Re: [Qemu-devel] [PATCH] PPC: Introduce 32bit only cmp ops

[Aurelien Jarno <aurelien@aurel32.net>]

On Wed, May 08, 2013 at 12:06:52PM +0200, Alexander Graf wrote:
> When running a 32bit target CPU with qemu-(system-)-ppc, NARROW_MODE
> is not set, so we never get to leverage the "32bit only" code path in
> the compare op handlers.
> 
> Introduce new handlers based on the 32bit only flag. That way we can
> have 2 separate functions for 32bit mode and 64bit mode, which can
> handle NARROW_MODE.
> 
> Reported-by: Torbjorn Granlund <tg@gmplib.org>
> Signed-off-by: Alexander Graf <agraf@suse.de>
> ---
>  target-ppc/translate.c |   48 ++++++++++++++++++++++++++++++++++++++++--------
>  1 files changed, 40 insertions(+), 8 deletions(-)
> 
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index a018616..002f9ae 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -675,7 +675,7 @@ static inline void gen_set_Rc0(DisasContext *ctx, TCGv reg)
>  /* cmp */
>  static void gen_cmp(DisasContext *ctx)
>  {
> -    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
> +    if (!(ctx->opcode & 0x00200000)) {
>          gen_op_cmp32(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)],
>                       1, crfD(ctx->opcode));
>      } else {
> @@ -684,10 +684,17 @@ static void gen_cmp(DisasContext *ctx)
>      }
>  }
>  
> +/* cmp 32bit only */
> +static void gen_cmp32(DisasContext *ctx)
> +{
> +    gen_op_cmp32(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)],
> +                 1, crfD(ctx->opcode));
> +}
> +
>  /* cmpi */
>  static void gen_cmpi(DisasContext *ctx)
>  {
> -    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
> +    if (!(ctx->opcode & 0x00200000)) {
>          gen_op_cmpi32(cpu_gpr[rA(ctx->opcode)], SIMM(ctx->opcode),
>                        1, crfD(ctx->opcode));
>      } else {
> @@ -696,10 +703,17 @@ static void gen_cmpi(DisasContext *ctx)
>      }
>  }
>  
> +/* cmpi 32bit only */
> +static void gen_cmpi32(DisasContext *ctx)
> +{
> +    gen_op_cmpi32(cpu_gpr[rA(ctx->opcode)], SIMM(ctx->opcode),
> +                  1, crfD(ctx->opcode));
> +}
> +
>  /* cmpl */
>  static void gen_cmpl(DisasContext *ctx)
>  {
> -    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
> +    if (!(ctx->opcode & 0x00200000)) {
>          gen_op_cmp32(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)],
>                       0, crfD(ctx->opcode));
>      } else {
> @@ -708,10 +722,17 @@ static void gen_cmpl(DisasContext *ctx)
>      }
>  }
>  
> +/* cmpl 32bit only */
> +static void gen_cmpl32(DisasContext *ctx)
> +{
> +    gen_op_cmp32(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)],
> +                 0, crfD(ctx->opcode));
> +}
> +
>  /* cmpli */
>  static void gen_cmpli(DisasContext *ctx)
>  {
> -    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
> +    if (!(ctx->opcode & 0x00200000)) {
>          gen_op_cmpi32(cpu_gpr[rA(ctx->opcode)], UIMM(ctx->opcode),
>                        0, crfD(ctx->opcode));
>      } else {
> @@ -720,6 +741,13 @@ static void gen_cmpli(DisasContext *ctx)
>      }
>  }
>  
> +/* cmpli 32bit only */
> +static void gen_cmpli32(DisasContext *ctx)
> +{
> +    gen_op_cmpi32(cpu_gpr[rA(ctx->opcode)], UIMM(ctx->opcode),
> +                  0, crfD(ctx->opcode));
> +}
> +
>  /* isel (PowerPC 2.03 specification) */
>  static void gen_isel(DisasContext *ctx)
>  {
> @@ -8638,10 +8666,14 @@ GEN_SPE(efdtsteq,  speundef,  0x1F, 0x0B, 0x00600000, 0xFFFFFFFF, PPC_SPE_DOUBLE
>  
>  static opcode_t opcodes[] = {
>  GEN_HANDLER(invalid, 0x00, 0x00, 0x00, 0xFFFFFFFF, PPC_NONE),
> -GEN_HANDLER(cmp, 0x1F, 0x00, 0x00, 0x00400000, PPC_INTEGER),
> -GEN_HANDLER(cmpi, 0x0B, 0xFF, 0xFF, 0x00400000, PPC_INTEGER),
> -GEN_HANDLER(cmpl, 0x1F, 0x00, 0x01, 0x00400000, PPC_INTEGER),
> -GEN_HANDLER(cmpli, 0x0A, 0xFF, 0xFF, 0x00400000, PPC_INTEGER),
> +GEN_HANDLER(cmp, 0x1F, 0x00, 0x00, 0x00400000, PPC_64B),
> +GEN_HANDLER_E(cmp32, 0x1F, 0x00, 0x00, 0x00400000, PPC_NONE, PPC2_32B),

You have to declare the L bit as invalid, so that trying to execute a
64-bit cmp* instruction on a 32-bit CPU causes an invalid instruction
exception.

> +GEN_HANDLER(cmpi, 0x0B, 0xFF, 0xFF, 0x00400000, PPC_64B),
> +GEN_HANDLER_E(cmpi32, 0x0B, 0xFF, 0xFF, 0x00400000, PPC_NONE, PPC2_32B),
> +GEN_HANDLER(cmpl, 0x1F, 0x00, 0x01, 0x00400000, PPC_64B),
> +GEN_HANDLER_E(cmpl32, 0x1F, 0x00, 0x01, 0x00400000, PPC_NONE, PPC2_32B),
> +GEN_HANDLER(cmpli, 0x0A, 0xFF, 0xFF, 0x00400000, PPC_64B),
> +GEN_HANDLER_E(cmpli32, 0x0A, 0xFF, 0xFF, 0x00400000, PPC_NONE, PPC2_32B),
>  GEN_HANDLER_E(cmpb, 0x1F, 0x1C, 0x0F, 0x00000001, PPC_NONE, PPC2_ISA205),
>  GEN_HANDLER(isel, 0x1F, 0x0F, 0xFF, 0x00000001, PPC_ISEL),
>  GEN_HANDLER(addi, 0x0E, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),
> -- 
> 1.6.0.2
> 
> 
> 

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