| Kai Tietz | 518dd33 | 2007-08-10 09:54:15 +0000 | [diff] [blame^] | 1 | /*
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| 2 | * Written by J.T. Conklin <jtc@netbsd.org>.
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| 3 | * Public domain.
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| 4 | *
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| 5 | * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.
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| 6 | * Removed header file dependency for use in libmingwex.a by
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| 7 | * Danny Smith <dannysmith@users.sourceforge.net>
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| 8 | */
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| 9 |
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| 10 | .file "log1pl.S"
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| 11 | .text
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| 12 | .align 4
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| 13 | /* The fyl2xp1 can only be used for values in
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| 14 | -1 + sqrt(2) / 2 <= x <= 1 - sqrt(2) / 2
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| 15 | 0.29 is a safe value.
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| 16 | */
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| 17 | limit: .tfloat 0.29
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| 18 | /* Please note: we use a double value here. Since 1.0 has
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| 19 | an exact representation this does not effect the accuracy
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| 20 | but it helps to optimize the code. */
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| 21 | one: .double 1.0
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| 22 |
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| 23 | /*
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| 24 | * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29,
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| 25 | * otherwise fyl2x with the needed extra computation.
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| 26 | */
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| 27 | .globl _log1pl;
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| 28 | .def _log1pl; .scl 2; .type 32; .endef
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| 29 | _log1pl:
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| 30 | fldln2
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| 31 | fldt 4(%esp)
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| 32 | fxam
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| 33 | fnstsw
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| 34 | fld %st
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| 35 | sahf
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| 36 | jc 3f // in case x is NaN or ±Inf
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| 37 | 4:
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| 38 | fabs
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| 39 | fldt limit
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| 40 | fcompp
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| 41 | fnstsw
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| 42 | sahf
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| 43 | jnc 2f
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| 44 | faddl one
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| 45 | fyl2x
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| 46 | ret
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| 47 |
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| 48 | 2: fyl2xp1
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| 49 | ret
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| 50 |
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| 51 | 3: jp 4b // in case x is ±Inf
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| 52 | fstp %st(1)
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| 53 | fstp %st(1)
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| 54 | ret
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