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-rw-r--r--arch/m68k/math-emu/fp_log.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/arch/m68k/math-emu/fp_log.c b/arch/m68k/math-emu/fp_log.c
new file mode 100644
index 00000000000..87b4f015856
--- /dev/null
+++ b/arch/m68k/math-emu/fp_log.c
@@ -0,0 +1,223 @@
+/*
+
+ fp_trig.c: floating-point math routines for the Linux-m68k
+ floating point emulator.
+
+ Copyright (c) 1998-1999 David Huggins-Daines / Roman Zippel.
+
+ I hereby give permission, free of charge, to copy, modify, and
+ redistribute this software, in source or binary form, provided that
+ the above copyright notice and the following disclaimer are included
+ in all such copies.
+
+ THIS SOFTWARE IS PROVIDED "AS IS", WITH ABSOLUTELY NO WARRANTY, REAL
+ OR IMPLIED.
+
+*/
+
+#include "fp_emu.h"
+
+static const struct fp_ext fp_one =
+{
+ .exp = 0x3fff,
+};
+
+extern struct fp_ext *fp_fadd(struct fp_ext *dest, const struct fp_ext *src);
+extern struct fp_ext *fp_fdiv(struct fp_ext *dest, const struct fp_ext *src);
+extern struct fp_ext *fp_fmul(struct fp_ext *dest, const struct fp_ext *src);
+
+struct fp_ext *
+fp_fsqrt(struct fp_ext *dest, struct fp_ext *src)
+{
+ struct fp_ext tmp, src2;
+ int i, exp;
+
+ dprint(PINSTR, "fsqrt\n");
+
+ fp_monadic_check(dest, src);
+
+ if (IS_ZERO(dest))
+ return dest;
+
+ if (dest->sign) {
+ fp_set_nan(dest);
+ return dest;
+ }
+ if (IS_INF(dest))
+ return dest;
+
+ /*
+ * sqrt(m) * 2^(p) , if e = 2*p
+ * sqrt(m*2^e) =
+ * sqrt(2*m) * 2^(p) , if e = 2*p + 1
+ *
+ * So we use the last bit of the exponent to decide wether to
+ * use the m or 2*m.
+ *
+ * Since only the fractional part of the mantissa is stored and
+ * the integer part is assumed to be one, we place a 1 or 2 into
+ * the fixed point representation.
+ */
+ exp = dest->exp;
+ dest->exp = 0x3FFF;
+ if (!(exp & 1)) /* lowest bit of exponent is set */
+ dest->exp++;
+ fp_copy_ext(&src2, dest);
+
+ /*
+ * The taylor row arround a for sqrt(x) is:
+ * sqrt(x) = sqrt(a) + 1/(2*sqrt(a))*(x-a) + R
+ * With a=1 this gives:
+ * sqrt(x) = 1 + 1/2*(x-1)
+ * = 1/2*(1+x)
+ */
+ fp_fadd(dest, &fp_one);
+ dest->exp--; /* * 1/2 */
+
+ /*
+ * We now apply the newton rule to the function
+ * f(x) := x^2 - r
+ * which has a null point on x = sqrt(r).
+ *
+ * It gives:
+ * x' := x - f(x)/f'(x)
+ * = x - (x^2 -r)/(2*x)
+ * = x - (x - r/x)/2
+ * = (2*x - x + r/x)/2
+ * = (x + r/x)/2
+ */
+ for (i = 0; i < 9; i++) {
+ fp_copy_ext(&tmp, &src2);
+
+ fp_fdiv(&tmp, dest);
+ fp_fadd(dest, &tmp);
+ dest->exp--;
+ }
+
+ dest->exp += (exp - 0x3FFF) / 2;
+
+ return dest;
+}
+
+struct fp_ext *
+fp_fetoxm1(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("fetoxm1\n");
+
+ fp_monadic_check(dest, src);
+
+ if (IS_ZERO(dest))
+ return dest;
+
+ return dest;
+}
+
+struct fp_ext *
+fp_fetox(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("fetox\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_ftwotox(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("ftwotox\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_ftentox(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("ftentox\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_flogn(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("flogn\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_flognp1(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("flognp1\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_flog10(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("flog10\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_flog2(struct fp_ext *dest, struct fp_ext *src)
+{
+ uprint("flog2\n");
+
+ fp_monadic_check(dest, src);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_fgetexp(struct fp_ext *dest, struct fp_ext *src)
+{
+ dprint(PINSTR, "fgetexp\n");
+
+ fp_monadic_check(dest, src);
+
+ if (IS_INF(dest)) {
+ fp_set_nan(dest);
+ return dest;
+ }
+ if (IS_ZERO(dest))
+ return dest;
+
+ fp_conv_long2ext(dest, (int)dest->exp - 0x3FFF);
+
+ fp_normalize_ext(dest);
+
+ return dest;
+}
+
+struct fp_ext *
+fp_fgetman(struct fp_ext *dest, struct fp_ext *src)
+{
+ dprint(PINSTR, "fgetman\n");
+
+ fp_monadic_check(dest, src);
+
+ if (IS_ZERO(dest))
+ return dest;
+
+ if (IS_INF(dest))
+ return dest;
+
+ dest->exp = 0x3FFF;
+
+ return dest;
+}
+