; fltfunct_64.asm  call math routine  double sin(double x) 
; compile:	nasm -f elf64 fltfunct_64.asm 
; link:		gcc -m64 -o fltfunct_64 fltfunct_64.o -lm # needs math library
; run:		./fltfunct_64 > fltfunct_64.out
; view:		cat fltfunct_64.out
	
	extern	sin		; must extern all library functions
	extern	printf
	section .data
x:	dq	0.7853975	; Pi/4 = 45 degrees
y:	dq	0.0		; should be about 7.07E-1
fmt:	db	"y= %e = sin(%e)",10,0

	section .text
	global	main
main:	push	rbp		; set up stack

	movq	xmm0, qword [x]	; pass argument to sin()
	call	sin		; all "C" math uses double
	movq	qword [y], xmm0	; save result

	mov	rdi, fmt	; print
	movq	xmm0, qword [y]
	movq	xmm1, qword [x]
	mov	rax,2		; 2 doubles
	call	printf

	pop	rbx		; restore stack
	mov	rax,0		; no error return
	ret			; return to operating system

; result:	7.071063e-01 = sin(7.853975e-01)