为什么int32_t和int16_t在printf输出中有相同的位数?

#include <stdio.h>
#include <stdint.h>

int main()
{
  uint32_t a = 0xF0FF1FFF;
  printf("a = 0x%x\n",a);
  uint16_t b = a;
  printf("b = 0x%x\n",b);


  int32_t c = 0xF0FF8FFF;
  printf("c = 0x%x\n",c);
  int16_t d = c;
  printf("d = 0x%x\n",d);

  int32_t e = d;
  printf("e = 0x%x\n",e);

  return 0;
}

输出:

a = 0xf0ff1fff
b = 0x1fff
c = 0xf0ff8fff
d = 0xffff8fff
e = 0xffff8fff

在这个例子中,为什么 d 打印32位 b ?