Shipwright/soh/include/libc/stdarg.h

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#ifndef STDARG_H
#define STDARG_H
// When building with GCC, use the official vaarg macros to avoid warnings
// and possibly bad codegen.
#ifdef __GNUC__
#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) (((uintptr_t)(((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) \
( \
(((s32)list & 0x1) /* 1 byte aligned? */ \
? (list = (char*)((s32)list + 7), (char*)((s32)list - 6 - _VA_FP_SAVE_AREA)) \
: (((s32)list & 0x2) /* 2 byte aligned? */ \
? (list = (char*)((s32)list + 10), (char*)((s32)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(f64)) \
? __va_double_arg(list, mode) \
: __va_stack_arg(list, mode))))[-1]
#define va_end(__list)
#endif
#endif