user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<double_to_ieee_80>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x20,%rsp
  movsd  %xmm0,-0x18(%rbp)
  mov    %rdi,-0x20(%rbp)
  movb   $0x0,-0xb(%rbp)
  movw   $0x0,-0xa(%rbp)
  movl   $0x0,-0x8(%rbp)
  movl   $0x0,-0x4(%rbp)
  pxor   %xmm0,%xmm0
  comisd -0x18(%rbp),%xmm0
  jbe    L18
  movb   $0x1,-0xb(%rbp)
  movsd  -0x18(%rbp),%xmm0
  movq   D31(%rip),%xmm1
  xorpd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
L18:
  pxor   %xmm0,%xmm0
  ucomisd -0x18(%rbp),%xmm0
  jp     L7
  pxor   %xmm0,%xmm0
  ucomisd -0x18(%rbp),%xmm0
  je     L17
L7:
  mov    -0x18(%rbp),%rax
  movq   %rax,%xmm0
  call   <log@plt>
  movq   %xmm0,%rax
  movsd  D44(%rip),%xmm0
  movq   %rax,%xmm1
  divsd  %xmm0,%xmm1
  movsd  D37(%rip),%xmm0
  addsd  %xmm1,%xmm0
  cvttsd2si %xmm0,%eax
  mov    %ax,-0xa(%rbp)
  movswl -0xa(%rbp),%eax
  pxor   %xmm1,%xmm1
  cvtsi2sd %eax,%xmm1
  movsd  D4(%rip),%xmm0
  subsd  %xmm1,%xmm0
  mov    D21(%rip),%rax
  movapd %xmm0,%xmm1
  movq   %rax,%xmm0
  call   <pow@plt>
  movsd  -0x18(%rbp),%xmm1
  mulsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  mov    -0x18(%rbp),%rax
  movq   %rax,%xmm0
  call   <myDoubleToUlong@plt>
  mov    %eax,-0x8(%rbp)
  mov    -0x8(%rbp),%eax
  mov    %eax,%edi
  call   <myUlongToDouble@plt>
  pxor   %xmm1,%xmm1
  cvtsi2sd %rax,%xmm1
  movsd  -0x18(%rbp),%xmm0
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  movsd  -0x18(%rbp),%xmm1
  movsd  D34(%rip),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  mov    -0x18(%rbp),%rax
  movq   %rax,%xmm0
  call   <myDoubleToUlong@plt>
  mov    %eax,-0x4(%rbp)
L17:
  movzbl -0xb(%rbp),%eax
  shl    $0x7,%eax
  mov    %eax,%edx
  movzwl -0xa(%rbp),%eax
  sar    $0x8,%ax
  mov    %edx,%ecx
  or     %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  movzwl -0xa(%rbp),%edx
  mov    %dl,(%rax)
  mov    -0x8(%rbp),%eax
  shr    $0x18,%eax
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x8(%rbp),%eax
  shr    $0x10,%eax
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x8(%rbp),%eax
  shr    $0x8,%eax
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    -0x8(%rbp),%edx
  mov    %dl,(%rax)
  mov    -0x4(%rbp),%eax
  shr    $0x18,%eax
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x4(%rbp),%eax
  shr    $0x10,%eax
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x4(%rbp),%eax
  shr    $0x8,%eax
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    -0x4(%rbp),%edx
  mov    %dl,(%rax)
  nop
  leave
  ret
```

tool_calls: name: extract_symbolic_data
arguments: label: D31
type_guessed: f32[2]
name: extract_symbolic_data
arguments: label: D44
type_guessed: byte[8]
name: extract_symbolic_data
arguments: label: D37
type_guessed: f64
name: extract_symbolic_data
arguments: label: D4
type_guessed: f32[2]
name: extract_symbolic_data
arguments: label: D21
type_guessed: f64
name: extract_symbolic_data
arguments: label: D34
type_guessed: f32[2]

tool: {"D31": [0.0,-0.0]}

tool: {"D44": [0xef,0x39,0xfa,0xfe,0x42,0x2e,0xe6,0x3f]}

tool: D37: 16383

tool: {"D4": [0.0,6.50091552734375]}

tool: D21: 2

tool: {"D34": [0.0,30.0]}

assistant: ```c
void double_to_ieee_80(double val, unsigned char *p) {
  unsigned char sign = 0;
  short exp = 0;
  unsigned int mant1 = 0;
  unsigned int mant0 = 0;
  if (val < 0.0) {
    sign = 1;
    val = -val;
  }
  if (val != 0.0) {
    exp = (short)(log(val) / log(2.0) + 16383.0);
    val *= pow(2.0, 31.0 + 16383.0 - (double)exp);
    mant1 = myDoubleToUlong(val);
    val -= myUlongToDouble(mant1);
    val *= pow(2.0, 32.0);
    mant0 = myDoubleToUlong(val);
  }
  *p++ = ((sign << 7) | (exp >> 8));
  *p++ = 0xFF & exp;
  *p++ = 0xFF & (mant1 >> 24);
  *p++ = 0xFF & (mant1 >> 16);
  *p++ = 0xFF & (mant1 >> 8);
  *p++ = 0xFF & (mant1);
  *p++ = 0xFF & (mant0 >> 24);
  *p++ = 0xFF & (mant0 >> 16);
  *p++ = 0xFF & (mant0 >> 8);
  *p++ = 0xFF & (mant0);
}
```