user: What is the c source code of the assembly code below:

```asm
<calc_xi_sum_dev>:
  endbr64
  test   %r9d,%r9d
  jle    L77
  push   %r15
  mov    %rdi,%r11
  movaps %xmm0,%xmm1
  movaps %xmm0,%xmm2
  push   %r14
  shufps $0x0,%xmm1,%xmm1
  push   %r13
  push   %r12
  mov    %r9d,%r12d
  push   %rbp
  mov    %r12d,%r14d
  mov    %rsi,%rbp
  push   %rbx
  mov    %rcx,%rbx
  mov    0x38(%rsp),%ecx
  and    $0xfffffffc,%r14d
  mov    0x40(%rsp),%eax
  imul   %r9d,%ecx
  imul   %r9d,%eax
  mov    %r14d,-0x40(%rsp)
  movslq %ecx,%rcx
  lea    (%rdx,%rcx,4),%r10
  lea    (%rax,%r9,1),%edx
  movslq %r9d,%rcx
  shr    $0x2,%r9d
  movslq %edx,%rdx
  sub    $0x1,%r9d
  lea    -0x1(%rcx),%rsi
  lea    (%r8,%rdx,4),%rdi
  movslq %eax,%r8
  shl    $0x4,%r9
  lea    0x0(,%rcx,4),%rdx
  imul   %rdx,%rsi
  lea    (%rbx,%r8,4),%r15
  mov    %r15,-0x70(%rsp)
  add    %r9,%r15
  mov    %r14d,%r9d
  imul   %r12d,%r9d
  mov    %rsi,-0x60(%rsp)
  lea    -0x1(%rcx,%r8,1),%rsi
  lea    (%rbx,%rsi,4),%rsi
  mov    %r9d,-0x3c(%rsp)
  lea    (%rax,%r14,1),%r9d
  movslq %r9d,%r9
  mov    %rsi,-0x58(%rsp)
  lea    (%rdx,%rbp,1),%rsi
  lea    (%rbx,%r9,4),%r9
  mov    %rsi,-0x48(%rsp)
  lea    0x0(,%rcx,8),%rsi
  mov    %r9,-0x38(%rsp)
  lea    0x1(%r14),%r9d
  add    $0x2,%r14d
  mov    %r9d,%r13d
  mov    %r9d,-0x30(%rsp)
  add    %eax,%r9d
  add    %r14d,%eax
  cltq
  imul   %r12d,%r13d
  movslq %r9d,%r9
  mov    %rsi,-0x50(%rsp)
  lea    (%rbx,%rax,4),%rax
  lea    (%rbx,%r9,4),%r9
  mov    %rcx,%rsi
  mov    %r14d,-0x2c(%rsp)
  mov    %rax,-0x18(%rsp)
  lea    -0x1(%r12),%eax
  lea    (%rcx,%rcx,2),%rcx
  shl    $0x4,%rsi
  mov    %r9,-0x28(%rsp)
  add    %r8,%rax
  mov    %r14d,%r9d
  shl    $0x2,%rcx
  imul   %r12d,%r9d
  lea    0x4(%rbx,%rax,4),%rax
  mov    %r13d,-0x20(%rsp)
  mov    %r12d,%r14d
  mov    %rax,-0x10(%rsp)
  xor    %r13d,%r13d
  mov    %r9d,-0x1c(%rsp)
  xor    %r9d,%r9d
  nop
L14:
  mov    -0x60(%rsp),%rax
  lea    (%rax,%r9,1),%rbx
  lea    (%r11,%r9,1),%rax
  add    %r11,%rbx
  cmp    %rdi,%rbx
  setb   %r12b
  cmp    %rdi,%rax
  seta   %r8b
  or     %r8d,%r12d
  cmp    %r10,%rbx
  setb   %r8b
  cmp    %r10,%rax
  seta   -0x61(%rsp)
  or     -0x61(%rsp),%r8b
  and    %r12d,%r8d
  cmp    $0x3,%r14d
  seta   %r12b
  and    %r12d,%r8d
  cmp    -0x58(%rsp),%rax
  seta   %r12b
  cmp    -0x70(%rsp),%rbx
  setb   %bl
  or     %ebx,%r12d
  test   %r12b,%r8b
  je     L59
  mov    -0x48(%rsp),%rbx
  mov    %rax,%r8
  add    %r9,%rbx
  sub    %rbx,%r8
  cmp    -0x50(%rsp),%r8
  jbe    L59
  movss  (%r10),%xmm5
  movss  (%rdi),%xmm4
  lea    0x0(%rbp,%r9,1),%r8
  mov    -0x70(%rsp),%rbx
  shufps $0x0,%xmm5,%xmm5
  shufps $0x0,%xmm4,%xmm4
  nopl   0x0(%rax)
L21:
  movss  (%r8,%rcx,1),%xmm0
  movss  (%r8,%rdx,2),%xmm3
  mov    %rbx,%r12
  add    $0x10,%rbx
  movss  (%r8,%rdx,1),%xmm6
  movups -0x10(%rbx),%xmm7
  unpcklps %xmm0,%xmm3
  movss  (%r8),%xmm0
  add    %rsi,%r8
  unpcklps %xmm6,%xmm0
  movss  (%rax,%rdx,2),%xmm6
  movlhps %xmm3,%xmm0
  movss  (%rax,%rcx,1),%xmm3
  mulps  %xmm7,%xmm0
  movss  (%rax,%rdx,1),%xmm7
  unpcklps %xmm3,%xmm6
  movss  (%rax),%xmm3
  unpcklps %xmm7,%xmm3
  movlhps %xmm6,%xmm3
  mulps  %xmm5,%xmm0
  mulps  %xmm4,%xmm0
  divps  %xmm1,%xmm0
  addps  %xmm3,%xmm0
  movaps %xmm0,%xmm3
  movss  %xmm0,(%rax)
  shufps $0x55,%xmm0,%xmm3
  movss  %xmm3,(%rax,%rdx,1)
  movaps %xmm0,%xmm3
  unpckhps %xmm0,%xmm3
  shufps $0xff,%xmm0,%xmm0
  movss  %xmm3,(%rax,%rdx,2)
  movss  %xmm0,(%rax,%rcx,1)
  add    %rsi,%rax
  cmp    %r15,%r12
  jne    L21
  cmp    -0x40(%rsp),%r14d
  je     L61
  mov    -0x3c(%rsp),%eax
  add    %r13d,%eax
  cltq
  movss  0x0(%rbp,%rax,4),%xmm0
  lea    (%r11,%rax,4),%r8
  mov    -0x38(%rsp),%rax
  mulss  (%rax),%xmm0
  mulss  (%r10),%xmm0
  mulss  (%rdi),%xmm0
  divss  %xmm2,%xmm0
  addss  (%r8),%xmm0
  movss  %xmm0,(%r8)
  cmp    -0x30(%rsp),%r14d
  jle    L61
  mov    -0x20(%rsp),%eax
  add    %r13d,%eax
  cltq
  movss  0x0(%rbp,%rax,4),%xmm0
  lea    (%r11,%rax,4),%r8
  mov    -0x28(%rsp),%rax
  mulss  (%rax),%xmm0
  mulss  (%r10),%xmm0
  mulss  (%rdi),%xmm0
  divss  %xmm2,%xmm0
  addss  (%r8),%xmm0
  movss  %xmm0,(%r8)
  cmp    -0x2c(%rsp),%r14d
  jle    L61
  mov    -0x1c(%rsp),%eax
  add    %r13d,%eax
  cltq
  movss  0x0(%rbp,%rax,4),%xmm0
  lea    (%r11,%rax,4),%r8
  mov    -0x18(%rsp),%rax
  mulss  (%rax),%xmm0
  mulss  (%r10),%xmm0
  mulss  (%rdi),%xmm0
  divss  %xmm2,%xmm0
  addss  (%r8),%xmm0
  movss  %xmm0,(%r8)
L61:
  add    $0x1,%r13d
  add    $0x4,%r9
  add    $0x4,%r10
  add    $0x4,%rdi
  cmp    %r13d,%r14d
  jne    L14
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L59:
  mov    -0x70(%rsp),%r8
  mov    -0x10(%rsp),%rbx
  mov    %r9,%rax
  nopl   (%rax)
L66:
  movss  (%r8),%xmm0
  mulss  0x0(%rbp,%rax,1),%xmm0
  add    $0x4,%r8
  mulss  (%r10),%xmm0
  mulss  (%rdi),%xmm0
  divss  %xmm2,%xmm0
  addss  (%r11,%rax,1),%xmm0
  movss  %xmm0,(%r11,%rax,1)
  add    %rdx,%rax
  cmp    %r8,%rbx
  jne    L66
  jmp    L61
L77:
  ret
```

assistant: ```c
void calc_xi_sum_dev(float *xi_sum_d, float *a_d, float *b_d, float *alpha_d, float *beta_d, float sum_ab, int nstates, int obs_t, int t) {
  int i, j;
  for (i = 0; i < nstates; ++i) {
    for (j = 0; j < nstates; ++j) {
      xi_sum_d[(j * nstates) + i] += alpha_d[(t * nstates) + j] * a_d[(j * nstates) + i] * b_d[(obs_t * nstates) + i] * beta_d[((t + 1) * nstates) + i] / sum_ab;
    }
  }
}
```