title: STM32F4xx调用arm_math.h库date: 2020-07-17 14:57:12tags:categories: STM32学习记录为什么要用到这个库这段时间在调
2021-12-13 07:45
第23章 DSP辅助运算-math_help中函数的使用本期教程主要讲解math_help文件中函数的使用，这个文件也是ARM官方提供的，这些函数相对都比较容易，同时使用频率也很高。希望初学的同学
2021-08-17 07:43
第23章 DSP辅助运算-math_help中函数的使用本期教程主要讲解math_help文件中函数的使用，这个文件也是ARM官方提供的，这些函数相对都比较容易，同时使用频率也很高。希望初学的同学
2021-08-17 07:07
在单周期内完成，而Cortex-M3需要多个指令和多个周期才能完成同样的功能。本实验通过调用MATH库进行测试。三、资料下载（实验源码+详细文档操作说明）1、源代码2、实验指导书3、STM32CubeMx详细操作说明4、原理图`
2020-04-14 22:47
DEMO-V3/CM3/core_cm3.hSTM32奋斗板-CAN通信DEMO-V3/CM3/stm32f10x.hSTM32奋斗板-CAN通信DEMO-V3/CM3/system_stm32f10x....
2021-08-19 06:45
转dsp系列教程本期教程主要讲解math_help文件中函数的使用，这个文件也是ARM官方提供的，这些函数相对都比较容易，同时使用频率也很高。希望初学的同学学习并掌握。 22.1 函数讲解 22.3
2016-09-26 09:57
1.文件目录结构CMSIS----core_cm3.c\hstm32f10x.h system_stm32f10x.c\h 启动文件OBJ----编译生成文件project—keil工程
2021-08-24 06:30
math.h中。解决办法：在Ubuntu的gcc编译环境下，直接使用lm参数即可，例如gcc -o Gen Gen.c -lm在Eclipse的集成开发环境中，可以在设置中添加包含libm库来实现，具体如下所示：
2020-02-23 20:10
core_cm3.hsystem_stm32f10x.c 设置系统以及总线时钟system_stm32f10x.hstm32f10x_it.c 用于编写中断服...
2021-08-20 07:53
hypot ( )/* -- C语言库函数源代码 - */ /* hypot函数对于给定的直角三角形的两个直角边， 求其斜边的长度。*///一般的常规算法：double my_hypot01(double x, double y){ double hypotenuse; x = fabs(x); y = fabs(y); if (x < y) { double temp = x; x = y; y = temp; } if (x == 0.) return 0.; else { hypotenuse = y/x; return x*sqrt(1.+hypotenuse*hypotenuse); }}#define __SQRT_DBL_MAX 1.3e+154#define __SQRT_DBL_MIN 2.3e-162double my_hypot02(double x, double y){ double ratio; double r, t, s, p, q; x = fabs(x), y = fabs(y); if (x < y) { double temp = x; x = y; y = temp; }//保持x 是两个直角边中较长的边，y是较短的边。 if (y == 0.) return x; /* 主要考虑的是当x很大而y很小，那么它们的平方和将会造成 丢失小数的现象。首先要判断y是否是太小，x是不是太大。 如果出现这种情况则用，第一个公式来处理。其他的则用 这样可以让求出的斜边更加精确一些。 */ if ((ratio = y / x) > __SQRT_DBL_MIN && x < __SQRT_DBL_MAX) return x * sqrt(1. + ratio*ratio); else {//使用3次迭代是增加精确度。 r = ratio*ratio, p = x, q = y; do {t = 4.+ r;if (t == 4.)break;s = r / t;p += 2. * s * p;q *= s;r = (q / p) * (q / p); } while (1); return p; }}struct complex{ double x; double y;}double cabs(struct complex x){ return hypot(z.x,z.y);}//hypot 函数的封装（这里不再举调用的例子了。） # define DBL_MAX 1.79769313486231e+308# define DBL_MIN 2.22507385850721e-308int main(void){ printf("hypot(3, 4)=%25.17e\n",hypot(3., 4.)); printf("hypot(3*10^150,4*10^150)=%25.17g\n",hypot(3.e+150, 4.e+150)); printf("hypot(3*10^306,4*10^306)=%25.17g\n",hypot(3.e+306, 4.e+306)); printf("hypot(3*10^-320,4*10^-320)=%25.17g\n",hypot(3.e-320, 4.e-320)); printf("hypot(0.7*DBL_MAX,0.7*DBL_MAX) =%25.17g\n",hypot(0.7*DBL_MAX,0.7*DBL_MAX)); printf("hypot(DBL_MAX, 1.0) =%25.17g\n",hypot(DBL_MAX, 1.0)); printf("hypot(1.0, DBL_MAX) =%25.17g\n",hypot(1.0, DBL_MAX)); printf("hypot(0.0, DBL_MAX) =%25.17g\n",hypot(0.0, DBL_MAX)); printf("\n************************************************************\n"); printf("hypot(3, 4)=%25.17e\n",my_hypot01(3., 4.)); printf("hypot(3*10^150,4*10^150)=%25.17g\n",my_hypot01(3.e+150, 4.e+150)); printf("hypot(3*10^306,4*10^306)=%25.17g\n",my_hypot01(3.e+306, 4.e+306)); printf("hypot(3*10^-320,4*10^-320)=%25.17g\n",my_hypot01(3.e-320, 4.e-320)); printf("hypot(0.7*DBL_MAX,0.7*DBL_MAX) =%25.17g\n",my_hypot01(0.7*DBL_MAX,0.7*DBL_MAX)); printf("hypot(DBL_MAX, 1.0) =%25.17g\n",my_hypot01(DBL_MAX, 1.0)); printf("hypot(1.0, DBL_MAX) =%25.17g\n",my_hypot01(1.0, DBL_MAX)); printf("hypot(0.0, DBL_MAX) =%25.17g\n",my_hypot01(0.0, DBL_MAX));printf("\n************************************************************\n"); printf("hypot(3, 4)=%25.17e\n",my_hypot02(3., 4.)); printf("hypot(3*10^150,4*10^150)=%25.17g\n",my_hypot02(3.e+150, 4.e+150)); printf("hypot(3*10^306,4*10^306)=%25.17g\n",my_hypot02(3.e+306, 4.e+306)); printf("hypot(3*10^-320,4*10^-320)=%25.17g\n",my_hypot02(3.e-320, 4.e-320)); printf("hypot(0.7*DBL_MAX,0.7*DBL_MAX) =%25.17g\n",my_hypot02(0.7*DBL_MAX,0.7*DBL_MAX)); printf("hypot(DBL_MAX, 1.0) =%25.17g\n",my_hypot02(DBL_MAX, 1.0)); printf("hypot(1.0, DBL_MAX) =%25.17g\n",my_hypot02(1.0, DBL_MAX)); printf("hypot(0.0, DBL_MAX) =%25.17g\n",my_hypot02(0.0, DBL_MAX)); return 0;}modf ( )/* -- C语言库函数源代码 - */ /* 将浮点数x分解成整数部分和小数部分。 返回小数部分，将整数部分存入* iptr所指内存中。*/double my_modf01(double x, double *iptr) { double ret = fmod(x,1.0); *iptr = x - ret; return ret;}//这个函数算法比较简单，也容易让人理解。//下面的这个函数理解起来就有点困难了。typedef struct { unsigned int mantissal:32; unsigned int mantissah:20; unsigned int exponent:11; unsigned int sign:1;}double_t;//这个结构体在IEEE.h定义。double my_modf02(double x, double *y){ double_t * z = (double_t *)&x; double_t * iptr = (double_t *)y; int j0; unsigned int i; j0 = z->exponent - 0x3ff;/* exponent of x */ if(j0mantissah == 0 && z->mantissal == 0 ) {*y = x;return 0.0;}i = (0x000fffff)>>j0;iptr->sign = z->sign;iptr->exponent = z->exponent;iptr->mantissah = z->mantissah&(~i);iptr->mantissal = 0;if ( x == *y ) {x = 0.0;z->sign = iptr->sign;return x;} return x - *y; } } else if (j0>51) {/* no fraction part */ *y = x; if ( isnan(x) || isinf(x) )return x; x = 0.0; z->sign = iptr->sign; return x; } else { /* fraction part in low x */ i = ((unsigned)(0xffffffff))>>(j0-20); iptr->sign = z->sign; iptr->exponent = z->exponent; iptr->mantissah = z->mantissah; iptr->mantissal = z->mantissal&(~i); if ( x == *y ) {x = 0.0;z->sign = iptr->sign;return x; } return x - *y; }}//下面是两个要用到的函数int isnan(double d){ union { unsigned long long l; double d; } u; u.d=d; return (u.l==0x7FF8000000000000ll || u.l==0x7FF0000000000000ll || u.l==0xfff8000000000000ll);}int isinf(double d) { union { unsigned long long l; double d; } u; u.d=d; return (u.l==0x7FF0000000000000ll?1:u.l==0xFFF0000000000000ll?-1:0);}int main(){ double x,y; x = 12345678901.1234567; printf("%f = (%f) + (%f) \n",x,y,modf(x,&y)); printf("%f = (%f) + (%f) \n",x,y,my_modf01(x,&y)); printf("%f = (%f) + (%f) \n",x,y,my_modf02(x,&y)); printf("\n******************************************\n"); printf("%f = (%f) + (%f) \n",-x,y,modf(-x,&y)); printf("%f = (%f) + (%f) \n",-x,y,my_modf01(-x,&y)); printf("%f = (%f) + (%f) \n",-x,y,my_modf02(-x,&y)); return 0;}fmod ( )/* -- C语言库函数源代码 - */ /* 计算x/y的余数。返回x-n*y，符号同y。 n=[x/y](向离开零的方向取整)*/double my_fmod01(double x, double y){ register double ret; __asm__( "1:fprem\n\t" "fstsw %%ax\n\t" "sahf\n\t" "jp1b" : "=t" (ret) : "0" (x), "u" (y) : "ax", "cc" ); return ret;}double my_fmod02(double x, double y){ double temp, ret; if (y == 0.0) return 0.0; temp = floor(x/y); ret = x - temp * y; if ((x < 0.0) != (y < 0.0)) ret = ret - y; return ret;}int main(){ double x,y; x = 80.8,y = 3.0; printf("fmod(%f,%f) = %f\n",x,y,fmod(x,y)); printf("my_fmod01(%f,%f) = %f\n",x,y,my_fmod01(x,y)); printf("my_fmod02(%f,%f) = %f\n",x,y,my_fmod01(x,y)); printf("\n******************************************\n"); x = -55.968,y = 8.8; printf("fmod(%f,%f) = %f\n",x,y,fmod(x,y)); printf("my_fmod01(%f,%f) = %f\n",x,y,my_fmod01(x,y)); printf("my_fmod02(%f,%f) = %f\n",x,y,my_fmod01(x,y)); return 0;} ldexp ( )/* -- C语言库函数源代码 - */ /* 装载浮点数，v是尾数，e为指数。 如：x=ldexp(1.0,6);则表示要转载的浮点数是1.0*2^6*/double my_ldexp01(double v, int e){ double two = 2.0; if (e < 0) { e = -e; /*这句话和后面的if语句是用来对两位溢出码的机器*/ if (e < 0) return 0.0; while (e > 0) {if (e & 1) v /= two;two *= two; e >>= 1; } } else if (e > 0) { while (e > 0) {if (e & 1) v *= two;two *= two;e >>= 1; } } return v;}double my_ldexp02(double v, int e){ double temp1, texp, temp2; texp = e; __asm__( "fscale " : "=u" (temp2), "=t" (temp1) : "0" (texp), "1" (v) ); return (temp1);}main(){ float x,y; y = 1.0; x=my_ldexp01(y,6);// 1.0*2^6 printf("2^6=%.2f\n",x); x=my_ldexp01(-y,6);// 1.0*2^6 printf("2^6=%.2f\n",x); x=my_ldexp02(y,6);// 1.0*2^6 printf("2^6=%.2f\n",x); x=my_ldexp02(-y,6);// 1.0*2^6 printf("2^6=%.2f\n",x); return 0;} frexp ( )/* -- C语言库函数源代码 - */ /* 把浮点数x分解成尾数和指数。x=m*2^exptr，m为规格化小数。 返回尾数m，并将指数存入exptr中。*/double my_frexp01(double x, int *exptr){ union { double d; unsigned char c[8]; } u; u.d = x; //得到移码，并减去1022得到指数值。 *exptr = (int)(((u.c[7] & 0x7f) > 4)) - 1022; //把指数部分置为0x03FE u.c[7] &= 0x80; u.c[7] |= 0x3f; u.c[6] &= 0x0f; u.c[6] |= 0xe0; return u.d;}double my_frexp02(double x, int *eptr){ union { double v; struct {unsigned mantissa2 : 32;unsigned mantissa1 : 20;unsigned exponent : 11;unsigned sign :1; } s; } u; if (x) { u.v = x; //得到移码，并减去1022得到指数值。 *eptr = u.s.exponent - 1022; //把指数部分置为0x03FE u.s.exponent = 1022; return(u.v); } else { *eptr = 0; return((double)0); }}main(){ float x,y; int exp; y = 64.0; x = my_frexp01(y,&exp); printf("%f=%.2f*2^%d\n",y,x,exp); x = my_frexp01(-y,&exp); printf("%f=%.2f*2^%d\n",y,x,exp); printf("\n************************\n"); x = my_frexp02(y,&exp); printf("%f=%.2f*2^%d\n",y,x,exp); x = my_frexp02(-y,&exp); printf("%f=%.2f*2^%d\n",y,x,exp); return 0;} tanh ( )/* -- C语言库函数源代码 - */ double my_tanh(double x){ double ret,temp; if (x > 50) return 1; else if (x < -50) return -1; else { ret = exp(x); temp = 1.0 / ret; return ( (ret - temp) / (ret + temp)); }}//计算x的双曲正切值。int main(){ double a = 0.5; printf("tanh(%f)= %f\n",a,tanh(a)); printf("my_tanh(%f) = %f\n",a,my_tanh(a)); a = -0.5; printf("tanh(%f)= %f\n",a,tanh(a)); printf("my_tanh(%f) = %f\n",a,my_tanh(a)); return 0;}sinh ( )/* -- C语言库函数源代码 - */ double my_sinh(double x){ double ret; if(x >= 0.0) { ret = exp(x); return (ret - 1.0/ret) / 2.0; } else { ret = exp(-x); return (1.0/ret - ret) / 2.0; }}//计算x的双曲正弦值。int main(){ double a = 0.5; printf("sinh(%f)= %f\n",a,sinh(a)); printf("my_sinh(%f) = %f\n",a,my_sinh(a)); a = -0.5; printf("sinh(%f)= %f\n",a,sinh(a)); printf("my_sinh(%f) = %f\n",a,my_sinh(a)); return 0;}cosh ( )/* -- C语言库函数源代码 - */ double my_cosh(double x){ double ret; ret = exp(fabs(x)); return (ret + 1.0/ret) / 2.0;}//计算x的双曲余弦值。int main(){ double a = 0.5; printf("cosh(%f)= %f\n",a,cosh(a)); printf("my_cosh(%f) = %f\n",a,my_cosh(a)); a = -0.5; printf("cosh(%f)= %f\n",a,cosh(a)); printf("my_cosh(%f) = %f\n",a,my_cosh(a)); return 0;}acos( )/* -- C语言库函数源代码 - */ double atan2 (double x, double y){ register double ret; __asm__( "fpatan\n\t" "fld %%st(0)" : "=t" (ret) : "0" (y), "u" (x) ); return ret;}//求x / y的反正切值。double my_acos(double x){return atan2 (sqrt (1.0 - x * x), x);}//求x的反余弦值。int main(){ double a = 0.5; printf("acos(%f)= %f\n",a,acos(a)); printf("my_acos(%f) = %f\n",a,my_acos(a)); a = -0.5; printf("acos(%f)= %f\n",a,acos(a)); printf("my_acos(%f) = %f\n",a,my_acos(a)); return 0;}
2011-03-26 10:24
