/* * Written by J.T. Conklin <jtc@netbsd.org>. * Public domain. * Adapted for float by Ulrich Drepper <drepper@cygnus.com>. * * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>. */ #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##@GOTOFF(%edx) #else # define MO(op) op #endif .text ENTRY(__ieee754_logf) fldln2 // log(2) flds 4(%esp) // x : log(2) fxam fnstsw #ifdef PIC LOAD_PIC_REG (dx) #endif fld %st // x : x : log(2) sahf jc 3f // in case x is NaN or +-Inf 4: 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 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: jp 4b // in case x is +-Inf fstp %st(1) fstp %st(1) ret END (__ieee754_logf) ENTRY(__logf_finite) fldln2 // log(2) flds 4(%esp) // x : log(2) #ifdef PIC LOAD_PIC_REG (dx) #endif 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 fstp %st(1) // x-1 : log(2) fyl2xp1 // log(x) ret END(__logf_finite)