SpaghettiKart/include/libc/stdarg.h

#ifndef STDARG_H
#define STDARG_H

// When not building with IDO, use the builtin vaarg macros for portability.
#ifndef __sgi
#define va_list __builtin_va_list
#define va_start __builtin_va_start
#define va_arg __builtin_va_arg
#define va_end __builtin_va_end
#else

typedef char* va_list;
#define _FP 1
#define _INT 0
#define _STRUCT 2

#define _VA_FP_SAVE_AREA 0x10
#define _VA_ALIGN(p, a) (((unsigned int) (((char*) p) + ((a) > 4 ? (a) : 4) - 1)) & -((a) > 4 ? (a) : 4))
#define va_start(vp, parmN) (vp = ((va_list) & parmN + sizeof(parmN)))

#define __va_stack_arg(list, mode)                                                             \
    (((list) = (char*) _VA_ALIGN(list, __builtin_alignof(mode)) + _VA_ALIGN(sizeof(mode), 4)), \
     (((char*) list) - (_VA_ALIGN(sizeof(mode), 4) - sizeof(mode))))

#define __va_double_arg(list, mode)                                                                   \
    ((((long) list & 0x1) /* 1 byte aligned? */                                                       \
          ? (list = (char*) ((long) list + 7), (char*) ((long) list - 6 - _VA_FP_SAVE_AREA))          \
          : (((long) list & 0x2) /* 2 byte aligned? */                                                \
                 ? (list = (char*) ((long) list + 10), (char*) ((long) list - 24 - _VA_FP_SAVE_AREA)) \
                 : __va_stack_arg(list, mode))))

#define va_arg(list, mode)                                                                   \
    ((mode*) (((__builtin_classof(mode) == _FP && __builtin_alignof(mode) == sizeof(double)) \
                   ? __va_double_arg(list, mode)                                             \
                   : __va_stack_arg(list, mode))))[-1]
#define va_end(__list)

#endif
#endif