user: What is the c source code of the assembly code below:

```asm
<main>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x68(%rsp)
  xor    %eax,%eax
  movq   $0x0,(%rsp)
  movq   $0x0,0x8(%rsp)
  movq   $0x0,0x10(%rsp)
  movq   $0x0,0x18(%rsp)
  movq   $0x0,0x20(%rsp)
  movq   $0x0,0x28(%rsp)
  movq   $0x0,0x30(%rsp)
  movq   $0x0,0x38(%rsp)
  movq   $0x0,0x40(%rsp)
  movq   $0x0,0x48(%rsp)
  movq   $0x0,0x50(%rsp)
  movq   $0x0,0x58(%rsp)
  movl   $0x0,0x60(%rsp)
  cmp    $0x1,%edi
  jle    L54
  mov    %rsi,%rbx
  lea    -0x2(%rdi),%eax
  lea    0x8(%rsi,%rax,8),%r14
  lea    D12(%rip),%r13
  mov    %rsp,%r12
  lea    D4(%rip),%rbp
  jmp    L46
  mov    %r12,%rdi
  call   <atof@plt>
  call   <dapush@plt>
L64:
  cmp    %rbx,%r14
  je     L54
L46:
  mov    %r13,%rdi
  call   <ungets@plt>
  add    $0x8,%rbx
  mov    (%rbx),%rdi
  call   <ungets@plt>
  mov    %r12,%rdi
  call   <getop@plt>
  sub    $0x2a,%eax
  cmp    $0x6,%eax
  ja     L65
  mov    %eax,%eax
  movslq 0x0(%rbp,%rax,4),%rax
  add    %rbp,%rax
  notrack jmp *%rax
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %xmm0,%r15
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %r15,%xmm1
  addsd  %xmm1,%xmm0
  call   <dapush@plt>
  jmp    L64
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %xmm0,%r15
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %r15,%xmm2
  subsd  %xmm2,%xmm0
  call   <dapush@plt>
  jmp    L64
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %xmm0,%r15
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %r15,%xmm3
  mulsd  %xmm3,%xmm0
  call   <dapush@plt>
  jmp    L64
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %xmm0,%r15
  mov    $0x0,%eax
  call   <dapop@plt>
  movq   %r15,%xmm4
  divsd  %xmm4,%xmm0
  call   <dapush@plt>
  jmp    L64
L65:
  mov    %rsp,%rsi
  lea    D14(%rip),%rdi
  mov    $0x0,%eax
  call   <printf@plt>
L54:
  mov    $0x0,%eax
  call   <dapop@plt>
  lea    D33(%rip),%rdi
  mov    $0x1,%eax
  call   <printf@plt>
  mov    0x68(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L24
  mov    $0x0,%eax
  add    $0x78,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L24:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: unpack_data
arguments: label: D12
type: string
name: unpack_data
arguments: label: D14
type: string
name: unpack_data
arguments: label: D33
type: string

tool: D12:  

tool: D14: Error: Unknown command '%s'


tool: D33: %.8g


assistant: ```c
int main(int argc, char *argv[]) {
  char operator[100] = "";
  double operand;
  while (--argc > 0) {
    ungets(" ");
    ungets(*++argv);
    switch (getop(operator)) {
    case '0':
      dapush(atof(operator));
      break;
    case '+':
      dapush(dapop() + dapop());
      break;
    case '-':
      operand = dapop();
      dapush(dapop() - operand);
      break;
    case '*':
      dapush(dapop() * dapop());
      break;
    case '/':
      operand = dapop();
      dapush(dapop() / operand);
      break;
    default:
      printf("Error: Unknown command '%s'\n", operator);
      argc = 1;
      break;
    }
  }
  printf("%.8g\n", dapop());
  return 0;
}
```