Computes both the sine and the cosine of the source operand in register ST(0), stores the sine in ST(0), and pushes the cosine onto the top of the FPU register stack. (This instruction is faster than executing the FSIN and FCOS instructions in succession.) The source operand must be given in radians and must be within the range -2^63 to +2^63. The following table shows the results obtained when taking the sine and cosine of various classes of numbers, assuming that underflow does not occur.

If the source operand is outside the acceptable range, the C2 flag in the FPU status word is set, and the value in register ST(0) remains unchanged. The instruction does not raise an exception when the source operand is out of range. It is up to the program to check the C2 flag for out-ofrange conditions. Source values outside the range -2^63 to +2^63 can be reduced to the range of the instruction by subtracting an appropriate integer multiple of 2Pi or by using the FPREM instruction with a divisor of 2Pi. See the section titled "Pi" in Chapter 8 of the IA-32 Intel Architecture Software Developer's Manual, Volume 1, for a discussion of the proper value to use for pi in performing such reductions.

if(ST(0) < (1 << 63)) {
	C2 = 0;
	Temporary = Cosine(ST(0));
	ST(0) = Sine(ST(0));
	Top = Top - 1;
	ST(0) = Temporary;
}
else C2 = 1; //source operand out of range

C1 Set to 0 if stack underflow occurred; set to 1 of stack overflow occurs. Set if result was rounded up; cleared otherwise. C2 Set to 1 if outside range (-2^63 < source operand < +2^63); otherwise, set to 0. C0, C3 Undefined.