1. 15 8月, 2013 1 次提交
    • S
      math: fix asin, atan, log1p, tanh to raise underflow on subnormal · c599f4f4
      Szabolcs Nagy 提交于
      for these functions f(x)=x for small inputs, because f(0)=0 and
      f'(0)=1, but for subnormal values they should raise the underflow
      flag (required by annex F), if they are approximated by a polynomial
      around 0 then spurious underflow should be avoided (not required by
      annex F)
      
      all these functions should raise inexact flag for small x if x!=0,
      but it's not required by the standard and it does not seem a worthy
      goal, so support for it is removed in some cases.
      
      raising underflow:
      - x*x may not raise underflow for subnormal x if FLT_EVAL_METHOD!=0
      - x*x may raise spurious underflow for normal x if FLT_EVAL_METHOD==0
      - in case of double subnormal x, store x as float
      - in case of float subnormal x, store x*x as float
      c599f4f4
  2. 16 5月, 2013 1 次提交
    • S
      math: use double_t for temporaries to avoid stores on i386 · e216951f
      Szabolcs Nagy 提交于
      When FLT_EVAL_METHOD!=0 (only i386 with x87 fp) the excess
      precision of an expression must be removed in an assignment.
      (gcc needs -fexcess-precision=standard or -std=c99 for this)
      
      This is done by extra load/store instructions which adds code
      bloat when lot of temporaries are used and it makes the result
      less precise in many cases.
      Using double_t and float_t avoids these issues on i386 and
      it makes no difference on other archs.
      
      For now only a few functions are modified where the excess
      precision is clearly beneficial (mostly polynomial evaluations
      with temporaries).
      
      object size differences on i386, gcc-4.8:
                   old   new
      __cosdf.o    123    95
      __cos.o      199   169
      __sindf.o    131    95
      __sin.o      225   203
      __tandf.o    207   151
      __tan.o      605   499
      erff.o      1470  1416
      erf.o       1703  1649
      j0f.o       1779  1745
      j0.o        2308  2274
      j1f.o       1602  1568
      j1.o        2286  2252
      tgamma.o    1431  1424
      math/*.o   64164 63635
      e216951f
  3. 12 12月, 2012 1 次提交
    • S
      math: clean up inverse trigonometric functions · b12a73d5
      Szabolcs Nagy 提交于
      modifications:
      * avoid unsigned->signed conversions
      * removed various volatile hacks
      * use FORCE_EVAL when evaluating only for side-effects
      * factor out R() rational approximation instead of manual inline
      * __invtrigl.h now only provides __invtrigl_R, __pio2_hi and __pio2_lo
      * use 2*pio2_hi, 2*pio2_lo instead of pi_hi, pi_lo
      
      otherwise the logic is not changed, long double versions will
      need a revisit when a genaral long double cleanup happens
      b12a73d5
  4. 20 3月, 2012 1 次提交
    • N
      code cleanup of named constants · 0cbb6547
      nsz 提交于
      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).
      0cbb6547
  5. 14 3月, 2012 1 次提交
  6. 13 3月, 2012 1 次提交
    • R
      first commit of the new libm! · b69f695a
      Rich Felker 提交于
      thanks to the hard work of Szabolcs Nagy (nsz), identifying the best
      (from correctness and license standpoint) implementations from freebsd
      and openbsd and cleaning them up! musl should now fully support c99
      float and long double math functions, and has near-complete complex
      math support. tgmath should also work (fully on gcc-compatible
      compilers, and mostly on any c99 compiler).
      
      based largely on commit 0376d44a890fea261506f1fc63833e7a686dca19 from
      nsz's libm git repo, with some additions (dummy versions of a few
      missing long double complex functions, etc.) by me.
      
      various cleanups still need to be made, including re-adding (if
      they're correct) some asm functions that were dropped.
      b69f695a