user: What is the c source code of the assembly code below:

```asm
<transformation_D2>:
  endbr64
  push   %r15
  mov    %rsi,%r8
  mov    %rdx,%rsi
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x28,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x18(%rsp)
  xor    %eax,%eax
  lea    0x14(%rsp),%r9
L78:
  movzbl (%r8,%rax,1),%edx
  xor    (%rcx,%rax,1),%dl
  mov    %dl,(%r9,%rax,1)
  add    $0x1,%rax
  cmp    $0x4,%rax
  jne    L78
  movzbl 0x17(%rsp),%eax
  movzbl 0x14(%rsp),%ebx
  mov    %r9,%rbp
  mov    %r9,%r12
  xor    %edx,%edx
  shr    $0x3,%al
  lea    (%rbx,%rbx,1),%r14d
  mov    %al,0xf(%rsp)
L170:
  movzbl (%rdi,%rdx,1),%eax
  movzbl (%rsi,%rdx,1),%r15d
  movzbl (%rcx,%rdx,1),%r13d
  test   %rdx,%rdx
  je     L77
  movzbl -0x1(%r12),%r11d
  lea    (%rbx,%rbx,1),%r10d
  shr    $0x7,%r11b
  or     %r11d,%r10d
  cmp    $0x3,%edx
  je     L234
L149:
  shr    $0x3,%bl
  xor    %r15d,%eax
  mov    %ebx,%r11d
  movzbl 0x1(%r12),%ebx
  xor    %r13d,%eax
  mov    %ebx,%r13d
  shl    $0x5,%r13d
  or     %r13d,%r11d
  xor    %r11d,%eax
  xor    %r10d,%eax
  mov    %al,(%rdi,%rdx,1)
L74:
  add    $0x1,%rdx
  add    $0x1,%r12
  jmp    L170
  nopl   0x0(%rax,%rax,1)
L77:
  mov    %r14d,%r10d
  jmp    L149
  nopl   (%rax)
L234:
  xor    %eax,%r15d
  xor    0xf(%rsp),%r15b
  xor    %r13d,%r15d
  xor    %r10d,%r15d
  mov    %r15b,(%rdi,%rdx,1)
  cmp    $0x3,%rdx
  jne    L126
  xor    %eax,%eax
L200:
  movzbl (%rsi,%rax,1),%edx
  xor    (%rdi,%rax,1),%dl
  mov    %dl,(%r9,%rax,1)
  add    $0x1,%rax
  cmp    $0x4,%rax
  jne    L200
  movzbl 0x17(%rsp),%eax
  movzbl 0x14(%rsp),%ebx
  mov    %r9,%r12
  xor    %edx,%edx
  shr    $0x3,%al
  lea    (%rbx,%rbx,1),%r14d
  mov    %al,0xf(%rsp)
L123:
  movzbl (%r8,%rdx,1),%eax
  movzbl (%rcx,%rdx,1),%r15d
  movzbl (%rdi,%rdx,1),%r13d
  test   %rdx,%rdx
  je     L216
  movzbl -0x1(%r12),%r11d
  lea    (%rbx,%rbx,1),%r10d
  shr    $0x7,%r11b
  or     %r11d,%r10d
  cmp    $0x3,%edx
  je     L238
L55:
  shr    $0x3,%bl
  xor    %r15d,%eax
  mov    %ebx,%r11d
  movzbl 0x1(%r12),%ebx
  xor    %r13d,%eax
  mov    %ebx,%r13d
  shl    $0x5,%r13d
  or     %r13d,%r11d
  xor    %r11d,%eax
  xor    %r10d,%eax
  mov    %al,(%r8,%rdx,1)
L20:
  add    $0x1,%rdx
  add    $0x1,%r12
  jmp    L123
  nop
L216:
  mov    %r14d,%r10d
  jmp    L55
  nopl   (%rax)
L238:
  xor    %eax,%r15d
  xor    0xf(%rsp),%r15b
  xor    %r13d,%r15d
  xor    %r10d,%r15d
  mov    %r15b,(%r8,%rdx,1)
  cmp    $0x3,%rdx
  jne    L36
  xor    %eax,%eax
L263:
  movzbl (%rcx,%rax,1),%edx
  xor    (%r8,%rax,1),%dl
  mov    %dl,(%r9,%rax,1)
  add    $0x1,%rax
  cmp    $0x4,%rax
  jne    L263
  movzbl 0x14(%rsp),%r10d
  movzbl 0x17(%rsp),%r11d
  xor    %edx,%edx
  shr    $0x3,%r11b
  lea    (%r10,%r10,1),%ebx
L192:
  movzbl (%rsi,%rdx,1),%eax
  movzbl (%rdi,%rdx,1),%r15d
  movzbl (%r8,%rdx,1),%r14d
  test   %rdx,%rdx
  je     L252
  movzbl -0x1(%rbp),%r13d
  lea    (%r10,%r10,1),%r12d
  shr    $0x7,%r13b
  or     %r13d,%r12d
  cmp    $0x3,%edx
  je     L21
L204:
  shr    $0x3,%r10b
  xor    %r15d,%eax
  mov    %r10d,%r13d
  movzbl 0x1(%rbp),%r10d
  xor    %r14d,%eax
  mov    %r10d,%r14d
  shl    $0x5,%r14d
  or     %r14d,%r13d
  xor    %r13d,%eax
  xor    %r12d,%eax
  mov    %al,(%rsi,%rdx,1)
L75:
  add    $0x1,%rdx
  add    $0x1,%rbp
  jmp    L192
  nopl   0x0(%rax)
L252:
  mov    %ebx,%r12d
  jmp    L204
  nopl   (%rax)
L21:
  xor    %eax,%r15d
  xor    %r11d,%r15d
  xor    %r14d,%r15d
  xor    %r12d,%r15d
  mov    %r15b,(%rsi,%rdx,1)
  cmp    $0x3,%rdx
  jne    L177
  xor    %eax,%eax
L24:
  movzbl (%rdi,%rax,1),%edx
  xor    (%rsi,%rax,1),%dl
  mov    %dl,(%r9,%rax,1)
  add    $0x1,%rax
  cmp    $0x4,%rax
  jne    L24
  movzbl 0x14(%rsp),%r9d
  xor    %edi,%edi
  lea    0x13(%rsp),%rbx
  lea    0x15(%rsp),%r11
  movslq %edi,%r10
  lea    (%r9,%r9,1),%ebp
  test   %rdi,%rdi
  je     L208
L12:
  movzbl (%rbx,%rdi,1),%eax
  lea    (%r9,%r9,1),%r12d
  shr    $0x7,%al
  or     %eax,%r12d
  cmp    $0x3,%edi
  je     L116
L251:
  shr    $0x3,%r9b
  movzbl (%rcx,%rdi,1),%eax
  xor    (%r8,%rdi,1),%al
  mov    %r9d,%r10d
  movzbl (%r11,%rdi,1),%r9d
  xor    (%rsi,%rdi,1),%al
  mov    %r9d,%edx
  shl    $0x5,%edx
  or     %r10d,%edx
  xor    %edx,%eax
  xor    %r12d,%eax
  mov    %al,(%rcx,%rdi,1)
  add    $0x1,%rdi
  movslq %edi,%r10
  test   %rdi,%rdi
  jne    L12
L208:
  mov    %ebp,%r12d
  jmp    L251
  nopl   0x0(%rax,%rax,1)
L116:
  movzbl 0x17(%rsp),%edx
  add    %r10,%rcx
  mov    %r12d,%eax
  shr    $0x3,%dl
  xor    %edx,%eax
  xor    (%rcx),%al
  xor    (%r8,%r10,1),%al
  xor    (%rsi,%r10,1),%al
  mov    %al,(%rcx)
  mov    0x18(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L91
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L91:
  call   <__stack_chk_fail@plt>
L177:
  movzbl 0x1(%rbp),%r10d
  jmp    L75
L36:
  movzbl 0x1(%r12),%ebx
  jmp    L20
L126:
  movzbl 0x1(%r12),%ebx
  jmp    L74
```

assistant: ```c
void transformation_D2(unsigned char *x0, unsigned char *x1, unsigned char *x2, unsigned char *x3) {
  const int LEN = 32;
  unsigned char temp[LEN / 8];
  int i;
  unsigned char extL = 0, extR = 0, L = 0;
  for (i = 0; i < LEN / 8; i++)
    temp[i] = x1[i] ^ x3[i];
  for (i = 0; i < LEN / 8; i++) {
    extL = i == 0 ? temp[0] << 1 : (temp[i] << 1) | (temp[i - 1] >> 7);
    extR = i == LEN / 8 - 1 ? temp[i] >> 3 : (temp[i] >> 3) | (temp[i + 1] << 5);
    L = extL ^ extR;
    x0[i] = x0[i] ^ x2[i] ^ x3[i] ^ L;
  }
  for (i = 0; i < LEN / 8; i++)
    temp[i] = x2[i] ^ x0[i];
  for (i = 0; i < LEN / 8; i++) {
    extL = i == 0 ? temp[0] << 1 : (temp[i] << 1) | (temp[i - 1] >> 7);
    extR = i == LEN / 8 - 1 ? temp[i] >> 3 : (temp[i] >> 3) | (temp[i + 1] << 5);
    L = extL ^ extR;
    x1[i] = x1[i] ^ x3[i] ^ x0[i] ^ L;
  }
  for (i = 0; i < LEN / 8; i++)
    temp[i] = x3[i] ^ x1[i];
  for (i = 0; i < LEN / 8; i++) {
    extL = i == 0 ? temp[0] << 1 : (temp[i] << 1) | (temp[i - 1] >> 7);
    extR = i == LEN / 8 - 1 ? temp[i] >> 3 : (temp[i] >> 3) | (temp[i + 1] << 5);
    L = extL ^ extR;
    x2[i] = x2[i] ^ x0[i] ^ x1[i] ^ L;
  }
  for (i = 0; i < LEN / 8; i++)
    temp[i] = x0[i] ^ x2[i];
  for (i = 0; i < LEN / 8; i++) {
    extL = i == 0 ? temp[0] << 1 : (temp[i] << 1) | (temp[i - 1] >> 7);
    extR = i == LEN / 8 - 1 ? temp[i] >> 3 : (temp[i] >> 3) | (temp[i + 1] << 5);
    L = extL ^ extR;
    x3[i] = x3[i] ^ x1[i] ^ x2[i] ^ L;
  }
}
```