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

```asm
<cftmdl>:
  endbr64
  push   %r15
  mov    %rcx,%rax
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  lea    0x0(,%rsi,4),%ebx
  mov    %edi,-0x14(%rsp)
  mov    %ebx,-0x18(%rsp)
  test   %esi,%esi
  jle    L104
  movslq %esi,%r8
  lea    -0x1(%rsi),%r11d
  xor    %ecx,%ecx
  xor    %edi,%edi
  shl    $0x3,%r8
  shr    %r11d
  lea    (%rdx,%r8,1),%r10
  add    $0x1,%r11d
  lea    (%r10,%r8,1),%r9
  add    %r9,%r8
  nopl   0x0(%rax)
L70:
  movupd (%r10,%rcx,1),%xmm6
  movupd (%rdx,%rcx,1),%xmm2
  add    $0x1,%edi
  movupd (%rdx,%rcx,1),%xmm0
  movupd (%r9,%rcx,1),%xmm1
  addpd  %xmm6,%xmm2
  subpd  %xmm6,%xmm0
  movupd (%r8,%rcx,1),%xmm6
  subpd  %xmm6,%xmm1
  movapd %xmm2,%xmm4
  movapd %xmm0,%xmm3
  shufpd $0x1,%xmm1,%xmm1
  subpd  %xmm1,%xmm3
  addpd  %xmm1,%xmm0
  movupd (%r9,%rcx,1),%xmm1
  addpd  %xmm6,%xmm1
  movapd %xmm0,%xmm6
  movsd  %xmm3,%xmm6
  movsd  %xmm0,%xmm3
  addpd  %xmm1,%xmm4
  subpd  %xmm1,%xmm2
  movups %xmm4,(%rdx,%rcx,1)
  movups %xmm2,(%r9,%rcx,1)
  movups %xmm6,(%r10,%rcx,1)
  movups %xmm3,(%r8,%rcx,1)
  add    $0x10,%rcx
  cmp    %r11d,%edi
  jb     L70
L104:
  mov    -0x18(%rsp),%ebx
  movsd  0x10(%rax),%xmm3
  lea    (%rsi,%rbx,1),%ecx
  unpcklpd %xmm3,%xmm3
  cmp    %ecx,%ebx
  jge    L121
  movslq -0x18(%rsp),%r14
  movslq %esi,%rbp
  lea    -0x1(%rsi),%ebx
  mov    %ebx,-0x28(%rsp)
  lea    (%r14,%rbp,1),%rcx
  lea    0x0(,%r14,8),%rdi
  lea    (%rcx,%rbp,1),%r8
  lea    0x20(%rdi),%r15
  shl    $0x3,%rcx
  lea    0x4(%r8,%rbp,1),%r10
  lea    0x20(%rcx),%r12
  shl    $0x3,%r8
  shl    $0x3,%r10
  cmp    %rcx,%r15
  lea    0x20(%r8),%r13
  setle  %bl
  cmp    %r12,%rdi
  lea    -0x20(%r10),%r9
  setge  %r11b
  or     %ebx,%r11d
  cmpl   $0x1,-0x28(%rsp)
  seta   %bl
  and    %ebx,%r11d
  cmp    %r8,%r12
  setle  %bl
  cmp    %r13,%rcx
  setge  -0x20(%rsp)
  or     -0x20(%rsp),%bl
  and    %r11d,%ebx
  cmp    %r8,%r15
  setle  %r11b
  cmp    %r13,%rdi
  setge  -0x20(%rsp)
  or     -0x20(%rsp),%r11b
  and    %ebx,%r11d
  cmp    %r13,%r9
  setge  %bl
  cmp    %r10,%r8
  setge  %r13b
  or     %r13d,%ebx
  and    %r11d,%ebx
  cmp    %r9,%r12
  setle  %r11b
  cmp    %r10,%rcx
  setge  %r12b
  or     %r12d,%r11d
  test   %r11b,%bl
  je     L44
  cmp    %r9,%r15
  setle  %r11b
  cmp    %r10,%rdi
  setge  %r10b
  or     %r10b,%r11b
  je     L44
  mov    -0x28(%rsp),%r11d
  add    %rdx,%rdi
  add    %rdx,%rcx
  add    %rdx,%r8
  add    %rdx,%r9
  xor    %r10d,%r10d
  shr    %r11d
  add    $0x1,%r11d
  mov    %r11d,%ebx
  shr    %ebx
  shl    $0x5,%rbx
  nopl   0x0(%rax)
L137:
  movupd 0x10(%rdi,%r10,1),%xmm6
  movlpd 0x8(%rdi,%r10,1),%xmm6
  movupd (%rdi,%r10,1),%xmm0
  movupd 0x10(%rcx,%r10,1),%xmm1
  movlpd 0x8(%rcx,%r10,1),%xmm1
  movupd (%rcx,%r10,1),%xmm2
  movapd %xmm6,%xmm9
  movupd (%r8,%r10,1),%xmm5
  movhpd 0x10(%rdi,%r10,1),%xmm0
  movupd (%r9,%r10,1),%xmm10
  addpd  %xmm1,%xmm9
  subpd  %xmm1,%xmm6
  movapd %xmm0,%xmm4
  movupd 0x10(%r8,%r10,1),%xmm1
  movlpd 0x8(%r8,%r10,1),%xmm1
  movhpd 0x10(%rcx,%r10,1),%xmm2
  movhpd 0x10(%r8,%r10,1),%xmm5
  movupd 0x10(%r9,%r10,1),%xmm7
  movlpd 0x8(%r9,%r10,1),%xmm7
  movhpd 0x10(%r9,%r10,1),%xmm10
  addpd  %xmm2,%xmm4
  subpd  %xmm2,%xmm0
  movapd %xmm5,%xmm8
  movapd %xmm1,%xmm2
  subpd  %xmm10,%xmm5
  addpd  %xmm10,%xmm8
  addpd  %xmm7,%xmm2
  movapd %xmm9,%xmm10
  subpd  %xmm7,%xmm1
  movapd %xmm4,%xmm7
  addpd  %xmm2,%xmm10
  addpd  %xmm8,%xmm7
  subpd  %xmm8,%xmm4
  subpd  %xmm9,%xmm2
  movapd %xmm7,%xmm11
  unpckhpd %xmm10,%xmm7
  movups %xmm7,0x10(%rdi,%r10,1)
  unpcklpd %xmm10,%xmm11
  movapd %xmm2,%xmm7
  unpckhpd %xmm4,%xmm2
  movups %xmm11,(%rdi,%r10,1)
  unpcklpd %xmm4,%xmm7
  movups %xmm2,0x10(%r8,%r10,1)
  movapd %xmm0,%xmm2
  addpd  %xmm1,%xmm0
  movups %xmm7,(%r8,%r10,1)
  subpd  %xmm1,%xmm2
  movapd %xmm6,%xmm7
  addpd  %xmm5,%xmm7
  subpd  %xmm6,%xmm5
  movapd %xmm2,%xmm4
  subpd  %xmm7,%xmm4
  movapd %xmm5,%xmm1
  addpd  %xmm7,%xmm2
  subpd  %xmm0,%xmm1
  addpd  %xmm5,%xmm0
  mulpd  %xmm3,%xmm4
  mulpd  %xmm3,%xmm2
  mulpd  %xmm3,%xmm1
  mulpd  %xmm3,%xmm0
  movapd %xmm4,%xmm7
  unpcklpd %xmm2,%xmm7
  unpckhpd %xmm2,%xmm4
  movapd %xmm1,%xmm2
  movups %xmm7,(%rcx,%r10,1)
  unpcklpd %xmm0,%xmm2
  unpckhpd %xmm0,%xmm1
  movups %xmm4,0x10(%rcx,%r10,1)
  movups %xmm2,(%r9,%r10,1)
  movups %xmm1,0x10(%r9,%r10,1)
  add    $0x20,%r10
  cmp    %rbx,%r10
  jne    L137
  mov    -0x18(%rsp),%ebx
  mov    %r11d,%ecx
  and    $0xfffffffe,%ecx
  lea    (%rbx,%rcx,2),%r8d
  cmp    %r11d,%ecx
  je     L121
  lea    (%r8,%rsi,1),%edi
  movslq %r8d,%r8
  lea    (%rdx,%r8,8),%r9
  lea    (%rsi,%rdi,1),%ecx
  movslq %edi,%rdi
  movupd (%r9),%xmm6
  lea    (%rdx,%rdi,8),%rdi
  movslq %ecx,%r8
  add    %esi,%ecx
  movsd  (%rdi),%xmm0
  movupd (%rdi),%xmm1
  movslq %ecx,%rcx
  lea    (%rdx,%r8,8),%r8
  lea    (%rdx,%rcx,8),%rcx
  movapd %xmm6,%xmm7
  movupd (%r8),%xmm5
  movsd  0x8(%r9),%xmm4
  addpd  %xmm6,%xmm1
  subsd  %xmm0,%xmm7
  movupd (%rcx),%xmm6
  movsd  (%rcx),%xmm2
  movsd  0x8(%rdi),%xmm0
  addpd  %xmm5,%xmm6
  subsd  %xmm0,%xmm4
  movapd %xmm5,%xmm0
  movsd  0x8(%rcx),%xmm5
  movapd %xmm1,%xmm9
  subsd  %xmm2,%xmm0
  movsd  0x8(%r8),%xmm2
  unpckhpd %xmm9,%xmm9
  subsd  %xmm5,%xmm2
  movapd %xmm6,%xmm5
  addpd  %xmm1,%xmm5
  subsd  %xmm6,%xmm1
  movups %xmm5,(%r9)
  movapd %xmm6,%xmm5
  movapd %xmm7,%xmm6
  unpckhpd %xmm5,%xmm5
  subsd  %xmm2,%xmm6
  addsd  %xmm7,%xmm2
  subsd  %xmm9,%xmm5
  unpcklpd %xmm1,%xmm5
  movapd %xmm6,%xmm1
  movups %xmm5,(%r8)
  movapd %xmm0,%xmm5
  subsd  %xmm4,%xmm0
  addsd  %xmm4,%xmm5
  subsd  %xmm5,%xmm1
  addsd  %xmm6,%xmm5
  unpcklpd %xmm5,%xmm1
  mulpd  %xmm3,%xmm1
  movups %xmm1,(%rdi)
  movapd %xmm0,%xmm1
  addsd  %xmm2,%xmm0
  subsd  %xmm2,%xmm1
  unpcklpd %xmm0,%xmm1
  mulpd  %xmm3,%xmm1
  movups %xmm1,(%rcx)
L121:
  add    %ebx,%ebx
  mov    %ebx,-0x10(%rsp)
  cmp    -0x14(%rsp),%ebx
  jge    L117
  movslq -0x18(%rsp),%rdi
  movslq %esi,%r15
  movslq %ebx,%rcx
  lea    -0x1(%rsi),%ebp
  mov    %rcx,%r12
  mov    %esi,-0xc(%rsp)
  shr    %ebp
  lea    0x10(%rax),%r13
  mov    %edi,%r14d
  add    %r15,%rdi
  add    $0x20,%rax
  add    $0x1,%ebp
  add    %rcx,%rdi
  add    %ecx,%r14d
  lea    0x0(,%rcx,8),%rbx
  add    %r15,%rcx
  lea    (%rdx,%rdi,8),%r8
  lea    (%rdx,%rcx,8),%rdi
  mov    %r15,%rdx
  add    %esi,%r14d
  neg    %rdx
  shl    $0x3,%r15
  lea    0x0(,%rdx,8),%rcx
  mov    %rcx,-0x20(%rsp)
  xchg   %ax,%ax
L54:
  movsd  0x8(%r13),%xmm9
  movsd  (%rax),%xmm11
  movsd  0x8(%rax),%xmm10
  mov    -0xc(%rsp),%esi
  movapd %xmm9,%xmm8
  movsd  0x0(%r13),%xmm6
  movapd %xmm11,%xmm12
  addsd  %xmm9,%xmm8
  lea    (%r12,%rsi,1),%edx
  movsd  %xmm6,-0x28(%rsp)
  movapd %xmm8,%xmm0
  mulsd  %xmm10,%xmm0
  mulsd  %xmm11,%xmm8
  subsd  %xmm0,%xmm12
  subsd  %xmm10,%xmm8
  cmp    %edx,%r12d
  jge    L128
  mov    -0x20(%rsp),%rcx
  movapd %xmm6,%xmm14
  lea    (%rdi,%r15,1),%rsi
  xor    %edx,%edx
  movapd %xmm9,%xmm13
  unpcklpd %xmm12,%xmm12
  lea    (%rsi,%r15,1),%r9
  lea    (%rdi,%rcx,1),%r10
  unpcklpd %xmm8,%xmm8
  unpcklpd %xmm14,%xmm14
  xor    %ecx,%ecx
  unpcklpd %xmm13,%xmm13
  unpcklpd %xmm11,%xmm11
  unpcklpd %xmm10,%xmm10
  nopl   0x0(%rax,%rax,1)
L57:
  movupd (%r10,%rdx,1),%xmm7
  movupd (%rdi,%rdx,1),%xmm4
  add    $0x1,%ecx
  movupd (%r9,%rdx,1),%xmm5
  movupd (%rdi,%rdx,1),%xmm6
  movapd %xmm7,%xmm1
  subpd  %xmm4,%xmm1
  movupd (%rsi,%rdx,1),%xmm4
  addpd  %xmm7,%xmm6
  addpd  %xmm4,%xmm5
  movapd %xmm4,%xmm0
  movupd (%r9,%rdx,1),%xmm4
  movapd %xmm1,%xmm7
  movapd %xmm6,%xmm3
  subpd  %xmm4,%xmm0
  shufpd $0x1,%xmm1,%xmm7
  subpd  %xmm5,%xmm3
  addpd  %xmm6,%xmm5
  movapd %xmm0,%xmm4
  shufpd $0x1,%xmm0,%xmm4
  movapd %xmm4,%xmm15
  movapd %xmm3,%xmm2
  movups %xmm5,(%r10,%rdx,1)
  addpd  %xmm1,%xmm15
  subpd  %xmm4,%xmm1
  mulpd  %xmm14,%xmm3
  mulpd  %xmm13,%xmm2
  movapd %xmm15,%xmm4
  movsd  %xmm1,%xmm4
  movsd  %xmm15,%xmm1
  movapd %xmm7,%xmm15
  subpd  %xmm0,%xmm15
  addpd  %xmm7,%xmm0
  mulpd  %xmm11,%xmm4
  shufpd $0x1,%xmm2,%xmm2
  mulpd  %xmm12,%xmm1
  movapd %xmm3,%xmm5
  subpd  %xmm2,%xmm5
  addpd  %xmm3,%xmm2
  movapd %xmm15,%xmm7
  movsd  %xmm0,%xmm7
  movsd  %xmm15,%xmm0
  mulpd  %xmm10,%xmm7
  movsd  %xmm5,%xmm2
  movups %xmm2,(%rsi,%rdx,1)
  mulpd  %xmm8,%xmm0
  movapd %xmm4,%xmm2
  subpd  %xmm7,%xmm2
  addpd  %xmm4,%xmm7
  movsd  %xmm2,%xmm7
  movapd %xmm1,%xmm2
  subpd  %xmm0,%xmm2
  addpd  %xmm1,%xmm0
  movups %xmm7,(%rdi,%rdx,1)
  movsd  %xmm2,%xmm0
  movups %xmm0,(%r9,%rdx,1)
  add    $0x10,%rdx
  cmp    %ebp,%ecx
  jb     L57
L128:
  movsd  -0x28(%rsp),%xmm6
  movsd  0x10(%rax),%xmm10
  movsd  0x18(%rax),%xmm8
  mov    -0x18(%rsp),%ecx
  movapd %xmm6,%xmm7
  movapd %xmm10,%xmm11
  addsd  %xmm6,%xmm7
  lea    (%rcx,%r12,1),%edx
  movapd %xmm7,%xmm0
  mulsd  %xmm8,%xmm0
  mulsd  %xmm10,%xmm7
  subsd  %xmm0,%xmm11
  subsd  %xmm8,%xmm7
  cmp    %edx,%r14d
  jle    L100
  mov    -0x20(%rsp),%rsi
  lea    -0x1(%r14),%r11d
  movapd %xmm6,%xmm12
  xor    %ecx,%ecx
  sub    %edx,%r11d
  unpcklpd %xmm10,%xmm10
  unpcklpd %xmm7,%xmm7
  xor    %edx,%edx
  xorpd  D3(%rip),%xmm9
  shr    %r11d
  lea    (%rsi,%r8,1),%r10
  lea    (%r15,%r8,1),%rsi
  add    $0x1,%r11d
  lea    (%r15,%rsi,1),%r9
  unpcklpd %xmm8,%xmm8
  unpcklpd %xmm9,%xmm9
  unpcklpd %xmm12,%xmm12
  unpcklpd %xmm11,%xmm11
  nopl   (%rax)
L32:
  movupd (%r10,%rdx,1),%xmm5
  movupd (%r8,%rdx,1),%xmm3
  add    $0x1,%ecx
  movupd (%r9,%rdx,1),%xmm0
  movupd (%r8,%rdx,1),%xmm6
  movapd %xmm5,%xmm13
  movupd (%rsi,%rdx,1),%xmm4
  subpd  %xmm3,%xmm13
  movupd (%rsi,%rdx,1),%xmm3
  addpd  %xmm5,%xmm6
  movupd (%r9,%rdx,1),%xmm5
  subpd  %xmm0,%xmm3
  addpd  %xmm4,%xmm5
  movapd %xmm13,%xmm14
  movapd %xmm6,%xmm4
  movapd %xmm13,%xmm1
  shufpd $0x1,%xmm13,%xmm1
  movapd %xmm3,%xmm0
  subpd  %xmm5,%xmm4
  addpd  %xmm6,%xmm5
  shufpd $0x1,%xmm3,%xmm0
  subpd  %xmm0,%xmm14
  addpd  %xmm13,%xmm0
  movapd %xmm4,%xmm2
  movups %xmm5,(%r10,%rdx,1)
  mulpd  %xmm9,%xmm4
  movapd %xmm14,%xmm13
  mulpd  %xmm12,%xmm2
  movsd  %xmm0,%xmm13
  movsd  %xmm14,%xmm0
  mulpd  %xmm10,%xmm0
  movapd %xmm1,%xmm14
  subpd  %xmm3,%xmm1
  addpd  %xmm3,%xmm14
  mulpd  %xmm11,%xmm13
  movapd %xmm4,%xmm5
  movapd %xmm14,%xmm3
  shufpd $0x1,%xmm2,%xmm2
  subpd  %xmm2,%xmm5
  addpd  %xmm4,%xmm2
  movsd  %xmm1,%xmm3
  movsd  %xmm14,%xmm1
  mulpd  %xmm8,%xmm1
  mulpd  %xmm7,%xmm3
  movsd  %xmm5,%xmm2
  movups %xmm2,(%rsi,%rdx,1)
  movapd %xmm0,%xmm2
  subpd  %xmm1,%xmm2
  addpd  %xmm0,%xmm1
  movsd  %xmm2,%xmm1
  movups %xmm1,(%r8,%rdx,1)
  movapd %xmm13,%xmm1
  subpd  %xmm3,%xmm1
  addpd  %xmm13,%xmm3
  movapd %xmm3,%xmm0
  movsd  %xmm1,%xmm0
  movups %xmm0,(%r9,%rdx,1)
  add    $0x10,%rdx
  cmp    %r11d,%ecx
  jb     L32
L100:
  mov    -0x10(%rsp),%esi
  add    $0x10,%r13
  add    $0x20,%rax
  add    %rbx,%r8
  add    %rbx,%rdi
  add    %esi,%r12d
  add    %esi,%r14d
  cmp    %r12d,-0x14(%rsp)
  jg     L54
L117:
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L44:
  mov    -0x28(%rsp),%r10d
  lea    0x0(%rbp,%rbp,1),%r9
  add    %rdx,%rdi
  add    %rdx,%rcx
  lea    (%r9,%r14,1),%r8
  add    %rbp,%r9
  shr    %r10d
  add    %r14,%r9
  lea    (%rdx,%r8,8),%r8
  lea    (%r14,%r10,2),%r10
  lea    (%rdx,%r9,8),%r9
  lea    0x10(%rdx,%r10,8),%r10
  nopl   0x0(%rax,%rax,1)
L15:
  movupd (%rdi),%xmm6
  movsd  (%rcx),%xmm0
  add    $0x10,%rdi
  add    $0x10,%rcx
  movupd -0x10(%rcx),%xmm1
  movupd (%r8),%xmm5
  add    $0x10,%r9
  add    $0x10,%r8
  movapd %xmm6,%xmm7
  movsd  -0x8(%rdi),%xmm4
  movsd  -0x10(%r9),%xmm2
  addpd  %xmm6,%xmm1
  subsd  %xmm0,%xmm7
  movupd -0x10(%r9),%xmm6
  movsd  -0x8(%rcx),%xmm0
  addpd  %xmm5,%xmm6
  subsd  %xmm0,%xmm4
  movapd %xmm5,%xmm0
  movsd  -0x8(%r9),%xmm5
  subsd  %xmm2,%xmm0
  movsd  -0x8(%r8),%xmm2
  movapd %xmm1,%xmm9
  unpckhpd %xmm9,%xmm9
  subsd  %xmm5,%xmm2
  movapd %xmm6,%xmm5
  addpd  %xmm1,%xmm5
  subsd  %xmm6,%xmm1
  movups %xmm5,-0x10(%rdi)
  movapd %xmm6,%xmm5
  movapd %xmm7,%xmm6
  unpckhpd %xmm5,%xmm5
  subsd  %xmm2,%xmm6
  addsd  %xmm7,%xmm2
  subsd  %xmm9,%xmm5
  unpcklpd %xmm1,%xmm5
  movapd %xmm6,%xmm1
  movups %xmm5,-0x10(%r8)
  movapd %xmm0,%xmm5
  subsd  %xmm4,%xmm0
  addsd  %xmm4,%xmm5
  subsd  %xmm5,%xmm1
  addsd  %xmm6,%xmm5
  unpcklpd %xmm5,%xmm1
  mulpd  %xmm3,%xmm1
  movups %xmm1,-0x10(%rcx)
  movapd %xmm0,%xmm1
  addsd  %xmm2,%xmm0
  subsd  %xmm2,%xmm1
  unpcklpd %xmm0,%xmm1
  mulpd  %xmm3,%xmm1
  movups %xmm1,-0x10(%r9)
  cmp    %r10,%rdi
  jne    L15
  mov    -0x18(%rsp),%ebx
  jmp    L121
```

tool_calls: name: retrieve_data
arguments: data_tag: D3
data_type: byte[16]

tool: {"D3": [0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00]}

assistant: ```c
void cftmdl(int n, int l, double *a, double const *w) {
  int j, j1, j2, j3, k, k1, k2, m, m2;
  double wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
  double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
  m = l << 2;
  for (j = 0; j < l; j += 2) {
    j1 = j + l;
    j2 = j1 + l;
    j3 = j2 + l;
    x0r = a[j] + a[j1];
    x0i = a[j + 1] + a[j1 + 1];
    x1r = a[j] - a[j1];
    x1i = a[j + 1] - a[j1 + 1];
    x2r = a[j2] + a[j3];
    x2i = a[j2 + 1] + a[j3 + 1];
    x3r = a[j2] - a[j3];
    x3i = a[j2 + 1] - a[j3 + 1];
    a[j] = x0r + x2r;
    a[j + 1] = x0i + x2i;
    a[j2] = x0r - x2r;
    a[j2 + 1] = x0i - x2i;
    a[j1] = x1r - x3i;
    a[j1 + 1] = x1i + x3r;
    a[j3] = x1r + x3i;
    a[j3 + 1] = x1i - x3r;
  }
  wk1r = w[2];
  for (j = m; j < l + m; j += 2) {
    j1 = j + l;
    j2 = j1 + l;
    j3 = j2 + l;
    x0r = a[j] + a[j1];
    x0i = a[j + 1] + a[j1 + 1];
    x1r = a[j] - a[j1];
    x1i = a[j + 1] - a[j1 + 1];
    x2r = a[j2] + a[j3];
    x2i = a[j2 + 1] + a[j3 + 1];
    x3r = a[j2] - a[j3];
    x3i = a[j2 + 1] - a[j3 + 1];
    a[j] = x0r + x2r;
    a[j + 1] = x0i + x2i;
    a[j2] = x2i - x0i;
    a[j2 + 1] = x0r - x2r;
    x0r = x1r - x3i;
    x0i = x1i + x3r;
    a[j1] = wk1r * (x0r - x0i);
    a[j1 + 1] = wk1r * (x0r + x0i);
    x0r = x3i + x1r;
    x0i = x3r - x1i;
    a[j3] = wk1r * (x0i - x0r);
    a[j3 + 1] = wk1r * (x0i + x0r);
  }
  k1 = 0;
  m2 = 2 * m;
  for (k = m2; k < n; k += m2) {
    k1 += 2;
    k2 = 2 * k1;
    wk2r = w[k1];
    wk2i = w[k1 + 1];
    wk1r = w[k2];
    wk1i = w[k2 + 1];
    wk3r = wk1r - 2 * wk2i * wk1i;
    wk3i = 2 * wk2i * wk1r - wk1i;
    for (j = k; j < l + k; j += 2) {
      j1 = j + l;
      j2 = j1 + l;
      j3 = j2 + l;
      x0r = a[j] + a[j1];
      x0i = a[j + 1] + a[j1 + 1];
      x1r = a[j] - a[j1];
      x1i = a[j + 1] - a[j1 + 1];
      x2r = a[j2] + a[j3];
      x2i = a[j2 + 1] + a[j3 + 1];
      x3r = a[j2] - a[j3];
      x3i = a[j2 + 1] - a[j3 + 1];
      a[j] = x0r + x2r;
      a[j + 1] = x0i + x2i;
      x0r -= x2r;
      x0i -= x2i;
      a[j2] = wk2r * x0r - wk2i * x0i;
      a[j2 + 1] = wk2r * x0i + wk2i * x0r;
      x0r = x1r - x3i;
      x0i = x1i + x3r;
      a[j1] = wk1r * x0r - wk1i * x0i;
      a[j1 + 1] = wk1r * x0i + wk1i * x0r;
      x0r = x1r + x3i;
      x0i = x1i - x3r;
      a[j3] = wk3r * x0r - wk3i * x0i;
      a[j3 + 1] = wk3r * x0i + wk3i * x0r;
    }
    wk1r = w[k2 + 2];
    wk1i = w[k2 + 3];
    wk3r = wk1r - 2 * wk2r * wk1i;
    wk3i = 2 * wk2r * wk1r - wk1i;
    for (j = k + m; j < l + (k + m); j += 2) {
      j1 = j + l;
      j2 = j1 + l;
      j3 = j2 + l;
      x0r = a[j] + a[j1];
      x0i = a[j + 1] + a[j1 + 1];
      x1r = a[j] - a[j1];
      x1i = a[j + 1] - a[j1 + 1];
      x2r = a[j2] + a[j3];
      x2i = a[j2 + 1] + a[j3 + 1];
      x3r = a[j2] - a[j3];
      x3i = a[j2 + 1] - a[j3 + 1];
      a[j] = x0r + x2r;
      a[j + 1] = x0i + x2i;
      x0r -= x2r;
      x0i -= x2i;
      a[j2] = -wk2i * x0r - wk2r * x0i;
      a[j2 + 1] = -wk2i * x0i + wk2r * x0r;
      x0r = x1r - x3i;
      x0i = x1i + x3r;
      a[j1] = wk1r * x0r - wk1i * x0i;
      a[j1 + 1] = wk1r * x0i + wk1i * x0r;
      x0r = x1r + x3i;
      x0i = x1i - x3r;
      a[j3] = wk3r * x0r - wk3i * x0i;
      a[j3 + 1] = wk3r * x0i + wk3i * x0r;
    }
  }
}
```