43 lines
2.6 KiB
ArmAsm
43 lines
2.6 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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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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