mirror of
https://github.com/jart/cosmopolitan.git
synced 2026-11-09 17:20:11 -10:00
42 lines
2.6 KiB
ArmAsm
42 lines
2.6 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.internal.h"
|
|
#include "libc/notice.inc"
|
|
.source __FILE__
|
|
|
|
// 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()
|
|
malloc_usable_size:
|
|
jmp *hook_malloc_usable_size(%rip)
|
|
.endfn malloc_usable_size,globl
|