user: 下面的汇编指令对应的C源代码是什么：

```asm
<lowertriag>:
  endbr64
  push   %r15
  lea    -0x1(%rsi),%eax
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x70,%rsp
  mov    %esi,-0x30(%rsp)
  test   %eax,%eax
  jle    L141
  movslq %eax,%r15
  lea    -0x2(%rsi),%eax
  mov    %rdi,%rbp
  mov    %esi,%edi
  imul   %esi,%eax
  neg    %edi
  lea    (%rsi,%rsi,1),%ebx
  mov    %esi,-0x20(%rsp)
  movslq %edi,%r10
  movslq %esi,%rdi
  mov    %ebx,-0x2c(%rsp)
  lea    0x0(,%r10,8),%r14
  mov    %rdi,0x48(%rsp)
  lea    (%rsi,%rax,1),%edx
  movslq %eax,%rcx
  add    %eax,%eax
  mov    %r14,-0x48(%rsp)
  cltq
  movslq %edx,%r9
  mov    %rcx,0x28(%rsp)
  add    %edx,%edx
  mov    %ebx,%ecx
  add    %r15,%rax
  sub    %edi,%ebx
  movslq %edx,%r11
  lea    0x0(%rbp,%rax,4),%rax
  lea    -0x1(%rbx),%edx
  neg    %ecx
  mov    %ebx,-0x6c(%rsp)
  mov    %edx,-0xc(%rsp)
  lea    0x4(,%rdx,4),%rsi
  lea    (%r9,%r9,1),%rdx
  movslq %ecx,%r8
  mov    %rax,0x10(%rsp)
  lea    -0x4(%r14),%rax
  mov    %rdi,%rcx
  mov    %rax,0x58(%rsp)
  lea    (%r15,%rdx,1),%rax
  shl    $0x2,%rax
  mov    %r9,0x30(%rsp)
  lea    (%rdi,%rdx,1),%r9
  mov    %rax,-0x68(%rsp)
  lea    -0xc(%rbp,%rax,1),%r14
  lea    0x0(%rbp,%r9,4),%r12
  lea    0x0(,%r8,4),%rax
  mov    %r10,0x40(%rsp)
  add    %r10,%r10
  mov    %rax,-0x28(%rsp)
  mov    %rdi,%rax
  neg    %rax
  mov    %r10,-0x40(%rsp)
  lea    -0x4(,%r8,4),%r10
  add    %rax,%rax
  mov    %r15,-0x38(%rsp)
  mov    %rax,0x60(%rsp)
  mov    %ebx,%eax
  shr    $0x2,%eax
  mov    %r8,-0x50(%rsp)
  sub    $0x1,%eax
  mov    %r9,-0x60(%rsp)
  add    $0x1,%rax
  mov    %r10,0x50(%rsp)
  shl    $0x4,%rax
  mov    %rax,%r13
  mov    %ebx,%eax
  and    $0xfffffffc,%ebx
  mov    %ebx,%edi
  mov    %ebx,-0x4(%rsp)
  add    %ecx,%ebx
  mov    %ebx,0x4(%rsp)
  mov    %eax,%ebx
  sub    %edi,%ebx
  mov    %ebx,0x38(%rsp)
  nopl   0x0(%rax)
L52:
  mov    0x10(%rsp),%rbx
  mov    0x48(%rsp),%r10
  add    $0x4,%rsi
  mov    0x60(%rsp),%rax
  mov    -0x20(%rsp),%r15d
  mov    %rsi,0x8(%rsp)
  mov    $0xfffffffffffffffc,%rsi
  movss  (%rbx,%r10,8),%xmm3
  mov    -0x60(%rsp),%rbx
  mov    -0x38(%rsp),%rdx
  mov    %rax,%r8
  lea    (%r11,%rax,1),%rcx
  add    %rax,%rbx
  mov    %r15d,%eax
  and    $0xfffffffc,%r15d
  neg    %r8
  shr    $0x2,%eax
  mov    %edx,-0x1c(%rsp)
  sub    %rdx,%r10
  mov    %edx,%edi
  lea    -0x1(%rax),%r9d
  mov    %edx,%eax
  sub    $0x1,%edi
  mov    %r15d,-0x10(%rsp)
  sub    %r15d,%eax
  mov    %edi,-0x74(%rsp)
  not    %r9
  mov    0x28(%rsp),%rdi
  mov    %eax,(%rsp)
  lea    0x0(,%rdx,4),%rax
  mov    %r10,%rdx
  sub    0x30(%rsp),%rdi
  shl    $0x2,%rdx
  sub    %rax,%rsi
  mov    -0x1c(%rsp),%eax
  mov    0x10(%rsp),%r10
  mov    %rsi,0x18(%rsp)
  mov    -0x68(%rsp),%rsi
  lea    0xc(,%rdi,8),%rdi
  shl    $0x4,%r9
  add    $0x1,%eax
  mov    %rdx,0x20(%rsp)
  mov    %eax,0x3c(%rsp)
  lea    -0xc(%rsi),%rdx
  sub    %r15d,%eax
  lea    -0x18(%rbp,%rsi,1),%rsi
  mov    %rdx,-0x58(%rsp)
  mov    %rsi,-0x18(%rsp)
  mov    %eax,-0x8(%rsp)
  nopl   0x0(%rax,%rax,1)
L186:
  movss  (%r10),%xmm2
  divss  %xmm3,%xmm2
  cmp    $0x8,%rdi
  jbe    L193
  cmpq   $0x2,-0x38(%rsp)
  jbe    L50
  mov    -0x18(%rsp),%rax
  movaps %xmm2,%xmm4
  shufps $0x0,%xmm4,%xmm4
  lea    (%rax,%rdi,1),%rdx
  xor    %eax,%eax
  nopl   0x0(%rax)
L145:
  movups (%r14,%rax,1),%xmm1
  movups (%rdx,%rax,1),%xmm0
  shufps $0x1b,%xmm1,%xmm1
  mulps  %xmm4,%xmm1
  shufps $0x1b,%xmm0,%xmm0
  subps  %xmm1,%xmm0
  shufps $0x1b,%xmm0,%xmm0
  movups %xmm0,(%rdx,%rax,1)
  sub    $0x10,%rax
  cmp    %rax,%r9
  jne    L145
  mov    -0x10(%rsp),%eax
  mov    -0x20(%rsp),%esi
  cmp    %esi,%eax
  je     L93
  mov    -0x1c(%rsp),%esi
  mov    -0x8(%rsp),%r15d
  cmp    %esi,%eax
  je     L111
  mov    %eax,%edx
  mov    (%rsp),%eax
  mov    %eax,-0x70(%rsp)
L187:
  mov    -0x58(%rsp),%rsi
  add    $0x1,%edx
  mov    -0x68(%rsp),%rax
  movaps %xmm2,%xmm4
  neg    %rdx
  shufps $0xe0,%xmm4,%xmm4
  shl    $0x2,%rdx
  add    %rdi,%rsi
  add    %rdx,%rsi
  add    %rbp,%rdx
  movq   (%rdx,%rax,1),%xmm1
  add    %rbp,%rsi
  mov    -0x70(%rsp),%eax
  mov    %r15d,%edx
  movq   (%rsi),%xmm0
  and    $0xfffffffe,%edx
  shufps $0xe1,%xmm1,%xmm1
  sub    %edx,%eax
  mulps  %xmm4,%xmm1
  shufps $0xe1,%xmm0,%xmm0
  subps  %xmm1,%xmm0
  shufps $0xe1,%xmm0,%xmm0
  movlps %xmm0,(%rsi)
  cmp    %r15d,%edx
  je     L93
L48:
  cltq
  lea    (%rcx,%rax,1),%rdx
  add    %r11,%rax
  movss  0x0(%rbp,%rax,4),%xmm1
  lea    0x0(%rbp,%rdx,4),%rdx
  movss  (%rdx),%xmm0
  mulss  %xmm2,%xmm1
  subss  %xmm1,%xmm0
  movss  %xmm0,(%rdx)
L93:
  mov    -0x30(%rsp),%esi
  cmp    %esi,-0x2c(%rsp)
  jle    L183
  lea    -0x10(%rdi),%rax
  cmp    $0x8,%rax
  jbe    L7
  cmpl   $0x1,-0x6c(%rsp)
  je     L7
  cmpl   $0x2,-0xc(%rsp)
  jbe    L75
  movaps %xmm2,%xmm4
  lea    -0xc(%rdi,%r12,1),%rdx
  xor    %eax,%eax
  shufps $0x0,%xmm4,%xmm4
  nopl   0x0(%rax)
L161:
  movups (%r12,%rax,1),%xmm1
  movups (%rdx,%rax,1),%xmm0
  mulps  %xmm4,%xmm1
  subps  %xmm1,%xmm0
  movups %xmm0,(%rdx,%rax,1)
  add    $0x10,%rax
  cmp    %r13,%rax
  jne    L161
  mov    -0x4(%rsp),%edx
  mov    -0x6c(%rsp),%eax
  cmp    %eax,%edx
  je     L183
  mov    0x38(%rsp),%eax
  cmp    $0x1,%eax
  mov    %eax,%r15d
  mov    0x4(%rsp),%eax
  je     L10
L226:
  lea    (%rbx,%rdx,1),%rsi
  add    -0x60(%rsp),%rdx
  movaps %xmm2,%xmm4
  movq   0x0(%rbp,%rdx,4),%xmm1
  shufps $0xe0,%xmm4,%xmm4
  lea    0x0(%rbp,%rsi,4),%rsi
  mov    %r15d,%edx
  movq   (%rsi),%xmm0
  and    $0xfffffffe,%edx
  mulps  %xmm4,%xmm1
  add    %edx,%eax
  subps  %xmm1,%xmm0
  movlps %xmm0,(%rsi)
  cmp    %r15d,%edx
  je     L183
L10:
  cltq
  lea    (%rax,%rcx,1),%rdx
  add    %r11,%rax
  mulss  0x0(%rbp,%rax,4),%xmm2
  lea    0x0(%rbp,%rdx,4),%rdx
  movss  (%rdx),%xmm0
  subss  %xmm2,%xmm0
  movss  %xmm0,(%rdx)
L183:
  mov    -0x50(%rsp),%rsi
  subl   $0x1,-0x74(%rsp)
  mov    -0x74(%rsp),%eax
  add    -0x28(%rsp),%r10
  add    -0x48(%rsp),%rdi
  add    %rsi,%rcx
  sub    %rsi,%r8
  add    -0x40(%rsp),%rbx
  cmp    $0xffffffff,%eax
  jne    L186
  mov    0x40(%rsp),%rbx
  add    %rbx,0x28(%rsp)
  add    %rsi,%r11
  add    %rbx,0x30(%rsp)
  mov    -0x40(%rsp),%rbx
  add    %rbx,-0x60(%rsp)
  mov    0x50(%rsp),%rbx
  add    %rbx,0x10(%rsp)
  mov    0x58(%rsp),%rbx
  subl   $0x1,-0x20(%rsp)
  add    -0x48(%rsp),%r12
  add    %rbx,-0x68(%rsp)
  add    %rbx,%r14
  mov    0x8(%rsp),%rsi
  subq   $0x1,-0x38(%rsp)
  jne    L52
L141:
  add    $0x70,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  xchg   %ax,%ax
L193:
  mov    0x18(%rsp),%rax
  lea    (%rax,%r10,1),%rdx
  mov    %r10,%rax
  nopl   0x0(%rax)
L115:
  movss  (%rax,%r8,4),%xmm1
  movss  (%rax),%xmm0
  sub    $0x4,%rax
  mulss  %xmm2,%xmm1
  subss  %xmm1,%xmm0
  movss  %xmm0,0x4(%rax)
  cmp    %rax,%rdx
  jne    L115
  jmp    L93
  nopl   (%rax)
L7:
  mov    0x20(%rsp),%rax
  mov    0x8(%rsp),%rsi
  add    %r10,%rax
  lea    (%rsi,%r10,1),%rdx
  nopl   0x0(%rax)
L168:
  movss  (%rax,%r8,4),%xmm1
  movss  (%rax),%xmm0
  add    $0x4,%rax
  mulss  %xmm2,%xmm1
  subss  %xmm1,%xmm0
  movss  %xmm0,-0x4(%rax)
  cmp    %rdx,%rax
  jne    L168
  jmp    L183
L50:
  mov    -0x1c(%rsp),%eax
  mov    0x3c(%rsp),%r15d
  xor    %edx,%edx
  mov    %eax,-0x70(%rsp)
  jmp    L187
L75:
  mov    -0x6c(%rsp),%r15d
  mov    %esi,%eax
  xor    %edx,%edx
  jmp    L226
L111:
  mov    (%rsp),%eax
  jmp    L48
```

assistant: ```c
void lowertriag(float *array, int n) {
  int i, j;
  for (j = n - 1; j >= 1; j--) {
    int k = j, l;
    float pivot1 = *(array + (2 * n) * j + j);
    for (l = k - 1; l >= 0; l--) {
      float next = *(array + (2 * n) * (l) + j) / pivot1;
      for (i = j; i >= 0; i--) {
        *(array + (2 * n) * l + i) -= *(array + (2 * n) * (k) + i) * next;
      }
      for (i = n; i < 2 * n; i++) {
        *(array + (2 * n) * l + i) -= *(array + (2 * n) * (k) + i) * next;
      }
    }
  }
}
```