github.com/afumu/libc@v0.0.6/musl/src/math/i386/log1p.s (about)

     1  .global log1p
     2  .type log1p,@function
     3  log1p:
     4  	mov 8(%esp),%eax
     5  	fldln2
     6  	and $0x7fffffff,%eax
     7  	fldl 4(%esp)
     8  	cmp $0x3fd28f00,%eax
     9  	ja 1f
    10  	cmp $0x00100000,%eax
    11  	jb 2f
    12  	fyl2xp1
    13  	fstpl 4(%esp)
    14  	fldl 4(%esp)
    15  	ret
    16  1:	fld1
    17  	faddp
    18  	fyl2x
    19  	fstpl 4(%esp)
    20  	fldl 4(%esp)
    21  	ret
    22  		# subnormal x, return x with underflow
    23  2:	fsts 4(%esp)
    24  	fstp %st(1)
    25  	ret