user: 下面的汇编指令对应的C源代码是什么：

```asm
<pbkdf2_sha1>:
  endbr64
  push   %r15
  push   %r14
  mov    %rdx,%r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x88,%rsp
  mov    %rcx,0x20(%rsp)
  mov    %r8d,0x8(%rsp)
  mov    %r9,0x28(%rsp)
  mov    %fs:0x28,%rax
  mov    %rax,0x78(%rsp)
  mov    0xc0(%rsp),%rax
  lea    -0x1(%rax),%rdx
  mov    $0xfffffffe,%eax
  cmp    %rax,%rdx
  ja     L86
  test   %r8d,%r8d
  jne    L110
L86:
  xor    %eax,%eax
L45:
  mov    0x78(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L117
  add    $0x88,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L110:
  mov    0x20(%rsp),%r13
  mov    %rdi,%rbx
  mov    %rsi,%rbp
  lea    0x4(%r13),%rax
  mov    %rax,%rdi
  mov    %rax,0x10(%rsp)
  call   <malloc@plt>
  mov    %rax,%r12
  test   %rax,%rax
  je     L86
  mov    0xc0(%rsp),%rsi
  mov    $0xcccccccd,%edx
  mov    %r12,%rdi
  lea    -0x1(%rsi),%eax
  imul   %rdx,%rax
  mov    %r13d,%edx
  lea    0x40(%rsp),%r13
  mov    %rax,%rsi
  shr    $0x24,%rsi
  mov    %rsi,%r15
  mov    %esi,0x3c(%rsp)
  lea    0x1(%rsi),%esi
  mov    %esi,0x38(%rsp)
  mov    %r14,%rsi
  call   <memcpy@plt>
  lea    0x2(%r15),%esi
  mov    0x10(%rsp),%eax
  movl   $0x1,0xc(%rsp)
  mov    %esi,0x34(%rsp)
  lea    0x60(%rsp),%rsi
  lea    0x74(%rsp),%r15
  mov    %rsi,(%rsp)
  mov    %eax,0x30(%rsp)
  mov    %r13,%rax
  mov    %rbp,%r13
  mov    %rbx,%rbp
  mov    %rax,%rbx
L1:
  mov    (%rsp),%rdi
  xor    %esi,%esi
  mov    $0x14,%edx
  mov    $0x1,%r14d
  call   <memset@plt>
  mov    0xc(%rsp),%esi
  mov    %esi,%eax
  shr    $0x18,%eax
  mov    %eax,0x10(%rsp)
  mov    %esi,%eax
  shr    $0x10,%eax
  mov    %al,0x1b(%rsp)
  mov    %esi,%eax
  movzbl %ah,%eax
  mov    %eax,0x1c(%rsp)
  mov    %rbx,%rax
  mov    %r14d,%ebx
  mov    %r15,%r14
  mov    %rax,%r15
  nopl   0x0(%rax,%rax,1)
L48:
  cmp    $0x1,%ebx
  je     L71
  mov    %r15,%r8
  mov    $0x14,%ecx
  mov    %r15,%rdx
  mov    %r13,%rsi
  mov    %rbp,%rdi
  call   <hmac_sha1@plt>
L24:
  mov    (%rsp),%rax
  mov    %r15,%rdx
  cs nopw 0x0(%rax,%rax,1)
L42:
  movzbl (%rdx),%ecx
  xor    %cl,(%rax)
  add    $0x1,%rax
  add    $0x1,%rdx
  cmp    %rax,%r14
  jne    L42
  add    $0x1,%ebx
  cmp    %ebx,0x8(%rsp)
  jae    L48
  mov    %r15,%rbx
  mov    %r14,%r15
  mov    0xc(%rsp),%r14d
  lea    (%r14,%r14,4),%eax
  lea    -0x14(,%rax,4),%edi
  add    0x28(%rsp),%rdi
  cmp    %r14d,0x38(%rsp)
  je     L84
  mov    (%rsp),%rsi
  mov    $0x14,%edx
  call   <memcpy@plt>
  mov    %r14d,%esi
  add    $0x1,%esi
  mov    %esi,0xc(%rsp)
  cmp    %esi,0x34(%rsp)
  jne    L1
  mov    %r12,%rdi
  call   <free@plt>
  mov    $0x1,%eax
  jmp    L45
  nopl   (%rax)
L71:
  mov    0x20(%rsp),%rax
  movzbl 0x10(%rsp),%edi
  mov    %r15,%r8
  mov    %r12,%rdx
  mov    0x30(%rsp),%ecx
  mov    %r13,%rsi
  mov    %dil,(%r12,%rax,1)
  movzbl 0x1b(%rsp),%edi
  mov    %dil,0x1(%r12,%rax,1)
  movzbl 0x1c(%rsp),%edi
  mov    %dil,0x2(%r12,%rax,1)
  movzbl 0xc(%rsp),%edi
  mov    %dil,0x3(%r12,%rax,1)
  mov    %rbp,%rdi
  call   <hmac_sha1@plt>
  jmp    L24
L84:
  mov    0x3c(%rsp),%eax
  mov    0xc0(%rsp),%edx
  mov    (%rsp),%rsi
  lea    (%rax,%rax,4),%eax
  shl    $0x2,%eax
  sub    %eax,%edx
  call   <memcpy@plt>
  mov    %r12,%rdi
  call   <free@plt>
  mov    $0x1,%eax
  jmp    L45
L117:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int pbkdf2_sha1(const char *password, size_t Plen, const char *salt, size_t Slen, unsigned int c, char *derivedKey, size_t dkLen) {
  unsigned int hLen = 20;
  char U[20], T[20];
  unsigned int u, l, r, i, k;
  char *tmp;
  size_t tmplen = Slen + 4;
  if (!c || !dkLen || dkLen > 4294967295U)
    return 0;
  l = (((int)dkLen - 1) / hLen) + 1;
  r = (int)dkLen - (l - 1) * hLen;
  if (!(tmp = (char *)malloc(tmplen)))
    return 0;
  memcpy(tmp, salt, Slen);
  for (i = 1; i <= l; i++) {
    memset(T, 0, hLen);
    for (u = 1; u <= c; u++) {
      if (u == 1) {
        tmp[Slen + 0] = (i & 0xff000000) >> 24;
        tmp[Slen + 1] = (i & 0x00ff0000) >> 16;
        tmp[Slen + 2] = (i & 0x0000ff00) >> 8;
        tmp[Slen + 3] = (i & 0x000000ff) >> 0;
        hmac_sha1(password, Plen, tmp, tmplen, U);
      } else
        hmac_sha1(password, Plen, U, hLen, U);
      for (k = 0; k < hLen; k++)
        T[k] ^= U[k];
    }
    memcpy(derivedKey + (i - 1) * hLen, T, i == l ? r : hLen);
  }
  free(tmp);
  return 1;
}
```