/**
 * @file rtems/score/sparc.h
 */

/*
 *  This include file contains information pertaining to the SPARC
 *  processor family.
 *
 *  COPYRIGHT (c) 1989-1999.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.com/license/LICENSE.
 *
 *  $Id$
 */

#ifndef _RTEMS_SCORE_SPARC_H
#define _RTEMS_SCORE_SPARC_H

#ifdef __cplusplus
extern "C" {
#endif

/*
 *  This file contains the information required to build
 *  RTEMS for a particular member of the "sparc" family.  It does
 *  this by setting variables to indicate which implementation
 *  dependent features are present in a particular member
 *  of the family.
 *
 *  Currently recognized feature flags:
 *
 *    + SPARC_HAS_FPU
 *        0 - no HW FPU
 *        1 - has HW FPU (assumed to be compatible w/90C602)
 *
 *    + SPARC_HAS_BITSCAN
 *        0 - does not have scan instructions
 *        1 - has scan instruction  (not currently implemented)
 *
 *    + SPARC_NUMBER_OF_REGISTER_WINDOWS
 *        8 is the most common number supported by SPARC implementations.
 *        SPARC_PSR_CWP_MASK is derived from this value.
 */

/*
 *  Some higher end SPARCs have a bitscan instructions. It would
 *  be nice to take advantage of them.  Right now, there is no
 *  port to a CPU model with this feature and no (untested) code
 *  that is based on this feature flag.
 */

#define SPARC_HAS_BITSCAN                0

/*
 *  This should be OK until a port to a higher end SPARC processor
 *  is made that has more than 8 register windows.  If this cannot
 *  be determined based on multilib settings (v7/v8/v9), then the
 *  cpu_asm.S code that depends on this will have to move to libcpu.
 */

#define SPARC_NUMBER_OF_REGISTER_WINDOWS 8

/*
 * Compile the SPARC kernel with runtime FPU detection. This is used
 * by RTEMS kernels built without FPU but still need to be able to
 * run tasks with FPU enabled. This way the kernel is SPARC (v7/v8)  
 * with or without FPU compatible.
 */

#define SPARC_DYNAMIC_FPU_DETECTION      1

/*
 *  This should be determined based on some soft float derived
 *  cpp predefine but gcc does not currently give us that information.
 */

#if !defined(SPARC_DYNAMIC_FPU_DETECTION) && defined(_SOFT_FLOAT)
#define SPARC_HAS_FPU 0
#else
#define SPARC_HAS_FPU 1
#endif

#if SPARC_HAS_FPU
#define CPU_MODEL_NAME "w/FPU"
#else
#define CPU_MODEL_NAME "w/soft-float"
#endif

/*
 *  Define the name of the CPU family.
 */

#define CPU_NAME "SPARC"

/*
 *  Miscellaneous constants
 */

/*
 *  PSR masks and starting bit positions
 *
 *  NOTE: Reserved bits are ignored.
 */

#if (SPARC_NUMBER_OF_REGISTER_WINDOWS == 8)
#define SPARC_PSR_CWP_MASK               0x07   /* bits  0 -  4 */
#elif (SPARC_NUMBER_OF_REGISTER_WINDOWS == 16)
#define SPARC_PSR_CWP_MASK               0x0F   /* bits  0 -  4 */
#elif (SPARC_NUMBER_OF_REGISTER_WINDOWS == 32)
#define SPARC_PSR_CWP_MASK               0x1F   /* bits  0 -  4 */
#else
#error "Unsupported number of register windows for this cpu"
#endif

#define SPARC_PSR_ET_MASK   0x00000020   /* bit   5 */
#define SPARC_PSR_PS_MASK   0x00000040   /* bit   6 */
#define SPARC_PSR_S_MASK    0x00000080   /* bit   7 */
#define SPARC_PSR_PIL_MASK  0x00000F00   /* bits  8 - 11 */
#define SPARC_PSR_EF_MASK   0x00001000   /* bit  12 */
#define SPARC_PSR_EC_MASK   0x00002000   /* bit  13 */
#define SPARC_PSR_ICC_MASK  0x00F00000   /* bits 20 - 23 */
#define SPARC_PSR_VER_MASK  0x0F000000   /* bits 24 - 27 */
#define SPARC_PSR_IMPL_MASK 0xF0000000   /* bits 28 - 31 */

#define SPARC_PSR_CWP_BIT_POSITION   0   /* bits  0 -  4 */
#define SPARC_PSR_ET_BIT_POSITION    5   /* bit   5 */
#define SPARC_PSR_PS_BIT_POSITION    6   /* bit   6 */
#define SPARC_PSR_S_BIT_POSITION     7   /* bit   7 */
#define SPARC_PSR_PIL_BIT_POSITION   8   /* bits  8 - 11 */
#define SPARC_PSR_EF_BIT_POSITION   12   /* bit  12 */
#define SPARC_PSR_EC_BIT_POSITION   13   /* bit  13 */
#define SPARC_PSR_ICC_BIT_POSITION  20   /* bits 20 - 23 */
#define SPARC_PSR_VER_BIT_POSITION  24   /* bits 24 - 27 */
#define SPARC_PSR_IMPL_BIT_POSITION 28   /* bits 28 - 31 */

#ifndef ASM

/*
 *  Standard nop
 */

#define nop() \
  do { \
    asm volatile ( "nop" ); \
  } while ( 0 )

/*
 *  Get and set the PSR
 */

#define sparc_get_psr( _psr ) \
  do { \
     (_psr) = 0; \
     asm volatile( "rd %%psr, %0" :  "=r" (_psr) : "0" (_psr) ); \
  } while ( 0 )

#define sparc_set_psr( _psr ) \
  do { \
    asm volatile ( "mov  %0, %%psr " : "=r" ((_psr)) : "0" ((_psr)) ); \
    nop(); \
    nop(); \
    nop(); \
  } while ( 0 )

/*
 *  Get and set the TBR
 */

#define sparc_get_tbr( _tbr ) \
  do { \
     (_tbr) = 0; /* to avoid unitialized warnings */ \
     asm volatile( "rd %%tbr, %0" :  "=r" (_tbr) : "0" (_tbr) ); \
  } while ( 0 )

#define sparc_set_tbr( _tbr ) \
  do { \
     asm volatile( "wr %0, 0, %%tbr" :  "=r" (_tbr) : "0" (_tbr) ); \
  } while ( 0 )

/*
 *  Get and set the WIM
 */

#define sparc_get_wim( _wim ) \
  do { \
    asm volatile( "rd %%wim, %0" :  "=r" (_wim) : "0" (_wim) ); \
  } while ( 0 )

#define sparc_set_wim( _wim ) \
  do { \
    asm volatile( "wr %0, %%wim" :  "=r" (_wim) : "0" (_wim) ); \
    nop(); \
    nop(); \
    nop(); \
  } while ( 0 )

/*
 *  Get and set the Y
 */

#define sparc_get_y( _y ) \
  do { \
    asm volatile( "rd %%y, %0" :  "=r" (_y) : "0" (_y) ); \
  } while ( 0 )

#define sparc_set_y( _y ) \
  do { \
    asm volatile( "wr %0, %%y" :  "=r" (_y) : "0" (_y) ); \
  } while ( 0 )

/*
 *  Manipulate the interrupt level in the psr
 */

uint32_t sparc_disable_interrupts(void);
void sparc_enable_interrupts(uint32_t);

#define sparc_flash_interrupts( _level ) \
  do { \
    register uint32_t   _ignored = 0; \
    \
    sparc_enable_interrupts( (_level) ); \
    _ignored = sparc_disable_interrupts(); \
  } while ( 0 )

#define sparc_get_interrupt_level( _level ) \
  do { \
    register uint32_t   _psr_level = 0; \
    \
    sparc_get_psr( _psr_level ); \
    (_level) = \
      (_psr_level & SPARC_PSR_PIL_MASK) >> SPARC_PSR_PIL_BIT_POSITION; \
  } while ( 0 )

#endif

#ifdef __cplusplus
}
#endif

#endif /* _RTEMS_SCORE_SPARC_H */
