user: 请将以下的汇编代码转换成C语言代码：

```asm
<rdft>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  mov    %edi,%ebx
  mov    %esi,0xc(%rsp)
  mov    %rdx,%rbp
  mov    %rcx,%r12
  mov    %r8,%r13
  mov    (%rcx),%r14d
  lea    0x0(,%r14,4),%eax
  cmp    %edi,%eax
  jl     L58
L55:
  mov    0x4(%r12),%r15d
  lea    0x0(,%r15,4),%eax
  cmp    %ebx,%eax
  jl     L124
L21:
  cmpl   $0x0,0xc(%rsp)
  js     L22
  cmp    $0x4,%ebx
  jg     L17
  je     L75
L7:
  movss  0x0(%rbp),%xmm0
  movss  0x4(%rbp),%xmm1
  movaps %xmm0,%xmm2
  addss  %xmm1,%xmm2
  movss  %xmm2,0x0(%rbp)
  subss  %xmm1,%xmm0
  movss  %xmm0,0x4(%rbp)
L39:
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L58:
  mov    %edi,%r14d
  sar    $0x2,%r14d
  mov    %r8,%rdx
  mov    %rcx,%rsi
  mov    %r14d,%edi
  call   <makewt@plt>
  jmp    L55
L124:
  mov    %ebx,%r15d
  sar    $0x2,%r15d
  movslq %r14d,%rax
  lea    0x0(%r13,%rax,4),%rdx
  mov    %r12,%rsi
  mov    %r15d,%edi
  call   <makect@plt>
  jmp    L21
L17:
  mov    %r13,%r8
  mov    %r14d,%ecx
  mov    %r12,%rdx
  mov    %rbp,%rsi
  mov    %ebx,%edi
  call   <cftfsub@plt>
  movslq %r14d,%r14
  lea    0x0(%r13,%r14,4),%rcx
  mov    %r15d,%edx
  mov    %rbp,%rsi
  mov    %ebx,%edi
  call   <rftfsub@plt>
  jmp    L7
L75:
  mov    %r13,%r8
  mov    %r14d,%ecx
  mov    %r12,%rdx
  mov    %rbp,%rsi
  mov    $0x4,%edi
  call   <cftfsub@plt>
  jmp    L7
L22:
  movss  0x0(%rbp),%xmm0
  movaps %xmm0,%xmm1
  subss  0x4(%rbp),%xmm1
  mulss  D2(%rip),%xmm1
  movss  %xmm1,0x4(%rbp)
  subss  %xmm1,%xmm0
  movss  %xmm0,0x0(%rbp)
  cmp    $0x4,%ebx
  jg     L4
  jne    L39
  mov    %r13,%r8
  mov    %r14d,%ecx
  mov    %r12,%rdx
  mov    %rbp,%rsi
  mov    $0x4,%edi
  call   <cftbsub@plt>
  jmp    L39
L4:
  movslq %r14d,%rax
  lea    0x0(%r13,%rax,4),%rcx
  mov    %r15d,%edx
  mov    %rbp,%rsi
  mov    %ebx,%edi
  call   <rftbsub@plt>
  mov    %r13,%r8
  mov    %r14d,%ecx
  mov    %r12,%rdx
  mov    %rbp,%rsi
  mov    %ebx,%edi
  call   <cftbsub@plt>
  jmp    L39
```

tool_calls: name: retrieve_data
arguments: data_tag: D2
type: f32

tool: D2: 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);
    }
  }
}
```