软件仿真与程序在开发板跑，指令运行周期相差较大，其原因是什么？是工程配置的问题还是其他原因？需要哪些优化？
测试平台C6678LE开发板，程序单核运行
具体测试结果如下：
软件仿真结果 ，simulation
FFT点数 运行时间 运行指令周期数数
N = 8 radix = 2 TIME: 0.171000 us CYCLES:171
N = 16 radix = 4 TIME: 0.199000 us CYCLES:199
N = 32 radix = 2 TIME: 0.334000 us CYCLES:334
N = 64 radix = 4 TIME: 0.468000 us CYCLES:468
N = 128 radix = 2 TIME: 0.937000 us CYCLES:937
N = 256 radix = 4 TIME: 1.607000 us CYCLES:1607
N = 512 radix = 2 TIME: 3.676000 us CYCLES:3676
N = 1024 radix = 4 TIME: 7.018000 us CYCLES:7018
N = 2048 radix = 2 TIME: 16.543000 us CYCLES:16543
N = 4096 radix = 4 TIME: 32.685000 us CYCLES:32685
N = 8192 radix = 2 TIME: 76.258000 us CYCLES:76258
N = 16384 radix = 4 TIME: 152.048000 us CYCLES:152048
N = 32768 radix = 2 TIME: 348.709000 us CYCLES:348709
N = 65536 radix = 4 TIME: 696.883000 us CYCLES:696883
开发板运行结果：
数据存放在DDR3中 定义DDR3段的时候采用.DDR3:load>>DDR3 采用load指令
FFT点数 运行时间 运行指令周期数数
N = 8 radix = 2 TIME: 0.215000 us CYCLES:215
N = 16 radix = 4 TIME: 0.243000 us CYCLES:243
N = 32 radix = 2 TIME: 0.401000 us CYCLES:401
N = 64 radix = 4 TIME: 0.617000 us CYCLES:617
N = 128 radix = 2 TIME: 1.207000 us CYCLES:1207
N = 256 radix = 4 TIME: 2.168000 us CYCLES:2168
N = 512 radix = 2 TIME: 4.793000 us CYCLES:4793
N = 1024 radix = 4 TIME: 9.256000 us CYCLES:9256
N = 2048 radix = 2 TIME: 21.034000 us CYCLES:21034
N = 4096 radix = 4 TIME: 51.208000 us CYCLES:51208
N = 8192 radix = 2 TIME: 266.581000 us CYCLES:266581
N = 16384 radix = 4 TIME: 539.959000 us CYCLES:539959
N = 32768 radix = 2 TIME: 1512.223000 us CYCLES:1512223
N = 65536 radix = 4 TIME: 3096.024000 us CYCLES:3096024
