61 lines
3.1 KiB
ArmAsm
61 lines
3.1 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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/ Allocates / resizes / frees memory, e.g.
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/
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/ Returns a pointer to a chunk of size n that contains the same data as
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/ does chunk p up to the minimum of (n, p's size) bytes, or null if no
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/ space is available.
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/
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/ If p is NULL, realloc is equivalent to malloc.
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/ If p is not NULL and n is 0, realloc is equivalent to free.
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/
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/ The returned pointer may or may not be the same as p. The algorithm
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/ prefers extending p in most cases when possible, otherwise it employs
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/ the equivalent of a malloc-copy-free sequence.
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/
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/ Please note that p is NOT free()'d should realloc() fail, thus:
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/
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/ if ((p2 = realloc(p, n2))) {
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/ p = p2;
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/ ...
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/ } else {
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/ ...
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/ }
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/
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/ if n is for fewer bytes than already held by p, the newly unused
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/ space is lopped off and freed if possible.
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/
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/ The old unix realloc convention of allowing the last-free'd chunk to
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/ be used as an argument to realloc is not supported.
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/
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/ @param rdi (p) is address of current allocation or NULL
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/ @param rsi (n) is number of bytes needed
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/ @return rax is result, or NULL w/ errno w/o free(p)
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/ @note realloc(p=0, n=0) → malloc(32)
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/ @note realloc(p≠0, n=0) → free(p)
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/ @see dlrealloc()
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realloc:
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jmp *hook$realloc(%rip)
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.endfn realloc,globl
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