add exceptions.c for pic32

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1696 bbd45198-f89e-11dd-88c7-29a3b14d5316

libcpu/mips/pic32/exceptions.c

+/*********************************************************************
+ *
+ *                  Generic Exception Handler
+ *
+ *********************************************************************
+ * FileName:        exceptions.c
+ * Dependencies:
+ *
+ * Processor:       PIC32
+ *
+ * Complier:        MPLAB C32
+ *                  MPLAB IDE
+ * Company:         Microchip Technology, Inc.
+ * Author:			Darren Wenn
+ *
+ * Software License Agreement
+ *
+ * The software supplied herewith by Microchip Technology Incorporated
+ * (the Company) for its PIC32/PIC24 Microcontroller is intended
+ * and supplied to you, the Companys customer, for use solely and
+ * exclusively on Microchip PIC32/PIC24 Microcontroller products.
+ * The software is owned by the Company and/or its supplier, and is
+ * protected under applicable copyright laws. All rights are reserved.
+ * Any use in violation of the foregoing restrictions may subject the
+ * user to criminal sanctions under applicable laws, as well as to
+ * civil liability for the breach of the terms and conditions of this
+ * license.
+ *
+ * THIS SOFTWARE IS PROVIDED IN AN AS IS CONDITION. NO WARRANTIES,
+ * WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED
+ * TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT,
+ * IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR
+ * CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
+ *
+ *
+ *
+ ********************************************************************/
+
+#include <p32xxxx.h>
+
+// declared static in case exception condition would prevent
+// auto variable being created
+static enum {
+	EXCEP_IRQ = 0,			// interrupt
+	EXCEP_AdEL = 4,			// address error exception (load or ifetch)
+	EXCEP_AdES,				// address error exception (store)
+	EXCEP_IBE,				// bus error (ifetch)
+	EXCEP_DBE,				// bus error (load/store)
+	EXCEP_Sys,				// syscall
+	EXCEP_Bp,				// breakpoint
+	EXCEP_RI,				// reserved instruction
+	EXCEP_CpU,				// coprocessor unusable
+	EXCEP_Overflow,			// arithmetic overflow
+	EXCEP_Trap,				// trap (possible divide by zero)
+	EXCEP_IS1 = 16,			// implementation specfic 1
+	EXCEP_CEU,				// CorExtend Unuseable
+	EXCEP_C2E				// coprocessor 2
+} _excep_code;
+
+static unsigned int _epc_code;
+static unsigned int _excep_addr;
+
+#include <rtthread.h>
+// this function overrides the normal _weak_ generic handler
+void _general_exception_handler(void)
+{
+	asm volatile("mfc0 %0,$13" : "=r" (_excep_code));
+	asm volatile("mfc0 %0,$14" : "=r" (_excep_addr));
+
+	_excep_code = (_excep_code & 0x0000007C) >> 2;
+
+	rt_kprintf("\r\n_excep_code : %08X\r\n",_excep_code);
+	rt_kprintf("_excep_addr : %08X\r\n",_excep_addr);
+	switch(_excep_code)
+	{
+	    case EXCEP_IRQ:rt_kprintf("interrupt\r\n");break;
+	    case EXCEP_AdEL:rt_kprintf("address error exception (load or ifetch)\r\n");break;
+	    case EXCEP_AdES:rt_kprintf("address error exception (store)\r\n");break;
+	    case EXCEP_IBE:rt_kprintf("bus error (ifetch)\r\n");break;
+	    case EXCEP_DBE:rt_kprintf("bus error (load/store)\r\n");break;
+	    case EXCEP_Sys:rt_kprintf("syscall\r\n");break;
+	    case EXCEP_Bp:rt_kprintf("breakpoint\r\n");break;
+	    case EXCEP_RI:rt_kprintf("reserved instruction\r\n");break;
+	    case EXCEP_CpU:rt_kprintf("coprocessor unusable\r\n");break;
+	    case EXCEP_Overflow:rt_kprintf("arithmetic overflow\r\n");break;
+	    case EXCEP_Trap:rt_kprintf("trap (possible divide by zero)\r\n");break;
+	    case EXCEP_IS1:rt_kprintf("implementation specfic 1\r\n");break;
+	    case EXCEP_CEU:rt_kprintf("CorExtend Unuseable\r\n");break;
+	    case EXCEP_C2E:rt_kprintf("coprocessor 2\r\n");break;
+	    default : rt_kprintf("unkown exception\r\n");break;
+	}
+
+	while (1) {
+		// Examine _excep_code to identify the type of exception
+		// Examine _excep_addr to find the address that caused the exception
+	}
+}