user: 这段汇编代码用C语言表示是什么样的：

```asm
<fndsep>:
  endbr64
  push   %r15
  mov    %r9,%r15
  push   %r14
  mov    %rdx,%r14
  push   %r13
  mov    %rsi,%r13
  push   %r12
  mov    %edi,%r12d
  push   %rbp
  mov    %rcx,%rbp
  push   %rbx
  sub    $0x28,%rsp
  mov    0x60(%rsp),%rbx
  mov    0x68(%rsp),%edi
  mov    %r8,0x8(%rsp)
  mov    %rbx,%rsi
  mov    %fs:0x28,%rax
  mov    %rax,0x18(%rsp)
  xor    %eax,%eax
  call   <zeroi@plt>
  mov    0x8(%rsp),%r8
  mov    %r15,%r9
  mov    %r14,%rdx
  lea    0x14(%rsp),%rcx
  mov    %r13,%rsi
  mov    %r12d,%edi
  call   <fnroot@plt>
  movslq 0x14(%rsp),%r9
  mov    0x8(%rsp),%r8
  cmp    $0x5,%r9d
  jle    L92
  mov    (%r8,%r9,4),%eax
  xor    %edx,%edx
  mov    %eax,%r10d
  shr    $0x1f,%r10d
  add    %eax,%r10d
  xor    %eax,%eax
  sar    %r10d
  jmp    L163
  nopl   (%rax)
L74:
  mov    %rcx,%rax
L163:
  mov    (%r8,%rax,4),%esi
  mov    %eax,%edi
  cmp    %edx,%r10d
  jle    L49
  add    0x4(%r8,%rax,4),%edx
  lea    0x1(%rax),%rcx
  lea    0x1(%rax),%edi
  sub    %esi,%edx
  cmp    %rcx,%r9
  jne    L74
L94:
  movslq %edi,%rdi
  mov    0x8(%r8,%rax,4),%r10d
  movslq (%r8,%rdi,4),%r9
  cmp    %r10d,%r9d
  jge    L132
  lea    -0x1(%r10),%edx
  movslq %r9d,%rcx
  sub    %r9d,%edx
  lea    (%r15,%rcx,4),%rax
  add    %rcx,%rdx
  lea    0x4(%r15,%rdx,4),%rcx
  nopl   0x0(%rax)
L134:
  movslq (%rax),%rdx
  add    $0x4,%rax
  movl   $0xffffffff,(%rbx,%rdx,4)
  cmp    %rax,%rcx
  jne    L134
L132:
  xor    %r12d,%r12d
  cmp    %esi,%r9d
  jle    L109
  mov    %r9d,%eax
  movslq %esi,%rdx
  xor    %r12d,%r12d
  sub    %esi,%eax
  lea    (%r15,%rdx,4),%r8
  sub    $0x1,%eax
  add    %rdx,%rax
  lea    0x4(%r15,%rax,4),%r11
  nopl   (%rax)
L114:
  movslq (%r8),%rdx
  mov    0x0(%r13,%rdx,8),%rax
  mov    0x8(%r13,%rdx,8),%rcx
  mov    %rdx,%rsi
  cmp    %rcx,%rax
  jae    L127
  lea    (%r14,%rdx,4),%rdi
  nopl   0x0(%rax)
L120:
  movslq (%rax),%rdx
  mov    (%rbx,%rdx,4),%edx
  test   %edx,%edx
  jns    L166
  movslq %r12d,%rax
  add    $0x1,%r12d
  mov    %esi,0x0(%rbp,%rax,4)
  mov    %rcx,%rax
  movl   $0xffffffff,(%rdi)
L166:
  add    $0x4,%rax
  cmp    %rcx,%rax
  jb     L120
L127:
  add    $0x4,%r8
  cmp    %r8,%r11
  jne    L114
L109:
  cmp    %r10d,%r9d
  jge    L139
  sub    $0x1,%r10d
  lea    (%rbx,%r9,4),%rdi
  xor    %esi,%esi
  sub    %r9d,%r10d
  lea    0x4(,%r10,4),%rdx
  call   <memset@plt>
L139:
  mov    0x18(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L63
  add    $0x28,%rsp
  mov    %r12d,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L49:
  lea    -0x1(%rax),%eax
  cltq
  mov    (%r8,%rax,4),%esi
  jmp    L94
L92:
  add    $0x1,%r9d
  sub    $0x8,%rsp
  mov    (%r15),%esi
  mov    %rbp,%rcx
  movslq %r9d,%rax
  mov    %r13,%rdx
  mov    %r8,%r9
  mov    (%r8,%rax,4),%r12d
  push   %rbx
  mov    %r14,%r8
  mov    %r12d,%edi
  call   <subrcm@plt>
  pop    %rcx
  pop    %rsi
  test   %r12d,%r12d
  jle    L139
  movslq %r12d,%rcx
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L38:
  movslq (%r15,%rax,4),%rdx
  mov    %edx,0x0(%rbp,%rax,4)
  add    $0x1,%rax
  movl   $0xffffffff,(%r14,%rdx,4)
  cmp    %rax,%rcx
  jne    L38
  jmp    L139
L63:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int fndsep(int root, int **padj, int *mask, int *sep, int *xls, int *ls, int *work, int neqns) {
  int nlvl, nsep, i, node, midlvl, midbeg, mp1beg, mp1end;
  int *ptr;
  int minone = -1;
  zeroi(neqns, work);
  root = fnroot(root, padj, mask, &nlvl, xls, ls);
  if (nlvl < 6) {
    nsep = xls[nlvl + 1];
    node = ls[0];
    subrcm(nsep, node, padj, sep, mask, xls, work);
    for (i = 0; i < nsep; i++) {
      node = ls[i];
      sep[i] = node;
      mask[node] |= minone;
    }
    return (nsep);
  }
  midlvl = (nlvl + 2) / 2;
  {
    int j, k, l;
    ;
    k = xls[nlvl];
    j = k / 2;
    l = 0;
    for (k = 0; k < nlvl && l < j; k++) {
      if (l < j) {
        l += (xls[k + 1] - xls[k]);
      }
    }
    k--;
    midlvl = k;
    midbeg = xls[midlvl];
    mp1beg = xls[midlvl + 1];
    mp1end = xls[midlvl + 2];
  }
  for (i = mp1beg; i < mp1end; i++) {
    node = ls[i];
    work[node] |= minone;
  }
  nsep = 0;
  for (i = midbeg; i < mp1beg; i++) {
    node = ls[i];
    for (ptr = padj[node]; ptr < padj[node + 1]; ptr++) {
      if (work[*ptr] < 0) {
        sep[nsep] = node;
        nsep++;
        mask[node] |= minone;
        ptr = padj[node + 1];
      }
    }
  }
  for (i = mp1beg; i < mp1end; i++) {
    node = ls[i];
    work[i] &= 0;
  }
  return (nsep);
}
```