putc               38 user/printf.c      putc(fd, buf[i]);
putc               44 user/printf.c    putc(fd, '0');
putc               45 user/printf.c    putc(fd, 'x');
putc               47 user/printf.c      putc(fd, digits[x >> (sizeof(uint64) * 8 - 4)]);
putc               64 user/printf.c          putc(fd, c0);
putc              100 user/printf.c            putc(fd, *s);
putc              102 user/printf.c          putc(fd, '%');
putc              105 user/printf.c          putc(fd, '%');
putc              106 user/printf.c          putc(fd, c0);
putc              123 user/printf.c            putc(fd, *s);
putc              127 user/printf.c          putc(fd, va_arg(ap, uint));
putc              129 user/printf.c          putc(fd, c);
putc              132 user/printf.c          putc(fd, '%');
putc              133 user/printf.c          putc(fd, c);