EdkCompatibilityPkg/Foundation/Include/EfiStdArg.h

   1 /*++
   2
   3 Copyright (c) 2004, Intel Corporation. All rights reserved.<BR>
   4 This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13
  14   EfiStdArg.h
  15
  16 Abstract:
  17
  18   Support for variable length argument lists using the ANSI standard.
  19
  20   Since we are using the ANSI standard we used the standard nameing and
  21   did not folow the coding convention
  22
  23   VA_LIST  - typedef for argument list.
  24   VA_START (VA_LIST Marker, argument before the ...) - Init Marker for use.
  25   VA_END (VA_LIST Marker) - Clear Marker
  26   VA_ARG (VA_LIST Marker, var arg size) - Use Marker to get an argumnet from
  27     the ... list. You must know the size and pass it in this macro.
  28
  29   example:
  30
  31   UINTN
  32   ExampleVarArg (
  33     IN UINTN  NumberOfArgs,
  34     ...
  35     )
  36   {
  37     VA_LIST Marker;
  38     UINTN   Index;
  39     UINTN   Result;
  40
  41     //
  42     // Initialize the Marker
  43     //
  44     VA_START (Marker, NumberOfArgs);
  45     for (Index = 0, Result = 0; Index < NumberOfArgs; Index++) {
  46       //
  47       // The ... list is a series of UINTN values, so average them up.
  48       //
  49       Result += VA_ARG (Marker, UINTN);
  50     }
  51
  52     VA_END (Marker);
  53     return Result
  54   }
  55
  56 --*/
  57
  58 #ifndef _EFISTDARG_H_
  59 #define _EFISTDARG_H_
  60
  61 /**
  62   Return the size of argument that has been aligned to sizeof (UINTN).
  63
  64   @param  n    The parameter size to be aligned.
  65
  66   @return The aligned size.
  67 **/
  68 #define _INT_SIZE_OF(n) ((sizeof (n) + sizeof (UINTN) - 1) &~(sizeof (UINTN) - 1))
  69
  70 #if defined(__CC_ARM)
  71 //
  72 // RVCT ARM variable argument list support.
  73 //
  74
  75 ///
  76 /// Variable used to traverse the list of arguments. This type can vary by
  77 /// implementation and could be an array or structure.
  78 ///
  79 #ifdef __APCS_ADSABI
  80   typedef int         *va_list[1];
  81   #define VA_LIST     va_list
  82 #else
  83   typedef struct __va_list { void *__ap; } va_list;
  84   #define VA_LIST                          va_list
  85 #endif
  86
  87 #define VA_START(Marker, Parameter)   __va_start(Marker, Parameter)
  88
  89 #define VA_ARG(Marker, TYPE)          __va_arg(Marker, TYPE)
  90
  91 #define VA_END(Marker)                ((void)0)
  92
  93 #elif defined(__GNUC__) && !defined(NO_BUILTIN_VA_FUNCS)
  94 //
  95 // Use GCC built-in macros for variable argument lists.
  96 //
  97
  98 ///
  99 /// Variable used to traverse the list of arguments. This type can vary by
 100 /// implementation and could be an array or structure.
 101 ///
 102 typedef __builtin_va_list VA_LIST;
 103
 104 #define VA_START(Marker, Parameter)  __builtin_va_start (Marker, Parameter)
 105
 106 #define VA_ARG(Marker, TYPE)         ((sizeof (TYPE) < sizeof (UINTN)) ? (TYPE)(__builtin_va_arg (Marker, UINTN)) : (TYPE)(__builtin_va_arg (Marker, TYPE)))
 107
 108 #define VA_END(Marker)               __builtin_va_end (Marker)
 109
 110 #else
 111 ///
 112 /// Variable used to traverse the list of arguments. This type can vary by
 113 /// implementation and could be an array or structure.
 114 ///
 115 typedef CHAR8 *VA_LIST;
 116
 117 /**
 118   Retrieves a pointer to the beginning of a variable argument list, based on
 119   the name of the parameter that immediately precedes the variable argument list.
 120
 121   This function initializes Marker to point to the beginning of the variable
 122   argument list that immediately follows Parameter.  The method for computing the
 123   pointer to the next argument in the argument list is CPU-specific following the
 124   EFIAPI ABI.
 125
 126   @param   Marker       The VA_LIST used to traverse the list of arguments.
 127   @param   Parameter    The name of the parameter that immediately precedes
 128                         the variable argument list.
 129
 130   @return  A pointer to the beginning of a variable argument list.
 131
 132 **/
 133 #define VA_START(Marker, Parameter) (Marker = (VA_LIST) & (Parameter) + _INT_SIZE_OF (Parameter))
 134
 135 /**
 136   Returns an argument of a specified type from a variable argument list and updates
 137   the pointer to the variable argument list to point to the next argument.
 138
 139   This function returns an argument of the type specified by TYPE from the beginning
 140   of the variable argument list specified by Marker.  Marker is then updated to point
 141   to the next argument in the variable argument list.  The method for computing the
 142   pointer to the next argument in the argument list is CPU-specific following the EFIAPI ABI.
 143
 144   @param   Marker   VA_LIST used to traverse the list of arguments.
 145   @param   TYPE     The type of argument to retrieve from the beginning
 146                     of the variable argument list.
 147
 148   @return  An argument of the type specified by TYPE.
 149
 150 **/
 151 #define VA_ARG(Marker, TYPE)   (*(TYPE *) ((Marker += _INT_SIZE_OF (TYPE)) - _INT_SIZE_OF (TYPE)))
 152
 153 /**
 154   Terminates the use of a variable argument list.
 155
 156   This function initializes Marker so it can no longer be used with VA_ARG().
 157   After this macro is used, the only way to access the variable argument list is
 158   by using VA_START() again.
 159
 160   @param   Marker   VA_LIST used to traverse the list of arguments.
 161
 162 **/
 163 #define VA_END(Marker)      (Marker = (VA_LIST) 0)
 164
 165 #endif
 166
 167 #endif