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

```asm
<s_memcpy1oa>:
  endbr64
  push   %r15
  mov    $0x8,%eax
  push   %r14
  mov    %eax,%r15d
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rdi,%rbx
  mov    %eax,%edi
  sub    0x48(%rsp),%eax
  sub    0x40(%rsp),%edi
  sub    0x38(%rsp),%r15d
  mov    %edi,-0x8(%rsp)
  mov    %eax,-0x4(%rsp)
  test   %r9d,%r9d
  je     L25
  mov    %esi,%r11d
  mov    %rdx,%r12
  mov    %rcx,%r14
  mov    %r9d,%ebp
  xor    %eax,%eax
  jmp    L37
  nopl   (%rax)
L70:
  add    $0x1,%rax
  cmp    %rax,%rbp
  je     L25
L37:
  movzbl (%r8,%rax,1),%edx
  movzbl (%rbx,%rax,1),%ecx
  not    %edx
  cmp    %r11d,%ecx
  jne    L70
  cmp    $0xff,%dl
  je     L70
  movzbl (%r14,%rax,1),%r10d
  test   %dl,%dl
  jne    L73
  mov    %r10b,(%r12,%rax,1)
  add    $0x1,%rax
  cmp    %rax,%rbp
  jne    L37
L25:
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L73:
  movzbl 0x50(%rsp),%ecx
  mov    %r10d,%r9d
  mov    %r10d,%r13d
  movzbl (%r12,%rax,1),%edi
  movzbl %dl,%edx
  sar    %cl,%r9d
  mov    %r15d,%ecx
  mov    %edi,%esi
  shl    %cl,%r9d
  movzbl 0x58(%rsp),%ecx
  sar    %cl,%r13d
  movzbl -0x8(%rsp),%ecx
  shl    %cl,%r13d
  movzbl 0x60(%rsp),%ecx
  sar    %cl,%r10d
  movzbl -0x4(%rsp),%ecx
  shl    %cl,%r10d
  movzbl 0x50(%rsp),%ecx
  sar    %cl,%esi
  mov    %r15d,%ecx
  shl    %cl,%esi
  movzbl %r9b,%ecx
  movzbl %sil,%esi
  sub    %ecx,%esi
  mov    %r15d,%ecx
  imul   %edx,%esi
  sar    $0x8,%esi
  add    %esi,%r9d
  mov    %edi,%esi
  movzbl %r9b,%r9d
  sar    %cl,%r9d
  movzbl 0x50(%rsp),%ecx
  shl    %cl,%r9d
  movzbl 0x58(%rsp),%ecx
  sar    %cl,%esi
  movzbl -0x8(%rsp),%ecx
  shl    %cl,%esi
  movzbl %r13b,%ecx
  movzbl %sil,%esi
  sub    %ecx,%esi
  movzbl -0x8(%rsp),%ecx
  imul   %edx,%esi
  sar    $0x8,%esi
  add    %r13d,%esi
  movzbl %sil,%esi
  sar    %cl,%esi
  movzbl 0x58(%rsp),%ecx
  shl    %cl,%esi
  movzbl 0x60(%rsp),%ecx
  or     %r9d,%esi
  mov    -0x4(%rsp),%r9d
  sar    %cl,%edi
  mov    %r9d,%ecx
  shl    %cl,%edi
  movzbl %r10b,%ecx
  movzbl %dil,%edi
  sub    %ecx,%edi
  mov    %r9d,%ecx
  imul   %edi,%edx
  sar    $0x8,%edx
  add    %r10d,%edx
  movzbl %dl,%edx
  sar    %cl,%edx
  movzbl 0x60(%rsp),%ecx
  shl    %cl,%edx
  or     %edx,%esi
  mov    %sil,(%r12,%rax,1)
  jmp    L70
```

assistant: ```c
void s_memcpy1oa(unsigned char *m, int id, void *dest, void *src, unsigned char *mask, int n, int rl, int gl, int bl, int ro, int go, int bo) {
  unsigned char a;
  unsigned char sr;
  unsigned char sg;
  unsigned char sb;
  unsigned char dr;
  unsigned char dg;
  unsigned char db;
  unsigned char *d = (unsigned char *)dest;
  unsigned char *s = (unsigned char *)src;
  unsigned char *m_ = (unsigned char *)mask;
  rl = 8 - rl;
  gl = 8 - gl;
  bl = 8 - bl;
  while (n--) {
    a = ~*m_;
    if ((*m == id) && (a != 0xff)) {
      if (a == 0x00) {
        *d = *s;
      } else {
        dr = (*d >> ro) << rl;
        dg = (*d >> go) << gl;
        db = (*d >> bo) << bl;
        sr = (*s >> ro) << rl;
        sg = (*s >> go) << gl;
        sb = (*s >> bo) << bl;
        dr = (a * (dr - sr) >> 8) + sr;
        dg = (a * (dg - sg) >> 8) + sg;
        db = (a * (db - sb) >> 8) + sb;
        *d = ((dr >> rl) << ro) | ((dg >> gl) << go) | ((db >> bl) << bo);
      }
    }
    d++;
    s++;
    m++;
    m_++;
  };
}
```