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

```asm
<kernel_dtrmv_u_n_8_lib4>:
  endbr64
  test   %edi,%edi
  jle    L99
  push   %r12
  push   %rbp
  push   %rbx
  mov    %edi,%r10d
  shl    $0x2,%edx
  movslq %edx,%rdx
  lea    (%rsi,%rdx,8),%rdi
  movsd  0x8(%rcx),%xmm1
  movsd  0x10(%rcx),%xmm0
  movsd  0x18(%rcx),%xmm3
  movsd  (%rsi),%xmm4
  mulsd  (%rcx),%xmm4
  pxor   %xmm2,%xmm2
  addsd  %xmm2,%xmm4
  movapd %xmm1,%xmm5
  mulsd  0x20(%rsi),%xmm5
  addsd  %xmm5,%xmm4
  mulsd  0x28(%rsi),%xmm1
  addsd  %xmm2,%xmm1
  movapd %xmm0,%xmm5
  mulsd  0x40(%rsi),%xmm5
  addsd  %xmm4,%xmm5
  movapd %xmm0,%xmm4
  mulsd  0x48(%rsi),%xmm4
  addsd  %xmm4,%xmm1
  mulsd  0x50(%rsi),%xmm0
  addsd  %xmm2,%xmm0
  movapd %xmm3,%xmm8
  mulsd  0x60(%rsi),%xmm8
  addsd  %xmm5,%xmm8
  movapd %xmm3,%xmm7
  mulsd  0x68(%rsi),%xmm7
  addsd  %xmm1,%xmm7
  movapd %xmm3,%xmm6
  mulsd  0x70(%rsi),%xmm6
  addsd  %xmm0,%xmm6
  mulsd  0x78(%rsi),%xmm3
  addsd  %xmm2,%xmm3
  movsd  0x20(%rcx),%xmm4
  movsd  0x28(%rcx),%xmm1
  movsd  0x30(%rcx),%xmm0
  movsd  0x38(%rcx),%xmm11
  movapd %xmm4,%xmm5
  mulsd  0x80(%rsi),%xmm5
  addsd  %xmm8,%xmm5
  movapd %xmm4,%xmm9
  mulsd  0x88(%rsi),%xmm9
  addsd  %xmm7,%xmm9
  movapd %xmm4,%xmm8
  mulsd  0x90(%rsi),%xmm8
  addsd  %xmm6,%xmm8
  movapd %xmm4,%xmm7
  mulsd  0x98(%rsi),%xmm7
  addsd  %xmm3,%xmm7
  mulsd  0x80(%rdi),%xmm4
  addsd  %xmm2,%xmm4
  movapd %xmm1,%xmm6
  mulsd  0xa0(%rsi),%xmm6
  addsd  %xmm5,%xmm6
  movapd %xmm1,%xmm5
  mulsd  0xa8(%rsi),%xmm5
  addsd  %xmm9,%xmm5
  movapd %xmm1,%xmm9
  mulsd  0xb0(%rsi),%xmm9
  addsd  %xmm8,%xmm9
  movapd %xmm1,%xmm3
  mulsd  0xb8(%rsi),%xmm3
  addsd  %xmm7,%xmm3
  movapd %xmm1,%xmm8
  mulsd  0xa0(%rdi),%xmm8
  addsd  %xmm4,%xmm8
  mulsd  0xa8(%rdi),%xmm1
  addsd  %xmm2,%xmm1
  movapd %xmm0,%xmm7
  mulsd  0xc0(%rsi),%xmm7
  addsd  %xmm6,%xmm7
  movapd %xmm0,%xmm6
  mulsd  0xc8(%rsi),%xmm6
  addsd  %xmm5,%xmm6
  movapd %xmm0,%xmm5
  mulsd  0xd0(%rsi),%xmm5
  addsd  %xmm9,%xmm5
  movapd %xmm0,%xmm4
  mulsd  0xd8(%rsi),%xmm4
  addsd  %xmm3,%xmm4
  movapd %xmm0,%xmm3
  mulsd  0xc0(%rdi),%xmm3
  addsd  %xmm8,%xmm3
  movapd %xmm0,%xmm8
  mulsd  0xc8(%rdi),%xmm8
  addsd  %xmm8,%xmm1
  mulsd  0xd0(%rdi),%xmm0
  addsd  %xmm2,%xmm0
  movapd %xmm11,%xmm10
  mulsd  0xe0(%rsi),%xmm10
  addsd  %xmm7,%xmm10
  movapd %xmm11,%xmm9
  mulsd  0xe8(%rsi),%xmm9
  addsd  %xmm6,%xmm9
  movapd %xmm11,%xmm8
  mulsd  0xf0(%rsi),%xmm8
  addsd  %xmm5,%xmm8
  movapd %xmm11,%xmm7
  mulsd  0xf8(%rsi),%xmm7
  addsd  %xmm4,%xmm7
  movapd %xmm11,%xmm6
  mulsd  0xe0(%rdi),%xmm6
  addsd  %xmm3,%xmm6
  movapd %xmm11,%xmm5
  mulsd  0xe8(%rdi),%xmm5
  addsd  %xmm1,%xmm5
  movapd %xmm11,%xmm4
  mulsd  0xf0(%rdi),%xmm4
  addsd  %xmm0,%xmm4
  mulsd  0xf8(%rdi),%xmm11
  addsd  %xmm2,%xmm11
  lea    0x100(%rsi),%r11
  add    $0x100,%rdi
  lea    0x40(%rcx),%rbx
  cmp    $0xb,%r10d
  jle    L36
  lea    -0xc(%r10),%r12d
  shr    $0x2,%r12d
  mov    %r12d,%ebp
  lea    0x3(%rbp),%rdx
  shl    $0x7,%rdx
  lea    (%rsi,%rdx,1),%rsi
  mov    %rdi,%rdx
  mov    %rbx,%rcx
  mov    %r11,%rax
L6:
  movsd  (%rcx),%xmm2
  movsd  0x8(%rcx),%xmm1
  movsd  0x10(%rcx),%xmm0
  movsd  0x18(%rcx),%xmm3
  movapd %xmm2,%xmm12
  mulsd  (%rax),%xmm12
  addsd  %xmm12,%xmm10
  movapd %xmm2,%xmm12
  mulsd  0x8(%rax),%xmm12
  addsd  %xmm12,%xmm9
  movapd %xmm2,%xmm12
  mulsd  0x10(%rax),%xmm12
  addsd  %xmm8,%xmm12
  movapd %xmm2,%xmm13
  mulsd  0x18(%rax),%xmm13
  addsd  %xmm7,%xmm13
  movapd %xmm2,%xmm8
  mulsd  (%rdx),%xmm8
  addsd  %xmm6,%xmm8
  movapd %xmm2,%xmm7
  mulsd  0x8(%rdx),%xmm7
  addsd  %xmm5,%xmm7
  movapd %xmm2,%xmm6
  mulsd  0x10(%rdx),%xmm6
  addsd  %xmm4,%xmm6
  mulsd  0x18(%rdx),%xmm2
  addsd  %xmm11,%xmm2
  movapd %xmm1,%xmm4
  mulsd  0x20(%rax),%xmm4
  addsd  %xmm4,%xmm10
  movapd %xmm1,%xmm11
  mulsd  0x28(%rax),%xmm11
  addsd  %xmm9,%xmm11
  movapd %xmm1,%xmm4
  mulsd  0x30(%rax),%xmm4
  addsd  %xmm4,%xmm12
  movapd %xmm1,%xmm5
  mulsd  0x38(%rax),%xmm5
  addsd  %xmm13,%xmm5
  movapd %xmm1,%xmm4
  mulsd  0x20(%rdx),%xmm4
  addsd  %xmm8,%xmm4
  movapd %xmm1,%xmm9
  mulsd  0x28(%rdx),%xmm9
  addsd  %xmm7,%xmm9
  movapd %xmm1,%xmm8
  mulsd  0x30(%rdx),%xmm8
  addsd  %xmm6,%xmm8
  mulsd  0x38(%rdx),%xmm1
  addsd  %xmm2,%xmm1
  movapd %xmm0,%xmm13
  mulsd  0x40(%rax),%xmm13
  addsd  %xmm10,%xmm13
  movapd %xmm0,%xmm2
  mulsd  0x48(%rax),%xmm2
  addsd  %xmm2,%xmm11
  movapd %xmm0,%xmm7
  mulsd  0x50(%rax),%xmm7
  addsd  %xmm12,%xmm7
  movapd %xmm0,%xmm6
  mulsd  0x58(%rax),%xmm6
  addsd  %xmm5,%xmm6
  movapd %xmm0,%xmm5
  mulsd  0x40(%rdx),%xmm5
  addsd  %xmm4,%xmm5
  movapd %xmm0,%xmm4
  mulsd  0x48(%rdx),%xmm4
  addsd  %xmm9,%xmm4
  movapd %xmm0,%xmm2
  mulsd  0x50(%rdx),%xmm2
  addsd  %xmm8,%xmm2
  mulsd  0x58(%rdx),%xmm0
  addsd  %xmm1,%xmm0
  movapd %xmm3,%xmm10
  mulsd  0x60(%rax),%xmm10
  addsd  %xmm13,%xmm10
  movapd %xmm3,%xmm9
  mulsd  0x68(%rax),%xmm9
  addsd  %xmm11,%xmm9
  movapd %xmm3,%xmm8
  mulsd  0x70(%rax),%xmm8
  addsd  %xmm7,%xmm8
  movapd %xmm3,%xmm7
  mulsd  0x78(%rax),%xmm7
  addsd  %xmm6,%xmm7
  movapd %xmm3,%xmm6
  mulsd  0x60(%rdx),%xmm6
  addsd  %xmm5,%xmm6
  movapd %xmm3,%xmm5
  mulsd  0x68(%rdx),%xmm5
  addsd  %xmm4,%xmm5
  movapd %xmm3,%xmm4
  mulsd  0x70(%rdx),%xmm4
  addsd  %xmm2,%xmm4
  mulsd  0x78(%rdx),%xmm3
  addsd  %xmm0,%xmm3
  movapd %xmm3,%xmm11
  sub    $0xffffffffffffff80,%rax
  sub    $0xffffffffffffff80,%rdx
  add    $0x20,%rcx
  cmp    %rsi,%rax
  jne    L6
  lea    0x1(%rbp),%rax
  mov    %rax,%rdx
  shl    $0x7,%rdx
  add    %rdx,%r11
  add    %rdx,%rdi
  shl    $0x5,%rax
  add    %rax,%rbx
  lea    0xc(,%r12,4),%eax
L13:
  cmp    %eax,%r10d
  jle    L53
  sub    $0x1,%r10d
  sub    %eax,%r10d
  lea    0x8(,%r10,8),%rdx
  mov    $0x0,%eax
L80:
  movsd  (%rbx,%rax,1),%xmm0
  movapd %xmm0,%xmm1
  mulsd  (%r11,%rax,4),%xmm1
  addsd  %xmm1,%xmm10
  movapd %xmm0,%xmm1
  mulsd  0x8(%r11,%rax,4),%xmm1
  addsd  %xmm1,%xmm9
  movapd %xmm0,%xmm1
  mulsd  0x10(%r11,%rax,4),%xmm1
  addsd  %xmm1,%xmm8
  movapd %xmm0,%xmm1
  mulsd  0x18(%r11,%rax,4),%xmm1
  addsd  %xmm1,%xmm7
  movapd %xmm0,%xmm1
  mulsd  (%rdi,%rax,4),%xmm1
  addsd  %xmm1,%xmm6
  movapd %xmm0,%xmm1
  mulsd  0x8(%rdi,%rax,4),%xmm1
  addsd  %xmm1,%xmm5
  movapd %xmm0,%xmm1
  mulsd  0x10(%rdi,%rax,4),%xmm1
  addsd  %xmm1,%xmm4
  mulsd  0x18(%rdi,%rax,4),%xmm0
  addsd  %xmm0,%xmm11
  add    $0x8,%rax
  cmp    %rdx,%rax
  jne    L80
L53:
  test   %r9d,%r9d
  jne    L74
  movsd  %xmm10,(%r8)
  movsd  %xmm9,0x8(%r8)
  movsd  %xmm8,0x10(%r8)
  movsd  %xmm7,0x18(%r8)
  movsd  %xmm6,0x20(%r8)
  movsd  %xmm5,0x28(%r8)
  movsd  %xmm4,0x30(%r8)
  movsd  %xmm11,0x38(%r8)
L82:
  pop    %rbx
  pop    %rbp
  pop    %r12
  ret
L36:
  mov    $0x8,%eax
  jmp    L13
L74:
  cmp    $0x1,%r9d
  je     L98
  movsd  (%r8),%xmm0
  subsd  %xmm10,%xmm0
  movsd  %xmm0,(%r8)
  movsd  0x8(%r8),%xmm0
  subsd  %xmm9,%xmm0
  movsd  %xmm0,0x8(%r8)
  movsd  0x10(%r8),%xmm0
  subsd  %xmm8,%xmm0
  movsd  %xmm0,0x10(%r8)
  movsd  0x18(%r8),%xmm0
  subsd  %xmm7,%xmm0
  movsd  %xmm0,0x18(%r8)
  movsd  0x20(%r8),%xmm0
  subsd  %xmm6,%xmm0
  movsd  %xmm0,0x20(%r8)
  movsd  0x28(%r8),%xmm0
  subsd  %xmm5,%xmm0
  movsd  %xmm0,0x28(%r8)
  movsd  0x30(%r8),%xmm0
  subsd  %xmm4,%xmm0
  movsd  %xmm0,0x30(%r8)
  movsd  0x38(%r8),%xmm0
  subsd  %xmm11,%xmm0
  movsd  %xmm0,0x38(%r8)
  jmp    L82
L98:
  addsd  (%r8),%xmm10
  movsd  %xmm10,(%r8)
  addsd  0x8(%r8),%xmm9
  movsd  %xmm9,0x8(%r8)
  addsd  0x10(%r8),%xmm8
  movsd  %xmm8,0x10(%r8)
  addsd  0x18(%r8),%xmm7
  movsd  %xmm7,0x18(%r8)
  addsd  0x20(%r8),%xmm6
  movsd  %xmm6,0x20(%r8)
  addsd  0x28(%r8),%xmm5
  movsd  %xmm5,0x28(%r8)
  addsd  0x30(%r8),%xmm4
  movsd  %xmm4,0x30(%r8)
  addsd  0x38(%r8),%xmm11
  movsd  %xmm11,0x38(%r8)
  jmp    L82
L99:
  ret
```

assistant: ```c
void kernel_dtrmv_u_n_8_lib4(int kmax, double *A0, int sda, double *x, double *y, int alg) {
  if (kmax <= 0)
    return;
  double *A1 = A0 + 4 * sda;
  const int lda = 4;
  int k;
  double x_0, x_1, x_2, x_3, y_0 = 0, y_1 = 0, y_2 = 0, y_3 = 0, y_4 = 0, y_5 = 0, y_6 = 0, y_7 = 0;
  x_0 = x[0];
  x_1 = x[1];
  x_2 = x[2];
  x_3 = x[3];
  y_0 += A0[0 + lda * 0] * x_0;
  y_0 += A0[0 + lda * 1] * x_1;
  y_1 += A0[1 + lda * 1] * x_1;
  y_0 += A0[0 + lda * 2] * x_2;
  y_1 += A0[1 + lda * 2] * x_2;
  y_2 += A0[2 + lda * 2] * x_2;
  y_0 += A0[0 + lda * 3] * x_3;
  y_1 += A0[1 + lda * 3] * x_3;
  y_2 += A0[2 + lda * 3] * x_3;
  y_3 += A0[3 + lda * 3] * x_3;
  A0 += 4 * lda;
  A1 += 4 * lda;
  x += 4;
  x_0 = x[0];
  x_1 = x[1];
  x_2 = x[2];
  x_3 = x[3];
  y_0 += A0[0 + lda * 0] * x_0;
  y_1 += A0[1 + lda * 0] * x_0;
  y_2 += A0[2 + lda * 0] * x_0;
  y_3 += A0[3 + lda * 0] * x_0;
  y_4 += A1[0 + lda * 0] * x_0;
  y_0 += A0[0 + lda * 1] * x_1;
  y_1 += A0[1 + lda * 1] * x_1;
  y_2 += A0[2 + lda * 1] * x_1;
  y_3 += A0[3 + lda * 1] * x_1;
  y_4 += A1[0 + lda * 1] * x_1;
  y_5 += A1[1 + lda * 1] * x_1;
  y_0 += A0[0 + lda * 2] * x_2;
  y_1 += A0[1 + lda * 2] * x_2;
  y_2 += A0[2 + lda * 2] * x_2;
  y_3 += A0[3 + lda * 2] * x_2;
  y_4 += A1[0 + lda * 2] * x_2;
  y_5 += A1[1 + lda * 2] * x_2;
  y_6 += A1[2 + lda * 2] * x_2;
  y_0 += A0[0 + lda * 3] * x_3;
  y_1 += A0[1 + lda * 3] * x_3;
  y_2 += A0[2 + lda * 3] * x_3;
  y_3 += A0[3 + lda * 3] * x_3;
  y_4 += A1[0 + lda * 3] * x_3;
  y_5 += A1[1 + lda * 3] * x_3;
  y_6 += A1[2 + lda * 3] * x_3;
  y_7 += A1[3 + lda * 3] * x_3;
  A0 += 4 * lda;
  A1 += 4 * lda;
  x += 4;
  k = 8;
  for (; k < kmax - 3; k += 4) {
    x_0 = x[0];
    x_1 = x[1];
    x_2 = x[2];
    x_3 = x[3];
    y_0 += A0[0 + lda * 0] * x_0;
    y_1 += A0[1 + lda * 0] * x_0;
    y_2 += A0[2 + lda * 0] * x_0;
    y_3 += A0[3 + lda * 0] * x_0;
    y_4 += A1[0 + lda * 0] * x_0;
    y_5 += A1[1 + lda * 0] * x_0;
    y_6 += A1[2 + lda * 0] * x_0;
    y_7 += A1[3 + lda * 0] * x_0;
    y_0 += A0[0 + lda * 1] * x_1;
    y_1 += A0[1 + lda * 1] * x_1;
    y_2 += A0[2 + lda * 1] * x_1;
    y_3 += A0[3 + lda * 1] * x_1;
    y_4 += A1[0 + lda * 1] * x_1;
    y_5 += A1[1 + lda * 1] * x_1;
    y_6 += A1[2 + lda * 1] * x_1;
    y_7 += A1[3 + lda * 1] * x_1;
    y_0 += A0[0 + lda * 2] * x_2;
    y_1 += A0[1 + lda * 2] * x_2;
    y_2 += A0[2 + lda * 2] * x_2;
    y_3 += A0[3 + lda * 2] * x_2;
    y_4 += A1[0 + lda * 2] * x_2;
    y_5 += A1[1 + lda * 2] * x_2;
    y_6 += A1[2 + lda * 2] * x_2;
    y_7 += A1[3 + lda * 2] * x_2;
    y_0 += A0[0 + lda * 3] * x_3;
    y_1 += A0[1 + lda * 3] * x_3;
    y_2 += A0[2 + lda * 3] * x_3;
    y_3 += A0[3 + lda * 3] * x_3;
    y_4 += A1[0 + lda * 3] * x_3;
    y_5 += A1[1 + lda * 3] * x_3;
    y_6 += A1[2 + lda * 3] * x_3;
    y_7 += A1[3 + lda * 3] * x_3;
    A0 += 4 * lda;
    A1 += 4 * lda;
    x += 4;
  }
  for (; k < kmax; k++) {
    x_0 = x[0];
    y_0 += A0[0 + lda * 0] * x_0;
    y_1 += A0[1 + lda * 0] * x_0;
    y_2 += A0[2 + lda * 0] * x_0;
    y_3 += A0[3 + lda * 0] * x_0;
    y_4 += A1[0 + lda * 0] * x_0;
    y_5 += A1[1 + lda * 0] * x_0;
    y_6 += A1[2 + lda * 0] * x_0;
    y_7 += A1[3 + lda * 0] * x_0;
    A0 += 1 * lda;
    A1 += 1 * lda;
    x += 1;
  }
  if (alg == 0) {
    y[0] = y_0;
    y[1] = y_1;
    y[2] = y_2;
    y[3] = y_3;
    y[4] = y_4;
    y[5] = y_5;
    y[6] = y_6;
    y[7] = y_7;
  } else if (alg == 1) {
    y[0] += y_0;
    y[1] += y_1;
    y[2] += y_2;
    y[3] += y_3;
    y[4] += y_4;
    y[5] += y_5;
    y[6] += y_6;
    y[7] += y_7;
  } else {
    y[0] -= y_0;
    y[1] -= y_1;
    y[2] -= y_2;
    y[3] -= y_3;
    y[4] -= y_4;
    y[5] -= y_5;
    y[6] -= y_6;
    y[7] -= y_7;
  }
}
```