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

```asm
<add_point>:
  endbr64
  pxor   %xmm0,%xmm0
  test   %ecx,%ecx
  je     L55
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rdi,%rbp
  mov    %rsi,%rbx
  mov    %rdx,%r11
  mov    %ecx,%r10d
  test   %r9d,%r9d
  jle    L29
  movslq %r9d,%rax
  lea    0x4(%r8,%rax,4),%r13
  lea    0x8(%r8),%rsi
  lea    0x2(%r9),%r12d
  mov    $0x2,%ecx
  movaps %xmm0,%xmm6
  lea    0x1(%r9,%r9,1),%r14d
  lea    0x8(%rdi),%r15
  movaps %xmm0,%xmm7
  jmp    L19
L63:
  movss  0x0(%r13),%xmm0
  mulss  -0x4(%r11,%rcx,4),%xmm2
  movaps %xmm0,%xmm1
  subss  %xmm2,%xmm1
  movss  %xmm1,0x0(%r13)
  mulss  -0x4(%r11,%rcx,4),%xmm3
  mulss  %xmm0,%xmm5
  addss  %xmm5,%xmm3
  movss  %xmm3,-0x4(%r11,%rcx,4)
L22:
  add    $0x1,%rcx
  add    $0x4,%rsi
  cmp    %r12,%rcx
  je     L29
L19:
  movss  -0x4(%rsi),%xmm2
  ucomiss %xmm6,%xmm2
  jp     L58
  ucomiss %xmm7,%xmm2
  je     L22
L58:
  movss  -0x4(%rbx,%rcx,4),%xmm3
  pxor   %xmm1,%xmm1
  cvtsi2ss %r10d,%xmm1
  movaps %xmm2,%xmm5
  mulss  %xmm1,%xmm5
  movaps %xmm2,%xmm0
  mulss  %xmm5,%xmm0
  addss  %xmm3,%xmm0
  divss  %xmm0,%xmm3
  divss  %xmm0,%xmm5
  mulss  %xmm3,%xmm1
  cvttss2si %xmm1,%r10d
  movss  %xmm0,-0x4(%rbx,%rcx,4)
  mov    %r14d,%eax
  sub    %ecx,%eax
  lea    -0x2(%rcx),%edx
  imul   %edx,%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %eax,%edx
  sar    %edx
  lea    0x1(%rdx),%eax
  cmp    %ecx,%r9d
  jl     L63
  cltq
  lea    0x0(%rbp,%rax,4),%rax
  mov    %r9d,%edi
  sub    %ecx,%edi
  movslq %edx,%rdx
  add    %rdx,%rdi
  lea    (%r15,%rdi,4),%rdi
  mov    %rsi,%rdx
L74:
  movss  (%rdx),%xmm0
  movaps %xmm2,%xmm4
  mulss  (%rax),%xmm4
  movaps %xmm0,%xmm1
  subss  %xmm4,%xmm1
  movss  %xmm1,(%rdx)
  movaps %xmm3,%xmm1
  mulss  (%rax),%xmm1
  mulss  %xmm5,%xmm0
  addss  %xmm1,%xmm0
  movss  %xmm0,(%rax)
  add    $0x4,%rdx
  add    $0x4,%rax
  cmp    %rdi,%rax
  jne    L74
  jmp    L63
L29:
  movslq %r9d,%r9
  movss  0x4(%r8,%r9,4),%xmm1
  pxor   %xmm0,%xmm0
  cvtsi2ss %r10d,%xmm0
  mulss  %xmm1,%xmm0
  mulss  %xmm1,%xmm0
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L55:
  ret
```

assistant: ```c
float add_point(r_bar, diag, theta_bar, weight, drow, ivars)
float *r_bar, *diag, *theta_bar, *drow;
int ivars;
{
  float ss_error = 0.0, c_bar, s_bar, xi, xk, di, d_prime_i;
  int i, k, next_r;
  if (weight != 0.0) {
    for (i = 1; i <= ivars; i++) {
      if (drow[i] != 0) {
        xi = drow[i];
        di = diag[i];
        d_prime_i = di + weight * xi * xi;
        c_bar = di / d_prime_i;
        s_bar = weight * xi / d_prime_i;
        weight = c_bar * weight;
        diag[i] = d_prime_i;
        next_r = (i - 1) * (2 * ivars - i) / 2 + 1;
        for (k = i + 1; k <= ivars; k++) {
          xk = drow[k];
          drow[k] = xk - xi * r_bar[next_r];
          r_bar[next_r] = c_bar * r_bar[next_r] + s_bar * xk;
          next_r++;
        }
        xk = drow[ivars + 1];
        drow[ivars + 1] = xk - xi * theta_bar[i];
        theta_bar[i] = c_bar * theta_bar[i] + s_bar * xk;
      }
    }
    ss_error = weight * drow[ivars + 1] * drow[ivars + 1];
  }
  return (ss_error);
}
```