mirror of
https://github.com/jart/cosmopolitan.git
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2fc507c98f
* modelines: tw -> sw shiftwidth, not textwidth. * space-surround modelines * fix irregular modelines * Fix modeline in titlegen.c
106 lines
3.6 KiB
ArmAsm
106 lines
3.6 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│ vi: set noet ft=asm ts=8 sw=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/dce.h"
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#include "libc/notice.inc"
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nop
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// Invokes deferred function calls.
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//
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// This offers behavior similar to std::unique_ptr. Functions
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// overwrite their return addresses jumping here, and pushing
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// exactly one entry on the shadow stack below. Functions may
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// repeat that process multiple times, in which case the body
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// of this gadget loops and unwinds as a natural consequence.
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//
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// @param rax,rdx,xmm0,xmm1,st0,st1 is return value
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// @see test/libc/runtime/gc_test.c
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.ftrace1
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__gc: .ftrace2
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#ifdef __x86_64__
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mov %fs:0,%rcx // __get_tls()
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mov 0x18(%rcx),%rcx // tls::garbages
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decl (%rcx) // --g->i
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mov (%rcx),%r8d // r8 = g->i
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mov 8(%rcx),%r9 // r9 = g->p
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js 9f
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shl $5,%r8
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lea (%r9,%r8),%r8
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mov 8(%r8),%r9
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mov 16(%r8),%rdi
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push 24(%r8)
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push %rbp
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mov %rsp,%rbp
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sub $32,%rsp
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mov %rax,-8(%rbp)
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mov %rdx,-16(%rbp)
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movdqa %xmm0,-32(%rbp)
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call *%r9
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movdqa -32(%rbp),%xmm0
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mov -16(%rbp),%rdx
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mov -8(%rbp),%rax
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leave
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ret
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9: ud2
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nop
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#elif defined(__aarch64__)
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// if this code fails
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// check if CosmoTib's size changed
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sub x8,x28,#192 // __get_tls()
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ldr x9,[x8,0x18] // tib::garbages
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ldr x10,[x9] // g->i
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ldr x8,[x9,8] // g->p
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sub x10,x10,#1 //
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str x10,[x9] //
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sbfiz x10,x10,5,32 //
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add x8,x8,x10 // g->p+i
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ldr x9,[x8,#8] // g->p[i].fn
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ldr x10,[x8,#16] // g->p[i].arg
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ldr x11,[x8,#24] // g->p[i].ret
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stp x29,x11,[sp,-208]!
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mov x29,sp
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stp x0,x1,[sp,16]
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stp x2,x3,[sp,32]
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stp x4,x5,[sp,48]
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stp x6,x7,[sp,64]
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stp q0,q1,[sp,80]
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stp q2,q3,[sp,112]
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stp q4,q5,[sp,144]
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stp q6,q7,[sp,176]
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mov x0,x10
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blr x9
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ldp q6,q7,[sp,176]
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ldp q4,q5,[sp,144]
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ldp q2,q3,[sp,112]
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ldp q0,q1,[sp,80]
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ldp x6,x7,[sp,64]
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ldp x4,x5,[sp,48]
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ldp x2,x3,[sp,32]
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ldp x0,x1,[sp,16]
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ldp x29,x30,[sp],208
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ret
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#endif /* __x86_64__ */
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.endfn __gc,globl,hidden
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