/* jmpbuf.h                  -*-C++-*-
 *
 *************************************************************************
 *
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 *  PLEASE NOTE: This file is a downstream copy of a file mainitained in
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 **************************************************************************/

/**
 * @file jmpbuf.h
 *
 * @brief Macros and functions to access the _JUMP_BUFFER initialized by a 
 * call to CILK_SETJMP before a cilk_spawn or cilk_sync.  The definition of
 * CILK_SETJMP and CILK_LONGJMP are OS dependent and in abi.h
 *
 */

#ifndef INCLUDED_JMPBUF_DOT_H
#define INCLUDED_JMPBUF_DOT_H

#include <cilk/common.h>
#include <internal/abi.h>
#include <stddef.h>
#include <setjmp.h>

#if 0 /* defined CILK_USE_C_SETJMP && defined JB_RSP */
#   define JMPBUF_SP(ctx) (ctx)[0].__jmpbuf[JB_RSP]
#   define JMPBUF_FP(ctx) (ctx)[0].__jmpbuf[JB_RBP]
#   define JMPBUF_PC(ctx) (ctx)[0].__jmpbuf[JB_PC]
#elif 0 /* defined CILK_USE_C_SETJMP && defined JB_SP */
#   define JMPBUF_SP(ctx) (ctx)[0].__jmpbuf[JB_SP]
#   define JMPBUF_FP(ctx) (ctx)[0].__jmpbuf[JB_BP]
#   define JMPBUF_PC(ctx) (ctx)[0].__jmpbuf[JB_PC]
#elif defined _WIN64
#   define JMPBUF_SP(ctx) ((_JUMP_BUFFER*)(&(ctx)))->Rsp
#   define JMPBUF_FP(ctx) ((_JUMP_BUFFER*)(&(ctx)))->Rbp
#   define JMPBUF_PC(ctx) ((_JUMP_BUFFER*)(&(ctx)))->Rip
#elif defined _WIN32
    /** Fetch stack pointer from a __cilkrts_stack_frame */
#   define JMPBUF_SP(ctx) (ctx).Esp
    /** Fetch frame pointer from a __cilkrts_stack_frame */
#   define JMPBUF_FP(ctx) (ctx).Ebp
    /** Fetch program counter from a __cilkrts_stack_frame */
#   define JMPBUF_PC(ctx) (ctx).Eip
#else /* defined __GNUC__ || defined __ICC */
    /* word 0 is frame address
     * word 1 is resume address
     * word 2 is stack address */
#   define JMPBUF_FP(ctx) (ctx)[0]
#   define JMPBUF_PC(ctx) (ctx)[1]
#   define JMPBUF_SP(ctx) (ctx)[2]
#endif

/**
 * @brief Get frame pointer from jump buffer in__cilkrts_stack_frame.
 */
#define FP(SF) JMPBUF_FP((SF)->ctx)

/**
 * @brief Get program counter from jump buffer in__cilkrts_stack_frame.
 */
#define PC(SF) JMPBUF_PC((SF)->ctx)

/**
 * @brief Get stack pointer from jump buffer in__cilkrts_stack_frame.
 */
#define SP(SF) JMPBUF_SP((SF)->ctx)

/**
 * @brief Some architecture-dependent stack adjustment.
 */
#if defined(__sparcv9) || (defined(__sparc__) && defined(__arch64__))
    // Subtract SPARC V9 stack bias so the actual stack starts at the
    // allocated area.
#   define CILK_ADJUST_SP(SP) ((SP) - 2047)
#   define CILK_UNADJUST_SP(SP) ((SP) + 2047)
#else
#   define CILK_ADJUST_SP(SP) (SP)
#   define CILK_UNADJUST_SP(SP) (SP)
#endif

__CILKRTS_BEGIN_EXTERN_C

/**
 * Fetch the stack pointer from a __cilkrts_stack_frame.  The jmpbuf was
 * initialized before a cilk_spawn or cilk_sync.
 *
 * @param sf __cilkrts_stack_frame containing the jmpbuf.
 *
 * @return the stack pointer from the ctx.
 */
inline char *__cilkrts_get_sp(__cilkrts_stack_frame *sf)
{
    return (char *)CILK_UNADJUST_SP(SP(sf));
}

/**
 * Calculate the frame size from __cilkrts_stack_frame.  The jmpbuf was
 * initialized before a cilk_spawn or cilk_sync.
 *
 * @warning Returning an arbitrary value on Windows!
 *
 * @param sf __cilkrts_stack_frame containing the jmpbuf.
 *
 * @return the stack pointer from the ctx.
 */
inline ptrdiff_t __cilkrts_get_frame_size(__cilkrts_stack_frame *sf)
{
#ifdef _WIN32
    if (0 == SP(sf))
        return 256;         // Arbitrary!
#endif
    return (ptrdiff_t)FP(sf) - (ptrdiff_t)SP(sf);
}

__CILKRTS_END_EXTERN_C

#endif // ! defined(INCLUDED_JMPBUF_DOT_H)