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

```asm
<gf64_mul>:
  endbr64
  push   %r15
  mov    %edi,%edx
  mov    %edi,%r8d
  mov    %edi,%r15d
  push   %r14
  shr    $0x2,%r8w
  shr    $0x4,%dx
  mov    %esi,%r11d
  push   %r13
  mov    %edx,%eax
  shr    $0x5,%r15w
  mov    %r8d,%r14d
  push   %r12
  shr    $0x2,%r11w
  and    %esi,%r14d
  mov    %r15d,%r13d
  push   %rbp
  mov    %edi,%ebp
  xor    %edi,%r13d
  mov    %esi,%r10d
  push   %rbx
  mov    %edi,%ebx
  shr    %bp
  mov    %esi,%r9d
  shr    $0x3,%bx
  shr    $0x3,%r10w
  mov    %esi,%r12d
  shr    $0x4,%r9w
  mov    %ebx,%ecx
  xor    %ebx,%eax
  shr    $0x5,%r12w
  xor    %r8d,%ecx
  mov    %ax,-0x8(%rsp)
  mov    %ebp,%eax
  mov    %cx,-0x2(%rsp)
  mov    %esi,%ecx
  shr    %cx
  mov    %r15w,-0x6(%rsp)
  xor    %edx,%r15d
  and    %ecx,%eax
  mov    %r15w,-0x4(%rsp)
  xor    %r14d,%eax
  mov    %r11d,%r14d
  and    %r13d,%r14d
  xor    %eax,%r14d
  mov    %r15d,%eax
  mov    %r8d,%r15d
  and    %r10d,%eax
  and    %ecx,%r15d
  xor    %r14d,%eax
  movzwl -0x8(%rsp),%r14d
  and    %r9d,%r14d
  xor    %eax,%r14d
  movzwl -0x2(%rsp),%eax
  and    %r12d,%eax
  xor    %eax,%r14d
  mov    %ebx,%eax
  and    %esi,%eax
  and    $0x1,%r14d
  xor    %eax,%r15d
  mov    %ebp,%eax
  shl    $0x2,%r14d
  and    %r11d,%eax
  xor    %r15d,%eax
  mov    %r10d,%r15d
  and    %r13d,%r15d
  and    %esi,%edi
  xor    %eax,%r15d
  movzwl -0x4(%rsp),%eax
  and    %r9d,%eax
  xor    %r15d,%eax
  movzwl -0x8(%rsp),%r15d
  and    %r12d,%r15d
  xor    %r15d,%eax
  and    $0x1,%eax
  shl    $0x3,%eax
  or     %r14d,%eax
  movzwl -0x6(%rsp),%r14d
  and    %ecx,%r14d
  mov    %r14d,%r15d
  mov    %edx,%r14d
  and    %r11d,%r14d
  xor    %r15d,%r14d
  movzwl -0x4(%rsp),%r15d
  xor    %r14d,%edi
  mov    %ebx,%r14d
  and    %r10d,%r14d
  xor    %edi,%r14d
  mov    %r8d,%edi
  and    %r9d,%edi
  xor    %r14d,%edi
  mov    %ebp,%r14d
  and    %r12d,%r14d
  xor    %r14d,%edi
  mov    %ebx,%r14d
  and    $0x1,%edi
  and    %ecx,%r14d
  or     %edi,%eax
  mov    %edx,%edi
  and    %esi,%edi
  xor    %edi,%r14d
  mov    %r8d,%edi
  and    %r11d,%edi
  xor    %r14d,%edi
  mov    %ebp,%r14d
  and    %r10d,%r14d
  xor    %edi,%r14d
  mov    %r9d,%edi
  and    %r13d,%edi
  xor    %r14d,%edi
  mov    %r15d,%r14d
  and    %r12d,%r14d
  xor    %r14d,%edi
  and    %ecx,%edx
  and    %r11d,%ebx
  and    %r15d,%r11d
  and    $0x1,%edi
  shl    $0x4,%edi
  or     %eax,%edi
  movzwl -0x6(%rsp),%eax
  and    %esi,%eax
  and    %ebp,%esi
  xor    %edx,%eax
  mov    %r8d,%edx
  xor    %ebp,%r8d
  and    %r10d,%edx
  xor    %ebx,%eax
  and    -0x8(%rsp),%r10w
  and    %r12d,%r8d
  xor    %edx,%eax
  mov    %ebp,%edx
  and    %r9d,%edx
  and    -0x2(%rsp),%r9w
  pop    %rbx
  xor    %edx,%eax
  mov    %r12d,%edx
  pop    %rbp
  pop    %r12
  and    %r13d,%edx
  xor    %edx,%eax
  mov    %ecx,%edx
  and    %r13d,%edx
  and    $0x1,%eax
  pop    %r13
  pop    %r14
  xor    %r11d,%edx
  shl    $0x5,%eax
  pop    %r15
  xor    %esi,%edx
  or     %edi,%eax
  xor    %r10d,%edx
  xor    %r9d,%edx
  xor    %r8d,%edx
  and    $0x1,%edx
  add    %edx,%edx
  or     %edx,%eax
  ret
```

assistant: ```c
unsigned short gf64_mul(unsigned short a, unsigned short b) {
  unsigned short tmp1, tmp2, tmp3, tmp4, tmp5;
  unsigned short c_bit0, c_bit1, c_bit2, c_bit3, c_bit4, c_bit5, c;
  tmp1 = ((a) ^ (a >> 5));
  tmp2 = ((a >> 4) ^ (a >> 5));
  tmp3 = ((a >> 3) ^ (a >> 4));
  tmp4 = ((a >> 2) ^ (a >> 3));
  tmp5 = ((a >> 1) ^ (a >> 2));
  c_bit0 = ((a & b) ^ ((a >> 5) & (b >> 1)) ^ ((a >> 4) & (b >> 2)) ^ ((a >> 3) & (b >> 3)) ^ ((a >> 2) & (b >> 4)) ^ ((a >> 1) & (b >> 5))) & 0x1;
  c_bit1 = (((a >> 1) & b) ^ (tmp1 & (b >> 1)) ^ (tmp2 & (b >> 2)) ^ (tmp3 & (b >> 3)) ^ (tmp4 & (b >> 4)) ^ (tmp5 & (b >> 5))) & 0x1;
  c_bit2 = (((a >> 2) & b) ^ ((a >> 1) & (b >> 1)) ^ (tmp1 & (b >> 2)) ^ (tmp2 & (b >> 3)) ^ (tmp3 & (b >> 4)) ^ (tmp4 & (b >> 5))) & 0x1;
  c_bit3 = (((a >> 3) & b) ^ ((a >> 2) & (b >> 1)) ^ ((a >> 1) & (b >> 2)) ^ (tmp1 & (b >> 3)) ^ (tmp2 & (b >> 4)) ^ (tmp3 & (b >> 5))) & 0x1;
  c_bit4 = (((a >> 4) & b) ^ ((a >> 3) & (b >> 1)) ^ ((a >> 2) & (b >> 2)) ^ ((a >> 1) & (b >> 3)) ^ (tmp1 & (b >> 4)) ^ (tmp2 & (b >> 5))) & 0x1;
  c_bit5 = (((a >> 5) & b) ^ ((a >> 4) & (b >> 1)) ^ ((a >> 3) & (b >> 2)) ^ ((a >> 2) & (b >> 3)) ^ ((a >> 1) & (b >> 4)) ^ (tmp1 & (b >> 5))) & 0x1;
  c = c_bit0 | (c_bit1 << 1) | (c_bit2 << 2) | (c_bit3 << 3) | (c_bit4 << 4) | (c_bit5 << 5);
  return c;
}
```