Re: [Qemu-devel] [PATCH v14 29/33] target-tilegx: Handle mtspr, mfspr

[Peter Maydell]

On 24 August 2015 at 17:17, Richard Henderson <address@hidden> wrote:
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target-tilegx/translate.c | 76 
> +++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 73 insertions(+), 3 deletions(-)
>
> diff --git a/target-tilegx/translate.c b/target-tilegx/translate.c
> index 1224a8e..210e912 100644
> --- a/target-tilegx/translate.c
> +++ b/target-tilegx/translate.c
> @@ -24,6 +24,7 @@
>  #include "tcg-op.h"
>  #include "exec/cpu_ldst.h"
>  #include "opcode_tilegx.h"
> +#include "spr_def_64.h"
>
>  #define FMT64X                          "%016" PRIx64
>
> @@ -1226,9 +1227,6 @@ static TileExcp gen_rri_opcode(DisasContext *dc, 
> unsigned opext,
>          tcg_gen_addi_tl(dest_gr(dc, srca), tsrca, imm);
>          mnemonic = "ldna_add";
>          break;
> -    case OE_IM(MFSPR, X1):
> -    case OE_IM(MTSPR, X1):
> -        return TILEGX_EXCP_OPCODE_UNIMPLEMENTED;
>      case OE_IM(ORI, X0):
>      case OE_IM(ORI, X1):
>          tcg_gen_ori_tl(tdest, tsrca, imm);
> @@ -1528,6 +1526,74 @@ static TileExcp gen_jump_opcode_x1(DisasContext *dc, 
> unsigned ext, int off)
>      return TILEGX_EXCP_NONE;
>  }
>
> +typedef struct {
> +    const char *name;
> +    intptr_t offset;
> +    void (*get)(TCGv, TCGv_ptr);
> +    void (*put)(TCGv_ptr, TCGv);
> +} TileSPR;
> +
> +static const TileSPR *find_spr(unsigned spr)
> +{
> +    /* Allow the compiler to construct the binary search tree.  */

This feels a bit overly clever to me but if we only have
three registers anyway it doesn't matter much.

> +#define D(N, O, G, P) \
> +    case SPR_##N: { static const TileSPR x = { #N, O, G, P }; return &x; }
> +
> +    switch (spr) {
> +    D(CMPEXCH_VALUE,
> +      offsetof(CPUTLGState, spregs[TILEGX_SPR_CMPEXCH]), 0, 0)
> +    D(SIM_CONTROL,
> +      offsetof(CPUTLGState, spregs[TILEGX_SPR_CRITICAL_SEC]), 0, 0)
> +    D(INTERRUPT_CRITICAL_SECTION,
> +      offsetof(CPUTLGState, spregs[TILEGX_SPR_SIM_CONTROL]), 0, 0)

Aren't the offsets on these two backwards ?

> +    }
> +
> +#undef D
> +
> +    qemu_log_mask(LOG_UNIMP, "UNIMP SPR %u\n", spr);
> +    return NULL;
> +}

-- PMM