg_out_modrm_offset(s, OPC_MOVL_EvGv, args[0], args[1], args[2]);
> +        tcg_out_modrm_offset(s, OPC_MOVL_EvGv | P_DATA16,
> +                             args[0], args[1], args[2]);
>          break;
>      case INDEX_op_st_i32:
>          tcg_out_st(s, TCG_TYPE_I32, args[0], args[1], args[2]);
> -- 
> 1.6.6.1
> 
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net