user: Demonstrate the C code that generates the assembly output below:

```asm
<dlsolve>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  mov    %edi,-0x7c(%rbp)
  mov    %esi,-0x80(%rbp)
  mov    %rdx,-0x88(%rbp)
  mov    %rcx,-0x90(%rbp)
  mov    $0x0,%ebx
  mov    -0x88(%rbp),%rax
  mov    %rax,-0x70(%rbp)
  jmp    L106
L43:
  mov    -0x70(%rbp),%rax
  lea    0x8(%rax),%r12
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    (%r12,%rax,1),%r13
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    0x0(%r13,%rax,1),%r14
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    (%r14,%rax,1),%r15
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    (%r15,%rax,1),%rdi
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  mov    %rax,%rcx
  add    %rdi,%rcx
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  mov    %rax,%rsi
  add    %rcx,%rsi
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  add    %rsi,%rax
  mov    %rax,%r9
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  %xmm0,-0x68(%rbp)
  movslq %ebx,%rax
  add    $0x1,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x60(%rbp)
  movslq %ebx,%rax
  add    $0x2,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x58(%rbp)
  movslq %ebx,%rax
  add    $0x3,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x50(%rbp)
  movslq %ebx,%rax
  add    $0x4,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r15,%rax
  lea    0x8(%rax),%r15
  movsd  (%rax),%xmm1
  mulsd  -0x50(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x48(%rbp)
  movslq %ebx,%rax
  add    $0x5,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r15,%rax
  lea    0x8(%rax),%r15
  movsd  (%rax),%xmm1
  mulsd  -0x50(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rdi,%rax
  lea    0x8(%rax),%rdi
  movsd  (%rax),%xmm1
  mulsd  -0x48(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x40(%rbp)
  movslq %ebx,%rax
  add    $0x6,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r15,%rax
  lea    0x8(%rax),%r15
  movsd  (%rax),%xmm1
  mulsd  -0x50(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rdi,%rax
  lea    0x8(%rax),%rdi
  movsd  (%rax),%xmm1
  mulsd  -0x48(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rcx,%rax
  lea    0x8(%rax),%rcx
  movsd  (%rax),%xmm1
  mulsd  -0x40(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x38(%rbp)
  movslq %ebx,%rax
  add    $0x7,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r15,%rax
  lea    0x8(%rax),%r15
  movsd  (%rax),%xmm1
  mulsd  -0x50(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rdi,%rax
  lea    0x8(%rax),%rdi
  movsd  (%rax),%xmm1
  mulsd  -0x48(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rcx,%rax
  lea    0x8(%rax),%rcx
  mov    %rcx,%r8
  movsd  (%rax),%xmm1
  mulsd  -0x40(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rsi,%rax
  lea    0x8(%rax),%rsi
  mov    %rsi,%rcx
  movsd  (%rax),%xmm1
  mulsd  -0x38(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x30(%rbp)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x60(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x58(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x50(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x48(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x40(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x38(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x30(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  mov    %ebx,-0x74(%rbp)
  jmp    L17
L104:
  mov    -0x74(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r15,%rax
  lea    0x8(%rax),%r15
  movsd  (%rax),%xmm1
  mulsd  -0x50(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rdi,%rax
  lea    0x8(%rax),%rsi
  mov    %rsi,%rdi
  movsd  (%rax),%xmm1
  mulsd  -0x48(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r8,%rax
  lea    0x8(%rax),%rsi
  mov    %rsi,%r8
  movsd  (%rax),%xmm1
  mulsd  -0x40(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %rcx,%rax
  lea    0x8(%rax),%rcx
  movsd  (%rax),%xmm1
  mulsd  -0x38(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r9,%rax
  lea    0x8(%rax),%rsi
  mov    %rsi,%r9
  movsd  (%rax),%xmm1
  mulsd  -0x30(%rbp),%xmm1
  mov    -0x74(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x74(%rbp)
L17:
  mov    -0x74(%rbp),%eax
  cmp    -0x80(%rbp),%eax
  jl     L104
  mov    -0x7c(%rbp),%eax
  shl    $0x3,%eax
  cltq
  add    $0x8,%rax
  shl    $0x3,%rax
  add    %rax,-0x70(%rbp)
L106:
  mov    -0x80(%rbp),%eax
  sub    $0x7,%eax
  cmp    %eax,%ebx
  jl     L43
  jmp    L109
L82:
  mov    -0x70(%rbp),%rax
  lea    0x8(%rax),%r12
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    (%r12,%rax,1),%r13
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    0x0(%r13,%rax,1),%r14
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    (%r14,%rax,1),%r15
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  %xmm0,-0x68(%rbp)
  movslq %ebx,%rax
  add    $0x1,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x60(%rbp)
  movslq %ebx,%rax
  add    $0x2,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x58(%rbp)
  movslq %ebx,%rax
  add    $0x3,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x50(%rbp)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x60(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x58(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x50(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  mov    %ebx,-0x74(%rbp)
  jmp    L36
L9:
  mov    -0x74(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r14,%rax
  lea    0x8(%rax),%r14
  movsd  (%rax),%xmm1
  mulsd  -0x58(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r15,%rax
  lea    0x8(%rax),%r15
  movsd  (%rax),%xmm1
  mulsd  -0x50(%rbp),%xmm1
  mov    -0x74(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x74(%rbp)
L36:
  mov    -0x74(%rbp),%eax
  cmp    -0x80(%rbp),%eax
  jl     L9
  mov    -0x7c(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x4,%rax
  shl    $0x3,%rax
  add    %rax,-0x70(%rbp)
L109:
  mov    -0x80(%rbp),%eax
  sub    $0x3,%eax
  cmp    %eax,%ebx
  jl     L82
  mov    -0x80(%rbp),%eax
  sub    $0x1,%eax
  cmp    %eax,%ebx
  jge    L73
  mov    -0x70(%rbp),%rax
  lea    0x8(%rax),%r12
  mov    -0x7c(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  lea    (%r12,%rax,1),%r13
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  %xmm0,-0x68(%rbp)
  movslq %ebx,%rax
  add    $0x1,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x60(%rbp)
  add    $0x1,%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x60(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
  mov    %ebx,-0x74(%rbp)
  jmp    L27
L70:
  mov    -0x74(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    %r12,%rax
  lea    0x8(%rax),%r12
  movsd  (%rax),%xmm1
  mulsd  -0x68(%rbp),%xmm1
  subsd  %xmm1,%xmm0
  mov    %r13,%rax
  lea    0x8(%rax),%r13
  movsd  (%rax),%xmm1
  mulsd  -0x60(%rbp),%xmm1
  mov    -0x74(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x90(%rbp),%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x74(%rbp)
L27:
  mov    -0x74(%rbp),%eax
  cmp    -0x80(%rbp),%eax
  jl     L70
L73:
  nop
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
```

assistant: ```c
void dlsolve(int ldm, int ncol, double *M, double *rhs) {
  int k;
  double x0, x1, x2, x3, x4, x5, x6, x7;
  double *M0;
  register double *Mki0, *Mki1, *Mki2, *Mki3, *Mki4, *Mki5, *Mki6, *Mki7;
  register int firstcol = 0;
  M0 = &M[0];
  while (firstcol < ncol - 7) {
    Mki0 = M0 + 1;
    Mki1 = Mki0 + ldm + 1;
    Mki2 = Mki1 + ldm + 1;
    Mki3 = Mki2 + ldm + 1;
    Mki4 = Mki3 + ldm + 1;
    Mki5 = Mki4 + ldm + 1;
    Mki6 = Mki5 + ldm + 1;
    Mki7 = Mki6 + ldm + 1;
    x0 = rhs[firstcol];
    x1 = rhs[firstcol + 1] - x0 * *Mki0++;
    x2 = rhs[firstcol + 2] - x0 * *Mki0++ - x1 * *Mki1++;
    x3 = rhs[firstcol + 3] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++;
    x4 = rhs[firstcol + 4] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++ - x3 * *Mki3++;
    x5 = rhs[firstcol + 5] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++ - x3 * *Mki3++ - x4 * *Mki4++;
    x6 = rhs[firstcol + 6] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++ - x3 * *Mki3++ - x4 * *Mki4++ - x5 * *Mki5++;
    x7 = rhs[firstcol + 7] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++ - x3 * *Mki3++ - x4 * *Mki4++ - x5 * *Mki5++ - x6 * *Mki6++;
    rhs[++firstcol] = x1;
    rhs[++firstcol] = x2;
    rhs[++firstcol] = x3;
    rhs[++firstcol] = x4;
    rhs[++firstcol] = x5;
    rhs[++firstcol] = x6;
    rhs[++firstcol] = x7;
    ++firstcol;
    for (k = firstcol; k < ncol; k++)
      rhs[k] = rhs[k] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++ - x3 * *Mki3++ - x4 * *Mki4++ - x5 * *Mki5++ - x6 * *Mki6++ - x7 * *Mki7++;
    M0 += 8 * ldm + 8;
  }
  while (firstcol < ncol - 3) {
    Mki0 = M0 + 1;
    Mki1 = Mki0 + ldm + 1;
    Mki2 = Mki1 + ldm + 1;
    Mki3 = Mki2 + ldm + 1;
    x0 = rhs[firstcol];
    x1 = rhs[firstcol + 1] - x0 * *Mki0++;
    x2 = rhs[firstcol + 2] - x0 * *Mki0++ - x1 * *Mki1++;
    x3 = rhs[firstcol + 3] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++;
    rhs[++firstcol] = x1;
    rhs[++firstcol] = x2;
    rhs[++firstcol] = x3;
    ++firstcol;
    for (k = firstcol; k < ncol; k++)
      rhs[k] = rhs[k] - x0 * *Mki0++ - x1 * *Mki1++ - x2 * *Mki2++ - x3 * *Mki3++;
    M0 += 4 * ldm + 4;
  }
  if (firstcol < ncol - 1) {
    Mki0 = M0 + 1;
    Mki1 = Mki0 + ldm + 1;
    x0 = rhs[firstcol];
    x1 = rhs[firstcol + 1] - x0 * *Mki0++;
    rhs[++firstcol] = x1;
    ++firstcol;
    for (k = firstcol; k < ncol; k++)
      rhs[k] = rhs[k] - x0 * *Mki0++ - x1 * *Mki1++;
  }
}
```