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

```asm
<dottn>:
  endbr64
  push   %r15
  mov    %rcx,%rax
  push   %r14
  mov    %r8,%r14
  mov    %r9,%r8
  push   %r13
  imul   %r14,%rax
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rsi,%rbx
  sub    $0x78,%rsp
  mov    %rdi,0x60(%rsp)
  mov    %rdx,0x48(%rsp)
  mov    %rcx,0x50(%rsp)
  test   %rax,%rax
  je     L71
  lea    0x0(,%rax,4),%rdx
  xor    %esi,%esi
  mov    %r9,%rdi
  call   <memset@plt>
  mov    %rax,%r8
L71:
  cmpq   $0x0,0x48(%rsp)
  je     L130
  cmpq   $0x0,0x50(%rsp)
  je     L130
  test   %r14,%r14
  je     L130
  lea    0x0(,%r14,4),%rax
  xor    %edi,%edi
  movq   $0x0,0x40(%rsp)
  mov    %rax,0x18(%rsp)
  add    %r8,%rax
  mov    %rax,0x58(%rsp)
  lea    -0x1(%r14),%rax
  mov    %rax,0x20(%rsp)
  mov    %r14,%rax
  movq   $0x0,0x38(%rsp)
  shr    $0x2,%rax
  shl    $0x4,%rax
  mov    %rax,%r15
  mov    %r14,%rax
  and    $0xfffffffffffffffc,%rax
  mov    %rax,0x28(%rsp)
  lea    0x4(%rbx),%rax
  mov    %rax,0x68(%rsp)
  mov    %r14,%rax
  and    $0x3,%eax
  mov    %rax,0x30(%rsp)
  nopl   0x0(%rax)
L42:
  mov    0x68(%rsp),%rcx
  lea    0x0(,%rdi,4),%r10
  mov    0x60(%rsp),%rsi
  mov    %r8,%rdx
  mov    0x40(%rsp),%rax
  mov    0x58(%rsp),%r11
  add    %r10,%rcx
  add    %rbx,%r10
  mov    %rcx,0x10(%rsp)
  mov    0x50(%rsp),%rcx
  lea    (%rsi,%rax,4),%r9
  add    %rcx,%rax
  mov    %rax,0x40(%rsp)
  lea    (%rsi,%rax,4),%rax
  xor    %esi,%esi
  mov    %rax,0x8(%rsp)
  cs nopw 0x0(%rax,%rax,1)
L158:
  mov    %r9,%rcx
  add    $0x4,%r9
  cmp    %r9,%rdx
  setae  %al
  cmp    %r11,%rcx
  setae  %bpl
  or     %ebp,%eax
  mov    %rdx,%rbp
  sub    0x10(%rsp),%rbp
  cmp    $0x8,%rbp
  seta   %bpl
  test   %bpl,%al
  je     L70
  cmp    $0x1,%r14
  je     L70
  cmpq   $0x2,0x20(%rsp)
  jbe    L19
  movss  (%rcx),%xmm1
  xor    %eax,%eax
  shufps $0x0,%xmm1,%xmm1
  nop
L56:
  movups (%r10,%rax,1),%xmm0
  movups (%rdx,%rax,1),%xmm2
  mulps  %xmm1,%xmm0
  addps  %xmm2,%xmm0
  movups %xmm0,(%rdx,%rax,1)
  add    $0x10,%rax
  cmp    %r15,%rax
  jne    L56
  mov    0x28(%rsp),%rax
  cmp    %rax,%r14
  je     L118
  mov    0x30(%rsp),%rbp
  mov    %rbp,%r12
  cmp    $0x1,%rbp
  je     L95
L80:
  lea    (%rax,%rdi,1),%r13
  movss  (%rcx),%xmm1
  lea    (%rax,%rsi,1),%rbp
  movq   (%rbx,%r13,4),%xmm0
  lea    (%r8,%rbp,4),%rbp
  shufps $0xe0,%xmm1,%xmm1
  mulps  %xmm1,%xmm0
  movq   0x0(%rbp),%xmm1
  addps  %xmm0,%xmm1
  movlps %xmm1,0x0(%rbp)
  mov    %r12,%rbp
  and    $0xfffffffffffffffe,%rbp
  add    %rbp,%rax
  cmp    %rbp,%r12
  je     L118
L95:
  lea    (%rsi,%rax,1),%rbp
  add    %rdi,%rax
  movss  (%rbx,%rax,4),%xmm0
  lea    (%r8,%rbp,4),%rbp
  mulss  (%rcx),%xmm0
  addss  0x0(%rbp),%xmm0
  movss  %xmm0,0x0(%rbp)
L118:
  mov    0x18(%rsp),%rax
  add    %r14,%rsi
  add    %rax,%rdx
  add    %rax,%r11
  cmp    0x8(%rsp),%r9
  jne    L158
  addq   $0x1,0x38(%rsp)
  add    %r14,%rdi
  mov    0x38(%rsp),%rax
  cmp    %rax,0x48(%rsp)
  jne    L42
L130:
  add    $0x78,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L70:
  mov    %r10,%rbp
  mov    %rdx,%rax
  cs nopw 0x0(%rax,%rax,1)
L11:
  movss  0x0(%rbp),%xmm0
  mulss  (%rcx),%xmm0
  add    $0x4,%rax
  add    $0x4,%rbp
  addss  -0x4(%rax),%xmm0
  movss  %xmm0,-0x4(%rax)
  cmp    %rax,%r11
  jne    L11
  jmp    L118
L19:
  mov    %r14,%r12
  xor    %eax,%eax
  jmp    L80
```

assistant: ```c
void dottn(const float *a, const float *b, size_t m, size_t n, size_t o, float *d) {
  size_t i, j, k;
  for (i = 0; i < n * o; i++)
    d[i] = 0.0;
  for (k = 0; k < m; k++)
    for (i = 0; i < n; i++)
      for (j = 0; j < o; j++)
        d[i * o + j] += a[k * n + i] * b[k * o + j];
}
```