我把中断向量表中指向修改了，为什么当我把timerB换成TIMERA三色灯就可以闪了呢？？

//*****************************************************************************
//
// startup_ccs.c - Startup code for use with TI's Code Composer Studio.
//
// Copyright (c) 2012-2013 Texas Instruments Incorporated. All rights reserved.
// Software License Agreement
//
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
//
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// 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. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 1.0 of the EK-TM4C123GXL Firmware Package.
//
//*****************************************************************************

#include <stdint.h>
#include "inc/hw_nvic.h"
#include "inc/hw_types.h"

//*****************************************************************************
//
// Forward declaration of the default fault handlers.
//
//*****************************************************************************
void ResetISR(void);
static void NmiSR(void);
static void FaultISR(void);
static void IntDefaultHandler(void);

//*****************************************************************************
//
// External declaration for the reset handler that is to be called when the
// processor is started
//
//*****************************************************************************
extern void _c_int00(void);
extern void Timer0IntHandler();

//*****************************************************************************
//
// Linker variable that marks the top of the stack.
//
//*****************************************************************************
extern uint32_t __STACK_TOP;

//*****************************************************************************
//
// The vector table. Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000 or at the start of
// the program if located at a start address other than 0.
//
//*****************************************************************************
#pragma DATA_SECTION(g_pfnVectors, ".intvecs")
void (* const g_pfnVectors[])(void) =
{
(void (*)(void))((uint32_t)&__STACK_TOP),
// The initial stack pointer
ResetISR, // The reset handler
NmiSR, // The NMI handler
FaultISR, // The hard fault handler
IntDefaultHandler, // The MPU fault handler
IntDefaultHandler, // The bus fault handler
IntDefaultHandler, // The usage fault handler
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // SVCall handler
IntDefaultHandler, // Debug monitor handler
0, // Reserved
IntDefaultHandler, // The PendSV handler
IntDefaultHandler, // The SysTick handler
IntDefaultHandler, // GPIO Port A
IntDefaultHandler, // GPIO Port B
IntDefaultHandler, // GPIO Port C
IntDefaultHandler, // GPIO Port D
IntDefaultHandler, // GPIO Port E
IntDefaultHandler, // UART0 Rx and Tx
IntDefaultHandler, // UART1 Rx and Tx
IntDefaultHandler, // SSI0 Rx and Tx
IntDefaultHandler, // I2C0 Master and Slave
IntDefaultHandler, // PWM Fault
IntDefaultHandler, // PWM Generator 0
IntDefaultHandler, // PWM Generator 1
IntDefaultHandler, // PWM Generator 2
IntDefaultHandler, // Quadrature Encoder 0
IntDefaultHandler, // ADC Sequence 0
IntDefaultHandler, // ADC Sequence 1
IntDefaultHandler, // ADC Sequence 2
IntDefaultHandler, // ADC Sequence 3
IntDefaultHandler, // Watchdog timer
Timer0IntHandler, // Timer 0 subtimer A
Timer0IntHandler, // Timer 0 subtimer B
IntDefaultHandler, // Timer 1 subtimer A
IntDefaultHandler, // Timer 1 subtimer B
IntDefaultHandler, // Timer 2 subtimer A
IntDefaultHandler, // Timer 2 subtimer B
IntDefaultHandler, // Analog Comparator 0
IntDefaultHandler, // Analog Comparator 1
IntDefaultHandler, // Analog Comparator 2
IntDefaultHandler, // System Control (PLL, OSC, BO)
IntDefaultHandler, // FLASH Control
IntDefaultHandler, // GPIO Port F
IntDefaultHandler, // GPIO Port G
IntDefaultHandler, // GPIO Port H
IntDefaultHandler, // UART2 Rx and Tx
IntDefaultHandler, // SSI1 Rx and Tx
IntDefaultHandler, // Timer 3 subtimer A
IntDefaultHandler, // Timer 3 subtimer B
IntDefaultHandler, // I2C1 Master and Slave
IntDefaultHandler, // Quadrature Encoder 1
IntDefaultHandler, // CAN0
IntDefaultHandler, // CAN1
IntDefaultHandler, // CAN2
0, // Reserved
IntDefaultHandler, // Hibernate
IntDefaultHandler, // USB0
IntDefaultHandler, // PWM Generator 3
IntDefaultHandler, // uDMA Software Transfer
IntDefaultHandler, // uDMA Error
IntDefaultHandler, // ADC1 Sequence 0
IntDefaultHandler, // ADC1 Sequence 1
IntDefaultHandler, // ADC1 Sequence 2
IntDefaultHandler, // ADC1 Sequence 3
0, // Reserved
0, // Reserved
IntDefaultHandler, // GPIO Port J
IntDefaultHandler, // GPIO Port K
IntDefaultHandler, // GPIO Port L
IntDefaultHandler, // SSI2 Rx and Tx
IntDefaultHandler, // SSI3 Rx and Tx
IntDefaultHandler, // UART3 Rx and Tx
IntDefaultHandler, // UART4 Rx and Tx
IntDefaultHandler, // UART5 Rx and Tx
IntDefaultHandler, // UART6 Rx and Tx
IntDefaultHandler, // UART7 Rx and Tx
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // I2C2 Master and Slave
IntDefaultHandler, // I2C3 Master and Slave
IntDefaultHandler, // Timer 4 subtimer A
IntDefaultHandler, // Timer 4 subtimer B
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // Timer 5 subtimer A
IntDefaultHandler, // Timer 5 subtimer B
IntDefaultHandler, // Wide Timer 0 subtimer A
IntDefaultHandler, // Wide Timer 0 subtimer B
IntDefaultHandler, // Wide Timer 1 subtimer A
IntDefaultHandler, // Wide Timer 1 subtimer B
IntDefaultHandler, // Wide Timer 2 subtimer A
IntDefaultHandler, // Wide Timer 2 subtimer B
IntDefaultHandler, // Wide Timer 3 subtimer A
IntDefaultHandler, // Wide Timer 3 subtimer B
IntDefaultHandler, // Wide Timer 4 subtimer A
IntDefaultHandler, // Wide Timer 4 subtimer B
IntDefaultHandler, // Wide Timer 5 subtimer A
IntDefaultHandler, // Wide Timer 5 subtimer B
IntDefaultHandler, // FPU
0, // Reserved
0, // Reserved
IntDefaultHandler, // I2C4 Master and Slave
IntDefaultHandler, // I2C5 Master and Slave
IntDefaultHandler, // GPIO Port M
IntDefaultHandler, // GPIO Port N
IntDefaultHandler, // Quadrature Encoder 2
0, // Reserved
0, // Reserved
IntDefaultHandler, // GPIO Port P (Summary or P0)
IntDefaultHandler, // GPIO Port P1
IntDefaultHandler, // GPIO Port P2
IntDefaultHandler, // GPIO Port P3
IntDefaultHandler, // GPIO Port P4
IntDefaultHandler, // GPIO Port P5
IntDefaultHandler, // GPIO Port P6
IntDefaultHandler, // GPIO Port P7
IntDefaultHandler, // GPIO Port Q (Summary or Q0)
IntDefaultHandler, // GPIO Port Q1
IntDefaultHandler, // GPIO Port Q2
IntDefaultHandler, // GPIO Port Q3
IntDefaultHandler, // GPIO Port Q4
IntDefaultHandler, // GPIO Port Q5
IntDefaultHandler, // GPIO Port Q6
IntDefaultHandler, // GPIO Port Q7
IntDefaultHandler, // GPIO Port R
IntDefaultHandler, // GPIO Port S
IntDefaultHandler, // PWM 1 Generator 0
IntDefaultHandler, // PWM 1 Generator 1
IntDefaultHandler, // PWM 1 Generator 2
IntDefaultHandler, // PWM 1 Generator 3
IntDefaultHandler // PWM 1 Fault
};

//*****************************************************************************
//
// This is the code that gets called when the processor first starts execution
// following a reset event. Only the absolutely necessary set is performed,
// after which the application supplied entry() routine is called. Any fancy
// actions (such as making decisions based on the reset cause register, and
// resetting the bits in that register) are left solely in the hands of the
// application.
//
//*****************************************************************************
void
ResetISR(void)
{
//
// Jump to the CCS C initialization routine. This will enable the
// floating-point unit as well, so that does not need to be done here.
//
__asm(" .global _c_int00\n"
" b.w _c_int00");
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a NMI. This
// simply enters an infinite loop, preserving the system state for examination
// by a debugger.
//
//*****************************************************************************
static void
NmiSR(void)
{
//
// Enter an infinite loop.
//
while(1)
{
}
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a fault
// interrupt. This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
FaultISR(void)
{
//
// Enter an infinite loop.
//
while(1)
{
}
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives an unexpected
// interrupt. This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
IntDefaultHandler(void)
{
//
// Go into an infinite loop.
//
while(1)
{
}
}