user: 请从给定的汇编指令推导出C源代码:

```asm
<rdft>:
  endbr64
  push   %r15
  mov    %esi,%r15d
  push   %r14
  push   %r13
  mov    %rcx,%r13
  push   %r12
  mov    %edi,%r12d
  push   %rbp
  mov    %rdx,%rbp
  push   %rbx
  mov    %r8,%rbx
  sub    $0x18,%rsp
  mov    (%rcx),%r14d
  lea    0x0(,%r14,4),%eax
  cmp    %edi,%eax
  jl     L75
L1:
  mov    0x4(%r13),%r9d
  lea    0x0(,%r9,4),%eax
  cmp    %r12d,%eax
  jl     L29
L2:
  test   %r15d,%r15d
  js     L25
  cmp    $0x4,%r12d
  jg     L80
  je     L103
L42:
  movss  0x0(%rbp),%xmm0
  movss  0x4(%rbp),%xmm1
  movaps %xmm0,%xmm2
  subss  %xmm1,%xmm0
  addss  %xmm1,%xmm2
  movss  %xmm0,0x4(%rbp)
  movss  %xmm2,0x0(%rbp)
L90:
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L25:
  movss  0x0(%rbp),%xmm0
  movaps %xmm0,%xmm1
  subss  0x4(%rbp),%xmm1
  mulss  D7(%rip),%xmm1
  subss  %xmm1,%xmm0
  movss  %xmm1,0x4(%rbp)
  movss  %xmm0,0x0(%rbp)
  cmp    $0x4,%r12d
  jg     L28
  jne    L90
  mov    %rbx,%r8
  mov    %r14d,%ecx
  mov    %r13,%rdx
  mov    %rbp,%rsi
  mov    $0x4,%edi
L41:
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    10b0 <cftbsub@plt>
  nopl   0x0(%rax,%rax,1)
L29:
  mov    %r12d,%r9d
  movslq %r14d,%rax
  mov    %r13,%rsi
  sar    $0x2,%r9d
  lea    (%rbx,%rax,4),%rdx
  mov    %r9d,%edi
  mov    %r9d,0xc(%rsp)
  call   <makect@plt>
  mov    0xc(%rsp),%r9d
  jmp    L2
L75:
  mov    %edi,%r14d
  mov    %r8,%rdx
  mov    %rcx,%rsi
  sar    $0x2,%r14d
  mov    %r14d,%edi
  call   <makewt@plt>
  jmp    L1
  nopw   0x0(%rax,%rax,1)
L80:
  mov    %r14d,%ecx
  mov    %r13,%rdx
  mov    %rbp,%rsi
  mov    %r12d,%edi
  mov    %rbx,%r8
  mov    %r9d,0xc(%rsp)
  movslq %r14d,%r14
  call   <cftfsub@plt>
  mov    0xc(%rsp),%edx
  lea    (%rbx,%r14,4),%rcx
  mov    %rbp,%rsi
  mov    %r12d,%edi
  call   <rftfsub@plt>
  jmp    L42
  nopl   0x0(%rax)
L28:
  movslq %r14d,%rax
  mov    %r9d,%edx
  mov    %rbp,%rsi
  mov    %r12d,%edi
  lea    (%rbx,%rax,4),%rcx
  call   <rftbsub@plt>
  mov    %rbx,%r8
  mov    %r14d,%ecx
  mov    %r13,%rdx
  mov    %rbp,%rsi
  mov    %r12d,%edi
  jmp    L41
  nopl   0x0(%rax)
L103:
  mov    %rbx,%r8
  mov    %r14d,%ecx
  mov    %r13,%rdx
  mov    %rbp,%rsi
  mov    $0x4,%edi
  call   <cftfsub@plt>
  jmp    L42
```

tool_calls: name: disassemble_data
arguments: data_tag: D7
type_guessed: f32

tool: D7: 0.5

assistant: ```c
void rdft(int n, int isgn, float *a, int *ip, float *w) {
  void makewt(int nw, int *ip, float *w);
  void makect(int nc, int *ip, float *c);
  void cftfsub(int n, float *a, int *ip, int nw, float *w);
  void cftbsub(int n, float *a, int *ip, int nw, float *w);
  void rftfsub(int n, float *a, int nc, float *c);
  void rftbsub(int n, float *a, int nc, float *c);
  int nw, nc;
  float xi;
  nw = ip[0];
  if (n > (nw << 2)) {
    nw = n >> 2;
    makewt(nw, ip, w);
  }
  nc = ip[1];
  if (n > (nc << 2)) {
    nc = n >> 2;
    makect(nc, ip, w + nw);
  }
  if (isgn >= 0) {
    if (n > 4) {
      cftfsub(n, a, ip, nw, w);
      rftfsub(n, a, nc, w + nw);
    } else if (n == 4) {
      cftfsub(n, a, ip, nw, w);
    }
    xi = a[0] - a[1];
    a[0] += a[1];
    a[1] = xi;
  } else {
    a[1] = ((float)0.5) * (a[0] - a[1]);
    a[0] -= a[1];
    if (n > 4) {
      rftbsub(n, a, nc, w + nw);
      cftbsub(n, a, ip, nw, w);
    } else if (n == 4) {
      cftbsub(n, a, ip, nw, w);
    }
  }
}
```