A.5.100 FSIN, FSINCOS: Sine and Cosine
FSIN ; D9 FE [386,FPU]
FSINCOS ; D9 FB [386,FPU]
FSIN calculates the sine of ST0 (in radians) and stores the result in
ST0. FSINCOS does the same, but then pushes the cosine of the same value
on the register stack, so that the sine ends up in ST1 and the cosine in
ST0. FSINCOS is faster than executing FSIN and FCOS (see section A.5.74)
in succession.
The absolute value of ST0 must be less than 2**63.