user: Demonstrate the C code that generates the assembly output below:

```asm
<FillImage420_>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x58,%rsp
  mov    %rdi,0x28(%rsp)
  mov    %edx,%ebx
  mov    %edx,0x20(%rsp)
  mov    %edx,%eax
  imul   %esi,%eax
  movslq %eax,%rdx
  add    %rdi,%rdx
  mov    %rdx,%r14
  mov    %rdx,0x30(%rsp)
  lea    (%rax,%rax,4),%edx
  lea    0x3(%rdx),%eax
  test   %edx,%edx
  cmovns %edx,%eax
  sar    $0x2,%eax
  cltq
  add    %rdi,%rax
  mov    %rax,0x38(%rsp)
  lea    0x7(%rbx),%ebp
  test   %ebx,%ebx
  cmovns %ebx,%ebp
  sar    $0x3,%ebp
  cmp    $0x7,%ebx
  jle    L13
  mov    %rdi,%r13
  mov    %rax,%r15
  lea    (%rsi,%rsi,1),%eax
  mov    %eax,0x1c(%rsp)
  mov    %esi,%ebx
  shr    $0x1f,%ebx
  add    %esi,%ebx
  sar    %ebx
  cltq
  shl    $0x2,%rax
  mov    %rax,0x8(%rsp)
  movslq %ebx,%rax
  shl    $0x2,%rax
  mov    %rax,0x10(%rsp)
  mov    $0x0,%r12d
L28:
  mov    0x1c(%rsp),%edx
  mov    $0x52,%esi
  mov    %r13,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0x5b,%esi
  mov    %r14,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0xf0,%esi
  mov    %r15,%rdi
  call   <memset@plt>
  add    0x8(%rsp),%r13
  mov    0x10(%rsp),%rax
  add    %rax,%r14
  add    %rax,%r15
  add    $0x1,%r12d
  cmp    %ebp,%r12d
  jl     L28
  lea    -0x1(%rbp),%eax
  add    $0x1,%rax
  cmpl   $0x7,0x20(%rsp)
  mov    $0x1,%edx
  cmovle %rdx,%rax
  mov    0x8(%rsp),%rcx
  imul   %rax,%rcx
  mov    %rcx,0x20(%rsp)
  mov    0x28(%rsp),%r13
  add    %rcx,%r13
  mov    %r13,0x48(%rsp)
  imul   0x10(%rsp),%rax
  mov    %rax,0x28(%rsp)
  mov    0x30(%rsp),%r14
  add    %rax,%r14
  mov    %r14,0x40(%rsp)
  mov    0x38(%rsp),%rcx
  add    %rax,%rcx
  mov    %rcx,0x30(%rsp)
  mov    %rcx,%r15
  mov    $0x0,%r12d
L46:
  mov    0x1c(%rsp),%edx
  mov    $0x91,%esi
  mov    %r13,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0x37,%esi
  mov    %r14,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0x23,%esi
  mov    %r15,%rdi
  call   <memset@plt>
  add    0x8(%rsp),%r13
  mov    0x10(%rsp),%rax
  add    %rax,%r14
  add    %rax,%r15
  add    $0x1,%r12d
  cmp    %ebp,%r12d
  jl     L46
  mov    0x48(%rsp),%r13
  add    0x20(%rsp),%r13
  mov    %r13,0x48(%rsp)
  mov    0x40(%rsp),%r14
  mov    0x28(%rsp),%rcx
  add    %rcx,%r14
  mov    %r14,0x38(%rsp)
  mov    0x30(%rsp),%rax
  add    %rcx,%rax
  mov    %rax,0x30(%rsp)
  mov    %rax,%r15
  mov    $0x0,%r12d
L32:
  mov    0x1c(%rsp),%edx
  mov    $0x29,%esi
  mov    %r13,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0xf0,%esi
  mov    %r14,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0x6f,%esi
  mov    %r15,%rdi
  call   <memset@plt>
  add    0x8(%rsp),%r13
  mov    0x10(%rsp),%rax
  add    %rax,%r14
  add    %rax,%r15
  add    $0x1,%r12d
  cmp    %ebp,%r12d
  jl     L32
  mov    0x48(%rsp),%r14
  add    0x20(%rsp),%r14
  mov    0x38(%rsp),%r13
  mov    0x28(%rsp),%rax
  add    %rax,%r13
  mov    0x30(%rsp),%r12
  add    %rax,%r12
  mov    $0x0,%r15d
L17:
  mov    0x1c(%rsp),%edx
  mov    $0xeb,%esi
  mov    %r14,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0x80,%esi
  mov    %r13,%rdi
  call   <memset@plt>
  mov    %ebx,%edx
  mov    $0x80,%esi
  mov    %r12,%rdi
  call   <memset@plt>
  add    0x8(%rsp),%r14
  mov    0x10(%rsp),%rax
  add    %rax,%r13
  add    %rax,%r12
  add    $0x1,%r15d
  cmp    %ebp,%r15d
  jl     L17
L13:
  add    $0x58,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void FillImage420_(unsigned char *image, int width, int height) {
  uint8_t *pY = (uint8_t *)(image);
  uint8_t *pU = (uint8_t *)(image + width * height);
  uint8_t *pV = (uint8_t *)(image + width * height * 5 / 4);
  int y, x;
  for (y = 0; y < height / 8; y++) {
    memset(pY, 0x52, width * 2);
    memset(pU, 0x5b, width / 2);
    memset(pV, 0xf0, width / 2);
    pY += width * 2;
    pU += width / 2;
    pV += width / 2;
  }
  for (y = 0; y < height / 8; y++) {
    memset(pY, 0x91, width * 2);
    memset(pU, 0x37, width / 2);
    memset(pV, 0x23, width / 2);
    pY += width * 2;
    pU += width / 2;
    pV += width / 2;
  }
  for (y = 0; y < height / 8; y++) {
    memset(pY, 0x29, width * 2);
    memset(pU, 0xf0, width / 2);
    memset(pV, 0x6f, width / 2);
    pY += width * 2;
    pU += width / 2;
    pV += width / 2;
  }
  for (y = 0; y < height / 8; y++) {
    memset(pY, 0xeb, width * 2);
    memset(pU, 0x80, width / 2);
    memset(pV, 0x80, width / 2);
    pY += width * 2;
    pU += width / 2;
    pV += width / 2;
  }
}
```