[Mesa-dev] [PATCH 08/16 v2] st/nine: Change x86 FPU Control word on device creation

[Ilia Mirkin]

On Sun, Apr 26, 2015 at 12:27 PM, Axel Davy <axel.davy at ens.fr> wrote:
> From: Tiziano Bacocco <tizbac2 at gmail.com>
>
> As on wined3d and windows, when D3DCREATE_FPU_PRESERVE is not
> specified, change the fpu control word to all exceptions masked,
> single precision, round to nearest.
>
> Signed-off-by: Axel Davy <axel.davy at ens.fr>
> Signed-off-by: Tiziano Bacocco <tizbac2 at gmail.com>
> ---
>  src/gallium/state_trackers/nine/device9.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
>
> diff --git a/src/gallium/state_trackers/nine/device9.c b/src/gallium/state_trackers/nine/device9.c
> index 1a776a7..0bd1717 100644
> --- a/src/gallium/state_trackers/nine/device9.c
> +++ b/src/gallium/state_trackers/nine/device9.c
> @@ -41,6 +41,7 @@
>
>  #include "pipe/p_screen.h"
>  #include "pipe/p_context.h"
> +#include "pipe/p_config.h"
>  #include "util/u_math.h"
>  #include "util/u_inlines.h"
>  #include "util/u_hash_table.h"
> @@ -53,6 +54,33 @@
>
>  #define DBG_CHANNEL DBG_DEVICE
>
> +#if defined(PIPE_CC_GCC) && (defined(PIPE_ARCH_X86) || defined(PIPE_ARCH_X86_64))
> +
> +#include <fpu_control.h>
> +
> +static void nine_setup_fpu()
> +{
> +    fpu_control_t c;
> +
> +    _FPU_GETCW(c);
> +    /* clear the control word */
> +    c &= _FPU_RESERVED;
> +    /* d3d9 doc/wine tests: mask all exceptions, use single-precision
> +     * and round to nearest */
> +    c |= _FPU_MASK_IM | _FPU_MASK_DM | _FPU_MASK_ZM | _FPU_MASK_OM |
> +         _FPU_MASK_UM | _FPU_MASK_PM | _FPU_SINGLE | _FPU_RC_NEAREST;
> +    _FPU_SETCW(c);

Again... why not use the fe* functions which are in C99 and you don't
have to do these checks?

fenv_t env;
feholdexcept(&env);
fesetenv(&env);
fesetround(FE_TONEAREST);

Hmmm... not sure about the _FPU_SINGLE thing -- what does that do?

> +}
> +
> +#else
> +
> +static void nine_setup_fpu(void)
> +{
> +    WARN_ONCE("FPU setup not supported on non-x86 platforms\n");
> +}
> +
> +#endif
> +
>  static void
>  NineDevice9_SetDefaultState( struct NineDevice9 *This, boolean is_reset )
>  {
> @@ -168,6 +196,9 @@ NineDevice9_ctor( struct NineDevice9 *This,
>      IDirect3D9_AddRef(This->d3d9);
>      ID3DPresentGroup_AddRef(This->present);
>
> +    if (!(This->params.BehaviorFlags & D3DCREATE_FPU_PRESERVE))
> +        nine_setup_fpu();
> +
>      This->pipe = This->screen->context_create(This->screen, NULL);
>      if (!This->pipe) { return E_OUTOFMEMORY; } /* guess */
>
> --
> 2.1.0
>
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