user: What would the C source look like for the assembly code provided here:

```asm
<internal_fiat_25519_add>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  mov    %rsi,%r12
  mov    $0x8,%esi
  push   %rbp
  mov    %rdx,%rbp
  push   %rbx
  mov    %rdi,%rbx
  mov    %r12d,%edi
  sub    $0x38,%rsp
  call   <_br2_load@plt>
  lea    0x8(%r12),%edi
  mov    $0x8,%esi
  mov    %rax,0x8(%rsp)
  call   <_br2_load@plt>
  lea    0x10(%r12),%edi
  mov    $0x8,%esi
  mov    %rax,%r15
  call   <_br2_load@plt>
  lea    0x18(%r12),%edi
  mov    $0x8,%esi
  mov    %rax,0x10(%rsp)
  call   <_br2_load@plt>
  lea    0x20(%r12),%edi
  mov    $0x8,%esi
  mov    %rax,0x18(%rsp)
  call   <_br2_load@plt>
  mov    %ebp,%edi
  mov    $0x8,%esi
  mov    %rax,0x20(%rsp)
  call   <_br2_load@plt>
  lea    0x8(%rbp),%edi
  mov    $0x8,%esi
  mov    %rax,0x28(%rsp)
  call   <_br2_load@plt>
  lea    0x10(%rbp),%edi
  mov    $0x8,%esi
  mov    %rax,%r13
  call   <_br2_load@plt>
  lea    0x18(%rbp),%edi
  mov    $0x8,%esi
  add    %r15,%r13
  mov    %rax,%r12
  call   <_br2_load@plt>
  lea    0x20(%rbp),%edi
  mov    $0x8,%esi
  mov    %rax,%r14
  call   <_br2_load@plt>
  mov    0x20(%rsp),%rbp
  mov    0x8(%rsp),%rsi
  mov    %ebx,%edi
  add    0x28(%rsp),%rsi
  mov    $0x8,%edx
  add    0x10(%rsp),%r12
  add    0x18(%rsp),%r14
  add    %rax,%rbp
  call   <_br2_store@plt>
  lea    0x8(%rbx),%edi
  mov    %r13,%rsi
  mov    $0x8,%edx
  call   <_br2_store@plt>
  lea    0x10(%rbx),%edi
  mov    %r12,%rsi
  mov    $0x8,%edx
  call   <_br2_store@plt>
  lea    0x18(%rbx),%edi
  mov    %r14,%rsi
  mov    $0x8,%edx
  call   <_br2_store@plt>
  add    $0x38,%rsp
  lea    0x20(%rbx),%edi
  mov    %rbp,%rsi
  pop    %rbx
  mov    $0x8,%edx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    1060 <_br2_store@plt>
```

assistant: ```c
void internal_fiat_25519_add(uintptr_t out0, uintptr_t in0, uintptr_t in1) {
  uintptr_t x0, x5, x1, x6, x2, x7, x3, x8, x4, x9, x10, x11, x12, x13, x14, x15, x16, x17, x18, x19;
  x0 = _br2_load((in0) + ((uintptr_t)0ULL), sizeof(uintptr_t));
  x1 = _br2_load((in0) + ((uintptr_t)8ULL), sizeof(uintptr_t));
  x2 = _br2_load((in0) + ((uintptr_t)16ULL), sizeof(uintptr_t));
  x3 = _br2_load((in0) + ((uintptr_t)24ULL), sizeof(uintptr_t));
  x4 = _br2_load((in0) + ((uintptr_t)32ULL), sizeof(uintptr_t));
  x5 = _br2_load((in1) + ((uintptr_t)0ULL), sizeof(uintptr_t));
  x6 = _br2_load((in1) + ((uintptr_t)8ULL), sizeof(uintptr_t));
  x7 = _br2_load((in1) + ((uintptr_t)16ULL), sizeof(uintptr_t));
  x8 = _br2_load((in1) + ((uintptr_t)24ULL), sizeof(uintptr_t));
  x9 = _br2_load((in1) + ((uintptr_t)32ULL), sizeof(uintptr_t));
  x10 = (x0) + (x5);
  x11 = (x1) + (x6);
  x12 = (x2) + (x7);
  x13 = (x3) + (x8);
  x14 = (x4) + (x9);
  x15 = x10;
  x16 = x11;
  x17 = x12;
  x18 = x13;
  x19 = x14;
  _br2_store((out0) + ((uintptr_t)0ULL), x15, sizeof(uintptr_t));
  _br2_store((out0) + ((uintptr_t)8ULL), x16, sizeof(uintptr_t));
  _br2_store((out0) + ((uintptr_t)16ULL), x17, sizeof(uintptr_t));
  _br2_store((out0) + ((uintptr_t)24ULL), x18, sizeof(uintptr_t));
  _br2_store((out0) + ((uintptr_t)32ULL), x19, sizeof(uintptr_t));
  return;
}
```