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

```asm
<coordinate_descent>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %esi,-0x2c(%rbp)
  mov    %edx,-0x30(%rbp)
  mov    %ecx,-0x34(%rbp)
  mov    %r8,-0x40(%rbp)
  mov    %r9,-0x48(%rbp)
  movl   $0x0,-0x14(%rbp)
  movq   $0x0,-0x10(%rbp)
  movq   $0x0,-0x8(%rbp)
  mov    -0x2c(%rbp),%eax
  cmp    -0x30(%rbp),%eax
  jne    L58
  mov    -0x2c(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edx
  mov    -0x40(%rbp),%rcx
  mov    -0x48(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <memcpy@plt>
  mov    -0x48(%rbp),%r8
  mov    -0x40(%rbp),%rdi
  mov    -0x34(%rbp),%ecx
  mov    -0x30(%rbp),%edx
  mov    -0x2c(%rbp),%esi
  mov    -0x28(%rbp),%rax
  mov    %r8,%r9
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <iterate_gs@plt>
  mov    %eax,-0x14(%rbp)
  cmpl   $0xffffffff,-0x14(%rbp)
  jne    L75
  movl   $0xffffffff,-0x14(%rbp)
  jmp    L75
L58:
  mov    -0x2c(%rbp),%eax
  cmp    -0x30(%rbp),%eax
  jle    L19
  mov    -0x30(%rbp),%eax
  imul   %eax,%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x10(%rbp)
  mov    -0x2c(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x8(%rbp)
  mov    -0x30(%rbp),%r8d
  mov    -0x10(%rbp),%rdi
  mov    -0x34(%rbp),%ecx
  mov    -0x30(%rbp),%edx
  mov    -0x2c(%rbp),%esi
  mov    -0x28(%rbp),%rax
  mov    %r8d,%r9d
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <relax_ata@plt>
  mov    -0x8(%rbp),%r8
  mov    -0x40(%rbp),%rdi
  mov    -0x34(%rbp),%ecx
  mov    -0x30(%rbp),%edx
  mov    -0x2c(%rbp),%esi
  mov    -0x28(%rbp),%rax
  mov    %r8,%r9
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <relax_atb@plt>
  mov    -0x48(%rbp),%r8
  mov    -0x8(%rbp),%rdi
  mov    -0x30(%rbp),%ecx
  mov    -0x30(%rbp),%edx
  mov    -0x30(%rbp),%esi
  mov    -0x10(%rbp),%rax
  mov    %r8,%r9
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <iterate_gs@plt>
  mov    %eax,-0x14(%rbp)
  cmpl   $0xffffffff,-0x14(%rbp)
  jne    L75
  movl   $0xffffffff,-0x14(%rbp)
  jmp    L75
L19:
  mov    -0x2c(%rbp),%eax
  imul   %eax,%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x10(%rbp)
  mov    -0x2c(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x8(%rbp)
  mov    -0x2c(%rbp),%r8d
  mov    -0x10(%rbp),%rdi
  mov    -0x34(%rbp),%ecx
  mov    -0x30(%rbp),%edx
  mov    -0x2c(%rbp),%esi
  mov    -0x28(%rbp),%rax
  mov    %r8d,%r9d
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <relax_aat@plt>
  mov    -0x8(%rbp),%r8
  mov    -0x40(%rbp),%rdi
  mov    -0x2c(%rbp),%ecx
  mov    -0x2c(%rbp),%edx
  mov    -0x2c(%rbp),%esi
  mov    -0x10(%rbp),%rax
  mov    %r8,%r9
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <iterate_gs@plt>
  mov    %eax,-0x14(%rbp)
  cmpl   $0xffffffff,-0x14(%rbp)
  jne    L79
  movl   $0xffffffff,-0x14(%rbp)
  jmp    L75
L79:
  mov    -0x48(%rbp),%r8
  mov    -0x8(%rbp),%rdi
  mov    -0x34(%rbp),%ecx
  mov    -0x30(%rbp),%edx
  mov    -0x2c(%rbp),%esi
  mov    -0x28(%rbp),%rax
  mov    %r8,%r9
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <relax_atb@plt>
L75:
  cmpq   $0x0,-0x10(%rbp)
  je     L54
  mov    -0x10(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
L54:
  cmpq   $0x0,-0x8(%rbp)
  je     L38
  mov    -0x8(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
L38:
  mov    -0x14(%rbp),%eax
  leave
  ret
```

assistant: ```c
int coordinate_descent(double *A, int m, int n, int stride, double *b, double *x0) {
  double *C, *c;
  int err;
  err = 0;
  C = NULL;
  c = NULL;
  if (m == n) {
    memcpy(x0, b, m * sizeof b[0]);
    if ((err = iterate_gs(A, m, n, stride, b, x0)) == -1) {
      err = -1;
      goto err_out;
    }
  } else if (m > n) {
    C = malloc(n * n * sizeof C[0]);
    c = malloc(m * sizeof c[0]);
    relax_ata(A, m, n, stride, C, n);
    relax_atb(A, m, n, stride, b, c);
    if ((err = iterate_gs(C, n, n, n, c, x0)) == -1) {
      err = -1;
      goto err_out;
    }
  } else {
    C = malloc(m * m * sizeof C[0]);
    c = malloc(m * sizeof c[0]);
    relax_aat(A, m, n, stride, C, m);
    if ((err = iterate_gs(C, m, m, m, b, c)) == -1) {
      err = -1;
      goto err_out;
    }
    relax_atb(A, m, n, stride, c, x0);
  }
err_out:
  if (C != NULL)
    free(C);
  if (c != NULL)
    free(c);
  return err;
}
```