Re: [Qemu-devel] [PATCH 5/x] ppc: Convert op_load_gpr_{T0, T1, T2} to TCG

[Andreas Färber]

Am 03.09.2008 um 20:26 schrieb Blue Swirl:

> On 9/3/08, Andreas Färber <address@hidden> wrote:
> > Here's what I've pieced together:
> >
> > - for ppc64 just use i64 op
> > - for ppc on 32-bit host use 2x i32 move, w/ TCGV_HIGH and w/o
> > - for ppc on 64-bit host use i32 move + i64 shift + i32 move
> >
> > static always_inline void gen_op_load_gpr64(TCGv t, int reg) {
> > #if defined(TARGET_PPC64)
> >  tcg_gen_mov_i64(t, cpu_gpr[reg]);
> > #else
> > #if TCG_TARGET_REG_BITS == 32
> >  tcg_gen_mov_i32(TCGV_HIGH(t), cpu_gprh[reg]);
> > #else
> >  tcg_gen_mov_i32(t, cpu_gprh[reg]);
> >  tcg_gen_shli_i64(t, t, 32);
> > #endif
> >  tcg_gen_mov_i32(t, cpu_gpr[reg]);
> > #endif
> > }
>
> Can't you use extu_i32_i64 followed by shift and then or? I think you
> should not use TCGV_HIGH outside tcg directory, it's an implementation
> detail.


Thanks for the suggestion! You mean like this?

static always_inline void gen_load_gpr64(TCGv t, int reg) {
#if defined(TARGET_PPC64)
  tcg_gen_mov_i64(t, cpu_gpr[reg]);
#else
  tcg_gen_extu_i32_i64(t, cpu_gprh[reg]);
  tcg_gen_shli_i64(t, t, 32);
  TCGv tmp = tcg_temp_local_new(TCG_TYPE_I64);
  tcg_gen_extu_i32_i64(tmp, cpu_gpr[reg]);
  tcg_gen_or_i64(t, t, tmp);
  tcg_temp_free(tmp);
#endif
}

static always_inline void gen_store_gpr64(int reg, TCGv t) {
#if defined(TARGET_PPC64)
  tcg_gen_mov_i64(cpu_gpr[reg], t);
#else
  tcg_gen_trunc_i64_i32(cpu_gpr[reg], t);
  TCGv tmp = tcg_temp_local_new(TCG_TYPE_I64);
  tcg_gen_shri_i64(tmp, t, 32);
  tcg_gen_trunc_i64_i32(cpu_gprh[reg], tmp);
  tcg_temp_free(tmp);
#endif
}

Andreas