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

```asm
<kernel_dtrsm_nn_ll_diag_2x2_vs_lib4>:
  endbr64
  push   %r12
  mov    %edi,%r10d
  mov    %esi,%r11d
  push   %rbp
  push   %rbx
  mov    0x28(%rsp),%r12
  mov    0x30(%rsp),%rbp
  test   %edx,%edx
  jle    L49
  mov    %edx,%ebx
  mov    %rcx,%rax
  cmp    $0x3,%edx
  jle    L108
  lea    -0x4(%rdx),%edi
  shl    $0x2,%r9d
  pxor   %xmm0,%xmm0
  mov    %r8,%rdx
  shr    $0x2,%edi
  movapd %xmm0,%xmm2
  movapd %xmm0,%xmm1
  movslq %r9d,%rsi
  lea    0x1(%rdi),%r9d
  shl    $0x3,%rsi
  movapd %xmm0,%xmm6
  mov    %r9,%rcx
  mov    %r9,%rdi
  shl    $0x7,%rcx
  add    %rax,%rcx
  nopl   0x0(%rax,%rax,1)
L95:
  movsd  0x20(%rdx),%xmm7
  movsd  (%rax),%xmm4
  sub    $0xffffffffffffff80,%rax
  movsd  (%rdx),%xmm5
  movsd  -0x78(%rax),%xmm3
  movapd %xmm4,%xmm8
  mulsd  %xmm7,%xmm4
  mulsd  %xmm5,%xmm8
  mulsd  %xmm3,%xmm5
  mulsd  %xmm7,%xmm3
  movsd  0x28(%rdx),%xmm7
  subsd  %xmm4,%xmm1
  movsd  -0x60(%rax),%xmm4
  subsd  %xmm8,%xmm6
  subsd  %xmm5,%xmm2
  movsd  0x8(%rdx),%xmm5
  movapd %xmm4,%xmm8
  subsd  %xmm3,%xmm0
  movsd  -0x58(%rax),%xmm3
  mulsd  %xmm7,%xmm4
  mulsd  %xmm5,%xmm8
  mulsd  %xmm3,%xmm5
  mulsd  %xmm7,%xmm3
  movsd  0x30(%rdx),%xmm7
  subsd  %xmm4,%xmm1
  movsd  -0x40(%rax),%xmm4
  subsd  %xmm8,%xmm6
  subsd  %xmm5,%xmm2
  movsd  0x10(%rdx),%xmm5
  movapd %xmm4,%xmm8
  subsd  %xmm3,%xmm0
  movsd  -0x38(%rax),%xmm3
  mulsd  %xmm7,%xmm4
  mulsd  %xmm5,%xmm8
  mulsd  %xmm3,%xmm5
  mulsd  %xmm7,%xmm3
  movsd  0x38(%rdx),%xmm7
  subsd  %xmm4,%xmm1
  movsd  -0x20(%rax),%xmm4
  subsd  %xmm8,%xmm6
  subsd  %xmm5,%xmm2
  movsd  0x18(%rdx),%xmm5
  movapd %xmm4,%xmm8
  add    %rsi,%rdx
  subsd  %xmm3,%xmm0
  movsd  -0x18(%rax),%xmm3
  mulsd  %xmm7,%xmm4
  mulsd  %xmm5,%xmm8
  mulsd  %xmm3,%xmm5
  mulsd  %xmm7,%xmm3
  subsd  %xmm4,%xmm1
  subsd  %xmm8,%xmm6
  subsd  %xmm5,%xmm2
  subsd  %xmm3,%xmm0
  cmp    %rcx,%rax
  jne    L95
  imul   %r9,%rsi
  shl    $0x2,%edi
  add    %rsi,%r8
  cmp    %edi,%ebx
  jle    L42
L51:
  movsd  (%rcx),%xmm4
  movsd  0x8(%rcx),%xmm3
  add    $0x1,%edi
  add    $0x20,%rcx
  movsd  (%r8),%xmm5
  movsd  0x20(%r8),%xmm7
  add    $0x8,%r8
  movapd %xmm4,%xmm8
  mulsd  %xmm5,%xmm8
  mulsd  %xmm7,%xmm4
  mulsd  %xmm3,%xmm5
  mulsd  %xmm7,%xmm3
  subsd  %xmm8,%xmm6
  subsd  %xmm4,%xmm1
  subsd  %xmm5,%xmm2
  subsd  %xmm3,%xmm0
  cmp    %edi,%ebx
  jg     L51
L42:
  mov    0x20(%rsp),%eax
  test   %eax,%eax
  je     L97
  addsd  (%r12),%xmm6
  addsd  0x8(%r12),%xmm2
  addsd  0x20(%r12),%xmm1
  addsd  0x28(%r12),%xmm0
L97:
  movsd  %xmm6,0x0(%rbp)
  cmp    $0x1,%r11d
  jle    L63
  movsd  %xmm1,0x20(%rbp)
  cmp    $0x1,%r10d
  jle    L18
  mov    0x38(%rsp),%rax
  movsd  0x8(%rax),%xmm4
  mulsd  %xmm4,%xmm6
  mulsd  %xmm4,%xmm1
  subsd  %xmm6,%xmm2
  subsd  %xmm1,%xmm0
  movsd  %xmm2,0x8(%rbp)
  movsd  %xmm0,0x28(%rbp)
L18:
  pop    %rbx
  pop    %rbp
  pop    %r12
  ret
  nopl   0x0(%rax)
L63:
  cmp    $0x1,%r10d
  jle    L18
  mov    0x38(%rsp),%rax
  mulsd  0x8(%rax),%xmm6
  subsd  %xmm6,%xmm2
  movsd  %xmm2,0x8(%rbp)
  pop    %rbx
  pop    %rbp
  pop    %r12
  ret
  xchg   %ax,%ax
L49:
  pxor   %xmm0,%xmm0
  movapd %xmm0,%xmm2
  movapd %xmm0,%xmm1
  movapd %xmm0,%xmm6
  jmp    L42
  nopl   (%rax)
L108:
  pxor   %xmm0,%xmm0
  xor    %edi,%edi
  movapd %xmm0,%xmm2
  movapd %xmm0,%xmm1
  movapd %xmm0,%xmm6
  jmp    L51
```

assistant: ```c
void kernel_dtrsm_nn_ll_diag_2x2_vs_lib4(int km, int kn, int kmax, double *A, double *B, int sdb, int alg, double *C, double *D, double *E) {
  const int bs = 4;
  int k;
  double tmp, a_0, a_1, b_0, b_1, e_1, e_2, e_3, d_00 = 0, d_01 = 0, d_10 = 0, d_11 = 0;
  if (kmax <= 0)
    goto add;
  for (k = 0; k < kmax - 3; k += 4) {
    a_0 = A[0 + bs * 0];
    a_1 = A[1 + bs * 0];
    b_0 = B[0 + bs * 0];
    b_1 = B[0 + bs * 1];
    d_00 -= a_0 * b_0;
    d_10 -= a_1 * b_0;
    d_01 -= a_0 * b_1;
    d_11 -= a_1 * b_1;
    a_0 = A[0 + bs * 1];
    a_1 = A[1 + bs * 1];
    b_0 = B[1 + bs * 0];
    b_1 = B[1 + bs * 1];
    d_00 -= a_0 * b_0;
    d_10 -= a_1 * b_0;
    d_01 -= a_0 * b_1;
    d_11 -= a_1 * b_1;
    a_0 = A[0 + bs * 2];
    a_1 = A[1 + bs * 2];
    b_0 = B[2 + bs * 0];
    b_1 = B[2 + bs * 1];
    d_00 -= a_0 * b_0;
    d_10 -= a_1 * b_0;
    d_01 -= a_0 * b_1;
    d_11 -= a_1 * b_1;
    a_0 = A[0 + bs * 3];
    a_1 = A[1 + bs * 3];
    b_0 = B[3 + bs * 0];
    b_1 = B[3 + bs * 1];
    d_00 -= a_0 * b_0;
    d_10 -= a_1 * b_0;
    d_01 -= a_0 * b_1;
    d_11 -= a_1 * b_1;
    A += 16;
    B += 4 * sdb;
  }
  for (; k < kmax; k++) {
    a_0 = A[0 + bs * 0];
    a_1 = A[1 + bs * 0];
    b_0 = B[0 + bs * 0];
    b_1 = B[0 + bs * 1];
    d_00 -= a_0 * b_0;
    d_10 -= a_1 * b_0;
    d_01 -= a_0 * b_1;
    d_11 -= a_1 * b_1;
    A += 4;
    B += 1;
  }
add:
  if (alg != 0) {
    d_00 += C[0 + bs * 0];
    d_10 += C[1 + bs * 0];
    d_01 += C[0 + bs * 1];
    d_11 += C[1 + bs * 1];
  }
  D[0 + bs * 0] = d_00;
  if (kn >= 2)
    D[0 + bs * 1] = d_01;
  if (km < 2)
    return;
  e_1 = E[1 + bs * 0];
  d_10 -= e_1 * d_00;
  d_11 -= e_1 * d_01;
  D[1 + bs * 0] = d_10;
  if (kn >= 2)
    D[1 + bs * 1] = d_11;
  return;
}
```