cosmopolitan/libc/tinymath/asinl.S

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
│vi: set et ft=asm ts=8 sw=8 fenc=utf-8                                     :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/macros.internal.h"

//	Returns arc sine of 𝑥.
//
//	@param	𝑥 is an 80-bit long double passed on stack in 16-bytes
//	@return	result of computation on FPU stack in %st
//	@define	atan2(𝑥,sqrt((1-𝑥)*(1+𝑥)))
//	@domain	-1 ≤ 𝑥 ≤ 1
asinl:	pushq	%rbp
	mov	%rsp,%rbp
	.profilable
	fldt	16(%rbp)
	fld1
	fld	%st
	fsub	%st(2)
	fxch
	fadd	%st(2)
	fmulp
	fsqrt
	fpatan
	leave
	ret
	.endfn	asinl,globl