user: 下面的汇编指令对应的C源代码是什么：

```asm
<backSubstitution>:
  endbr64
  push   %r15
  mov    %rsi,%r15
  push   %r14
  push   %r13
  mov    %rdx,%r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %edi,%ebx
  sub    $0x58,%rsp
  mov    %edi,0x4(%rsp)
  call   <zeros@plt>
  mov    %rax,0x48(%rsp)
  lea    -0x1(%rbx),%eax
  mov    %eax,0x44(%rsp)
  test   %eax,%eax
  jle    L86
  mov    0x4(%rsp),%eax
  test   %eax,%eax
  jg     L163
  movslq %eax,%rbp
L130:
  mov    0x4(%rsp),%edi
  mov    0x44(%rsp),%edx
  lea    0x0(,%rbp,8),%rcx
  movsd  -0x8(%r13,%rcx,1),%xmm0
  imul   %edi,%edx
  movslq %edx,%rax
  add    %rbp,%rax
  divsd  -0x8(%r15,%rax,8),%xmm0
  mov    0x48(%rsp),%rax
  movsd  %xmm0,-0x8(%rax,%rcx,1)
  mov    %edi,%eax
  sub    $0x2,%eax
  js     L37
  mov    %edi,%ebp
  cltq
  mov    0x48(%rsp),%rbx
  mov    0x44(%rsp),%edi
  mov    %ebp,%r10d
  sub    %ebp,%edx
  lea    0x0(,%rax,8),%rcx
  mov    $0x1,%r8d
  neg    %r10d
  movslq %edx,%rdx
  lea    0x0(%r13,%rcx,1),%r9
  movslq %r10d,%r10
  lea    0x1(%rdx,%rax,1),%rax
  lea    0x8(%rbx,%rcx,1),%rcx
  lea    -0x8(,%r10,8),%r11
  lea    (%r15,%rax,8),%rsi
  nopw   0x0(%rax,%rax,1)
L89:
  movsd  (%r9),%xmm0
  mov    %edi,%eax
  cmp    %edi,%ebp
  jle    L10
  cmp    $0x1,%r8d
  je     L21
  mov    %r8d,%r12d
  xor    %eax,%eax
  shr    %r12d
  shl    $0x4,%r12
  nopl   (%rax)
L45:
  movupd (%rcx,%rax,1),%xmm1
  movupd (%rsi,%rax,1),%xmm4
  add    $0x10,%rax
  mulpd  %xmm4,%xmm1
  subsd  %xmm1,%xmm0
  unpckhpd %xmm1,%xmm1
  subsd  %xmm1,%xmm0
  cmp    %r12,%rax
  jne    L45
  mov    %r8d,%r12d
  and    $0xfffffffe,%r12d
  lea    (%rdi,%r12,1),%eax
  cmp    %r8d,%r12d
  je     L10
L21:
  cltq
  lea    (%rax,%rdx,1),%r12
  movsd  (%r15,%r12,8),%xmm1
  mulsd  (%rbx,%rax,8),%xmm1
  subsd  %xmm1,%xmm0
L10:
  divsd  -0x8(%rsi),%xmm0
  sub    $0x8,%r9
  movsd  %xmm0,-0x8(%rcx)
  add    %r10,%rdx
  add    $0x1,%r8d
  add    %r11,%rsi
  sub    $0x8,%rcx
  sub    $0x1,%edi
  jne    L89
L37:
  mov    0x48(%rsp),%rax
  add    $0x58,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L163:
  movslq 0x4(%rsp),%rbp
  mov    0x44(%rsp),%eax
  xor    %r12d,%r12d
  movl   $0x0,0x30(%rsp)
  movl   $0x0,0x24(%rsp)
  lea    0x0(,%rbp,8),%rdi
  mov    %eax,0x34(%rsp)
  mov    %ebp,%r14d
  mov    %rdi,0x18(%rsp)
  mov    %ebp,0x40(%rsp)
  nopl   (%rax)
L94:
  mov    0x24(%rsp),%eax
  mov    %eax,%r8d
  add    $0x1,%eax
  mov    %eax,0x24(%rsp)
  cmp    %eax,0x4(%rsp)
  jle    L8
  movslq 0x30(%rsp),%rdx
  movslq 0x40(%rsp),%rcx
  lea    (%rdx,%r12,1),%rsi
  mov    %rdx,%r11
  lea    0x8(,%rsi,8),%rbx
  lea    (%r15,%rsi,8),%rax
  sub    %rcx,%r11
  mov    %rbx,0x10(%rsp)
  mov    %r14d,%ebx
  lea    (%r15,%rsi,8),%r9
  mov    %r14d,%esi
  and    $0xfffffffe,%ebx
  shr    %esi
  mov    %rax,0x8(%rsp)
  lea    0x1(%r12),%rax
  add    %ebx,%r8d
  mov    %ebx,0x20(%rsp)
  sub    $0x1,%esi
  mov    %rax,%rdi
  movslq %r8d,%r8
  mov    %rax,0x38(%rsp)
  add    $0x1,%rsi
  lea    (%rcx,%r12,1),%rax
  add    %r8,%rdx
  lea    (%r15,%rax,8),%rax
  shl    $0x4,%rsi
  lea    (%r15,%rdx,8),%r10
  mov    0x34(%rsp),%edx
  lea    0x8(,%rdx,8),%rbx
  mov    %rbx,0x28(%rsp)
  nopl   0x0(%rax,%rax,1)
L22:
  mov    0x8(%rsp),%rbx
  mov    %rax,%rdx
  movsd  (%rax),%xmm2
  sub    %r15,%rdx
  divsd  (%rbx),%xmm2
  cmp    0x10(%rsp),%rdx
  je     L20
  movapd %xmm2,%xmm3
  xor    %edx,%edx
  unpcklpd %xmm3,%xmm3
  cmp    $0x1,%r14d
  je     L20
  nopw   0x0(%rax,%rax,1)
L119:
  movupd (%r9,%rdx,1),%xmm1
  movupd (%rax,%rdx,1),%xmm0
  mulpd  %xmm3,%xmm1
  subpd  %xmm1,%xmm0
  movups %xmm0,(%rax,%rdx,1)
  add    $0x10,%rdx
  cmp    %rsi,%rdx
  jne    L119
  cmp    %r14d,0x20(%rsp)
  je     L14
  movsd  (%r10),%xmm1
  lea    (%r8,%rcx,1),%rdx
  lea    (%r15,%rdx,8),%rdx
  mulsd  %xmm2,%xmm1
  movsd  (%rdx),%xmm0
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rdx)
L14:
  mulsd  0x0(%r13,%r12,8),%xmm2
  movsd  0x0(%r13,%rdi,8),%xmm0
  add    %rbp,%rcx
  sub    %rbp,%r11
  add    0x18(%rsp),%rax
  subsd  %xmm2,%xmm0
  movsd  %xmm0,0x0(%r13,%rdi,8)
  add    $0x1,%rdi
  cmp    %edi,0x4(%rsp)
  jg     L22
L12:
  mov    0x4(%rsp),%edi
  subl   $0x1,0x34(%rsp)
  sub    $0x1,%r14d
  add    %edi,0x30(%rsp)
  mov    0x38(%rsp),%r12
  add    %edi,0x40(%rsp)
  mov    0x44(%rsp),%edi
  cmp    %edi,0x24(%rsp)
  jne    L94
  jmp    L130
  nopl   0x0(%rax,%rax,1)
L20:
  mov    0x28(%rsp),%rbx
  mov    %rax,%rdx
  add    %rax,%rbx
  nopl   0x0(%rax,%rax,1)
L175:
  movsd  (%rdx,%r11,8),%xmm1
  movsd  (%rdx),%xmm0
  add    $0x8,%rdx
  mulsd  %xmm2,%xmm1
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x8(%rdx)
  cmp    %rbx,%rdx
  jne    L175
  jmp    L14
L8:
  lea    0x1(%r12),%rax
  mov    %rax,0x38(%rsp)
  jmp    L12
L86:
  movslq 0x4(%rsp),%rbp
  jmp    L130
```

assistant: ```c
double *backSubstitution(int n, double *matrix, double b[]) {
  int i, j, k;
  double aux, temp;
  double *x = zeros(n);
  for (i = 0; i < (n - 1); i++) {
    for (j = (i + 1); j < n; j++) {
      aux = *(matrix + n * j + i) / *(matrix + n * i + i);
      for (k = i; k < n; k++) {
        *(matrix + n * j + k) -= (aux * (*(matrix + n * i + k)));
      }
      b[j] -= (aux * b[i]);
    }
  }
  x[n - 1] = b[n - 1] / *(matrix + n * (n - 1) + n - 1);
  for (i = (n - 2); i >= 0; i--) {
    temp = b[i];
    for (j = (i + 1); j < n; j++) {
      temp -= (*(matrix + n * i + j) * x[j]);
    }
    x[i] = temp / *(matrix + n * i + i);
  }
  return x;
}
```