$ cat sincos.c
#include <math.h>

void sincos(double theta, double *s, double *c)  {
    *s = sin(theta);
    *c = cos(theta);
}
$ gcc -O3 -S sincos.c
$ cat sincos.s
	.file	"sincos.c"
	.text
	.p2align 4,,15
.globl sincos
	.type	sincos, @function
sincos:
.LFB3:
	.cfi_startproc
	movq	%rbx, -16(%rsp)
	movq	%rbp, -8(%rsp)
	subq	$40, %rsp
	.cfi_def_cfa_offset 48
	movq	%rdi, %rbp
	.cfi_offset 6, -16
	.cfi_offset 3, -24
	leaq	8(%rsp), %rdi
	movq	%rsi, %rbx
	movq	%rsp, %rsi
	call	sincos
	movq	8(%rsp), %rax
	movq	%rax, (%rbp)
	movq	(%rsp), %rax
	movq	32(%rsp), %rbp
	movq	%rax, (%rbx)
	movq	24(%rsp), %rbx
	addq	$40, %rsp
	ret
	.cfi_endproc
.LFE3:
	.size	sincos, .-sincos
	.ident	"GCC: (Debian 4.4.5-8) 4.4.5"
	.section	.note.GNU-stack,"",@progbits