/*-*- 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"
#include "libc/notice.inc"

//	Returns the number of bytes you can actually use in
//	an allocated chunk, which may be more than you requested
//	(although often not) due to alignment and minimum size
//	constraints.
//
//	You can use this many bytes without worrying about overwriting
//	other allocated objects. This is not a particularly great
//	programming practice. malloc_usable_size can be more useful in
//	debugging and assertions, for example:
//
//	    p = malloc(n)
//	    assert(malloc_usable_size(p) >= 256)
//
//	@param	rdi is address of allocation
//	@return	rax is total number of bytes
//	@see	dlmalloc_usable_size()
//	@threadsafe
malloc_usable_size:
	jmp	*hook_malloc_usable_size(%rip)
	.endfn	malloc_usable_size,globl