42 lines
2.5 KiB
ArmAsm
42 lines
2.5 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.h"
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#include "libc/notice.inc"
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.source __FILE__
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/ Returns the number of bytes you can actually use in
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/ an allocated chunk, which may be more than you requested
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/ (although often not) due to alignment and minimum size
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/ constraints.
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/
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/ You can use this many bytes without worrying about overwriting
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/ other allocated objects. This is not a particularly great
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/ programming practice. malloc_usable_size can be more useful in
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/ debugging and assertions, for example:
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/
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/ p = malloc(n)
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/ assert(malloc_usable_size(p) >= 256)
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/
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/ @param rdi is address of allocation
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/ @return rax is total number of bytes
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/ @see dlmalloc_usable_size()
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malloc_usable_size:
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jmp *hook$malloc_usable_size(%rip)
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.endfn malloc_usable_size,globl
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