stdarg.h

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#ifndef __STDARG_H__
#define __STDARG_H__
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* va list parameter list.
 * On AArch64 va_list is the compiler builtin (see below); the flat
 * pointer version only applies to the legacy x86/x64 path. */
#if !defined(ARCH_ARM64) && !defined(__aarch64__)
typedef unsigned char* va_list;
#endif
 
/* width of stack == width of int */
#define STACKITEM int64_t
 
/* round up width of objects pushed on stack. The expression before the
    & ensures that we get 0 for objects of size 0. */
#define VA_SIZE(TYPE) ((sizeof(TYPE) + sizeof(STACKITEM) - 1) & ~(sizeof(STACKITEM) - 1))
 
#ifdef ARCH_X64
/* &(LASTARG) points to the LEFTMOST argument of the function call
    (before the ...) */
#define va_start(AP, LASTARG) (AP = ((va_list) & (LASTARG) + VA_SIZE(LASTARG)))
 
/* nothing for va_end */
#define va_end(AP)
 
#define va_arg(AP, TYPE) (AP += VA_SIZE(TYPE), *((TYPE*)(AP - VA_SIZE(TYPE))))
#elif defined(ARCH_ARM64) || defined(__aarch64__)
/* AArch64: use the compiler's native va_list/va_start/va_arg.
 * The old hand-rolled "ap = &last + 8" pointer walk is wrong on AArch64:
 * it only works when combined with the _store_stack_param register
 * snapshot, which covers printf/sprintf/snprintf but NOT forwarded
 * va_lists (vfprintf/vprintf/vsnprintf/vsprintf, I_Error, M_snprintf).
 * The builtins are correct for the target ABI (AAPCS64 or WoA). */
 
typedef __builtin_va_list va_list;
 
#define va_start(ap, last) __builtin_va_start(ap, last)
 
#define va_arg(ap, T) __builtin_va_arg(ap, T)
 
#define va_end(ap) __builtin_va_end(ap)
 
#define va_copy(dst, src) __builtin_va_copy(dst, src)
#endif
 
#ifdef __cplusplus
}
#endif
 
#endif