base/include/asm-ppc/rtai_fpu.h

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/*
COPYRIGHT (C) 2000  Paolo Mantegazza (mantegazza@aero.polimi.it)

This 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 of the License, or (at your option) any later version.

This 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 this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
*/

#ifndef _RTAI_ASM_PPC_FPU_H_
#define _RTAI_ASM_PPC_FPU_H_

#include <asm/processor.h>

typedef struct ppc_fpu_env { unsigned long fpu_reg[66]; } FPU_ENV;

#define save_cr0_and_clts(x)
#define restore_cr0(x)
#define enable_fpu()

#ifdef CONFIG_RTAI_FPU_SUPPORT
/*
 * Saving/restoring the FPU environment in PPC is like eating a cake, very simple. Just save/restore all of the floating 
 * point registers, recall they are always 64 bits long, and the floating point state register. Remark: at task init we
 * always enable FP, i.e. MSR flag FP set to 1, for real time tasks and accept default actions for faulty FLOPs, i.e. MSR 
 * flags FE0 and FE1 are set to zero.
 */

#define stringize(a) #a
#define str(a) stringize(a)

extern void __save_fpenv(FPU_ENV *fpenv);
#define save_fpenv(x) __save_fpenv(&(x))
#if 0
// FIXME: it does not work, waiting for cleanup!
static inline void __save_fpenv(FPU_ENV *env)
{
    asm(
    "stw     0,  -4(1)\n"
    "mfmsr    0\n"
    "ori      0, 0, " str(MSR_FP) "\n"
    "mtmsr    0\n"
    "lwz      0,  -4(1)\n"
    "isync\n"
    "stfd    0, 0*8(3)\n"
    "stfd    1, 1*8(3)\n"
    "stfd    2, 2*8(3)\n"
    "stfd    3, 3*8(3)\n"
    "stfd    4, 4*8(3)\n"
    "stfd    5, 5*8(3)\n"
    "stfd    6, 6*8(3)\n"
    "stfd    7, 7*8(3)\n"
    "stfd    8, 8*8(3)\n"
    "stfd    9, 9*8(3)\n"
    "stfd   10,10*8(3)\n"
    "stfd   11,11*8(3)\n"
    "stfd   12,12*8(3)\n"
    "stfd   13,13*8(3)\n"
    "stfd   14,14*8(3)\n"
    "stfd   15,15*8(3)\n"
    "stfd   16,16*8(3)\n"
    "stfd   17,17*8(3)\n"
    "stfd   18,18*8(3)\n"
    "stfd   19,19*8(3)\n"
    "stfd   20,20*8(3)\n"
    "stfd   21,21*8(3)\n"
    "stfd   22,22*8(3)\n"
    "stfd   23,23*8(3)\n"
    "stfd   24,24*8(3)\n"
    "stfd   25,25*8(3)\n"
    "stfd   26,26*8(3)\n"
    "stfd   27,27*8(3)\n"
    "stfd   28,28*8(3)\n"
    "stfd   29,29*8(3)\n"
    "stfd   30,30*8(3)\n"
    "stfd   31,31*8(3)\n"
    "mffs    0\n"
    "stfd    0,32*8(3)\n");
}
#endif

extern void __restore_fpenv(FPU_ENV *fpenv);
#define restore_fpenv(x) __restore_fpenv(&(x))
#if 0
// FIXME: it does not work, waiting for cleanup!
static inline void __restore_fpenv(FPU_ENV *env)
{
    asm(
    "lfd     0, 32*8(3)\n"
    "mtfsf   0xFF,0\n"
    "lfd     0, 0*8(3)\n"
    "lfd     1, 1*8(3)\n"
    "lfd     2, 2*8(3)\n"
    "lfd     3, 3*8(3)\n"
    "lfd     4, 4*8(3)\n"
    "lfd     5, 5*8(3)\n"
    "lfd     6, 6*8(3)\n"
    "lfd     7, 7*8(3)\n"
    "lfd     8, 8*8(3)\n"
    "lfd     9, 9*8(3)\n"
    "lfd    10,10*8(3)\n"
    "lfd    11,11*8(3)\n"
    "lfd    12,12*8(3)\n"
    "lfd    13,13*8(3)\n"
    "lfd    14,14*8(3)\n"
    "lfd    15,15*8(3)\n"
    "lfd    16,16*8(3)\n"
    "lfd    17,17*8(3)\n"
    "lfd    18,18*8(3)\n"
    "lfd    19,19*8(3)\n"
    "lfd    20,20*8(3)\n"
    "lfd    21,21*8(3)\n"
    "lfd    22,22*8(3)\n"
    "lfd    23,23*8(3)\n"
    "lfd    24,24*8(3)\n"
    "lfd    25,25*8(3)\n"
    "lfd    26,26*8(3)\n"
    "lfd    27,27*8(3)\n"
    "lfd    28,28*8(3)\n"
    "lfd    29,29*8(3)\n"
    "lfd    30,30*8(3)\n"
    "lfd    31,31*8(3)\n");
}
#endif

#define restore_task_fpenv(t) \
        do { \
               restore_fpenv((t)->thread.i387.fsave); \
        } while (0)

#define restore_fpenv_lxrt(t) restore_task_fpenv(t)

#define init_fpu(tsk) \
        do { /*init_xfpu();*/ tsk->used_math = 1; set_tsk_used_fpu(tsk); } while(0)

#define restore_fpu(tsk) \
        do { restore_fpenv_lxrt((tsk)); set_tsk_used_fpu(tsk); } while (0)

#define set_tsk_used_fpu(t)  do {  } while(0)

#else

#define save_fpenv(x)
#define restore_fpenv(x)
#define init_fpu(tsk)
#define restore_fpu(tsk)
#define set_tsk_used_fpu(t)

#endif


#endif

---