disable-newlib-io-long-double?

[chengzhiwei (C)]

Thanks! 
Check the file of vfprintf.c, I guess I found the reason:
# ifdef _NO_LONGDBL
			if (flags & LONGDBL) {
				_fpvalue = (double)GET_ARG (N, ap, _LONG_DOUBLE);
			} else {
				_fpvalue = GET_ARG (N, ap, double);
			}
There is an accuracy conversion step, but in my project, all of the long double symbols have been stripped away in libgcc.a, maybe I should patch the file of vfprintf.c.

zhiwei

-----邮件原件-----
发件人: Jim Wilson [mailto:jimw@sifive.com] 
发送时间: 2020年3月17日 4:51
收件人: chengzhiwei (C) <chengzhiwei6@huawei.com>; newlib@sourceware.org
主题: Re: disable-newlib-io-long-double?

On 3/16/20 4:37 AM, chengzhiwei (C) wrote:
> In my project, all of the quadrature symbols have been stripped away in libgcc.a, so when I built newlib toolchain based on riscv32 target, we used the option "--disable-newlib-io-long-double" to turn off the feature of long double. But when performing a floating-point calculation, the symbol "trunctfdf2" is not defined correctly:
> libc.a(lib_a-vfprintf.o): in function `.L60':vfprintf.c:(.text+0x3fe): undefined reference to `__trunctfdf2'

--disable-newlib-io-long-double is the default.  That configure option shouldn't do anything.

__trunctfdf2 comes from libgcc.  Are you linking with libgcc?

Of course, if you have long double disabled, it is odd that you get a call to trunctfdf2.  You should check how the vfprintf.c file was compiled.  There is a _NO_LONGDBL that should be defined by default, and should prevent any long double code from being enabled in that file.

Jim