rt-thread 32位有无符号类型

/* date type defination */
typedef signed char rt_int8_t;
typedef signed short rt_int16_t;
typedef signed long rt_int32_t;
typedef unsigned char rt_uint8_t;
typedef unsigned short rt_uint16_t;
typedef unsigned long rt_uint32_t;
typedef int rt_bool_t;

/* 32bit CPU */
typedef long rt_base_t;
typedef unsigned long rt_ubase_t;