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

```asm
<dmatvec>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  mov    %edi,-0x3c(%rbp)
  mov    %esi,-0x40(%rbp)
  mov    %edx,-0x44(%rbp)
  mov    %rcx,-0x50(%rbp)
  mov    %r8,-0x58(%rbp)
  mov    %r9,-0x60(%rbp)
  mov    $0x0,%ebx
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x30(%rbp)
  jmp    L34
L119:
  mov    -0x30(%rbp),%r12
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%r12,%rax,1),%r13
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    0x0(%r13,%rax,1),%r14
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%r14,%rax,1),%r15
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%r15,%rax,1),%rdi
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdi,%rax
  mov    %rax,%rcx
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rcx,%rax
  mov    %rax,%rsi
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rsi,%rax
  mov    %rax,%r10
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm3,%xmm8
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm9
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm10
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movapd %xmm6,%xmm11
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  movapd %xmm7,%xmm12
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm3,%xmm13
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm14
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm15
  movl   $0x0,-0x34(%rbp)
  jmp    L17
L16:
  mov    -0x34(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm0
  movapd %xmm0,%xmm2
  movapd %xmm8,%xmm6
  mulsd  %xmm6,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r13,%rax
  movsd  (%rax),%xmm0
  movapd %xmm9,%xmm7
  mulsd  %xmm7,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r14,%rax
  movsd  (%rax),%xmm0
  movapd %xmm10,%xmm3
  mulsd  %xmm3,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r15,%rax
  movsd  (%rax),%xmm0
  movapd %xmm11,%xmm4
  mulsd  %xmm4,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdi,%rax
  movsd  (%rax),%xmm0
  movapd %xmm12,%xmm5
  mulsd  %xmm5,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rcx,%rax
  movsd  (%rax),%xmm0
  movapd %xmm13,%xmm6
  mulsd  %xmm6,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rsi,%rax
  movsd  (%rax),%xmm0
  movapd %xmm14,%xmm7
  mulsd  %xmm7,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r10,%rax
  movsd  (%rax),%xmm0
  movapd %xmm15,%xmm3
  mulsd  %xmm3,%xmm0
  addsd  %xmm2,%xmm0
  mov    -0x34(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rdx,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x34(%rbp)
L17:
  mov    -0x34(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jl     L16
  mov    -0x3c(%rbp),%eax
  shl    $0x3,%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x30(%rbp)
L34:
  mov    -0x44(%rbp),%eax
  sub    $0x7,%eax
  cmp    %eax,%ebx
  jl     L119
  jmp    L97
L55:
  mov    -0x30(%rbp),%r12
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%r12,%rax,1),%r13
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    0x0(%r13,%rax,1),%r14
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%r14,%rax,1),%r15
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movapd %xmm1,%xmm8
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm9
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm10
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movapd %xmm6,%xmm11
  movl   $0x0,-0x34(%rbp)
  jmp    L60
L85:
  mov    -0x34(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm0
  movapd %xmm0,%xmm2
  movapd %xmm8,%xmm7
  mulsd  %xmm7,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r13,%rax
  movsd  (%rax),%xmm0
  movapd %xmm9,%xmm3
  mulsd  %xmm3,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r14,%rax
  movsd  (%rax),%xmm0
  movapd %xmm10,%xmm4
  mulsd  %xmm4,%xmm0
  addsd  %xmm0,%xmm2
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r15,%rax
  movsd  (%rax),%xmm0
  movapd %xmm11,%xmm5
  mulsd  %xmm5,%xmm0
  addsd  %xmm2,%xmm0
  mov    -0x34(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rdx,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x34(%rbp)
L60:
  mov    -0x34(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jl     L85
  mov    -0x3c(%rbp),%eax
  shl    $0x2,%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x30(%rbp)
L97:
  mov    -0x44(%rbp),%eax
  sub    $0x3,%eax
  cmp    %eax,%ebx
  jl     L55
  jmp    L64
L57:
  mov    -0x30(%rbp),%r12
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movapd %xmm1,%xmm8
  movl   $0x0,-0x34(%rbp)
  jmp    L70
L72:
  mov    -0x34(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm0
  movapd %xmm8,%xmm6
  mulsd  %xmm6,%xmm0
  mov    -0x34(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rdx,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x34(%rbp)
L70:
  mov    -0x34(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jl     L72
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x30(%rbp)
L64:
  cmp    -0x44(%rbp),%ebx
  jl     L57
  nop
  nop
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
```

assistant: ```c
void dmatvec(ldm, nrow, ncol, M, vec, Mxvec) int ldm;
int nrow;
int ncol;
double *M;
double *vec;
double *Mxvec;
{
  register double vi0, vi1, vi2, vi3, vi4, vi5, vi6, vi7;
  register double *Mki0, *Mki1, *Mki2, *Mki3, *Mki4, *Mki5, *Mki6, *Mki7;
  register int firstcol = 0;
  double *M0;
  int k;
  M0 = &M[0];
  while (firstcol < ncol - 7) {
    Mki0 = M0;
    Mki1 = Mki0 + ldm;
    Mki2 = Mki1 + ldm;
    Mki3 = Mki2 + ldm;
    Mki4 = Mki3 + ldm;
    Mki5 = Mki4 + ldm;
    Mki6 = Mki5 + ldm;
    Mki7 = Mki6 + ldm;
    vi0 = vec[firstcol++];
    vi1 = vec[firstcol++];
    vi2 = vec[firstcol++];
    vi3 = vec[firstcol++];
    vi4 = vec[firstcol++];
    vi5 = vec[firstcol++];
    vi6 = vec[firstcol++];
    vi7 = vec[firstcol++];
    for (k = 0; k < nrow; k++)
      Mxvec[k] += vi0 * Mki0[k] + vi1 * Mki1[k] + vi2 * Mki2[k] + vi3 * Mki3[k] + vi4 * Mki4[k] + vi5 * Mki5[k] + vi6 * Mki6[k] + vi7 * Mki7[k];
    M0 += 8 * ldm;
  }
  while (firstcol < ncol - 3) {
    Mki0 = M0;
    Mki1 = Mki0 + ldm;
    Mki2 = Mki1 + ldm;
    Mki3 = Mki2 + ldm;
    vi0 = vec[firstcol++];
    vi1 = vec[firstcol++];
    vi2 = vec[firstcol++];
    vi3 = vec[firstcol++];
    for (k = 0; k < nrow; k++)
      Mxvec[k] += vi0 * Mki0[k] + vi1 * Mki1[k] + vi2 * Mki2[k] + vi3 * Mki3[k];
    M0 += 4 * ldm;
  }
  while (firstcol < ncol) {
    Mki0 = M0;
    vi0 = vec[firstcol++];
    for (k = 0; k < nrow; k++)
      Mxvec[k] += vi0 * Mki0[k];
    M0 += ldm;
  }
}
```