user: 下面的汇编指令对应的C源代码是什么:

```asm
<BRBase58EncodeEx>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x48,%rsp
  mov    %rdi,-0x50(%rbp)
  mov    %rsi,-0x68(%rbp)
  mov    %rdx,%r15
  mov    %rcx,%rbx
  mov    %rcx,-0x48(%rbp)
  mov    %r8,%rdi
  mov    %r8,-0x58(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  call   <strlen@plt>
  cmp    $0x39,%eax
  setg   %dil
  movzbl %dil,%edi
  call   <assert@plt>
  test   %r15,%r15
  setne  %r13b
  setne  %dil
  movzbl %dil,%edi
  call   <assert@plt>
  test   %rbx,%rbx
  je     L92
  mov    $0x0,%r12d
  test   %r13b,%r13b
  je     L92
L234:
  cmpq   $0x0,(%r15,%r12,8)
  jne    L27
  add    $0x1,%r12
  cmp    %r12,-0x48(%rbp)
  ja     L234
  mov    -0x48(%rbp),%rdx
  sub    %r12,%rdx
  imul   $0x8a,%rdx,%rdx
  shr    $0x2,%rdx
  movabs $0x28f5c28f5c28f5c3,%rcx
  mov    %rdx,%rax
  mul    %rcx
  shr    $0x2,%rdx
  lea    0x1(%rdx),%rax
  lea    0x0(,%rax,8),%r14
  lea    0xf(%r14),%rdx
  mov    %rdx,%rsi
  and    $0xfffffffffffffff0,%rsi
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rcx
  sub    %rdx,%rcx
L65:
  cmp    %rcx,%rsp
  je     L4
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L65
L92:
  mov    $0x0,%r12d
L27:
  mov    -0x48(%rbp),%rdx
  sub    %r12,%rdx
  imul   $0x8a,%rdx,%rdx
  shr    $0x2,%rdx
  movabs $0x28f5c28f5c28f5c3,%rcx
  mov    %rdx,%rax
  mul    %rcx
  shr    $0x2,%rdx
  lea    0x1(%rdx),%rax
  lea    0x0(,%rax,8),%r14
  lea    0xf(%r14),%rdx
  mov    %rdx,%rsi
  and    $0xfffffffffffffff0,%rsi
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rcx
  sub    %rdx,%rcx
L141:
  cmp    %rcx,%rsp
  je     L157
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L141
L157:
  mov    %rsi,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L188
  orq    $0x0,-0x8(%rsp,%rdx,1)
L188:
  mov    %rsp,%rdi
  mov    %rdi,%rbx
  shl    $0x3,%eax
  mov    %eax,-0x6c(%rbp)
  mov    %eax,%edx
  mov    $0x0,%esi
  call   <memset@plt>
  cmp    %r12,-0x48(%rbp)
  jbe    L152
  test   %r13b,%r13b
  je     L152
  mov    %r12,%r13
  lea    -0x3c(%rbp),%rax
  mov    %rax,-0x60(%rbp)
L12:
  mov    (%r15,%r13,8),%eax
  mov    %r14,%rcx
L76:
  sub    $0x1,%rcx
  mov    (%rbx,%rcx,8),%edx
  shl    $0x8,%edx
  add    %eax,%edx
  movslq %edx,%rax
  imul   $0xffffffff8d3dcb09,%rax,%rax
  shr    $0x20,%rax
  add    %edx,%eax
  sar    $0x5,%eax
  mov    %edx,%esi
  sar    $0x1f,%esi
  sub    %esi,%eax
  imul   $0x3a,%eax,%esi
  sub    %esi,%edx
  movslq %edx,%rdx
  mov    %rdx,(%rbx,%rcx,8)
  test   %rcx,%rcx
  jne    L76
  mov    %eax,-0x3c(%rbp)
  mov    $0x0,%edx
  mov    -0x60(%rbp),%rsi
  mov    $0x4,%edi
  call   <_var_clean@plt>
  add    $0x1,%r13
  cmp    %r13,-0x48(%rbp)
  ja     L12
L152:
  mov    $0x0,%eax
L26:
  cmpq   $0x0,(%rbx,%rax,8)
  jne    L169
  add    $0x1,%rax
  cmp    %r14,%rax
  jne    L26
  mov    %r14,%rax
L169:
  mov    %rax,%rsi
  neg    %rsi
  lea    0x1(%r14,%r12,1),%rdx
  sub    %rax,%rdx
  mov    %rdx,%r13
  cmp    -0x68(%rbp),%rdx
  setbe  %r15b
  mov    -0x50(%rbp),%rdi
  test   %rdi,%rdi
  je     L259
  test   %r15b,%r15b
  je     L259
  test   %r12,%r12
  je     L261
  add    %rdi,%r12
L107:
  addq   $0x1,-0x50(%rbp)
  mov    -0x50(%rbp),%rdi
  mov    -0x58(%rbp),%rcx
  movzbl (%rcx),%edx
  mov    %dl,-0x1(%rdi)
  cmp    %r12,%rdi
  jne    L107
L148:
  cmp    %rax,%r14
  jbe    L237
  mov    %rax,%rdx
  add    %r12,%rsi
L142:
  add    $0x1,%rdx
  mov    -0x8(%rbx,%rdx,8),%rcx
  mov    -0x58(%rbp),%rdi
  movzbl (%rdi,%rcx,1),%ecx
  mov    %cl,-0x1(%rsi,%rdx,1)
  cmp    %r14,%rdx
  jne    L142
  sub    %rax,%r14
  add    %r14,%r12
L237:
  movb   $0x0,(%r12)
  mov    -0x6c(%rbp),%esi
  mov    %rbx,%rdi
  call   <mem_clean@plt>
  jmp    L50
L261:
  mov    -0x50(%rbp),%r12
  jmp    L148
L259:
  mov    -0x6c(%rbp),%esi
  mov    %rbx,%rdi
  call   <mem_clean@plt>
  cmpq   $0x0,-0x50(%rbp)
  je     L50
  test   %r15b,%r15b
  mov    $0x0,%eax
  cmove  %rax,%r13
L50:
  mov    -0x38(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L82
  mov    %r13,%rax
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L4:
  mov    %rsi,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L81
  orq    $0x0,-0x8(%rsp,%rdx,1)
L81:
  mov    %rsp,%rdi
  mov    %rdi,%rbx
  shl    $0x3,%eax
  mov    %eax,-0x6c(%rbp)
  mov    %eax,%edx
  mov    $0x0,%esi
  call   <memset@plt>
  jmp    L152
L82:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
size_t BRBase58EncodeEx(char *str, size_t strLen, const uint8_t *data, size_t dataLen, const char *alphabet) {
  const char *chars = alphabet;
  assert(strlen(alphabet) >= 58);
  size_t i, j, len, zcount = 0;
  assert(data != NULL);
  while (zcount < dataLen && data && data[zcount] == 0)
    zcount++;
  uint8_t buf[(dataLen - zcount) * 138 / 100 + 1];
  memset(buf, 0, sizeof(buf));
  for (i = zcount; data && i < dataLen; i++) {
    uint32_t carry = data[i];
    for (j = sizeof(buf); j > 0; j--) {
      carry += (uint32_t)buf[j - 1] << 8;
      buf[j - 1] = carry % 58;
      carry /= 58;
    }
    _var_clean(sizeof(*(&carry)), &carry, NULL);
  }
  i = 0;
  while (i < sizeof(buf) && buf[i] == 0)
    i++;
  len = (zcount + sizeof(buf) - i) + 1;
  if (str && len <= strLen) {
    while (zcount-- > 0)
      *(str++) = chars[0];
    while (i < sizeof(buf))
      *(str++) = chars[buf[i++]];
    *str = '\0';
  }
  mem_clean(buf, sizeof(buf));
  return (!str || len <= strLen) ? len : 0;
}
```