include/SDL_atomic.h
author Bob Pendleton <bob@pendleton.com>
Mon, 29 Jun 2009 19:54:43 +0000
changeset 3202 3aa519a5c676
parent 3199 3e1bf2b8bd81
child 3216 48a80f2a7ff2
permissions -rw-r--r--
I've made so many changes I don't dare continue until I check the current stuff in.

/test/testatomic.c performs absolutely basic tests to show that the function work as expected. Need a second test to do more detailed tests.

/include/SDL_atomic.h provides declarations for all included functions.

/src/atomic/linux/SDL_atomic.c provided all the functions. On a generic built the 64 bit functions work, but they are emulated. On a build for -march=pentium and above the 64 bit functions use native instructions
/src/atomic/dummy/SDL_atomic.c emulates all the operations using SDL_mutex.h.
/src/atomic/win32/SDL_atomic.c is a copy of dummy
/src/atomic/macosx/SDL_atomic.s is a copy of dummy

These versions of SDL_atomic.c provide a frame work for building the library with a mixture of native and emulated functions. This allows the whole library to be provided on all platforms. (I hope.)
I hope this fits with the SDL philosophy of either providing a common subset or emulating when the platform is missing a feature.

I have not added dummy, macosx, or win32 to the build. They are there as place holders for future work.

I have modified congifure.in to compile sources in /src/atomic/linux. (The SDL configure.in file is an amazing piece of work and I hope I didn't mess it up. :-)
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21  */
    22 
    23 /**
    24  * \file SDL_atomic.h
    25  *
    26  * Atomic operations.
    27  */
    28 
    29 #ifndef _SDL_atomic_h_
    30 #define _SDL_atomic_h_
    31 
    32 #include "SDL_stdinc.h"
    33 #include "SDL_platform.h"
    34 
    35 #include "begin_code.h"
    36 
    37 /* Set up for C function definitions, even when using C++ */
    38 #ifdef __cplusplus
    39 /* *INDENT-OFF* */
    40 extern "C" {
    41 /* *INDENT-ON* */
    42 #endif
    43 
    44 /**
    45  * These operations may, or may not, actually be implemented using
    46  * processor specific atomic operations. When possible they are
    47  * implemented as true processor specific atomic operations. When that
    48  * is not possible the are implemented using locks that *do* use the
    49  * available atomic operations. In rare cases they may be implemented
    50  * using SDL's mutex fuctions.
    51  */
    52 
    53 /* Function prototypes */
    54 
    55 /* 8 bit atomic operations */
    56 
    57 extern DECLSPEC Uint8 SDLCALL SDL_AtomicExchange8(Uint8 * ptr, Uint8 value);
    58 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet8(Uint8 * ptr,
    59                                                             Uint8 oldvalue, Uint8 newvalue);
    60 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet8(Uint8 * ptr);
    61 extern DECLSPEC void SDLCALL SDL_AtomicClear8(Uint8 * ptr);
    62 extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenIncrement8(Uint8 * ptr);
    63 extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenDecrement8(Uint8 * ptr);
    64 extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenAdd8(Uint8 * ptr, Uint8 value);
    65 extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenSubtract8(Uint8 * ptr, Uint8 value);
    66 extern DECLSPEC Uint8 SDLCALL SDL_AtomicIncrementThenFetch8(Uint8 * ptr);
    67 extern DECLSPEC Uint8 SDLCALL SDL_AtomicDecrementThenFetch8(Uint8 * ptr);
    68 extern DECLSPEC Uint8 SDLCALL SDL_AtomicAddThenFetch8(Uint8 * ptr, Uint8 value);
    69 extern DECLSPEC Uint8 SDLCALL SDL_AtomicSubtractThenFetch8(Uint8 * ptr, Uint8 value);
    70 
    71 /* 16 bit atomic operations */
    72 
    73 extern DECLSPEC Uint16 SDLCALL SDL_AtomicExchange16(Uint16 * ptr, Uint16 value);
    74 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet16(Uint16 * ptr,
    75                                                             Uint16 oldvalue, Uint16 newvalue);
    76 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet16(Uint16 * ptr);
    77 extern DECLSPEC void SDLCALL SDL_AtomicClear16(Uint16 * ptr);
    78 extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenIncrement16(Uint16 * ptr);
    79 extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenDecrement16(Uint16 * ptr);
    80 extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenAdd16(Uint16 * ptr, Uint16 value);
    81 extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenSubtract16(Uint16 * ptr, Uint16 value);
    82 extern DECLSPEC Uint16 SDLCALL SDL_AtomicIncrementThenFetch16(Uint16 * ptr);
    83 extern DECLSPEC Uint16 SDLCALL SDL_AtomicDecrementThenFetch16(Uint16 * ptr);
    84 extern DECLSPEC Uint16 SDLCALL SDL_AtomicAddThenFetch16(Uint16 * ptr, Uint16 value);
    85 extern DECLSPEC Uint16 SDLCALL SDL_AtomicSubtractThenFetch16(Uint16 * ptr, Uint16 value);
    86 
    87 /* 32 bit atomic operations */
    88 
    89 /**
    90  * \fn int SDL_AtomicExchange32(Uint32 * ptr, Uint32 value)
    91  *
    92  * \brief Atomically exchange two 32 bit values.
    93  *
    94  * \return the value point to by ptr.
    95  *
    96  * \param ptr points to the value to be fetched from *ptr.  
    97  * \param value is value to be stored at *ptr.
    98  *
    99  * The current value stored at *ptr is returned and it is replaced
   100  * with value. This function can be used to implement SDL_TestThenSet.
   101  *
   102  */
   103 extern DECLSPEC Uint32 SDLCALL SDL_AtomicExchange32(Uint32 * ptr, Uint32 value);
   104 /**
   105  * \fn int SDL_AtomicCompareThenSet32(Uint32 * ptr, Uint32 oldvalue, Uint32 newvalue)
   106  *
   107  * \brief If *ptr == oldvalue then replace the contents of *ptr by new value. 
   108  *
   109  * \return true if the newvalue was stored.
   110  *
   111  * \param *ptr is the value to be compared and replaced.
   112  * \param oldvalue is value to be compared to *ptr.
   113  * \param newvalue is value to be stored at *ptr.
   114  *
   115  */
   116 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet32(Uint32 * ptr,
   117                                                             Uint32 oldvalue, Uint32 newvalue);
   118 /**
   119  * \fn  SDL_bool SDL_AtomicTestThenSet32(Uint32 * ptr);
   120  *
   121  * \brief Check to see if *ptr == 0 and set it to non-zero.
   122  *
   123  * \return SDL_True if the value pointed to by ptr was zero and
   124  * SDL_False if it was not zero
   125  *
   126  * \param ptr points to the value to be tested and set.
   127  *
   128  */
   129 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet32(Uint32 * ptr);
   130 /**
   131  * \fn  void SDL_AtomicClear32(Uint32 * ptr);
   132  *
   133  * \brief set the value pointed to by ptr to be zero.
   134  *
   135  * \param ptr address of the value to be set to zero
   136  *
   137  */
   138 extern DECLSPEC void SDLCALL SDL_AtomicClear32(Uint32 * ptr);
   139 /**
   140  * \fn  Uint32 SDL_AtomicFetchThenIncrement32(Uint32 * ptr);
   141  *
   142  * \brief fetch the current value of *ptr and then increment that
   143  * value in place.
   144  *
   145  * \return the value before it was incremented.
   146  *
   147  * \param ptr address of the value to fetch and increment
   148  *
   149  */
   150 extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenIncrement32(Uint32 * ptr);
   151 /**
   152  * \fn  Uint32 SDL_AtomicFetchThenDecrement32(Uint32 * ptr);
   153  *
   154  * \brief fetch *ptr and then decrement the value in place.
   155  *
   156  * \return the value before it was decremented.
   157  *
   158  * \param ptr address of the value to fetch and drement
   159  *
   160  */
   161 extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenDecrement32(Uint32 * ptr);
   162 /**
   163  * \fn  Uint32 SDL_AtomicFetchThenAdd32(Uint32 * ptr, Uint32 value);
   164  *
   165  * \brief fetch the current value at ptr and then add value to *ptr.
   166  *
   167  * \return *ptr before the addition took place.
   168  *
   169  * \param ptr the address of data we are changing.
   170  * \param value the value to add to *ptr. 
   171  *
   172  */
   173 extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenAdd32(Uint32 * ptr, Uint32 value);
   174 /**
   175  * \fn  Uint32 SDL_AtomicFetchThenSubtract32(Uint32 * ptr, Uint32 value);
   176  *
   177  * \brief Fetch *ptr and then subtract value from it.
   178  *
   179  * \return *ptr before the subtraction took place.
   180  *
   181  * \param ptr the address of the data being changed.
   182  * \param value the value to subtract from *ptr.
   183  *
   184  */
   185 extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenSubtract32(Uint32 * ptr, Uint32 value);
   186 /**
   187  * \fn  Uint32 SDL_AtomicIncrementThenFetch32(Uint32 * ptr);
   188  *
   189  * \brief Add one to the data pointed to by ptr and return that value.
   190  *
   191  * \return the incremented value.
   192  *
   193  * \param ptr address of the data to increment.
   194  *
   195  */
   196 extern DECLSPEC Uint32 SDLCALL SDL_AtomicIncrementThenFetch32(Uint32 * ptr);
   197 /**
   198  * \fn  Uint32 SDL_AtomicDecrementThenFetch32(Uint32 * ptr);
   199  *
   200  * \brief Subtract one from data pointed to by ptr and return the new value.
   201  *
   202  * \return The decremented value.
   203  *
   204  * \param ptr The address of the data to decrement.
   205  *
   206  */
   207 extern DECLSPEC Uint32 SDLCALL SDL_AtomicDecrementThenFetch32(Uint32 * ptr);
   208 /**
   209  * \fn  Uint32 SDL_AtomicAddThenFetch32(Uint32 * ptr, Uint32 value);
   210  *
   211  * \brief Add value to the data pointed to by ptr and return result.
   212  *
   213  * \return The sum of *ptr and value.
   214  *
   215  * \param ptr The address of the data to be modified.
   216  * \param value The value to be added.
   217  *
   218  */
   219 extern DECLSPEC Uint32 SDLCALL SDL_AtomicAddThenFetch32(Uint32 * ptr, Uint32 value);
   220 /**
   221  * \fn  Uint32 SDL_AtomicSubtractThenFetch32(Uint32 * ptr, Uint32 value);
   222  *
   223  * \brief Subtract value from the data pointed to by ptr and return the result.
   224  *
   225  * \return the difference between *ptr and value.
   226  *
   227  * \param ptr The address of the data to be modified.
   228  * \param value The value to be subtracted.
   229  *
   230  */
   231 extern DECLSPEC Uint32 SDLCALL SDL_AtomicSubtractThenFetch32(Uint32 * ptr, Uint32 value);
   232 
   233 /* 64 bit atomic operations */
   234 #ifdef SDL_HAS_64BIT_TYPE
   235 
   236 extern DECLSPEC Uint64 SDLCALL SDL_AtomicExchange64(Uint64 * ptr, Uint64 value);
   237 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet64(Uint64 * ptr,
   238                                                             Uint64 oldvalue, Uint64 newvalue);
   239 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet64(Uint64 * ptr);
   240 extern DECLSPEC void SDLCALL SDL_AtomicClear64(Uint64 * ptr);
   241 extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenIncrement64(Uint64 * ptr);
   242 extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenDecrement64(Uint64 * ptr);
   243 extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenAdd64(Uint64 * ptr, Uint64 value);
   244 extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenSubtract64(Uint64 * ptr, Uint64 value);
   245 extern DECLSPEC Uint64 SDLCALL SDL_AtomicIncrementThenFetch64(Uint64 * ptr);
   246 extern DECLSPEC Uint64 SDLCALL SDL_AtomicDecrementThenFetch64(Uint64 * ptr);
   247 extern DECLSPEC Uint64 SDLCALL SDL_AtomicAddThenFetch64(Uint64 * ptr, Uint64 value);
   248 extern DECLSPEC Uint64 SDLCALL SDL_AtomicSubtractThenFetch64(Uint64 * ptr, Uint64 value);
   249 #endif /*  SDL_HAS_64BIT_TYPE */
   250 
   251 /* Ends C function definitions when using C++ */
   252 #ifdef __cplusplus
   253 /* *INDENT-OFF* */
   254 }
   255 /* *INDENT-ON* */
   256 #endif
   257 
   258 #include "close_code.h"
   259 
   260 #endif /* _SDL_atomic_h_ */
   261 
   262 /* vi: set ts=4 sw=4 expandtab: */