86 lines
2.1 KiB
ArmAsm
86 lines
2.1 KiB
ArmAsm
/**
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* \brief Startup code for Genode 64Bit applications
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* \author Sebastian Sumpf
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* \author Martin Stein
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* \date 2011-05-11
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*/
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/*
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* Copyright (C) 2011-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/**************************
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** .text (program code) **
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**************************/
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.text
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/* program entry-point */
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.global _start
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_start:
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/* make initial value of some registers available to higher-level code */
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movq __initial_ax@GOTPCREL(%rip), %rbx
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movq %rax, (%rbx)
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movq __initial_di@GOTPCREL(%rip), %rbx
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movq %rdi, (%rbx)
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movq __initial_sp@GOTPCREL(%rip), %rax
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movq %rsp, (%rax)
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/*
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* Install initial temporary environment that is replaced later by the
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* environment that init_main_thread creates.
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*/
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leaq _stack_high@GOTPCREL(%rip),%rax
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movq (%rax), %rsp
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/* if this is the dynamic linker, init_rtld relocates the linker */
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call init_rtld
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/* create proper environment for the main thread */
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call init_main_thread
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/* apply environment that was created by init_main_thread */
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movq init_main_thread_result@GOTPCREL(%rip), %rax
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movq (%rax), %rsp
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/* clear the base pointer in order that stack backtraces will work */
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xorq %rbp, %rbp
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/*
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* We jump into initial C code instead of calling it as it should never
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* return on the one hand and because the alignment of the stack pointer
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* that init_main_thread returned expects a jump at the other hand. The
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* latter matters because GCC expects the initial stack pointer to be
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* aligned to 16 byte for at least the handling of floating points.
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*/
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jmp _main
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/*********************************
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** .bss (non-initialized data) **
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*********************************/
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.bss
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/* stack of the temporary initial environment */
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.p2align 8
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.space 32 * 1024
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.global _stack_high
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_stack_high:
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/* initial value of the RSP, RAX and RDI register */
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.globl __initial_sp
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__initial_sp:
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.space 8
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.globl __initial_ax
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__initial_ax:
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.space 8
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.globl __initial_di
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__initial_di:
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.space 8
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