FSINCOS: Fix register address which writes cosine value back.

Modify fpu_sin()'s logic to avoid GCC's warning that has been
pointed out in the previous commit.
For fpu_cos() there is no such problem, but sync with fpu_sin().

avoid a GCC warning with this:

+#if defined(__GNUC__) && (__GNUC__ >= 5) && defined(__OPTIMIZE__)
+ x.fp_sign = 0;
+#endif

(ridiculous, but seems better than disabling the warning entirely.)

branches: 1.15.12;
Support sin(-0.0).

Clean up some useless codes.

Support tan(-0.0).

Implement inverse trigonometric functions (i.e., FACOS, FASIN, FATAN
instructions).
o arccos is calculated using arcsin.
o arcsin is calculated using arctan.
o arctan is calculated by the CORDIC.

Introduce the CORDIC algorithm.
o sine and cosine (e.g., FSIN, FCOS and FSINCOS instructions) is now
calculated in the CORDIC instead of Taylor expansion.
o tangent (FTAN) is not touched from a viewpoint of the code size.
o The CORDIC is applicable for hyperbolic functions (e.g., FSINH,
FCOSH, FTANH instructions), but I didn't use it because its working
range is poor.
o The CORDIC is also usable for inverse trigonometric functions,
I will commit it at next phase.
o The code size becomes a bit big. I cannot evaluate speed on m68k
for some reasons, but in test on i386 the CORDIC is approximately
100 times faster in sin/cos.

Improve how to use cmp/sub.

Introduce FPU_CONST_* constants to avoid a magic number.

u_int -> uint32_t

Remove about updating fpsr. It was introduced by me but obviously
duplicated with fpu_emul_arith().

branches: 1.6.2; 1.6.12;
Add hyperboric and trigonometric functions to m68k FPE, written by isaki@.
With these emulations (~4KB text) xeyes on XM6i works better.
Discussed with isaki@ at OSC 2011 Hiroshima.

fix indent. no functional changes.

Change about 4500 of the K&R function definitions to ANSI ones.
There are still about 1600 left, but they have ',' or /* ... */
in the actual variable definitions - which my awk script doesn't handle.
There are also many that need () -> (void).
(The script does handle misordered arguments.)

branches: 1.3.78; 1.3.86; 1.3.92;
merge ktrace-lwp.

__KERNEL_RCSID()

branches: 1.1.64;
Still incomplete, but much more complete FPE from Ken Nakata
<kenn@remus.rutgers.edu>. This emulator does not yet emulate
the following functions:
FSINH, FETOXM1, FTANH, FATAN, FASIN, FATANH, FSIN, FTAN,
FETOX, FTWOTOX, FTENTOX, FCOSH, FACOS, FCOS, FSINCOS
It is sufficient, however, to allow programs like df, w, and newfs,
to run to completion with correct results.
Portions of this code were based on the sparc fpe and on initial
work by gwr.

Modify fpu_sin()'s logic to avoid GCC's warning that has been
pointed out in the previous commit.
For fpu_cos() there is no such problem, but sync with fpu_sin().

avoid a GCC warning with this:

+#if defined(__GNUC__) && (__GNUC__ >= 5) && defined(__OPTIMIZE__)
+ x.fp_sign = 0;
+#endif

(ridiculous, but seems better than disabling the warning entirely.)

branches: 1.15.12;
Support sin(-0.0).

Clean up some useless codes.

Support tan(-0.0).

Implement inverse trigonometric functions (i.e., FACOS, FASIN, FATAN
instructions).
o arccos is calculated using arcsin.
o arcsin is calculated using arctan.
o arctan is calculated by the CORDIC.

Introduce the CORDIC algorithm.
o sine and cosine (e.g., FSIN, FCOS and FSINCOS instructions) is now
calculated in the CORDIC instead of Taylor expansion.
o tangent (FTAN) is not touched from a viewpoint of the code size.
o The CORDIC is applicable for hyperbolic functions (e.g., FSINH,
FCOSH, FTANH instructions), but I didn't use it because its working
range is poor.
o The CORDIC is also usable for inverse trigonometric functions,
I will commit it at next phase.
o The code size becomes a bit big. I cannot evaluate speed on m68k
for some reasons, but in test on i386 the CORDIC is approximately
100 times faster in sin/cos.

Improve how to use cmp/sub.

Introduce FPU_CONST_* constants to avoid a magic number.

u_int -> uint32_t

Remove about updating fpsr. It was introduced by me but obviously
duplicated with fpu_emul_arith().

branches: 1.6.2; 1.6.12;
Add hyperboric and trigonometric functions to m68k FPE, written by isaki@.
With these emulations (~4KB text) xeyes on XM6i works better.
Discussed with isaki@ at OSC 2011 Hiroshima.

fix indent. no functional changes.

Change about 4500 of the K&R function definitions to ANSI ones.
There are still about 1600 left, but they have ',' or /* ... */
in the actual variable definitions - which my awk script doesn't handle.
There are also many that need () -> (void).
(The script does handle misordered arguments.)

branches: 1.3.78; 1.3.86; 1.3.92;
merge ktrace-lwp.

__KERNEL_RCSID()

branches: 1.1.64;
Still incomplete, but much more complete FPE from Ken Nakata
<kenn@remus.rutgers.edu>. This emulator does not yet emulate
the following functions:
FSINH, FETOXM1, FTANH, FATAN, FASIN, FATANH, FSIN, FTAN,
FETOX, FTWOTOX, FTENTOX, FCOSH, FACOS, FCOS, FSINCOS
It is sufficient, however, to allow programs like df, w, and newfs,
to run to completion with correct results.
Portions of this code were based on the sparc fpe and on initial
work by gwr.