11、X87 FPU编程：浮点比较与数组处理

X87 FPU编程：浮点比较与数组处理

1. 浮点比较示例：CalcSphereAreaVolume

CalcSphereAreaVolume程序用于演示如何比较两个浮点数，同时展示了几个常见的x87 FPU常量加载指令的使用。以下是该程序的C++和汇编语言源代码：

CalcSphereAreaVolume.cpp

#include "stdafx.h"

extern "C" bool CalcSphereAreaVolume_(double r, double* sa, double* v);

int _tmain(int argc, _TCHAR* argv[])
{
    double r[] = { -1.0, 0.0, 1.0, 2.0, 3.0, 5.0, 10.0, 20.0 };
    int num_r = sizeof(r) / sizeof(double);

    for (int i = 0; i < num_r; i++)
    {
        double sa = -1;
        double v = -1;
        bool rc = CalcSphereAreaVolume_(r[i], &sa, &v);

        printf("rc: %d  r: %8.2lf  sa: %10.4lf  v: %10.4lf\n", rc, r[i], sa, v);
    }

    return 0;
}

CalcSphereAreaV