cosmopolitan/libc/mem/memalign.S

40 lines
2.5 KiB
ArmAsm

/*-*- 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.h"
#include "libc/notice.inc"
.source __FILE__
/ Allocates aligned memory.
/
/ Returns a pointer to a newly allocated chunk of n bytes, aligned in
/ accord with the alignment argument. The alignment argument should be
/ a power of two. If the argument is not a power of two, the nearest
/ greater power is used. 8-byte alignment is guaranteed by normal
/ malloc calls, so don't bother calling memalign with an argument of 8
/ or less.
/
/ @param rdi is alignment in bytes
/ @param rsi (newsize) is number of bytes needed
/ @return rax is memory address, or NULL w/ errno
/ @note overreliance on memalign is a sure way to fragment space
/ @see dlmemalign()
memalign:
jmp *hook$memalign(%rip)
.endfn memalign,globl