Note that -1 <=W <=1, as required for the series to converge.
ii. The argument Z is formed, such that Z=2*W*W-1.
iii. The SERIES GENERATOR is used to return (SIN (PI*W/2))/W
iv. Finally a simple multiplication gives SIN X.

37B5	sin	RST	0028 FP-CALC	X

Perform step i.

		DEFB	+39,get-argt	W


Perform step ii. The subroutine from now on is common to both the SINE and COSINE functions.

37B7	C-ENT	DEFB	+31,duplicate	W, W
		DEFB	+31,duplicate	W, W, W
		DEFB	+04,multiply	W, W*W
		DEFB	+31,duplicate	W, W*W, W*W
		DEFB	+0F,addition	W, 2*W*W
		DEFB	+A1,stk-one	W, 2*W*W, 1
		DEFB	+03,subtract	W, 2*W*W-1 = Z


Perform step iii, passing to the SERIES GENERATOR the parameter '6' and the six constants required.

		DEFB	+86,series-06	W, Z
	1.	DEFB	+14,exponent+64	
		DEFB	+E6,(+00,+00,+00)	
	2.	DEFB	+5C,exponent+6C	
		DEFB	+1F,+0B,(+00,+00)	
	3.	DEFB	+A3,exponent+73
		DEFB	+8F,+38,+EE,(+00)
	4.	DEFB	+E9,exponent+79
		DEFB	+15,+63,+BB,+23
	5.	DEFB	+EE,exponent+7E
		DEFB	+92,+0D,+CD,+ED
	6.	DEFB	+F1,exponent+81
		DEFB	+23,+5D,+1B,+EA

At the end of the last loop the 'last value' is (SIN (PI*W/2))/W.

Perform step v.

		DEFB	+04,multiply	SIN (PI*W/2) = SIN X (or =
				COS X)
		DEFB	+38,end-calc	
		RET		Finished: 'last value' = SIN X.
				or ('last value' = COS X)


THE 'TAN' FUNCTION
(Offset 21: 'tan')

This subroutine handles the function TAN X. The subroutine simply returns SIN X/COS X, with arithmetic overflow if COS X = 0.

37DA	tan	RST	0028,FP-CALC	X
		DEFB	+31,duplicate	X, X
		DEFB	+1F,sin	X, SIN X
		DEFB	+01,exchange	SIN X, X
		DEFB	+20,cos	SIN X,COS X
		DEFB	+05,division	SIN X/COS X = TAN X
				Report arithmetic overflow if
				needed.
		DEFB	+38,end-calc	TAN X
		RET		Finished: 'last value' = TAN X.