user: 请从给定的汇编指令推导出C源代码:

```asm
<benchmark>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x28,%rsp
  mov    %edi,%r14d
  mov    %esi,-0x44(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  mov    %esi,%eax
  cltq
  shl    $0x3,%rax
  lea    0xf(%rax),%rdx
  mov    %rdx,%rsi
  and    $0xfffffffffffffff0,%rsi
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rcx
  sub    %rdx,%rcx
L45:
  cmp    %rcx,%rsp
  je     L43
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L45
L43:
  mov    %rsi,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L63
  orq    $0x0,-0x8(%rsp,%rdx,1)
L63:
  mov    %rsp,%r13
  add    $0xf,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffffff0,%rcx
  and    $0xfffffffffffff000,%rax
  mov    %rsp,%rdx
  sub    %rax,%rdx
L136:
  cmp    %rdx,%rsp
  je     L131
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L136
L131:
  mov    %rcx,%rax
  and    $0xfff,%eax
  sub    %rax,%rsp
  test   %rax,%rax
  je     L146
  orq    $0x0,-0x8(%rsp,%rax,1)
L146:
  lea    0x7(%rsp),%r12
  mov    %r12,%rax
  shr    $0x3,%rax
  mov    %rax,-0x50(%rbp)
  and    $0xfffffffffffffff8,%r12
  mov    -0x44(%rbp),%eax
  test   %eax,%eax
  jle    L7
  mov    %eax,%r15d
  mov    $0x0,%ebx
L122:
  mov    $0x0,%eax
  call   <rand_double@plt>
  mulsd  D14(%rip),%xmm0
  subsd  D3(%rip),%xmm0
  movsd  %xmm0,0x0(%r13,%rbx,8)
  movq   $0x0,(%r12,%rbx,8)
  add    $0x1,%rbx
  cmp    %r15,%rbx
  jne    L122
L7:
  mov    $0x0,%eax
  call   <tic@plt>
  movq   %xmm0,%r15
  test   %r14d,%r14d
  jle    L116
  mov    $0x0,%ebx
L64:
  mov    $0x1,%r8d
  mov    %r12,%rcx
  mov    $0x1,%edx
  mov    %r13,%rsi
  mov    -0x44(%rbp),%edi
  call   <c_dswap@plt>
  movsd  (%r12),%xmm0
  ucomisd %xmm0,%xmm0
  jp     L108
  add    $0x1,%ebx
  cmp    %ebx,%r14d
  jne    L64
  jmp    L116
L108:
  lea    D21(%rip),%rdi
  call   <printf@plt>
L116:
  mov    $0x0,%eax
  call   <tic@plt>
  movq   %r15,%xmm1
  subsd  %xmm1,%xmm0
  movq   %xmm0,%rbx
  mov    -0x50(%rbp),%rax
  movsd  0x0(,%rax,8),%xmm0
  ucomisd %xmm0,%xmm0
  jp     L90
L81:
  mov    -0x38(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L123
  movq   %rbx,%xmm0
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L90:
  lea    D21(%rip),%rdi
  call   <printf@plt>
  jmp    L81
L123:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: disassemble_data
arguments: label: D14
type_infered: f64
name: disassemble_data
arguments: label: D3
type_infered: f64
name: disassemble_data
arguments: label: D21
type_infered: string

tool: D14: 20000

tool: D3: 10000

tool: D21: should not return NaN


assistant: ```c
double benchmark(int iterations, int len) {
  double elapsed;
  double x[len];
  double y[len];
  double t;
  int i;
  for (i = 0; i < len; i++) {
    x[i] = (rand_double() * 20000.0) - 10000.0;
    y[i] = 0.0;
  }
  t = tic();
  for (i = 0; i < iterations; i++) {
    c_dswap(len, x, 1, y, 1);
    if (y[0] != y[0]) {
      printf("should not return NaN\n");
      break;
    }
  }
  elapsed = tic() - t;
  if (y[0] != y[0]) {
    printf("should not return NaN\n");
  }
  return elapsed;
}
```