user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<counting_sort>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x40,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %edx,-0x34(%rbp)
  mov    %ecx,-0x38(%rbp)
  mov    %r8d,-0x3c(%rbp)
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x2,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x8(%rbp)
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x2,%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%rax
  mov    $0x0,%esi
  mov    %rax,%rdi
  call   <memset@plt>
  movl   $0x0,-0x1c(%rbp)
  jmp    L18
L3:
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  cltd
  idivl  -0x3c(%rbp)
  mov    %eax,%edx
  movslq %edx,%rax
  imul   $0x66666667,%rax,%rax
  shr    $0x20,%rax
  sar    $0x2,%eax
  mov    %edx,%ecx
  sar    $0x1f,%ecx
  sub    %ecx,%eax
  mov    %eax,-0xc(%rbp)
  mov    -0xc(%rbp),%ecx
  mov    %ecx,%eax
  shl    $0x2,%eax
  add    %ecx,%eax
  add    %eax,%eax
  sub    %eax,%edx
  mov    %edx,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rcx
  mov    -0x8(%rbp),%rax
  add    %rcx,%rax
  add    $0x1,%edx
  mov    %edx,(%rax)
  addl   $0x1,-0x1c(%rbp)
L18:
  mov    -0x1c(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jl     L3
  movl   $0x1,-0x18(%rbp)
  jmp    L44
L31:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%ecx
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rsi
  mov    -0x8(%rbp),%rax
  add    %rsi,%rax
  add    %ecx,%edx
  mov    %edx,(%rax)
  addl   $0x1,-0x18(%rbp)
L44:
  mov    -0x18(%rbp),%eax
  cmp    -0x38(%rbp),%eax
  jle    L31
  mov    -0x34(%rbp),%eax
  sub    $0x1,%eax
  mov    %eax,-0x14(%rbp)
  jmp    L4
L58:
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  cltd
  idivl  -0x3c(%rbp)
  mov    %eax,%edx
  movslq %edx,%rax
  imul   $0x66666667,%rax,%rax
  shr    $0x20,%rax
  sar    $0x2,%eax
  mov    %edx,%ecx
  sar    $0x1f,%ecx
  sub    %ecx,%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x10(%rbp),%ecx
  mov    %ecx,%eax
  shl    $0x2,%eax
  add    %ecx,%eax
  add    %eax,%eax
  sub    %eax,%edx
  mov    %edx,-0x10(%rbp)
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    -0x10(%rbp),%edx
  movslq %edx,%rdx
  lea    0x0(,%rdx,4),%rcx
  mov    -0x8(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rdx),%edx
  movslq %edx,%rdx
  shl    $0x2,%rdx
  lea    -0x4(%rdx),%rcx
  mov    -0x30(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rax),%eax
  mov    %eax,(%rdx)
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rcx
  mov    -0x8(%rbp),%rax
  add    %rcx,%rax
  sub    $0x1,%edx
  mov    %edx,(%rax)
  subl   $0x1,-0x14(%rbp)
L4:
  cmpl   $0x0,-0x14(%rbp)
  jns    L58
  mov    -0x8(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
  nop
  leave
  ret
```

assistant: ```c
void counting_sort(int a[], int *b, int size, int k, int unit) {
  int *c;
  c = (int *)malloc(sizeof(int) * size);
  memset(c, 0, (sizeof(int) * size));
  for (int j = 0; j < size; j++) {
    int offset = (a[j] / unit) % 10;
    c[offset] = c[offset] + 1;
  }
  for (int i = 1; i <= k; i++) {
    c[i] = c[i] + c[(i - 1)];
  }
  for (int j = (size - 1); j >= 0; j--) {
    int offset = (a[j] / unit) % 10;
    b[(c[offset] - 1)] = a[j];
    c[offset] = c[offset] - 1;
  }
  free(c);
}
```