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Diffstat (limited to 'winsup/mingw/mingwex/math/log10f.S')
| -rw-r--r-- | winsup/mingw/mingwex/math/log10f.S | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/winsup/mingw/mingwex/math/log10f.S b/winsup/mingw/mingwex/math/log10f.S new file mode 100644 index 000000000..90fc9af92 --- /dev/null +++ b/winsup/mingw/mingwex/math/log10f.S @@ -0,0 +1,48 @@ +/* + * Written by J.T. Conklin <jtc@netbsd.org>. + * Public domain. + * Adapted for float type by Ulrich Drepper <drepper@cygnus.com>. + * + * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>. + */ + + .file "log10f.S" + .text + .align 4 +one: .double 1.0 + /* It is not important that this constant is precise. It is only + a value which is known to be on the safe side for using the + fyl2xp1 instruction. */ +limit: .double 0.29 + + .text + .align 4 +.globl _log10f + .def _log10f; .scl 2; .type 32; .endef +_log10f: + fldlg2 // log10(2) + flds 4(%esp) // x : log10(2) + fxam + fnstsw + fld %st // x : x : log10(2) + sahf + jc 3f // in case x is NaN or ħInf +4: fsubl one // x-1 : x : log10(2) + fld %st // x-1 : x-1 : x : log10(2) + fabs // |x-1| : x-1 : x : log10(2) + fcompl limit // x-1 : x : log10(2) + fnstsw // x-1 : x : log10(2) + andb $0x45, %ah + jz 2f + fstp %st(1) // x-1 : log10(2) + fyl2xp1 // log10(x) + ret + +2: fstp %st(0) // x : log10(2) + fyl2x // log10(x) + ret + +3: jp 4b // in case x is ħInf + fstp %st(1) + fstp %st(1) + ret |