m68k/fpsp040/stwotox.S

2 |	stwotox.sa 3.1 12/10/90
6 |	stentox  --- 10**X
7 |	stentoxd --- 10**X for denormalized X
31 |		 N = 64(M + M') + j,  j = 0,1,2,...,63.
34 |		2**X = 2**(M') * 2**(M) * 2**(j/64) * exp(r).
38 |	1. If |X| > 16480*log_10(2) (base 10 log of 2), go to ExpBig.
42 |	3. Set y := X*log_2(10)*64 (base 2 log of 10). Set
44 |		 N = 64(M + M') + j,  j = 0,1,2,...,63.
49 |		and L10 is the natural log of 10. Then
50 |		10**X = 2**(M') * 2**(M) * 2**(j/64) * exp(r).
57 |		Fact1 := 2**(M) * Fact1
58 |		Fact2 := 2**(M) * Fact2
59 |		Thus Fact1 + Fact2 = 2**(M) * 2**(j/64).
64 |	4. Let AdjFact := 2**(M'). Return
243 	asrl		#1,%d0		| ...D0 IS M
244 	subl		%d0,%d2		| ...d2 IS M', N = 64(M+M') + J
246 	movew		%d2,ADJFACT(%a6)	| ...ADJFACT IS 2^(M')
249 |--D0 IS M WHERE N = 64(M+M') + J. NOTE THAT |M| <= 16140 BY DESIGN.
250 |--ADJFACT = 2^(M').
301 |--ENTRY POINT FOR 10**(X) FOR DENORMALIZED ARGUMENT
312 |--ENTRY POINT FOR 10**(X), HERE X IS FINITE, NON-ZERO, AND NOT NAN'S
330 |--USUAL CASE, 2^(-70) <= |X| <= 16480 LOG 2 / LOG 10
346 	asrl		#1,%d0		| ...D0 IS M
347 	subl		%d0,%d2		| ...d2 IS M', N = 64(M+M') + J
349 	movew		%d2,ADJFACT(%a6)	| ...ADJFACT IS 2^(M')
353 |--D0 IS M WHERE N = 64(M+M') + J. NOTE THAT |M| <= 16140 BY DESIGN.
354 |--ADJFACT = 2^(M').
383 |--ADJFACT CONTAINS 2**(M'), FACT1 + FACT2 = 2**(M) * 2**(J/64).
385 |--	2**(M'+M) * 2**(J/64) * EXP(R)
412 |--EXP(X) = 2^M*2^(J/64) + 2^M*2^(J/64)*(EXP(R)-1)  -  (1 OR 0)