s_ceill.s

glibc 2.9,最新版的C语言库函数

/*
 * Written by J.T. Conklin <[e-mail]>.
 * Changes for long double by Ulrich Drepper <[e-mail]>
 * Changes for x86-64 by Andreas Jaeger <[e-mail]>	
 * Public domain.
 */

#include <machine/asm.h>


ENTRY(__ceill)
	fldt	8(%rsp)

	fstcw	-4(%rsp)		/* store fpu control word */

	/* We use here %edx although only the low 1 bits are defined.
	   But none of the operations should care and they are faster
	   than the 16 bit operations.  */
	movl	$0x0800,%edx		/* round towards +oo */
	orl	-4(%rsp),%edx
	andl	$0xfbff,%edx
	movl	%edx,-8(%rsp)
	fldcw	-8(%rsp)		/* load modified control word */

	frndint				/* round */

	fldcw	-4(%rsp)		/* restore original control word */

	ret
END (__ceill)
weak_alias (__ceill, ceill)