.global expm1l
.type expm1l,@function
expm1l:
fldt 8(%rsp)
fldl2e
fmulp
movl $0xc2820000,-4(%rsp)
flds -4(%rsp)
fucomp %st(1)
fnstsw %ax
sahf
fld1
jb 1f
# x*log2e <= -65, return -1 without underflow
fstp %st(1)
fchs
ret
1: fld %st(1)
fabs
fucom %st(1)
fnstsw %ax
fstp %st(0)
fstp %st(0)
sahf
ja 1f
f2xm1
ret
1: push %rax
call 1f
pop %rax
fld1
fsubrp
ret
.global exp2l
.type exp2l,@function
exp2l:
fldt 8(%rsp)
1: fld %st(0)
sub $16,%rsp
fstpt (%rsp)
mov 8(%rsp),%ax
and $0x7fff,%ax
cmp $0x3fff+13,%ax
jb 4f # |x| < 8192
cmp $0x3fff+15,%ax
jae 3f # |x| >= 32768
fsts (%rsp)
cmpl $0xc67ff800,(%rsp)
jb 2f # x > -16382
movl $0x5f000000,(%rsp)
flds (%rsp) # 0x1p63
fld %st(1)
fsub %st(1)
faddp
fucomp %st(1)
fnstsw
sahf
je 2f # x - 0x1p63 + 0x1p63 == x
movl $1,(%rsp)
flds (%rsp) # 0x1p-149
fdiv %st(1)
fstps (%rsp) # raise underflow
2: fld1
fld %st(1)
frndint
fxch %st(2)
fsub %st(2) # st(0)=x-rint(x), st(1)=1, st(2)=rint(x)
f2xm1
faddp # 2^(x-rint(x))
1: fscale
fstp %st(1)
add $16,%rsp
ret
3: xor %eax,%eax
4: cmp $0x3fff-64,%ax
fld1
jb 1b # |x| < 0x1p-64
fstpt (%rsp)
fistl 8(%rsp)
fildl 8(%rsp)
fsubrp %st(1)
addl $0x3fff,8(%rsp)
f2xm1
fld1
faddp # 2^(x-rint(x))
fldt (%rsp) # 2^rint(x)
fmulp
add $16,%rsp
ret
