user: 请从给定的汇编指令推导出C源代码：

```asm
<algoritmo4>:
  endbr64
  push   %r15
  mov    %edx,%r11d
  push   %r14
  mov    %rsi,%r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rdi,-0x68(%rsp)
  cmp    $0x1,%edx
  jle    L103
  lea    -0x2(%rdx),%eax
  lea    -0x1(%rdx),%ebx
  mov    $0x4,%r15d
  xor    %r13d,%r13d
  mov    %eax,-0x48(%rsp)
  add    $0x2,%rax
  mov    %ebx,-0x4c(%rsp)
  mov    %rax,-0x10(%rsp)
  movq   $0x8,-0x18(%rsp)
  movq   $0x1,-0x38(%rsp)
  nopl   0x0(%rax)
L93:
  mov    -0x38(%rsp),%rsi
  cmp    %esi,%r11d
  jle    L114
  mov    -0x68(%rsp),%rax
  mov    -0x4c(%rsp),%ebx
  mov    (%rax,%r13,2),%r10
  lea    (%r10,%r13,1),%rax
  lea    (%r10,%r15,1),%r8
  mov    %rax,-0x60(%rsp)
  mov    %ebx,%eax
  and    $0xfffffffc,%ebx
  shr    $0x2,%eax
  mov    %ebx,-0x44(%rsp)
  lea    -0x1(%rax),%edi
  mov    %ebx,%eax
  add    %esi,%eax
  add    $0x1,%rdi
  movslq %eax,%rbx
  shl    $0x4,%rdi
  shl    $0x2,%rbx
  mov    %rdi,-0x70(%rsp)
  lea    (%r10,%rbx,1),%rcx
  mov    %rcx,-0x40(%rsp)
  lea    0x1(%rax),%ecx
  add    $0x2,%eax
  movslq %eax,%r12
  mov    %eax,-0x24(%rsp)
  movslq %ecx,%rbp
  shl    $0x2,%r12
  shl    $0x2,%rbp
  mov    %ecx,-0x28(%rsp)
  lea    (%r10,%r12,1),%rax
  lea    (%r10,%rbp,1),%rcx
  mov    %rax,-0x20(%rsp)
  mov    -0x18(%rsp),%rax
  mov    %rcx,-0x30(%rsp)
  add    %r10,%rax
  mov    %rax,-0x58(%rsp)
  nopl   0x0(%rax,%rax,1)
L3:
  mov    -0x68(%rsp),%rax
  mov    -0x60(%rsp),%rdi
  mov    (%rax,%rsi,8),%rcx
  lea    (%rcx,%r13,1),%r9
  mov    (%r9),%eax
  cltd
  idivl  (%rdi)
  movl   $0x0,(%r9)
  lea    (%rcx,%r15,1),%r9
  mov    %r9,%rdx
  sub    -0x58(%rsp),%rdx
  cmp    $0x8,%rdx
  jbe    L10
  cmpl   $0x2,-0x48(%rsp)
  jbe    L10
  movd   %eax,%xmm4
  mov    -0x70(%rsp),%rdi
  xor    %edx,%edx
  pshufd $0x0,%xmm4,%xmm2
  movdqa %xmm2,%xmm3
  psrlq  $0x20,%xmm3
  nopl   0x0(%rax)
L23:
  movdqu (%r8,%rdx,1),%xmm0
  movdqu (%r8,%rdx,1),%xmm1
  psrlq  $0x20,%xmm0
  pmuludq %xmm2,%xmm1
  pmuludq %xmm3,%xmm0
  pshufd $0x8,%xmm1,%xmm1
  pshufd $0x8,%xmm0,%xmm0
  punpckldq %xmm0,%xmm1
  movdqu (%r9,%rdx,1),%xmm0
  psubd  %xmm1,%xmm0
  movups %xmm0,(%r9,%rdx,1)
  add    $0x10,%rdx
  cmp    %rdi,%rdx
  jne    L23
  mov    %rdi,-0x70(%rsp)
  mov    -0x4c(%rsp),%edx
  cmp    %edx,-0x44(%rsp)
  je     L42
  mov    -0x40(%rsp),%rdi
  mov    (%rdi),%edx
  imul   %eax,%edx
  sub    %edx,(%rcx,%rbx,1)
  cmp    %r11d,-0x28(%rsp)
  jge    L42
  mov    -0x30(%rsp),%rdi
  mov    (%rdi),%edx
  imul   %eax,%edx
  sub    %edx,(%rcx,%rbp,1)
  cmp    -0x24(%rsp),%r11d
  jle    L42
  mov    -0x20(%rsp),%rdi
  mov    (%rdi),%edx
  imul   %eax,%edx
  sub    %edx,(%rcx,%r12,1)
L42:
  imul   (%r14,%r13,1),%eax
  sub    %eax,(%r14,%rsi,4)
  add    $0x1,%rsi
  cmp    %esi,%r11d
  jg     L3
L114:
  addq   $0x1,-0x38(%rsp)
  add    $0x4,%r13
  mov    -0x38(%rsp),%rax
  add    $0x4,%r15
  subl   $0x1,-0x48(%rsp)
  addq   $0x4,-0x18(%rsp)
  subl   $0x1,-0x4c(%rsp)
  cmp    -0x10(%rsp),%rax
  jne    L93
L103:
  mov    -0x68(%rsp),%rdi
  mov    %r14,%rsi
  pop    %rbx
  mov    %r11d,%edx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    1050 <algoritmo3@plt>
  nopw   0x0(%rax,%rax,1)
L10:
  mov    -0x38(%rsp),%rdx
  mov    -0x70(%rsp),%rdi
  nopw   0x0(%rax,%rax,1)
L40:
  mov    (%r10,%rdx,4),%r9d
  imul   %eax,%r9d
  sub    %r9d,(%rcx,%rdx,4)
  add    $0x1,%rdx
  cmp    %edx,%r11d
  jg     L40
  mov    %rdi,-0x70(%rsp)
  jmp    L42
```

assistant: ```c
int *algoritmo4(int **A, int *b, int n) {
  int m, i, j, k;
  for (k = 0; k < n - 1; k++) {
    for (i = k + 1; i < n; i++) {
      m = A[i][k] / A[k][k];
      A[i][k] = 0;
      for (j = k + 1; j < n; j++)
        A[i][j] = A[i][j] - m * A[k][j];
      b[i] = b[i] - m * b[k];
    }
  }
  return algoritmo3(A, b, n);
}
```