user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<log_btiln>:
  endbr64
  push   %r15
  push   %r14
  push   %rbp
  push   %rbx
  sub    $0x48,%rsp
  movsd  %xmm0,0x20(%rsp)
  movq   %xmm1,%r14
  movsd  %xmm2,0x8(%rsp)
  movsd  D124(%rip),%xmm0
  movapd %xmm1,%xmm4
  subsd  %xmm0,%xmm4
  movsd  %xmm4,0x28(%rsp)
  mov    $0x1b,%ebx
  movsd  D53(%rip),%xmm6
  movsd  %xmm6,(%rsp)
  movsd  %xmm0,0x18(%rsp)
  pxor   %xmm4,%xmm4
  movsd  %xmm4,0x10(%rsp)
L6:
  movsd  0x8(%rsp),%xmm1
  movsd  (%rsp),%xmm0
  call   <pow@plt>
  movapd %xmm0,%xmm7
  movsd  %xmm0,0x30(%rsp)
  movsd  D124(%rip),%xmm6
  addsd  0x8(%rsp),%xmm6
  movsd  %xmm6,0x38(%rsp)
  movsd  0x20(%rsp),%xmm1
  movsd  (%rsp),%xmm5
  divsd  %xmm5,%xmm1
  movsd  D124(%rip),%xmm2
  subsd  %xmm5,%xmm2
  movsd  D124(%rip),%xmm0
  divsd  %xmm2,%xmm0
  mulsd  %xmm7,%xmm6
  movapd %xmm6,%xmm2
  movapd %xmm7,%xmm4
  mulsd  %xmm5,%xmm4
  movsd  D124(%rip),%xmm3
  subsd  %xmm4,%xmm3
  divsd  %xmm3,%xmm2
  subsd  %xmm2,%xmm0
  mulsd  0x28(%rsp),%xmm0
  subsd  %xmm0,%xmm1
  pxor   %xmm0,%xmm0
  cmpltsd %xmm1,%xmm0
  movsd  0x18(%rsp),%xmm2
  andpd  %xmm0,%xmm2
  andnpd %xmm5,%xmm0
  movapd %xmm0,%xmm3
  orpd   %xmm2,%xmm3
  movsd  %xmm3,0x18(%rsp)
  pxor   %xmm2,%xmm2
  cmpltsd %xmm1,%xmm2
  andpd  %xmm2,%xmm5
  movsd  0x10(%rsp),%xmm7
  andnpd %xmm7,%xmm2
  orpd   %xmm5,%xmm2
  movsd  %xmm2,0x10(%rsp)
  movapd %xmm2,%xmm0
  addsd  %xmm3,%xmm0
  mulsd  D53(%rip),%xmm0
  movsd  %xmm0,(%rsp)
  sub    $0x1,%ebx
  jne    L6
  movsd  D124(%rip),%xmm6
  movapd %xmm0,%xmm4
  subsd  %xmm0,%xmm6
  movsd  %xmm6,0x10(%rsp)
  movsd  0x30(%rsp),%xmm0
  mulsd  %xmm4,%xmm0
  movsd  D124(%rip),%xmm7
  subsd  %xmm0,%xmm7
  movsd  %xmm7,0x18(%rsp)
  movapd %xmm4,%xmm0
  call   <log@plt>
  movq   %xmm0,%rbx
  movsd  0x18(%rsp),%xmm0
  call   <log@plt>
  movq   %xmm0,%rbp
  movsd  0x10(%rsp),%xmm0
  call   <log@plt>
  movq   %xmm0,%r15
  movsd  D124(%rip),%xmm2
  movsd  0x10(%rsp),%xmm1
  divsd  %xmm1,%xmm2
  divsd  %xmm1,%xmm2
  movsd  0x8(%rsp),%xmm1
  movsd  0x30(%rsp),%xmm6
  mulsd  %xmm6,%xmm1
  movsd  (%rsp),%xmm4
  divsd  %xmm4,%xmm1
  mulsd  %xmm6,%xmm6
  movapd %xmm6,%xmm0
  addsd  %xmm1,%xmm0
  mulsd  0x38(%rsp),%xmm0
  movsd  0x18(%rsp),%xmm6
  divsd  %xmm6,%xmm0
  divsd  %xmm6,%xmm0
  movapd %xmm2,%xmm1
  subsd  %xmm0,%xmm1
  movq   %r14,%xmm0
  mulsd  %xmm1,%xmm0
  movsd  0x20(%rsp),%xmm1
  divsd  %xmm4,%xmm1
  divsd  %xmm4,%xmm1
  addsd  %xmm1,%xmm0
  mulsd  D53(%rip),%xmm0
  divsd  D90(%rip),%xmm0
  call   <log@plt>
  movapd %xmm0,%xmm2
  movq   %rbx,%xmm0
  mulsd  0x20(%rsp),%xmm0
  movq   %rbp,%xmm1
  movq   %r15,%xmm6
  subsd  %xmm6,%xmm1
  mulsd  0x28(%rsp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  D53(%rip),%xmm1
  mulsd  %xmm2,%xmm1
  subsd  %xmm1,%xmm0
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r14
  pop    %r15
  ret
```

tool_calls: name: extract_symbolic_data
arguments: data_tag: D124
datatype: f64
name: extract_symbolic_data
arguments: data_tag: D53
datatype: f64
name: extract_symbolic_data
arguments: data_tag: D90
datatype: f64

tool: D124: 1

tool: D53: 0.5

tool: D90: 3.1416

assistant: ```c
double log_btiln(double a, double b, double n) {
  double b1 = b - 1.;
  int i;
  int niter = ceil(log(1e8) / log(2));
  double umin = 0., umax = 1., u = 0.5;
  double un;
  for (i = 0; i < niter; i++) {
    un = pow(u, n);
    double fprim = a / u - b1 * (1. / (1. - u) - (n + 1) * un / (1. - un * u));
    if (fprim > 0)
      umin = u;
    else
      umax = u;
    u = (umin + umax) / 2.;
  }
  double neg_fsecund = a / u / u + b * (1. / (1. - u) / (1. - u) - (n + 1.) * (n * un / u + un * un) / (1 - un * u) / (1 - un * u));
  double f = a * log(u) - (b1) * (log(1 - un * u) - log(1 - u));
  return (f - log(neg_fsecund / 2. / 3.1416) * 0.5);
}
```