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authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/x86_64/fpu/e_log10l.S
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
downloadglibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.gz
Prepare for radical source tree reorganization.zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control).
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+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Public domain.
+ *
+ * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.
+ *
+ * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>.
+ * Adapted for x86-64 by Andreas Jaeger <aj@suse.de>.
+ */
+
+#include <machine/asm.h>
+
+ .section .rodata.cst8,"aM",@progbits,8
+
+ .p2align 3
+ .type one,@object
+one: .double 1.0
+ ASM_SIZE_DIRECTIVE(one)
+ /* 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. */
+ .type limit,@object
+limit: .double 0.29
+ ASM_SIZE_DIRECTIVE(limit)
+
+
+#ifdef PIC
+# define MO(op) op##(%rip)
+#else
+# define MO(op) op
+#endif
+
+ .text
+ENTRY(__ieee754_log10l)
+ fldlg2 // log10(2)
+ fldt 8(%rsp) // x : log10(2)
+ fxam
+ fnstsw
+ fld %st // x : x : log10(2)
+ testb $1, %ah
+ jnz 3f // in case x is NaN or ħInf
+4: fsubl MO(one) // x-1 : x : log10(2)
+ fld %st // x-1 : x-1 : x : log10(2)
+ fabs // |x-1| : x-1 : x : log10(2)
+ fcompl MO(limit) // x-1 : x : log10(2)
+ fnstsw // x-1 : x : log10(2)
+ andb $0x45, %ah
+ jz 2f
+ fxam
+ fnstsw
+ andb $0x45, %ah
+ cmpb $0x40, %ah
+ jne 5f
+ fabs // log10(1) is +0 in all rounding modes.
+5: fstp %st(1) // x-1 : log10(2)
+ fyl2xp1 // log10(x)
+ ret
+
+2: fstp %st(0) // x : log10(2)
+ fyl2x // log10(x)
+ ret
+
+3: testb $4, %ah
+ jnz 4b // in case x is ħInf
+ fstp %st(1)
+ fstp %st(1)
+ fadd %st(0)
+ ret
+END(__ieee754_log10l)
+
+
+ENTRY(__log10l_finite)
+ fldlg2 // log10(2)
+ fldt 8(%rsp) // x : log10(2)
+ fld %st // x : x : log10(2)
+4: fsubl MO(one) // x-1 : x : log10(2)
+ fld %st // x-1 : x-1 : x : log10(2)
+ fabs // |x-1| : x-1 : x : log10(2)
+ fcompl MO(limit) // x-1 : x : log10(2)
+ fnstsw // x-1 : x : log10(2)
+ andb $0x45, %ah
+ jz 2b
+ fxam
+ fnstsw
+ andb $0x45, %ah
+ cmpb $0x40, %ah
+ jne 6f
+ fabs // log10(1) is +0 in all rounding modes.
+6: fstp %st(1) // x-1 : log10(2)
+ fyl2xp1 // log10(x)
+ ret
+END(__log10l_finite)