Re: [10/12] Add femode_t functions: s390

[Stefan Liebler <stli@linux.vnet.ibm.com>]

On 09/02/2016 11:58 PM, Joseph Myers wrote:
> This patch adds S/390 versions of fegetmode and fesetmode.  Untested.
>
> 2016-09-02  Joseph Myers  <joseph@codesourcery.com>
>
> 	* sysdeps/s390/fpu/fegetmode.c: New file.
> 	* sysdeps/s390/fpu/fesetmode.c: Likewise.
>
> diff --git a/sysdeps/s390/fpu/fegetmode.c b/sysdeps/s390/fpu/fegetmode.c
> new file mode 100644
> index 0000000..a6e67c2
> --- /dev/null
> +++ b/sysdeps/s390/fpu/fegetmode.c
> @@ -0,0 +1,27 @@
> +/* Store current floating-point control modes.  S/390 version.
> +   Copyright (C) 2016 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <fenv.h>
> +#include <fpu_control.h>
> +
> +int
> +fegetmode (femode_t *modep)
> +{
> +  _FPU_GETCW (*modep);
> +  return 0;
> +}
> diff --git a/sysdeps/s390/fpu/fesetmode.c b/sysdeps/s390/fpu/fesetmode.c
> new file mode 100644
> index 0000000..8feb9b6
> --- /dev/null
> +++ b/sysdeps/s390/fpu/fesetmode.c
> @@ -0,0 +1,38 @@
> +/* Install given floating-point control modes.  S/390 version.
> +   Copyright (C) 2016 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <fenv.h>
> +#include <fpu_control.h>
> +#include <fenv_libc.h>
> +
> +#define FPC_STATUS (FPC_FLAGS_MASK | FPC_DXC_MASK)
> +
> +int
> +fesetmode (const femode_t *modep)
> +{
> +  fpu_control_t fpc;
> +
> +  _FPU_GETCW (fpc);
> +  if (modep == FE_DFL_ENV)
> +    fpc = (fpc & FPC_STATUS) | _FPU_DEFAULT;
> +  else
> +    fpc = (fpc & FPC_STATUS) | (*modep & ~FPC_STATUS);
> +  _FPU_SETCW (fpc);
> +
> +  return 0;
> +}
>

Hi Joseph,

please compare against FE_DFL_MODE as you would compare different 
pointer types instead:
diff --git a/sysdeps/s390/fpu/fesetmode.c b/sysdeps/s390/fpu/fesetmode.c
index 8feb9b6..f95a777 100644
--- a/sysdeps/s390/fpu/fesetmode.c
+++ b/sysdeps/s390/fpu/fesetmode.c
@@ -28,7 +28,7 @@ fesetmode (const femode_t *modep)
    fpu_control_t fpc;

    _FPU_GETCW (fpc);
-  if (modep == FE_DFL_ENV)
+  if (modep == FE_DFL_MODE)
      fpc = (fpc & FPC_STATUS) | _FPU_DEFAULT;
    else
      fpc = (fpc & FPC_STATUS) | (*modep & ~FPC_STATUS);


Afterwards, glibc builds on s390/s390x and the new testcases run 
successfully.

Only as a side note to Yuri's comment:
gcc-s390 is smart enough and moves the (fpc & FPC_STATUS) up.
Furthermore it omits the or'ing with _FPU_DEFAULT as it is zero.

Thanks.
Stefan