user: 请从给定的汇编指令推导出C源代码：

```asm
<prestd>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %edi,-0x14(%rbp)
  mov    %rsi,-0x20(%rbp)
  mov    %edx,-0x18(%rbp)
  mov    %rcx,-0x28(%rbp)
  mov    %r8d,-0x2c(%rbp)
  mov    %r9,-0x38(%rbp)
  movss  %xmm0,-0x30(%rbp)
  movss  %xmm1,-0x3c(%rbp)
  movss  %xmm2,-0x40(%rbp)
  movss  %xmm3,-0x44(%rbp)
  movl   $0x0,-0x8(%rbp)
  jmp    L20
L4:
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x38(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  lea    (%rdx,%rax,1),%rdi
  movss  -0x3c(%rbp),%xmm0
  mov    -0x30(%rbp),%esi
  mov    -0x18(%rbp),%edx
  mov    -0x14(%rbp),%eax
  movaps %xmm0,%xmm1
  movd   %esi,%xmm0
  mov    %eax,%esi
  call   <mapstd_stride@plt>
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x18(%rbp),%edx
  mov    -0x14(%rbp),%eax
  mov    %eax,%esi
  mov    %rcx,%rdi
  call   <mean_stride@plt>
  movd   %xmm0,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movss  -0x4(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x18(%rbp),%edx
  mov    -0x14(%rbp),%eax
  mov    %eax,%esi
  mov    %rcx,%rdi
  call   <std_stride@plt>
  movd   %xmm0,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    0x20(%rbp),%rax
  add    %rdx,%rax
  movss  -0x4(%rbp),%xmm0
  movss  %xmm0,(%rax)
  addl   $0x1,-0x8(%rbp)
L20:
  mov    -0x8(%rbp),%eax
  cmp    -0x18(%rbp),%eax
  jl     L4
  movl   $0x0,-0x8(%rbp)
  jmp    L0
L3:
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    0x10(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  lea    (%rdx,%rax,1),%rdi
  movss  -0x44(%rbp),%xmm0
  mov    -0x40(%rbp),%esi
  mov    -0x2c(%rbp),%edx
  mov    -0x14(%rbp),%eax
  movaps %xmm0,%xmm1
  movd   %esi,%xmm0
  mov    %eax,%esi
  call   <mapstd_stride@plt>
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x2c(%rbp),%edx
  mov    -0x14(%rbp),%eax
  mov    %eax,%esi
  mov    %rcx,%rdi
  call   <mean_stride@plt>
  movd   %xmm0,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    0x28(%rbp),%rax
  add    %rdx,%rax
  movss  -0x4(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x2c(%rbp),%edx
  mov    -0x14(%rbp),%eax
  mov    %eax,%esi
  mov    %rcx,%rdi
  call   <std_stride@plt>
  movd   %xmm0,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    0x30(%rbp),%rax
  add    %rdx,%rax
  movss  -0x4(%rbp),%xmm0
  movss  %xmm0,(%rax)
  addl   $0x1,-0x8(%rbp)
L0:
  mov    -0x8(%rbp),%eax
  cmp    -0x2c(%rbp),%eax
  jl     L3
  nop
  nop
  leave
  ret
```

assistant: ```c
void prestd(int size, float *p, int leninp, float *t, int lenoup, float *pn, float *tn, float ymean, float ystd, float omean, float ostd, float *dmean, float *dstd, float *tmean, float *tstd) {
  int i;
  float temp;
  for (i = 0; i < leninp; ++i) {
    mapstd_stride(p + i, size, leninp, ymean, ystd, pn + i);
    temp = mean_stride(p + i, size, leninp);
    dmean[i] = temp;
    temp = std_stride(p + i, size, leninp);
    dstd[i] = temp;
  }
  for (i = 0; i < lenoup; ++i) {
    mapstd_stride(t + i, size, lenoup, omean, ostd, tn + i);
    temp = mean_stride(t + i, size, lenoup);
    tmean[i] = temp;
    temp = std_stride(t + i, size, lenoup);
    tstd[i] = temp;
  }
}
```