File content as of revision 445:9a3ffe6cfa19:

/* mbed Microcontroller Library - cmsis_nvic for STM32F4
 * Copyright (c) 2009-2011 ARM Limited. All rights reserved.
 *
 * CMSIS-style functionality to support dynamic vectors
 */ 
#include "cmsis_nvic.h"

#define NVIC_RAM_VECTOR_ADDRESS   (0x20000000)  // Location of vectors in RAM

static unsigned char vtor_relocated;

void NVIC_SetVector(IRQn_Type IRQn, uint32_t vector) {
    uint32_t *vectors = (uint32_t*)SCB->VTOR;
    uint32_t i;

    // Copy and switch to dynamic vectors if the first time called
    if (!vtor_relocated) {
        uint32_t *old_vectors = vectors;
        vectors = (uint32_t*)NVIC_RAM_VECTOR_ADDRESS;
        for (i=0; i<NVIC_NUM_VECTORS; i++) {
            vectors[i] = old_vectors[i];
        }
        SCB->VTOR = (uint32_t)NVIC_RAM_VECTOR_ADDRESS;
        vtor_relocated = 1;
    }
    vectors[IRQn + 16] = vector;
}

uint32_t NVIC_GetVector(IRQn_Type IRQn) {
    uint32_t *vectors = (uint32_t*)SCB->VTOR;
    return vectors[IRQn + 16];
}