user: Please show me the C implementation that matches the assembly code listed below:

```asm
<toeplitz_cache_create>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x28,%rsp
  mov    %esi,-0x4c(%rbp)
  mov    %rdx,%rbx
  mov    %fs:0x28,%rdx
  mov    %rdx,-0x38(%rbp)
  xor    %edx,%edx
  test   %esi,%esi
  jle    L152
  mov    %rdi,%r15
  mov    $0x0,%r14d
  mov    $0x80000000,%r12d
  jmp    L190
L202:
  mov    %rdx,%rcx
  and    $0xfff,%ecx
  sub    %rcx,%rsp
  test   %rcx,%rcx
  je     L155
  orq    $0x0,-0x8(%rsp,%rcx,1)
L155:
  mov    %rsp,%r13
  lea    0x0(,%rax,4),%esi
  mov    %r13,%rdi
  call   <bzero@plt>
  mov    D7(%rip),%rax
  mov    (%rax),%esi
  test   %esi,%esi
  jle    L35
  mov    %r14d,%edi
  imul   %esi,%edi
  mov    %r13,%r8
  lea    (%rsi,%rdi,1),%r9d
  jmp    L134
L17:
  add    $0x1,%ecx
  cmp    $0x20,%ecx
  je     L169
L79:
  lea    (%rcx,%rdi,1),%eax
  cltd
  idiv   %esi
  cltq
  mov    %esi,%r10d
  sub    %edx,%r10d
  sub    $0x1,%r10d
  mov    (%rbx,%rax,4),%eax
  bt     %r10d,%eax
  jae    L17
  mov    %r12d,%eax
  shr    %cl,%eax
  or     %eax,(%r8)
  jmp    L17
L169:
  add    $0x4,%r8
  add    $0x1,%edi
  cmp    %r9d,%edi
  je     L35
L134:
  mov    $0x0,%ecx
  jmp    L79
L35:
  mov    %r15,%r10
  mov    $0x0,%edi
  mov    D7(%rip),%r9
  jmp    L67
L77:
  sub    $0x1,%eax
  add    $0x4,%rdx
  cmp    $0xffffffff,%eax
  je     L33
L15:
  bt     %eax,%esi
  jae    L77
  xor    (%rdx),%ecx
  jmp    L77
L33:
  mov    %ecx,(%r10,%rdi,4)
  add    $0x1,%rdi
  cmp    $0x100,%rdi
  je     L34
L67:
  mov    %edi,%esi
  mov    (%r9),%r8d
  lea    -0x1(%r8),%eax
  mov    %r13,%rdx
  mov    $0x0,%ecx
  test   %r8d,%r8d
  jg     L15
  jmp    L33
L34:
  mov    -0x48(%rbp),%rsp
  add    $0x1,%r14d
  add    $0x400,%r15
  cmp    %r14d,-0x4c(%rbp)
  je     L152
L190:
  mov    %rsp,-0x48(%rbp)
  mov    D7(%rip),%rax
  mov    (%rax),%eax
  movslq %eax,%rdx
  lea    0xf(,%rdx,4),%rcx
  mov    %rcx,%rdx
  and    $0xfffffffffffffff0,%rdx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rsi
  sub    %rcx,%rsi
L21:
  cmp    %rsi,%rsp
  je     L202
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L21
L152:
  mov    -0x38(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L61
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L61:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void toeplitz_cache_create(uint32_t cache[][256], int cache_len, const uint8_t key_str[], __attribute__((unused)) int key_strlen) {
  int i;
  for (i = 0; i < cache_len; ++i) {
    uint32_t key[NBBY];
    int j, b, shift, val;
    bzero(key, sizeof(key));
    for (b = 0; b < NBBY; ++b) {
      for (j = 0; j < 32; ++j) {
        uint8_t k;
        int bit;
        bit = (i * NBBY) + b + j;
        k = key_str[bit / NBBY];
        shift = NBBY - (bit % NBBY) - 1;
        if (k & (1 << shift))
          key[b] |= 1 << (31 - j);
      }
    }
    for (val = 0; val < 256; ++val) {
      uint32_t res = 0;
      for (b = 0; b < NBBY; ++b) {
        shift = NBBY - b - 1;
        if (val & (1 << shift))
          res ^= key[b];
      }
      cache[i][val] = res;
    }
  }
}
```