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60 lines
3.1 KiB
ArmAsm
60 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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│ 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.internal.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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