user: 请将以下的汇编代码转换成C语言代码:

```asm
<Mupdate>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  mov    %edi,-0x24(%rbp)
  mov    %esi,-0x28(%rbp)
  movsd  %xmm0,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  mov    %rcx,-0x40(%rbp)
  mov    %r8,-0x48(%rbp)
  mov    %r9d,-0x4c(%rbp)
  mov    -0x28(%rbp),%eax
  lea    0x3(%rax),%edx
  test   %eax,%eax
  cmovs  %edx,%eax
  sar    $0x2,%eax
  mov    %eax,%r14d
  mov    -0x28(%rbp),%eax
  cltd
  shr    $0x1e,%edx
  add    %edx,%eax
  and    $0x3,%eax
  sub    %edx,%eax
  mov    %eax,-0x28(%rbp)
  mov    $0x0,%r13d
  jmp    L59
L54:
  movslq %r13d,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  -0x30(%rbp),%xmm0
  movapd %xmm0,%xmm4
  movslq %r13d,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%rdx,%rax,1),%r12
  mov    $0x0,%ebx
  jmp    L31
L11:
  lea    0x0(,%rbx,4),%eax
  cltq
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm1
  lea    0x0(,%rbx,4),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movapd %xmm4,%xmm2
  mulsd  %xmm2,%xmm0
  lea    0x0(,%rbx,4),%eax
  cltq
  shl    $0x3,%rax
  add    %r12,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm1
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x2,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm1
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x2,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x2,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x3,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm1
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x3,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  lea    0x0(,%rbx,4),%eax
  cltq
  add    $0x3,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
L31:
  cmp    %r14d,%ebx
  jl     L11
  lea    0x0(,%r14,4),%eax
  cltq
  shl    $0x3,%rax
  add    %rax,%r12
  lea    0x0(,%r14,4),%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x40(%rbp)
  mov    $0x0,%ebx
  jmp    L45
L5:
  movslq %ebx,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  movsd  (%rax),%xmm1
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movapd %xmm4,%xmm3
  mulsd  %xmm3,%xmm0
  movslq %ebx,%rax
  shl    $0x3,%rax
  add    %r12,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  add    $0x1,%ebx
L45:
  cmp    -0x28(%rbp),%ebx
  jl     L5
  add    $0x1,%r13d
L59:
  cmp    -0x24(%rbp),%r13d
  jl     L54
  nop
  nop
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %rbp
  ret
```

assistant: ```c
void Mupdate(m, n, alpha, x, y, A, j0) int m, n, j0;
double alpha;
double **A, *x, *y;
{
  register int i, j, n4;
  register double *Aref;
  register double tmp;
  n4 = n / 4;
  n = n % 4;
  for (i = 0; i < m; i++) {
    tmp = alpha * x[i];
    Aref = &(A[i][j0]);
    for (j = 0; j < n4; j++) {
      Aref[4 * j] += tmp * y[4 * j];
      Aref[4 * j + 1] += tmp * y[4 * j + 1];
      Aref[4 * j + 2] += tmp * y[4 * j + 2];
      Aref[4 * j + 3] += tmp * y[4 * j + 3];
    }
    Aref += 4 * n4;
    y += 4 * n4;
    for (j = 0; j < n; j++)
      Aref[j] += tmp * y[j];
  }
}
```