对于Cortex-M0或者M3处理器类型，由于没有FPU因此无法直接进行浮点运算，
只能将浮点数进行Q规格化 (q7、 q15或Q31)处理，如开平方运算：
M0/M3只能通过迭代法 （ 标准数学函数库 ） 计算，而M4直接调用VSQRT指令完成！
写了一个fpu_test.c
- #include "fpu_test.h"
- //float32_t arm_sin_f32(float32_t x);
- //float32_t arm_cos_f32(float32_t x);
- //static __INLINE arm_status arm_sqrt_f32(float32_t in, float32_t *pOut)
- /* ----------------------------------------------------------------------
- * Test input data for Floating point sin_cos example for 32-blockSize
- * Generated by the matlab randn() function
- * ------------------------------------------------------------------- */
- const float32_t testInput_f32[MAX_BLOCKSIZE] =
- {
- -1.244916875853235400, -4.793533929171324800, 0.360705030233248850, 0.827929644170887320, -3.299532218312426900, 3.427441903227623800, 3.422401784294607700, -0.108308165334010680,
- 0.941943896490312180, 0.502609575000365850, -0.537345278736373500, 2.088817392965764500, -1.693168684143455700, 6.283185307179590700, -0.392545884746175080, 0.327893095115825040,
- 3.070147440456292300, 0.170611405884662230, -0.275275082396073010, -2.395492805446796300, 0.847311163536506600, -3.845517018083148800, 2.055818378415868300, 4.672594161978930800,
- -1.990923030266425800, 2.469305197656249500, 3.609002606064021000, -4.586736582331667500, -4.147080139136136300, 1.643756718868359500, -1.150866392366494800, 1.985805026477433800
- };
- const float32_t testRefOutput_f32 = 1.000000000;
- /* ----------------------------------------------------------------------
- * Declare Global variables
- * ------------------------------------------------------------------- */
- uint32_t blockSize = 32;
- float32_t testOutput;
- float32_t cosOutput;
- float32_t sinOutput;
- float32_t cosSquareOutput;
- float32_t sinSquareOutput;
- /* ----------------------------------------------------------------------
- * Max magnitude FFT Bin test
- * ------------------------------------------------------------------- */
- arm_status status;
- int32_t float_test(void)
- {
- float32_t diff;
- uint32_t i;
- for(i=0; i< blockSize; i++)
- {
- cosOutput = arm_cos_f32(testInput_f32[i]);
- sinOutput = arm_sin_f32(testInput_f32[i]);
- arm_mult_f32(&cosOutput, &cosOutput, &cosSquareOutput, 1);
- arm_mult_f32(&sinOutput, &sinOutput, &sinSquareOutput, 1);
- arm_add_f32(&cosSquareOutput, &sinSquareOutput, &testOutput, 1);
- /* absolute value of difference between ref and test */
- diff = fabsf(testRefOutput_f32 - testOutput);
- /* Comparison of sin_cos value with reference */
- if(diff > DELTA)
- {
- status = ARM_MATH_TEST_FAILURE;
- printf("arm math test failure!!!!rn");
- }
- else
- {
- printf("arm math test Success!!!!rn");
- }
- }
- }
然后把fpu_test.h中的定义贴出来：
- #include "STM32f4xx.h"
- #include
- #include "arm_math.h"
- #include "core_cm4.h"
-
- //ARM_MATH_CM4 //要求使用m4的数学库函数,在工程选项卡中定义
- int32_t float_test(void);
- /* ----------------------------------------------------------------------
- * Defines each of the tests performed
- * ------------------------------------------------------------------- */
- #define MAX_BLOCKSIZE 32
- #define DELTA (0.0001f)
- #define __FPU_PRESENT 1 // FPU开关
- #ifndef __ARMVFP__ //要求在生成的代码中使用FPU
- #define __ARMVFP__
- #endif
ok了，此时串口就会疯狂打印出来计算的数值。
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zan~~~  没有图~
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/6 
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