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

```asm
<kernel_dtrsv_t_2_lib4_new>:
  endbr64
  test   %edi,%edi
  jle    L1
  push   %r15
  mov    %edi,%r11d
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  mov    %ecx,%ebp
  push   %rbx
  mov    %rsi,%rbx
  cmp    $0x4,%edi
  jg     L57
  pxor   %xmm0,%xmm0
  lea    0x10(%rsi),%rax
  lea    0x10(%r9),%rcx
  mov    $0x2,%r10d
  movapd %xmm0,%xmm5
L25:
  cmp    %r11d,%r10d
  jge    L83
  sub    $0x1,%r11d
  sub    %r10d,%r11d
  lea    0x8(%rax,%r11,8),%rdx
  xchg   %ax,%ax
L48:
  movsd  (%rcx),%xmm1
  movsd  (%rax),%xmm2
  add    $0x8,%rax
  add    $0x8,%rcx
  mulsd  %xmm1,%xmm2
  mulsd  0x18(%rax),%xmm1
  addsd  %xmm2,%xmm5
  addsd  %xmm1,%xmm0
  cmp    %rdx,%rax
  jne    L48
L83:
  movsd  0x8(%r9),%xmm1
  movsd  (%r9),%xmm2
  subsd  %xmm0,%xmm1
  test   %ebp,%ebp
  je     L110
  mulsd  0x8(%r8),%xmm1
  movsd  %xmm1,0x8(%r9)
  mulsd  0x8(%rbx),%xmm1
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  subsd  %xmm1,%xmm2
  subsd  %xmm5,%xmm2
  mulsd  (%r8),%xmm2
  movsd  %xmm2,(%r9)
  ret
  nopl   0x0(%rax,%rax,1)
L57:
  movsd  0x10(%rsi),%xmm2
  pxor   %xmm3,%xmm3
  shl    $0x2,%edx
  lea    0x20(%r9),%rdi
  movsd  0x10(%r9),%xmm1
  movsd  0x18(%r9),%xmm0
  movslq %edx,%r10
  movsd  0x18(%rsi),%xmm5
  lea    0x0(,%r10,8),%r12
  mulsd  %xmm1,%xmm2
  lea    (%rsi,%r12,1),%rax
  mulsd  0x30(%rsi),%xmm1
  prefetcht0 (%rax)
  mulsd  %xmm0,%xmm5
  mulsd  0x38(%rsi),%xmm0
  addsd  %xmm3,%xmm2
  addsd  %xmm3,%xmm1
  addsd  %xmm2,%xmm5
  addsd  %xmm1,%xmm0
  cmp    $0xb,%r11d
  jle    L2
  lea    -0xc(%r11),%r14d
  shl    $0x4,%r10
  lea    (%rax,%r12,1),%rsi
  mov    %rdi,%rcx
  shr    $0x3,%r14d
  mov    %r14d,%r15d
  mov    %r15,%rdx
  shl    $0x6,%rdx
  lea    0x60(%r9,%rdx,1),%r13
  mov    %rax,%rdx
  nopl   0x0(%rax)
L113:
  movsd  (%rcx),%xmm4
  movsd  (%rdx),%xmm6
  add    $0x40,%rcx
  prefetcht0 (%rsi)
  movsd  -0x38(%rcx),%xmm3
  movsd  -0x30(%rcx),%xmm2
  mulsd  %xmm4,%xmm6
  movsd  -0x28(%rcx),%xmm1
  mulsd  0x20(%rdx),%xmm4
  addsd  %xmm5,%xmm6
  movsd  0x8(%rdx),%xmm5
  addsd  %xmm0,%xmm4
  movsd  0x10(%rdx),%xmm0
  mulsd  %xmm3,%xmm5
  mulsd  0x28(%rdx),%xmm3
  mulsd  %xmm2,%xmm0
  mulsd  0x30(%rdx),%xmm2
  addsd  %xmm6,%xmm5
  movsd  0x18(%rdx),%xmm6
  addsd  %xmm4,%xmm3
  mulsd  %xmm1,%xmm6
  mulsd  0x38(%rdx),%xmm1
  addsd  %xmm5,%xmm0
  movsd  (%rsi),%xmm5
  add    %r10,%rdx
  addsd  %xmm3,%xmm2
  movsd  -0x20(%rcx),%xmm3
  prefetcht0 (%rdx)
  mulsd  %xmm3,%xmm5
  mulsd  0x20(%rsi),%xmm3
  addsd  %xmm0,%xmm6
  movsd  -0x8(%rcx),%xmm0
  movapd %xmm1,%xmm4
  movsd  -0x10(%rcx),%xmm1
  addsd  %xmm2,%xmm4
  movsd  -0x18(%rcx),%xmm2
  addsd  %xmm6,%xmm5
  addsd  %xmm4,%xmm3
  movsd  0x8(%rsi),%xmm4
  mulsd  %xmm2,%xmm4
  mulsd  0x28(%rsi),%xmm2
  addsd  %xmm5,%xmm4
  movsd  0x18(%rsi),%xmm5
  addsd  %xmm3,%xmm2
  movsd  0x10(%rsi),%xmm3
  mulsd  %xmm0,%xmm5
  mulsd  %xmm1,%xmm3
  mulsd  0x30(%rsi),%xmm1
  mulsd  0x38(%rsi),%xmm0
  add    %r10,%rsi
  addsd  %xmm4,%xmm3
  addsd  %xmm2,%xmm1
  addsd  %xmm3,%xmm5
  addsd  %xmm1,%xmm0
  cmp    %rcx,%r13
  jne    L113
  lea    0x1(%r15),%rdx
  imul   %rdx,%r10
  shl    $0x6,%rdx
  add    %rdx,%rdi
  add    %r10,%rax
  lea    0xc(,%r14,8),%r10d
L46:
  lea    -0x3(%r11),%edx
  cmp    %edx,%r10d
  jge    L45
  lea    -0x4(%r11),%r13d
  mov    %rax,%rsi
  sub    %r10d,%r13d
  shr    $0x2,%r13d
  lea    0x1(%r13),%r14d
  mov    %r14,%rcx
  shl    $0x5,%rcx
  add    %rdi,%rcx
  nopl   (%rax)
L36:
  mov    %rsi,%rdx
  movsd  (%rdi),%xmm3
  movsd  0x8(%rdi),%xmm2
  add    %r12,%rsi
  movsd  (%rdx),%xmm6
  movsd  0x10(%rdi),%xmm1
  add    $0x20,%rdi
  prefetcht0 (%rsi)
  movsd  -0x8(%rdi),%xmm4
  mulsd  %xmm3,%xmm6
  mulsd  0x20(%rdx),%xmm3
  addsd  %xmm5,%xmm6
  movsd  0x8(%rdx),%xmm5
  addsd  %xmm0,%xmm3
  movsd  0x10(%rdx),%xmm0
  mulsd  %xmm2,%xmm5
  mulsd  %xmm1,%xmm0
  mulsd  0x28(%rdx),%xmm2
  mulsd  0x30(%rdx),%xmm1
  addsd  %xmm6,%xmm5
  addsd  %xmm3,%xmm2
  addsd  %xmm5,%xmm0
  movsd  0x18(%rdx),%xmm5
  mulsd  %xmm4,%xmm5
  addsd  %xmm2,%xmm1
  mulsd  0x38(%rdx),%xmm4
  addsd  %xmm0,%xmm5
  movapd %xmm4,%xmm0
  addsd  %xmm1,%xmm0
  cmp    %rcx,%rdi
  jne    L36
  imul   %r14,%r12
  lea    0x4(%r10,%r13,4),%r10d
  add    %r12,%rax
  jmp    L25
  nopl   0x0(%rax)
L110:
  divsd  0x28(%rbx),%xmm1
  movsd  %xmm1,0x8(%r9)
  mulsd  0x8(%rbx),%xmm1
  subsd  %xmm1,%xmm2
  subsd  %xmm5,%xmm2
  divsd  (%rbx),%xmm2
  pop    %rbx
  movsd  %xmm2,(%r9)
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L1:
  ret
L2:
  mov    $0x4,%r10d
  jmp    L46
L45:
  mov    %rdi,%rcx
  jmp    L25
```

assistant: ```c
void kernel_dtrsv_t_2_lib4_new(int kmax, double *A, int sda, int use_inv_diag_A, double *inv_diag_A, double *x) {
  if (kmax <= 0)
    return;
  const int lda = 4;
  const int bs = 4;
  int k;
  double *tA, *tx;
  tA = A;
  tx = x;
  double x_0, x_1, x_2, x_3, y_0 = 0, y_1 = 0;
  k = 2;
  if (kmax > 4) {
    x_2 = x[2];
    x_3 = x[3];
    y_0 += A[2 + lda * 0] * x_2;
    y_1 += A[2 + lda * 1] * x_2;
    y_0 += A[3 + lda * 0] * x_3;
    y_1 += A[3 + lda * 1] * x_3;
    k = 4;
    A += 4 + (sda - 1) * lda;
    x += 4;
    __builtin_prefetch(A);
    for (; k < kmax - 7; k += 8) {
      __builtin_prefetch(A + sda * bs);
      x_0 = x[0];
      x_1 = x[1];
      x_2 = x[2];
      x_3 = x[3];
      y_0 += A[0 + lda * 0] * x_0;
      y_1 += A[0 + lda * 1] * x_0;
      y_0 += A[1 + lda * 0] * x_1;
      y_1 += A[1 + lda * 1] * x_1;
      y_0 += A[2 + lda * 0] * x_2;
      y_1 += A[2 + lda * 1] * x_2;
      y_0 += A[3 + lda * 0] * x_3;
      y_1 += A[3 + lda * 1] * x_3;
      A += sda * bs;
      x += 4;
      __builtin_prefetch(A + sda * bs);
      x_0 = x[0];
      x_1 = x[1];
      x_2 = x[2];
      x_3 = x[3];
      y_0 += A[0 + lda * 0] * x_0;
      y_1 += A[0 + lda * 1] * x_0;
      y_0 += A[1 + lda * 0] * x_1;
      y_1 += A[1 + lda * 1] * x_1;
      y_0 += A[2 + lda * 0] * x_2;
      y_1 += A[2 + lda * 1] * x_2;
      y_0 += A[3 + lda * 0] * x_3;
      y_1 += A[3 + lda * 1] * x_3;
      A += sda * bs;
      x += 4;
    }
    for (; k < kmax - 3; k += 4) {
      __builtin_prefetch(A + sda * bs);
      x_0 = x[0];
      x_1 = x[1];
      x_2 = x[2];
      x_3 = x[3];
      y_0 += A[0 + lda * 0] * x_0;
      y_1 += A[0 + lda * 1] * x_0;
      y_0 += A[1 + lda * 0] * x_1;
      y_1 += A[1 + lda * 1] * x_1;
      y_0 += A[2 + lda * 0] * x_2;
      y_1 += A[2 + lda * 1] * x_2;
      y_0 += A[3 + lda * 0] * x_3;
      y_1 += A[3 + lda * 1] * x_3;
      A += sda * bs;
      x += 4;
    }
  } else {
    A += 2;
    x += 2;
  }
  for (; k < kmax; k++) {
    x_0 = x[0];
    y_0 += A[0 + lda * 0] * x_0;
    y_1 += A[0 + lda * 1] * x_0;
    A += 1;
    x += 1;
  }
  A = tA;
  x = tx;
  if (use_inv_diag_A) {
    y_1 = x[1] - y_1;
    y_1 *= inv_diag_A[1];
    x[1] = y_1;
    y_0 = x[0] - A[1 + lda * 0] * y_1 - y_0;
    y_0 *= inv_diag_A[0];
    x[0] = y_0;
  } else {
    y_1 = x[1] - y_1;
    y_1 /= A[1 + lda * 1];
    x[1] = y_1;
    y_0 = x[0] - A[1 + lda * 0] * y_1 - y_0;
    y_0 /= A[0 + lda * 0];
    x[0] = y_0;
  }
}
```