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

```asm
<dgemm1>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rdi,-0x10(%rsp)
  mov    %rsi,-0x48(%rsp)
  mov    %rdx,-0x8(%rsp)
  mov    %ecx,-0x5c(%rsp)
  mov    %r8d,-0x40(%rsp)
  test   %ecx,%ecx
  jle    L97
  mov    %r8d,%ebx
  imul   %ecx,%ebx
  mov    %ebx,-0x2c(%rsp)
  movslq %r8d,%rax
  mov    %rax,-0x20(%rsp)
  movslq %ecx,%rax
  lea    0x0(,%rax,8),%r15
  mov    %r8d,-0x38(%rsp)
  movq   $0x0,-0x28(%rsp)
  movl   $0x0,-0x30(%rsp)
  movl   $0x0,-0x3c(%rsp)
  jmp    L49
L64:
  movslq %r12d,%rax
  mov    -0x48(%rsp),%rdi
  lea    (%rdi,%rax,8),%rcx
  mov    -0x50(%rsp),%rdx
  mov    %rbp,%r8
  mov    %r14d,%edi
L72:
  movsd  (%r8),%xmm1
  cmp    %r10d,%r9d
  jge    L129
  mov    %r11,%rax
L83:
  movapd %xmm1,%xmm0
  mulsd  (%rcx,%rax,8),%xmm0
  addsd  (%rdx,%rax,8),%xmm0
  movsd  %xmm0,(%rdx,%rax,8)
  add    $0x1,%rax
  cmp    %eax,%esi
  jg     L83
L129:
  add    $0x1,%edi
  add    %r15,%r8
  add    %r15,%rdx
  cmp    %r13d,%edi
  jne    L72
L74:
  add    $0x1,%ebx
  add    $0x8,%rbp
  add    -0x5c(%rsp),%r12d
  cmp    -0x58(%rsp),%ebx
  je     L28
L69:
  cmp    -0x54(%rsp),%r14d
  jl     L64
  jmp    L74
L28:
  mov    -0x40(%rsp),%eax
  add    %eax,%r9d
  add    %eax,%r10d
  add    -0x20(%rsp),%r11
  cmp    %r9d,-0x5c(%rsp)
  jle    L15
L140:
  mov    -0x30(%rsp),%r12d
  mov    -0x18(%rsp),%rbp
  mov    -0x3c(%rsp),%eax
  mov    %eax,%ebx
  mov    %r10d,%esi
  mov    -0x38(%rsp),%edi
  cmp    %edi,%eax
  jl     L69
  jmp    L28
L15:
  mov    -0x40(%rsp),%eax
  add    %eax,%r14d
  add    %eax,%r13d
  mov    -0x2c(%rsp),%ebx
  add    %ebx,-0x34(%rsp)
  cmp    %r14d,-0x5c(%rsp)
  jle    L27
L86:
  movslq -0x34(%rsp),%rax
  mov    -0x28(%rsp),%rbx
  lea    (%rax,%rbx,1),%rdx
  mov    -0x10(%rsp),%rbx
  lea    (%rbx,%rdx,8),%rbx
  mov    %rbx,-0x18(%rsp)
  mov    -0x8(%rsp),%rbx
  lea    (%rbx,%rax,8),%rax
  mov    %rax,-0x50(%rsp)
  mov    -0x40(%rsp),%eax
  mov    %eax,%r10d
  mov    $0x0,%r11d
  mov    $0x0,%r9d
  add    %r14d,%eax
  mov    %eax,-0x54(%rsp)
  jmp    L140
L27:
  mov    -0x40(%rsp),%ebx
  add    %ebx,-0x3c(%rsp)
  mov    -0x3c(%rsp),%eax
  add    %ebx,-0x38(%rsp)
  mov    -0x2c(%rsp),%edi
  add    %edi,-0x30(%rsp)
  mov    -0x20(%rsp),%rdi
  add    %rdi,-0x28(%rsp)
  cmp    %eax,-0x5c(%rsp)
  jle    L97
L49:
  mov    -0x40(%rsp),%r13d
  movl   $0x0,-0x34(%rsp)
  mov    $0x0,%r14d
  mov    -0x38(%rsp),%eax
  mov    %eax,-0x58(%rsp)
  jmp    L86
L97:
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void dgemm1(double *a, double *b, double *c, int n, int BLOCK_SIZE) {
  int i, j, k;
  int ii, jj, kk;
  for (k = 0; k < n; k += BLOCK_SIZE) {
    for (i = 0; i < n; i += BLOCK_SIZE) {
      for (j = 0; j < n; j += BLOCK_SIZE) {
        for (kk = k; kk < k + BLOCK_SIZE; kk++) {
          for (ii = i; ii < i + BLOCK_SIZE; ii++) {
            register double r = a[ii * n + kk];
            for (jj = j; jj < j + BLOCK_SIZE; jj++) {
              c[ii * n + jj] += r * b[kk * n + jj];
            }
          }
        }
      }
    }
  }
}
```