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

```asm
<jpegdct>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0xd8,%rsp
  mov    %rdi,0x58(%rsp)
  mov    %rsi,%r14
  mov    %fs:0x28,%rax
  mov    %rax,0xc8(%rsp)
  xor    %eax,%eax
  movq   $0xfffffffffffffffe,0x8(%rsp)
  mov    $0x2,%ebp
  movq   $0xa,0x20(%rsp)
  movq   $0xe,0x10(%rsp)
  movq   $0xc,0x18(%rsp)
  mov    $0xd,%r13d
  movl   $0x0,0x48(%rsp)
  movq   $0x0,0x50(%rsp)
  lea    0x80(%rsp),%r12
  jmp    L41
L51:
  mov    0x60(%rsp),%rsi
  mov    %rsi,%rax
  add    0x78(%rsp),%rax
  sub    0x78(%rsp),%rsi
  mov    0x68(%rsp),%rdx
  mov    %rdx,%r9
  add    0x70(%rsp),%r9
  sub    0x70(%rsp),%rdx
  lea    (%rax,%r9,1),%r8
  mov    0x48(%rsp),%ebx
  mov    %ebx,%ecx
  sar    %cl,%r8
  mov    %r8w,(%rdi)
  sub    %r9,%rax
  sar    %cl,%rax
  mov    0x28(%rsp),%rbx
  mov    %ax,(%rdi,%rbx,1)
  lea    (%rdx,%rsi,1),%eax
  cwtl
  movswl 0x14(%r14),%ecx
  imul   %ecx,%eax
  movswq 0x12(%r14),%rcx
  imul   %rcx,%rsi
  mov    %r13d,%ecx
  sar    %cl,%rsi
  add    %eax,%esi
  mov    0x30(%rsp),%rbx
  mov    %si,(%rdi,%rbx,1)
  movswq 0x16(%r14),%rcx
  imul   %rcx,%rdx
  mov    %r13d,%ecx
  sar    %cl,%rdx
  add    %edx,%eax
  mov    0x18(%rsp),%rbx
  mov    %ax,(%rdi,%rbx,1)
  mov    0x80(%rsp),%rcx
  mov    0x98(%rsp),%rax
  lea    (%rax,%rcx,1),%r11d
  movswl %r11w,%r11d
  movswl 0x4(%r14),%edx
  imul   %edx,%r11d
  movslq %r11d,%rdx
  mov    %rdx,0x60(%rsp)
  mov    0x88(%rsp),%rsi
  mov    0x90(%rsp),%rdx
  lea    (%rdx,%rsi,1),%ebx
  movswl %bx,%ebx
  movswl (%r14),%r8d
  imul   %r8d,%ebx
  movslq %ebx,%r8
  mov    %r8,0x68(%rsp)
  lea    (%rcx,%rdx,1),%r8
  lea    (%rax,%rsi,1),%r15
  lea    (%r8,%r15,1),%r10d
  movswl %r10w,%r10d
  movswl 0x10(%r14),%r9d
  imul   %r9d,%r10d
  movslq %r10d,%r10
  movswl 0x2(%r14),%r9d
  movswl %r8w,%r8d
  imul   %r8d,%r9d
  movslq %r9d,%r9
  add    %r10,%r9
  mov    %r9,0x70(%rsp)
  movswl 0x6(%r14),%r8d
  movswl %r15w,%r15d
  imul   %r15d,%r8d
  movslq %r8d,%r8
  add    %r10,%r8
  mov    %r8,0x78(%rsp)
  imul   0x8(%r14),%cx
  lea    (%rcx,%r11,1),%r10d
  add    %r9d,%r10d
  movswl %r10w,%r10d
  mov    %r13d,%ecx
  sar    %cl,%r10d
  mov    0x10(%rsp),%rcx
  mov    %r10w,(%rdi,%rcx,1)
  imul   0xc(%r14),%si
  add    %ebx,%esi
  add    %r8d,%esi
  movswl %si,%esi
  mov    %r13d,%ecx
  sar    %cl,%esi
  mov    0x20(%rsp),%rcx
  mov    %si,(%rdi,%rcx,1)
  imul   0xa(%r14),%dx
  add    %ebx,%edx
  add    %r9d,%edx
  movswl %dx,%edx
  mov    %r13d,%ecx
  sar    %cl,%edx
  mov    0x38(%rsp),%rbx
  mov    %dx,(%rdi,%rbx,1)
  imul   0xe(%r14),%ax
  add    %r11d,%eax
  add    %r8d,%eax
  cwtl
  sar    %cl,%eax
  mov    %ax,(%rdi,%rbp,1)
  add    0x40(%rsp),%rdi
  subw   $0x1,0x4e(%rsp)
  je     L44
L16:
  mov    %rdi,%r9
  mov    0x10(%rsp),%rax
  lea    (%rdi,%rax,1),%r8
  lea    0x60(%rsp),%rdx
  mov    %rdx,%rsi
L27:
  movswl (%r9),%eax
  movswl (%r8),%r10d
  lea    (%rax,%r10,1),%ecx
  movslq %ecx,%rcx
  mov    %rcx,(%rdx)
  sub    %r10d,%eax
  cltq
  mov    %rax,0x38(%rsi)
  add    %rbp,%r9
  add    0x8(%rsp),%r8
  add    $0x8,%rdx
  sub    $0x8,%rsi
  cmp    %r12,%rdx
  jne    L27
  jmp    L51
L44:
  mov    0x50(%rsp),%rdi
  lea    0x0(,%rdi,8),%rdx
  mov    %rdi,%rax
  sub    %rdx,%rax
  shl    $0x4,%rax
  add    %rax,0x58(%rsp)
  mov    %rdi,%rax
  add    $0x1,%rax
  mov    %rax,0x50(%rsp)
  addl   $0x3,0x48(%rsp)
  add    $0x3,%r13d
  addq   $0x54,0x18(%rsp)
  addq   $0x62,0x10(%rsp)
  addq   $0x46,0x20(%rsp)
  add    $0xe,%rbp
  subq   $0xe,0x8(%rsp)
  cmp    $0x2,%rax
  je     L17
L41:
  mov    0x50(%rsp),%rdi
  lea    0x0(,%rdi,8),%rax
  mov    %rax,%rdx
  sub    %rdi,%rdx
  lea    0x8(,%rdx,8),%rbx
  mov    %rbx,0x28(%rsp)
  mov    %rax,%rdx
  sub    %rdi,%rdx
  lea    0x4(,%rdx,4),%rbx
  mov    %rbx,0x30(%rsp)
  lea    (%rdi,%rdi,4),%rdx
  lea    (%rdi,%rdx,4),%rdx
  lea    0x6(%rdx,%rdx,1),%rbx
  mov    %rbx,0x38(%rsp)
  sub    %rax,%rdi
  lea    0x10(%rdi,%rdi,1),%rax
  mov    %rax,0x40(%rsp)
  mov    0x58(%rsp),%rdi
  movw   $0x8,0x4e(%rsp)
  jmp    L16
L17:
  mov    0xc8(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L46
  add    $0xd8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L46:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void jpegdct(short *d, short *r) {
  long int t[12];
  short i, j, k, m, n, p;
  for (k = 1, m = 0, n = 13, p = 8; k <= 8; k += 7, m += 3, n += 3, p -= 7, d -= 64) {
    for (i = 0; i < 8; i++, d += p) {
      for (j = 0; j < 4; j++) {
        t[j] = d[k * j] + d[k * (7 - j)];
        t[7 - j] = d[k * j] - d[k * (7 - j)];
      }
      t[8] = t[0] + t[3];
      t[9] = t[0] - t[3];
      t[10] = t[1] + t[2];
      t[11] = t[1] - t[2];
      d[0] = (t[8] + t[10]) >> m;
      d[4 * k] = (t[8] - t[10]) >> m;
      t[8] = (short)(t[11] + t[9]) * r[10];
      d[2 * k] = t[8] + (short)((t[9] * r[9]) >> n);
      d[6 * k] = t[8] + (short)((t[11] * r[11]) >> n);
      t[0] = (short)(t[4] + t[7]) * r[2];
      t[1] = (short)(t[5] + t[6]) * r[0];
      t[2] = t[4] + t[6];
      t[3] = t[5] + t[7];
      t[8] = (short)(t[2] + t[3]) * r[8];
      t[2] = (short)t[2] * r[1] + t[8];
      t[3] = (short)t[3] * r[3] + t[8];
      d[7 * k] = (short)(t[4] * r[4] + t[0] + t[2]) >> n;
      d[5 * k] = (short)(t[5] * r[6] + t[1] + t[3]) >> n;
      d[3 * k] = (short)(t[6] * r[5] + t[1] + t[2]) >> n;
      d[1 * k] = (short)(t[7] * r[7] + t[0] + t[3]) >> n;
    }
  }
}
```