user: Please show me the C implementation that matches the assembly code listed below:

```asm
<benchmark>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x48,%rsp
  mov    %edi,-0x44(%rbp)
  mov    %esi,-0x48(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x18(%rbp)
  xor    %eax,%eax
  mov    %rsp,%rax
  mov    %rax,%rbx
  mov    -0x48(%rbp),%eax
  movslq %eax,%rdx
  sub    $0x1,%rdx
  mov    %rdx,-0x38(%rbp)
  movslq %eax,%rdx
  mov    %rdx,%r10
  mov    $0x0,%r11d
  movslq %eax,%rdx
  mov    %rdx,%r8
  mov    $0x0,%r9d
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    $0x10,%eax
  sub    $0x1,%rax
  add    %rdx,%rax
  mov    $0x10,%esi
  mov    $0x0,%edx
  div    %rsi
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L76:
  cmp    %rdx,%rsp
  je     L105
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L76
L105:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L27
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L27:
  mov    %rsp,%rax
  add    $0x3,%rax
  shr    $0x2,%rax
  shl    $0x2,%rax
  mov    %rax,-0x30(%rbp)
  movl   $0x0,-0x3c(%rbp)
  jmp    L4
L85:
  mov    $0x0,%eax
  call   <rand_float@plt>
  movss  D21(%rip),%xmm1
  mulss  %xmm1,%xmm0
  movss  D16(%rip),%xmm1
  subss  %xmm1,%xmm0
  mov    -0x30(%rbp),%rax
  mov    -0x3c(%rbp),%edx
  movslq %edx,%rdx
  movss  %xmm0,(%rax,%rdx,4)
  addl   $0x1,-0x3c(%rbp)
L4:
  mov    -0x3c(%rbp),%eax
  cmp    -0x48(%rbp),%eax
  jl     L85
  pxor   %xmm0,%xmm0
  movss  %xmm0,-0x40(%rbp)
  mov    $0x0,%eax
  call   <tic@plt>
  movq   %xmm0,%rax
  mov    %rax,-0x28(%rbp)
  movl   $0x0,-0x3c(%rbp)
  jmp    L92
L58:
  mov    -0x30(%rbp),%rcx
  mov    -0x48(%rbp),%eax
  mov    $0x1,%edx
  mov    %rcx,%rsi
  mov    D49(%rip),%ecx
  movd   %ecx,%xmm0
  mov    %eax,%edi
  call   <stdlib_strided_sstdevtk@plt>
  movd   %xmm0,%eax
  mov    %eax,-0x40(%rbp)
  movss  -0x40(%rbp),%xmm0
  ucomiss -0x40(%rbp),%xmm0
  jnp    L18
  lea    D1(%rip),%rax
  mov    %rax,%rdi
  call   <printf@plt>
  jmp    L8
L18:
  addl   $0x1,-0x3c(%rbp)
L92:
  mov    -0x3c(%rbp),%eax
  cmp    -0x44(%rbp),%eax
  jl     L58
L8:
  mov    $0x0,%eax
  call   <tic@plt>
  movq   %xmm0,%rax
  movq   %rax,%xmm0
  subsd  -0x28(%rbp),%xmm0
  movsd  %xmm0,-0x20(%rbp)
  movss  -0x40(%rbp),%xmm0
  ucomiss -0x40(%rbp),%xmm0
  jnp    L70
  lea    D1(%rip),%rax
  mov    %rax,%rdi
  call   <printf@plt>
L70:
  movsd  -0x20(%rbp),%xmm0
  mov    %rbx,%rsp
  movq   %xmm0,%rax
  mov    -0x18(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L31
  call   <__stack_chk_fail@plt>
L31:
  movq   %rax,%xmm0
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

tool_calls: name: retrieve_data
arguments: tag: D21
type_guessed: byte[4]
name: retrieve_data
arguments: tag: D16
type_guessed: byte[4]
name: retrieve_data
arguments: tag: D49
type_guessed: byte[4]
name: retrieve_data
arguments: tag: D1
type_guessed: string

tool: {"D21": [0x00,0x40,0x9c,0x46]}

tool: {"D16": [0x00,0x40,0x1c,0x46]}

tool: {"D49": [0x00,0x00,0x80,0x3f]}

tool: D1: should not return NaN


assistant: ```c
double benchmark(int iterations, int len) {
  double elapsed;
  float x[len];
  float v;
  double t;
  int i;
  for (i = 0; i < len; i++) {
    x[i] = (rand_float() * 20000.0f) - 10000.0f;
  }
  v = 0.0f;
  t = tic();
  for (i = 0; i < iterations; i++) {
    v = stdlib_strided_sstdevtk(len, 1.0f, x, 1);
    if (v != v) {
      printf("should not return NaN\n");
      break;
    }
  }
  elapsed = tic() - t;
  if (v != v) {
    printf("should not return NaN\n");
  }
  return elapsed;
}
```