82 lines
2.4 KiB
ArmAsm
82 lines
2.4 KiB
ArmAsm
/*
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* Copyright (c) 2006-2022, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2006-09-15 QiuYi The first version
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* 2006-10-09 Bernard add rt_hw_context_switch_to implementation
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*/
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/**
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* @addtogroup ia32
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*/
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/*@{*/
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/*
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* void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
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*/
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.globl rt_hw_context_switch
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rt_hw_context_switch:
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pushfl /*pushed eflags*/
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/*
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* add by ssslady@gmail.com 2009-10-14
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* When we return again the esp should no be change.
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* The old code change the esp to esp-4 :-(.
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* A protection fault maybe occure for img created by some compiler,eg.gcc in the fedor-11
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* -------------------------------------------------------------------------
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* entry old code new code
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* EIP ->return esp EIP FLAGS ->return esp
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* ... FLAGS ->retern esp CS
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* CS EIP
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* EIP
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*/
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popl %eax /*get flags*/
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popl %ebx /*get eip*/
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pushl %eax /*push flags*/
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push %cs /*push cs*/
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pushl %ebx /*push eip*/
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/*-------------------------------------------------------------------
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*/
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/*push %cs*/ /*push cs register*/
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/*pushl 0x8(%esp)*/ /*pushed eip register*/
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pushl $0 /*fill irqno*/
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push %ds /*push ds register*/
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push %es /*push es register*/
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pushal /*push eax,ecx,edx,ebx,esp,ebp,esp,edi registers*/
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/*movl 0x40(%esp), %eax*/ /*to thread TCB*/
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/*movl 0x3c(%esp), %ebx*/ /*from thread TCB*/
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movl 0x3c(%esp), %eax /*to thread TCB*/
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movl 0x38(%esp), %ebx /*from thread TCB*/
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movl %esp, (%ebx) /*store esp in preempted tasks TCB*/
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movl (%eax), %esp /*get new task stack pointer*/
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popal /*restore new task TCB*/
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pop %es
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pop %ds
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add $4,%esp /*skip irqno*/
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iret
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/*
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* void rt_hw_context_switch_to(rt_uint32 to);
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*/
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.globl rt_hw_context_switch_to
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rt_hw_context_switch_to:
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push %ebp
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movl %esp, %ebp
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movl 0x8(%ebp), %eax /* to thread TCB */
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movl (%eax), %esp /* get new task stack pointer */
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popal /* restore new task TCB*/
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pop %es
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pop %ds
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add $4, %esp /* skip irqno */
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iret
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