add pic32 port

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1432 bbd45198-f89e-11dd-88c7-29a3b14d5316

libcpu/mips/pic32/context_gcc.S

+/*
+ * rt_base_t rt_hw_interrupt_disable()
+ */
+    .globl rt_hw_interrupt_disable
+rt_hw_interrupt_disable:
+
+/*
+ * void rt_hw_interrupt_enable(rt_base_t level)
+ */
+    .globl rt_hw_interrupt_enable
+rt_hw_interrupt_enable:
+
+/*
+ * void rt_hw_context_switch_to(rt_uint32 to)/*
+ * a0 --> to
+ */
+    .globl rt_hw_context_switch_to
+rt_hw_context_switch_to:
+
+/*
+ * void rt_hw_context_switch(rt_uint32 from, rt_uint32 to)
+ * a0 --> from
+ * a1 --> to
+ */
+    .globl rt_hw_context_switch
+rt_hw_context_switch:
+
+/*
+ * void rt_hw_context_switch_interrupt(rt_uint32 from, rt_uint32 to)/*
+ */
+    .globl rt_thread_switch_interrput_flag
+    .globl rt_interrupt_from_thread
+    .globl rt_interrupt_to_thread
+    .globl rt_hw_context_switch_interrupt
+rt_hw_context_switch_interrupt:
+

libcpu/mips/pic32/interrupt.c

+/*
+ * File      : interrupt.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2010, 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
+ * 2011-05-23     aozima       first implementation for PIC32.
+ */
+
+#include <rtthread.h>
+

libcpu/mips/pic32/stack.c

+/*
+ * File      : stack.c
+ * 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
+ * 2011-05-23     aozima       first implementation for PIC32.
+ */
+
+#include <rtthread.h>
+
+/**
+ * @addtogroup Loogonson SoC3210
+ */
+/*@{*/
+
+/**
+ * This function will initialize thread stack
+ *
+ * @param tentry the entry of thread
+ * @param parameter the parameter of entry
+ * @param stack_addr the beginning stack address
+ * @param texit the function will be called when thread exit
+ *
+ * @return stack address
+ */
+rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter, rt_uint8_t *stack_addr, void *texit)
+{
+	rt_uint32_t *stk;
+
+	/* return task's current stack address */
+	return (rt_uint8_t *)stk;
+}
+
+/*@}*/
+