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fix bug in rt_hw_context_swicth 

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@97 bbd45198-f89e-11dd-88c7-29a3b14d5316
This commit is contained in:
ssslady 2009-10-14 08:52:06 +00:00
parent b07743f604
commit 4e399f6e90
1 changed files with 28 additions and 4 deletions
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32
libcpu/ia32/context.S
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@ -24,15 +24,39 @@
.globl rt_hw_context_switch
rt_hw_context_switch:
pushfl /*pushed eflags*/
push %cs /*push cs register*/
pushl 0x8(%esp) /*pushed eip register*/
/*
* add by ssslady@gmail.com 2009-10-14
* When we return again the esp should no be change.
* The old code change the esp to esp-4 :-(.
* A protection fault maybe occure for img created by some compiler,eg.gcc in the fedor-11
* -------------------------------------------------------------------------
* entry old code new code
* EIP ->return esp EIP FLAGS ->return esp
* ... FLAGS ->retern esp CS
* CS EIP
* EIP
*/
popl %eax /*get flags*/
popl %ebx /*get eip*/
pushl %eax /*push flags*/
push %cs /*push cs*/
pushl %ebx /*push eip*/
/*-------------------------------------------------------------------
*/
/*push %cs*/ /*push cs register*/
/*pushl 0x8(%esp)*/ /*pushed eip register*/
pushl $0 /*fill irqno*/
push %ds /*push ds register*/
push %es /*push es register*/
pushal /*push eax,ecx,edx,ebx,esp,ebp,esp,edi registers*/
movl 0x40(%esp), %eax /*to thread TCB*/
movl 0x3c(%esp), %ebx /*from thread TCB*/
/*movl 0x40(%esp), %eax*/ /*to thread TCB*/
/*movl 0x3c(%esp), %ebx*/ /*from thread TCB*/
movl 0x3c(%esp), %eax /*to thread TCB*/
movl 0x38(%esp), %ebx /*from thread TCB*/
movl %esp, (%ebx) /*store esp in preempted tasks TCB*/
movl (%eax), %esp /*get new task stack pointer*/