user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/tests/ansi/fenv.c

@@ -0,0 +1,100 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <fenv.h>
+#include <float.h>
+#include <math.h>
+
+/* qemu-m68k < version 9.1.0 cannot run the test due to missing FPU logic. */
+#ifdef __m68k__
+int main() {
+	return 0;
+}
+#else
+#define NO_OPTIMIZE(x) asm volatile("" :: "r,m" (x) : "memory")
+
+static void div_by_zero() {
+	volatile float zero = 0.0f;
+	NO_OPTIMIZE(69.0f / zero);
+}
+
+static bool float_cmp(float a, float b) {
+	return a == b || fabs(a - b) < (fabs(a) + fabs(b)) * FLT_EPSILON;
+}
+
+static void test_rounding(float expectation1, float expectation2) {
+	float x;
+	volatile float f = 1.968750f;
+	volatile float m = 0x1.0p23f;
+
+	NO_OPTIMIZE(x = f + m);
+	assert(float_cmp(expectation1, x));
+	NO_OPTIMIZE(x = x - m);
+	assert(x == expectation2);
+}
+
+void test0() {
+	// test whether the divide-by-zero exception is raised
+	feclearexcept(FE_ALL_EXCEPT);
+	assert(fetestexcept(FE_ALL_EXCEPT) == 0);
+
+	div_by_zero();
+	int raised = fetestexcept(FE_DIVBYZERO);
+	assert((raised & FE_DIVBYZERO));
+}
+
+void test1() {
+	// test various rounding modes
+	feclearexcept(FE_DIVBYZERO);
+	assert(fetestexcept(FE_ALL_EXCEPT) == 0);
+
+	fesetround(FE_UPWARD);
+	assert(fegetround() == FE_UPWARD);
+	test_rounding(8388610.0f, 2.0f);
+
+	fesetround(FE_DOWNWARD);
+	assert(fegetround() == FE_DOWNWARD);
+	test_rounding(8388609.0f, 1.0f);
+
+	fesetround(FE_TONEAREST);
+	assert(fegetround() == FE_TONEAREST);
+	test_rounding(8388610.0f, 2.0f);
+
+	fesetround(FE_TOWARDZERO);
+	assert(fegetround() == FE_TOWARDZERO);
+	test_rounding(8388609.0f, 1.0f);
+}
+
+void test2() {
+	// test feraiseexcept
+	feclearexcept(FE_ALL_EXCEPT);
+	assert(fetestexcept(FE_ALL_EXCEPT) == 0);
+	assert(feraiseexcept(FE_DIVBYZERO | FE_OVERFLOW) == 0);
+	assert(fetestexcept(FE_ALL_EXCEPT) == (FE_DIVBYZERO | FE_OVERFLOW));
+}
+
+void test3() {
+	// test fe{get,set}env
+	feclearexcept(FE_ALL_EXCEPT);
+	assert(fetestexcept(FE_ALL_EXCEPT) == 0);
+	assert(feraiseexcept(FE_OVERFLOW) == 0);
+
+	fenv_t state;
+	assert(fegetenv(&state) == 0);
+	assert(fetestexcept(FE_ALL_EXCEPT) == FE_OVERFLOW);
+
+	div_by_zero();
+	assert(fetestexcept(FE_ALL_EXCEPT) == (FE_DIVBYZERO | FE_OVERFLOW));
+
+	assert(fesetenv(&state) == 0);
+	assert(fetestexcept(FE_ALL_EXCEPT) == FE_OVERFLOW);
+}
+
+int main() {
+	test0();
+	test1();
+	test2();
+	test3();
+
+	return 0;
+}
+#endif