Re: [Qemu-devel] [PATCH v2 19/22] target-mips: remove JR, BLTZAL, BGEZAL and add NAL, BAL instructions

[Aurelien Jarno <aurelien@aurel32.net>]

On Wed, Jun 11, 2014 at 04:19:49PM +0100, Leon Alrae wrote:
> From: Yongbok Kim <yongbok.kim@imgtec.com>
> 
> Signed-off-by: Yongbok Kim <yongbok.kim@imgtec.com>
> Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
> ---
>  disas/mips.c            |    2 ++
>  target-mips/translate.c |   18 ++++++++++++++++--
>  2 files changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/disas/mips.c b/disas/mips.c
> index dd2473e..e3e253f 100644
> --- a/disas/mips.c
> +++ b/disas/mips.c
> @@ -1313,6 +1313,8 @@ const struct mips_opcode mips_builtin_opcodes[] =
>  {"bgtzalc", "s,t,p",    0x1c000000, 0xffe00000, CBD|RD_s|RD_t,        0, I32R6},
>  {"bltzalc", "s,t,p",    0x1c000000, 0xfc000000, CBD|RD_s|RD_t,        0, I32R6},
>  {"bltuc",   "s,t,p",    0x1c000000, 0xfc000000, CBD|RD_s|RD_t,        0, I32R6},
> +{"nal",     "p",        0x04100000, 0xffff0000, WR_31,                0, I32R6},
> +{"bal",     "p",        0x04110000, 0xffff0000, UBD|WR_31,            0, I32R6},
>  {"bc1eqz",  "T,p",      0x45200000, 0xffe00000, CBD|RD_T|FP_S|FP_D,   0, I32R6},
>  {"bc1nez",  "T,p",      0x45a00000, 0xffe00000, CBD|RD_T|FP_S|FP_D,   0, I32R6},
>  {"bc2eqz",  "E,p",      0x49200000, 0xffe00000, CBD|RD_C2,            0, I32R6},
> diff --git a/target-mips/translate.c b/target-mips/translate.c
> index e635999..de35b77 100644
> --- a/target-mips/translate.c
> +++ b/target-mips/translate.c
> @@ -15809,6 +15809,9 @@ static void decode_opc_special_legacy(CPUMIPSState *env, DisasContext *ctx)
>          gen_muldiv(ctx, op1, 0, rs, rt);
>          break;
>  #endif
> +    case OPC_JR:
> +        gen_compute_branch(ctx, op1, 4, rs, rd, sa);
> +        break;
>      case OPC_SPIM:
>  #ifdef MIPS_STRICT_STANDARD
>          MIPS_INVAL("SPIM");
> @@ -15891,7 +15894,7 @@ static void decode_opc_special(CPUMIPSState *env, DisasContext *ctx)
>      case OPC_XOR:
>          gen_logic(ctx, op1, rd, rs, rt);
>          break;
> -    case OPC_JR ... OPC_JALR:
> +    case OPC_JALR:
>          gen_compute_branch(ctx, op1, 4, rs, rd, sa);
>          break;
>      case OPC_TGE ... OPC_TEQ: /* Traps */
> @@ -16860,9 +16863,20 @@ static void decode_opc (CPUMIPSState *env, DisasContext *ctx)
>              check_insn_opc_removed(ctx, ISA_MIPS32R6);
>          case OPC_BLTZ:
>          case OPC_BGEZ:
> +            gen_compute_branch(ctx, op1, 4, rs, -1, imm << 2);
> +            break;
>          case OPC_BLTZAL:
>          case OPC_BGEZAL:
> -            gen_compute_branch(ctx, op1, 4, rs, -1, imm << 2);
> +            if (ctx->insn_flags & ISA_MIPS32R6) {
> +                if (rs == 0) {
> +                    /* OPC_NAL, OPC_BAL */
> +                    gen_compute_branch(ctx, op1, 4, 0, -1, imm << 2);
> +                } else {
> +                    generate_exception(ctx, EXCP_RI);
> +                }
> +            } else {
> +                gen_compute_branch(ctx, op1, 4, rs, -1, imm << 2);
> +            }
>              break;
>          case OPC_TGEI ... OPC_TEQI: /* REGIMM traps */
>          case OPC_TNEI:

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

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net