user: What would the C source look like for the assembly code provided here:

```asm
<add_point>:
  endbr64
  pxor   %xmm0,%xmm0
  test   %ecx,%ecx
  je     L31
  lea    0x1(%r9),%eax
  push   %r15
  mov    %ecx,%r10d
  cltq
  push   %r14
  push   %r13
  push   %r12
  lea    (%r8,%rax,4),%r12
  push   %rbp
  push   %rbx
  test   %r9d,%r9d
  jle    L67
  mov    %rsi,%rbp
  mov    %rdi,%rbx
  lea    0x8(%r8),%rsi
  mov    %rdx,%r11
  lea    0x2(%r9),%r8d
  mov    $0x2,%ecx
  lea    0x1(%r9,%r9,1),%r13d
  lea    0x8(%rdi),%r14
  jmp    L15
  nopl   0x0(%rax)
L12:
  add    $0x1,%rcx
  add    $0x4,%rsi
  cmp    %r8,%rcx
  je     L67
L15:
  movss  -0x4(%rsi),%xmm3
  mov    %ecx,%edi
  ucomiss %xmm0,%xmm3
  jp     L51
  je     L12
L51:
  pxor   %xmm2,%xmm2
  movaps %xmm3,%xmm5
  movaps %xmm3,%xmm1
  movss  -0x4(%rbp,%rcx,4),%xmm4
  cvtsi2ss %r10d,%xmm2
  mov    %r13d,%eax
  lea    -0x2(%rdi),%edx
  sub    %edi,%eax
  imul   %edx,%eax
  mulss  %xmm2,%xmm5
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %eax,%edx
  sar    %edx
  mulss  %xmm5,%xmm1
  movaps %xmm5,%xmm6
  lea    0x1(%rdx),%eax
  addss  %xmm4,%xmm1
  divss  %xmm1,%xmm4
  movss  %xmm1,-0x4(%rbp,%rcx,4)
  divss  %xmm1,%xmm6
  mulss  %xmm4,%xmm2
  cvttss2si %xmm2,%r10d
  cmp    %ecx,%r9d
  jl     L68
  mov    %r9d,%r15d
  movslq %edx,%rdx
  cltq
  sub    %edi,%r15d
  lea    (%rbx,%rax,4),%rax
  add    %rdx,%r15
  mov    %rsi,%rdx
  lea    (%r14,%r15,4),%rdi
  nopw   0x0(%rax,%rax,1)
L19:
  movss  (%rax),%xmm5
  movss  (%rdx),%xmm1
  add    $0x4,%rax
  add    $0x4,%rdx
  mulss  %xmm3,%xmm5
  movaps %xmm1,%xmm2
  mulss  %xmm6,%xmm1
  subss  %xmm5,%xmm2
  movss  %xmm2,-0x4(%rdx)
  movss  -0x4(%rax),%xmm2
  mulss  %xmm4,%xmm2
  addss  %xmm2,%xmm1
  movss  %xmm1,-0x4(%rax)
  cmp    %rax,%rdi
  jne    L19
L68:
  mulss  -0x4(%r11,%rcx,4),%xmm3
  movss  (%r12),%xmm1
  add    $0x4,%rsi
  movaps %xmm1,%xmm2
  mulss  %xmm6,%xmm1
  subss  %xmm3,%xmm2
  movss  %xmm2,(%r12)
  mulss  -0x4(%r11,%rcx,4),%xmm4
  addss  %xmm1,%xmm4
  movss  %xmm4,-0x4(%r11,%rcx,4)
  add    $0x1,%rcx
  cmp    %r8,%rcx
  jne    L15
L67:
  pxor   %xmm0,%xmm0
  movss  (%r12),%xmm1
  pop    %rbx
  cvtsi2ss %r10d,%xmm0
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  mulss  %xmm1,%xmm0
  mulss  %xmm1,%xmm0
  ret
  xchg   %ax,%ax
L31:
  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);
}
```