glapi.c

winNT技术操作系统,国外开放的原代码和LIUX一样

/**
 * Search the table of static entrypoint functions for the named function
 * and return the corresponding glprocs_table_t entry.
 */
static const glprocs_table_t *
find_entry( const char * n )
{
   GLuint i;

   for (i = 0; static_functions[i].Name_offset >= 0; i++) {
      const char * test_name;

      test_name = gl_string_table + static_functions[i].Name_offset;
      if (strcmp(test_name, n) == 0) {
	 return & static_functions[i];
      }
   }
   return NULL;
}


/**
 * Return dispatch table offset of the named static (built-in) function.
 * Return -1 if function not found.
 */
static GLint
get_static_proc_offset(const char *funcName)
{
   const glprocs_table_t * const f = find_entry( funcName );

   if ( f != NULL ) {
      return f->Offset;
   }
   return -1;
}


#if !defined( XFree86Server )
#ifdef USE_X86_ASM

#if defined( GLX_USE_TLS )
extern       GLubyte gl_dispatch_functions_start[];
extern       GLubyte gl_dispatch_functions_end[];
#else
extern const GLubyte gl_dispatch_functions_start[];
#endif

# if defined(THREADS) && !defined(GLX_USE_TLS)
#  define X86_DISPATCH_FUNCTION_SIZE  32
# else
#  define X86_DISPATCH_FUNCTION_SIZE  16
# endif


/**
 * Return dispatch function address the named static (built-in) function.
 * Return NULL if function not found.
 */
static const _glapi_proc
get_static_proc_address(const char *funcName)
{
   const glprocs_table_t * const f = find_entry( funcName );

   if ( f != NULL ) {
      return (_glapi_proc) (gl_dispatch_functions_start 
                            + (X86_DISPATCH_FUNCTION_SIZE * f->Offset));
   }
   else {
      return NULL;
   }
}

#else


/**
 * Return pointer to the named static (built-in) function.
 * \return  NULL if function not found.
 */
static const _glapi_proc
get_static_proc_address(const char *funcName)
{
   const glprocs_table_t * const f = find_entry( funcName );
   return ( f != NULL ) ? f->Address : NULL;
}

#endif /* USE_X86_ASM */
#endif /* !defined( XFree86Server ) */


/**
 * Return the name of the function at the given offset in the dispatch
 * table.  For debugging only.
 */
static const char *
get_static_proc_name( GLuint offset )
{
   GLuint i;

   for (i = 0; static_functions[i].Name_offset >= 0; i++) {
      if (static_functions[i].Offset == offset) {
	 return gl_string_table + static_functions[i].Name_offset;
      }
   }
   return NULL;
}



/**********************************************************************
 * Extension function management.
 */

/*
 * Number of extension functions which we can dynamically add at runtime.
 */
#define MAX_EXTENSION_FUNCS 300


/*
 * The dispatch table size (number of entries) is the size of the
 * _glapi_table struct plus the number of dynamic entries we can add.
 * The extra slots can be filled in by DRI drivers that register new extension
 * functions.
 */
#define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)


/**
 * Track information about a function added to the GL API.
 */
struct _glapi_function {
   /**
    * Name of the function.
    */
   const char * name;


   /**
    * Text string that describes the types of the parameters passed to the
    * named function.   Parameter types are converted to characters using the
    * following rules:
    *   - 'i' for \c GLint, \c GLuint, and \c GLenum
    *   - 'p' for any pointer type
    *   - 'f' for \c GLfloat and \c GLclampf
    *   - 'd' for \c GLdouble and \c GLclampd
    */
   const char * parameter_signature;


   /**
    * Offset in the dispatch table where the pointer to the real function is
    * located.  If the driver has not requested that the named function be
    * added to the dispatch table, this will have the value ~0.
    */
   unsigned dispatch_offset;


   /**
    * Pointer to the dispatch stub for the named function.
    * 
    * \todo
    * The semantic of this field should be changed slightly.  Currently, it
    * is always expected to be non-\c NULL.  However, it would be better to
    * only allocate the entry-point stub when the application requests the
    * function via \c glXGetProcAddress.  This would save memory for all the
    * functions that the driver exports but that the application never wants
    * to call.
    */
   _glapi_proc dispatch_stub;
};


static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
static GLuint NumExtEntryPoints = 0;

#ifdef USE_SPARC_ASM
extern void __glapi_sparc_icache_flush(unsigned int *);
#endif

/**
 * Generate a dispatch function (entrypoint) which jumps through
 * the given slot number (offset) in the current dispatch table.
 * We need assembly language in order to accomplish this.
 */
static _glapi_proc
generate_entrypoint(GLuint functionOffset)
{
#if defined(USE_X86_ASM)
   /* 32 is chosen as something of a magic offset.  For x86, the dispatch
    * at offset 32 is the first one where the offset in the
    * "jmp OFFSET*4(%eax)" can't be encoded in a single byte.
    */
   const GLubyte * const template_func = gl_dispatch_functions_start 
     + (X86_DISPATCH_FUNCTION_SIZE * 32);
   GLubyte * const code = (GLubyte *) malloc( X86_DISPATCH_FUNCTION_SIZE );


   if ( code != NULL ) {
      (void) memcpy( code, template_func, X86_DISPATCH_FUNCTION_SIZE );
      fill_in_entrypoint_offset( (_glapi_proc) code, functionOffset );
   }

   return (_glapi_proc) code;
#elif defined(USE_SPARC_ASM)

#ifdef __arch64__
   static const unsigned int insn_template[] = {
	   0x05000000,	/* sethi	%uhi(_glapi_Dispatch), %g2	*/
	   0x03000000,	/* sethi	%hi(_glapi_Dispatch), %g1	*/
	   0x8410a000,	/* or		%g2, %ulo(_glapi_Dispatch), %g2	*/
	   0x82106000,	/* or		%g1, %lo(_glapi_Dispatch), %g1	*/
	   0x8528b020,	/* sllx		%g2, 32, %g2			*/
	   0xc2584002,	/* ldx		[%g1 + %g2], %g1		*/
	   0x05000000,	/* sethi	%hi(8 * glapioffset), %g2	*/
	   0x8410a000,	/* or		%g2, %lo(8 * glapioffset), %g2	*/
	   0xc6584002,	/* ldx		[%g1 + %g2], %g3		*/
	   0x81c0c000,	/* jmpl		%g3, %g0			*/
	   0x01000000	/*  nop						*/
   };
#else
   static const unsigned int insn_template[] = {
	   0x03000000,	/* sethi	%hi(_glapi_Dispatch), %g1	  */
	   0xc2006000,	/* ld		[%g1 + %lo(_glapi_Dispatch)], %g1 */
	   0xc6006000,	/* ld		[%g1 + %lo(4*glapioffset)], %g3	  */
	   0x81c0c000,	/* jmpl		%g3, %g0			  */
	   0x01000000	/*  nop						  */
   };
#endif
   unsigned int *code = (unsigned int *) malloc(sizeof(insn_template));
   unsigned long glapi_addr = (unsigned long) &_glapi_Dispatch;
   if (code) {
      memcpy(code, insn_template, sizeof(insn_template));

#ifdef __arch64__
      code[0] |= (glapi_addr >> (32 + 10));
      code[1] |= ((glapi_addr & 0xffffffff) >> 10);
      __glapi_sparc_icache_flush(&code[0]);
      code[2] |= ((glapi_addr >> 32) & ((1 << 10) - 1));
      code[3] |= (glapi_addr & ((1 << 10) - 1));
      __glapi_sparc_icache_flush(&code[2]);
      code[6] |= ((functionOffset * 8) >> 10);
      code[7] |= ((functionOffset * 8) & ((1 << 10) - 1));
      __glapi_sparc_icache_flush(&code[6]);
#else
      code[0] |= (glapi_addr >> 10);
      code[1] |= (glapi_addr & ((1 << 10) - 1));
      __glapi_sparc_icache_flush(&code[0]);
      code[2] |= (functionOffset * 4);
      __glapi_sparc_icache_flush(&code[2]);
#endif
   }
   return (_glapi_proc) code;
#else
   (void) functionOffset;
   return NULL;
#endif /* USE_*_ASM */
}


/**
 * This function inserts a new dispatch offset into the assembly language
 * stub that was generated with the preceeding function.
 */
static void
fill_in_entrypoint_offset(_glapi_proc entrypoint, GLuint offset)
{
#if defined(USE_X86_ASM)
   GLubyte * const code = (GLubyte *) entrypoint;

   
#if X86_DISPATCH_FUNCTION_SIZE == 32
   *((unsigned int *)(code + 11)) = 4 * offset;
   *((unsigned int *)(code + 22)) = 4 * offset;
#elif X86_DISPATCH_FUNCTION_SIZE == 16 && defined( GLX_USE_TLS )
   *((unsigned int *)(code +  8)) = 4 * offset;
#elif X86_DISPATCH_FUNCTION_SIZE == 16
   *((unsigned int *)(code +  7)) = 4 * offset;
#else
# error Invalid X86_DISPATCH_FUNCTION_SIZE!
#endif

#elif defined(USE_SPARC_ASM)

   /* XXX this hasn't been tested! */
   unsigned int *code = (unsigned int *) entrypoint;
#ifdef __arch64__
   code[6] = 0x05000000;  /* sethi	%hi(8 * glapioffset), %g2	*/
   code[7] = 0x8410a000;  /* or		%g2, %lo(8 * glapioffset), %g2	*/
   code[6] |= ((offset * 8) >> 10);
   code[7] |= ((offset * 8) & ((1 << 10) - 1));
   __glapi_sparc_icache_flush(&code[6]);
#else /* __arch64__ */
   code[2] = 0xc6006000;  /* ld		[%g1 + %lo(4*glapioffset)], %g3	  */
   code[2] |= (offset * 4);
   __glapi_sparc_icache_flush(&code[2]);
#endif /* __arch64__ */

#else

   /* an unimplemented architecture */
   (void) entrypoint;
   (void) offset;

#endif /* USE_*_ASM */
}


/**
 * Generate new entrypoint
 *
 * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 * never happens, and the user calls this function, he'll segfault.  That's
 * what you get when you try calling a GL function that doesn't really exist.
 * 
 * \param funcName  Name of the function to create an entry-point for.
 * 
 * \sa _glapi_add_entrypoint
 */

static struct _glapi_function *
add_function_name( const char * funcName )
{
   struct _glapi_function * entry = NULL;
   
   if (NumExtEntryPoints < MAX_EXTENSION_FUNCS) {
      _glapi_proc entrypoint = generate_entrypoint(~0);
      if (entrypoint != NULL) {
	 entry = & ExtEntryTable[NumExtEntryPoints];

	 ExtEntryTable[NumExtEntryPoints].name = str_dup(funcName);
	 ExtEntryTable[NumExtEntryPoints].parameter_signature = NULL;
	 ExtEntryTable[NumExtEntryPoints].dispatch_offset = ~0;
	 ExtEntryTable[NumExtEntryPoints].dispatch_stub = entrypoint;
	 NumExtEntryPoints++;
      }
   }

   return entry;
}


/**
 * Fill-in the dispatch stub for the named function.
 * 
 * This function is intended to be called by a hardware driver.  When called,
 * a dispatch stub may be created created for the function.  A pointer to this
 * dispatch function will be returned by glXGetProcAddress.
 *
 * \param function_names       Array of pointers to function names that should
 *                             share a common dispatch offset.
 * \param parameter_signature  String representing the types of the parameters