/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
│vi: set et ft=asm ts=8 tw=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"
.source	__FILE__

//	Performs raw System Five system call.
//
//	This function provides a direct path into system call support
//	that's friendly to C code, since it doesn't need an intermediate
//	thunk. It only supports arities up to six, since there's no way
//	to do more safely; this isn't a problem with Linux, although
//	certain BSD calls may not be available.
//
//	@param	%rdi is system call ordinal, which isn't translated,
//		and must be correct for the underlying host system
//	@param	%rsi,%rdx,%rcx,%r8,%r9 may supply parameters 1 through 5
//	@param	sixth is optionally pushed on the stack before call
//	@return	%rax has result, or -1 w/ errno on failure
syscall:mov	%rdi,%rax
	mov	%rsi,%rdi
	mov	%rdx,%rsi
	mov	%rcx,%rdx
	mov	%r8,%rcx		# ← intended
	mov	%r9,%r8
	mov	8(%rsp),%r9
	jmp	*__systemfive(%rip)
	.endfn	syscall,globl
