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* optimize scalbn familyRich Felker2012-03-203-7/+46
| | | | | | | | | | | | | | | | | | the fscale instruction is slow everywhere, probably because it involves a costly and unnecessary integer truncation operation that ends up being a no-op in common usages. instead, construct a floating point scale value with integer arithmetic and simply multiply by it, when possible. for float and double, this is always possible by going to the next-larger type. we use some cheap but effective saturating arithmetic tricks to make sure even very large-magnitude exponents fit. for long double, if the scaling exponent is too large to fit in the exponent of a long double value, we simply fallback to the expensive fscale method. on atom cpu, these changes speed up scalbn by over 30%. (min rdtsc timing dropped from 110 cycles to 70 cycles.)
* remquo asm: return quotient mod 8, as intended by the specRich Felker2012-03-191-17/+26
| | | | | this is a lot more efficient and also what is generally wanted. perhaps the bit shuffling could be more efficient...
* use alternate formula for acos asm to avoid loss of precisionRich Felker2012-03-191-3/+11
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* Merge remote branch 'nsz/master'Rich Felker2012-03-1994-806/+654
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| * code cleanup of named constantsnsz2012-03-1973-623/+513
| | | | | | | | | | | | | | zero, one, two, half are replaced by const literals The policy was to use the f suffix for float consts (1.0f), but don't use suffix for long double consts (these consts can be exactly represented as double).
| * fix remainder*.c: remove useless long double castnsz2012-03-192-15/+6
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| * don't try to create non-standard denormalization signalnsz2012-03-193-7/+4
| | | | | | | | | | | | | | | | Underflow exception is only raised when the result is invalid, but fmod is always exact. x87 has a denormalization exception, but that's nonstandard. And the superflous *1.0 will be optimized away by any compiler that does not honor signaling nans.
| * new modff.c code, fix nan handling in modflnsz2012-03-192-44/+26
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| * use scalbn or *2.0 instead of ldexp, fix fmalnsz2012-03-198-101/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | Some code assumed ldexp(x, 1) is faster than 2.0*x, but ldexp is a wrapper around scalbn which uses multiplications inside, so this optimization is wrong. This commit also fixes fmal which accidentally used ldexp instead of ldexpl loosing precision. There are various additional changes from the work-in-progress const cleanups.
| * fix long double const workaround in cbrtlnsz2012-03-191-5/+1
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| * don't inline __rem_pio2l so the code size is smallernsz2012-03-195-9/+1
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| * minor fix in __tanl (get sign properly)nsz2012-03-191-2/+1
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* | fix exp asmRich Felker2012-03-191-23/+22
| | | | | | | | | | | | | | | | | | | | | | | | exponents (base 2) near 16383 were broken due to (1) wrong cutoff, and (2) inability to fit the necessary range of scalings into a long double value. as a solution, we fall back to using frndint/fscale for insanely large exponents, and also have to special-case infinities here to avoid inf-inf generating nan. thankfully the costly code never runs in normal usage cases.
* | Merge remote branch 'nsz/master'Rich Felker2012-03-197-80/+3
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| * remove long double const workaroundsnsz2012-03-196-79/+2
| | | | | | | | | | | | | | | | Some long double consts were stored in two doubles as a workaround for x86_64 and i386 with the following comment: /* Long double constants are slow on these arches, and broken on i386. */ This is most likely old gcc bug related to the default x87 fpu precision setting (it's double instead of double extended on BSD).
| * fix erfl wrapper for long double==double casensz2012-03-191-1/+1
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* | bug fix: wrong opcode for writing long longRich Felker2012-03-192-2/+2
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* asm for log1pRich Felker2012-03-193-0/+45
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* asm for log2Rich Felker2012-03-193-0/+21
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* asm for remquoRich Felker2012-03-193-0/+43
| | | | | this could perhaps use some additional testing for corner cases, but it seems to be correct.
* optimize exponential asm for i386Rich Felker2012-03-192-58/+77
| | | | | | up to 30% faster exp2 by avoiding slow frndint and fscale functions. expm1 also takes a much more direct path for small arguments (the expected usage case).
* Merge remote branch 'nsz/master'Rich Felker2012-03-195-163/+208
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| * simplify scalbn*.c implementationsnsz2012-03-193-152/+65
| | | | | | | | | | The old scalbn.c was wrong and slow, the new one is just slow. (scalbn(0x1p+1023,-2097) should give 0x1p-1074, but the old code gave 0)
| * Merge branch 'master' of git://git.etalabs.net/muslnsz2012-03-199-0/+75
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| * \ Merge branch 'master' of git://git.etalabs.net/muslnsz2012-03-1921-0/+157
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| * \ \ Merge branch 'master' of git://git.etalabs.net/muslnsz2012-03-1914-1/+109
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| * \ \ \ Merge branch 'master' of git://git.etalabs.net/muslnsz2012-03-199-0/+89
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| * | | | | remove unnecessary TODO comments from fma.cnsz2012-03-191-5/+1
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| * | | | | fmal bug fix: nan input should not raise exceptionnsz2012-03-191-4/+4
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| * | | | | add fma implementation for x86nsz2012-03-191-7/+143
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | correctly rounded double precision fma using extended precision arithmetics for ld80 systems (x87)
* | | | | | fix broken modf family functionsRich Felker2012-03-193-27/+66
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* | | | | | asm for modf functionsRich Felker2012-03-193-0/+45
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* | | | | asm for floor/ceil/truncRich Felker2012-03-199-0/+75
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* | | | asm for scalbn familyRich Felker2012-03-199-0/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | unlike some implementations, these functions perform the equivalent of gcc's -ffloat-store on the result before returning. this is necessary to raise underflow/overflow/inexact exceptions, perform the correct rounding with denormals, etc.
* | | | asm for inverse trig functionsRich Felker2012-03-1912-0/+93
| |_|/ |/| | | | | | | | | | | | | | | | | unlike trig functions, these are easy to do in asm because they do not involve (arbitrary-precision) argument reduction. fpatan automatically takes care of domain issues, and in asin and acos, fsqrt takes care of them for us.
* | | asm for log functionsRich Felker2012-03-186-0/+42
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* | | fix broken exponential asmRich Felker2012-03-182-1/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | infinities were getting converted into nans. the new code simply tests for infinity and replaces it with a large magnitude value of the same sign. also, the fcomi instruction is apparently not part of the i387 instruction set, so avoid using it.
* | | asm for lrint family on i386Rich Felker2012-03-186-0/+46
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* | asm exponential functions for i386Rich Felker2012-03-189-0/+89
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* assembly optimizations for fmod/remainder functionsRich Felker2012-03-188-0/+88
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* asm versions of some simple math functions for i386 and x86_64Rich Felker2012-03-188-0/+48
| | | | | | | these are functions that have direct fpu approaches to implementation without problematic exception or rounding issues. x86_64 lacks float/double versions because i'm unfamiliar with the necessary sse code for performing these operations.
* simplify lround and llround functionsnsz2012-03-186-112/+20
| | | | | Simple wrappers around round is enough because spurious inexact exception is allowed.
* make lrint and llrint functions work without fenv supportnsz2012-03-186-6/+16
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* faster lrint and llrint functionsnsz2012-03-186-80/+99
| | | | | | | A faster workaround for spurious inexact exceptions when the result cannot be represented. The old code actually could be wrong, because gcc reordered the integer conversion and the exception check.
* fix loads of missing const in new libm, and some global vars (?!) in powlRich Felker2012-03-1819-49/+49
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* one more fenv availability issue: lroundRich Felker2012-03-171-0/+2
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* make fma and lrint functions build without full fenv supportRich Felker2012-03-164-4/+28
| | | | | | | | this is necessary to support archs where fenv is incomplete or unavailable (presently arm). fma, fmal, and the lrint family should work perfectly fine with this change; fmaf is slightly broken with respect to rounding as it depends on non-default rounding modes to do its work.
* other side of the signgam namespace fix: use the internal nameRich Felker2012-03-163-3/+7
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* make signgam a weak alias for an internal symbolRich Felker2012-03-161-2/+5
| | | | | otherwise, the standard C lgamma function will clobber a symbol in the namespace reserved for the application.
* fix namespace issues for lgamma, etc.Rich Felker2012-03-166-14/+23
| | | | standard functions cannot depend on nonstandard symbols