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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*
* Adapted for `long double' by Ulrich Drepper <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_logl)
fldln2 // log(2)
fldt 8(%rsp) // x : log(2)
fxam
fnstsw
fld %st // x : x : log(2)
testb $1, %ah
jnz 3f // in case x is NaN or +-Inf
movzwl 8+8(%rsp), %eax
cmpl $0xc000, %eax
jae 6f // x <= -2, avoid overflow from -LDBL_MAX - 1.
4: fsubl MO(one) // x-1 : x : log(2)
6: fld %st // x-1 : x-1 : x : log(2)
fabs // |x-1| : x-1 : x : log(2)
fcompl MO(limit) // x-1 : x : log(2)
fnstsw // x-1 : x : log(2)
andb $0x45, %ah
jz 2f
fxam
fnstsw
andb $0x45, %ah
cmpb $0x40, %ah
jne 5f
fabs // log(1) is +0 in all rounding modes.
5: fstp %st(1) // x-1 : log(2)
fyl2xp1 // log(x)
ret
2: fstp %st(0) // x : log(2)
fyl2x // log(x)
ret
3: testb $4, %ah
jnz 4b // in case x is +-Inf
fstp %st(1)
fstp %st(1)
fadd %st(0)
ret
END (__ieee754_logl)
ENTRY(__logl_finite)
fldln2 // log(2)
fldt 8(%rsp) // x : log(2)
fld %st // x : x : log(2)
fsubl MO(one) // x-1 : x : log(2)
fld %st // x-1 : x-1 : x : log(2)
fabs // |x-1| : x-1 : x : log(2)
fcompl MO(limit) // x-1 : x : log(2)
fnstsw // x-1 : x : log(2)
andb $0x45, %ah
jz 2b
fxam
fnstsw
andb $0x45, %ah
cmpb $0x40, %ah
jne 7f
fabs // log(1) is +0 in all rounding modes.
7: fstp %st(1) // x-1 : log(2)
fyl2xp1 // log(x)
ret
END (__logl_finite)
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