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Project/Src/rt-thread/libcpu/ia32/context_gcc.S

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+/*
+ * File      : context_gcc.S
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006, RT-Thread Development Team
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rt-thread.org/license/LICENSE
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2006-09-15     QiuYi        The first version
+ * 2006-10-09     Bernard      add rt_hw_context_switch_to implementation
+ */
+
+ /**
+ * @addtogroup ia32
+ */
+/*@{*/
+
+/*
+ * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to);
+ */
+.globl rt_hw_context_switch
+rt_hw_context_switch:
+	pushfl					/*pushed eflags*/
+/*
+ *	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 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*/
+
+	popal					/*restore new task TCB*/
+	pop %es
+	pop %ds
+	add $4,%esp				/*skip irqno*/
+	iret
+
+/*
+ * void rt_hw_context_switch_to(rt_uint32 to);
+ */
+.globl rt_hw_context_switch_to
+rt_hw_context_switch_to:
+	push %ebp
+	movl %esp, %ebp
+
+	movl 0x8(%ebp), %eax	/* to thread TCB */
+	movl (%eax), %esp		/* get new task stack pointer */
+
+	popal					/* restore new task TCB*/
+	pop %es
+	pop %ds
+	add $4, %esp			/* skip irqno */
+	iret
+
+/*
+ * void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to);
+ */
+.globl rt_thread_switch_interrupt_flag
+.globl rt_interrupt_from_thread
+.globl rt_interrupt_to_thread
+.globl rt_hw_context_switch_interrupt
+rt_hw_context_switch_interrupt:
+	pushl %ebp
+	movl %esp, %ebp
+	movl 0xc(%ebp), %eax
+	movl 0x8(%ebp), %ebx
+	
+	movl $rt_thread_switch_interrupt_flag, %ecx
+	movl (%ecx), %edx
+	cmp $0x1, %edx
+	jz _reswitch
+	
+	movl $0x1, %edx				/*set rt_thread_switch_interrupt_flag to 1*/
+	movl %edx, (%ecx)
+	movl $rt_interrupt_from_thread, %edx	/*set rt_interrupt_from_thread*/
+	movl %ebx, (%edx)
+_reswitch:
+	movl $rt_interrupt_to_thread, %edx		/*set rt_interrupt_to_thread*/
+	movl %eax, (%edx)
+	leave
+	ret