initial version

Book-Lite/linux-0.12/kernel/math/compare.c

@@ -0,0 +1,60 @@
+/*
+ * linux/kernel/math/compare.c
+ *
+ * (C) 1991 Linus Torvalds
+ */
+
+/*
+ * temporary real comparison routines
+ */
+
+#include <linux/math_emu.h>
+
+#define clear_Cx() (I387.swd &= ~0x4500)
+
+static void normalize(temp_real * a)
+{
+	int i = a->exponent & 0x7fff;
+	int sign = a->exponent & 0x8000;
+
+	if (!(a->a || a->b)) {
+		a->exponent = 0;
+		return;
+	}
+	while (i && a->b >= 0) {
+		i--;
+		__asm__("addl %0,%0 ; adcl %1,%1"
+			:"=r" (a->a),"=r" (a->b)
+			:"0" (a->a),"1" (a->b));
+	}
+	a->exponent = i | sign;
+}
+
+void ftst(const temp_real * a)
+{
+	temp_real b;
+
+	clear_Cx();
+	b = *a;
+	normalize(&b);
+	if (b.a || b.b || b.exponent) {
+		if (b.exponent < 0)
+			set_C0();
+	} else
+		set_C3();
+}
+
+void fcom(const temp_real * src1, const temp_real * src2)
+{
+	temp_real a;
+
+	a = *src1;
+	a.exponent ^= 0x8000;
+	fadd(&a,src2,&a);
+	ftst(&a);
+}
+
+void fucom(const temp_real * src1, const temp_real * src2)
+{
+	fcom(src1,src2);
+}