user: 请显示与下面列出的汇编代码相匹配的C语言实现:

```asm
<ep21R>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  mov    %rcx,-0x40(%rbp)
  mov    %r8d,-0x44(%rbp)
  mov    %r9d,-0x48(%rbp)
  mov    -0x44(%rbp),%eax
  imul   -0x48(%rbp),%eax
  mov    %eax,-0xc(%rbp)
  movl   $0x0,-0x10(%rbp)
  jmp    L45
L67:
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x8(%rbp)
  mov    -0x10(%rbp),%eax
  mov    %eax,-0x14(%rbp)
  jmp    L60
L51:
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  -0x8(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x8(%rbp)
  mov    -0x44(%rbp),%eax
  add    %eax,-0x14(%rbp)
L60:
  mov    -0x14(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jl     L51
  mov    -0x8(%rbp),%rax
  movq   %rax,%xmm0
  call   <sqrt@plt>
  movq   %xmm0,%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movq   D15(%rip),%xmm1
  andpd  %xmm0,%xmm1
  movsd  -0x8(%rbp),%xmm0
  comisd %xmm1,%xmm0
  jbe    L85
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  addsd  -0x8(%rbp),%xmm0
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  D4(%rip),%xmm1
  divsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%eax
  mov    %eax,-0x14(%rbp)
  jmp    L125
L109:
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movapd %xmm0,%xmm1
  divsd  -0x8(%rbp),%xmm1
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mulsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x44(%rbp),%eax
  add    %eax,-0x14(%rbp)
L125:
  mov    -0x14(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jl     L109
  jmp    L66
L85:
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  comisd -0x8(%rbp),%xmm0
  jb     L131
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rax,%rdx
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x30(%rbp),%rax
  add    %rcx,%rax
  movsd  (%rdx),%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%eax
  mov    %eax,-0x14(%rbp)
  jmp    L42
L90:
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rax,%rdx
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x28(%rbp),%rax
  add    %rcx,%rax
  movsd  (%rdx),%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x44(%rbp),%eax
  add    %eax,-0x14(%rbp)
L42:
  mov    -0x14(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jl     L90
  jmp    L66
L131:
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  pxor   %xmm0,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%eax
  mov    %eax,-0x14(%rbp)
  jmp    L76
L34:
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  pxor   %xmm0,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x44(%rbp),%eax
  add    %eax,-0x14(%rbp)
L76:
  mov    -0x14(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jl     L34
L66:
  addl   $0x1,-0x10(%rbp)
L45:
  mov    -0x10(%rbp),%eax
  cmp    -0x44(%rbp),%eax
  jl     L67
  nop
  nop
  leave
  ret
```

tool_calls: name: extract_symbolic_data
arguments: data_label: D15
type_guessed: qword
name: extract_symbolic_data
arguments: data_label: D4
type_guessed: byte[8]

tool: D15: 9223372036854775807

tool: {"D4": [0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x40]}

assistant: ```c
void ep21R(double *x, double *t, double *u, double *v, int n, int k) {
  int i, j, tn = n * k;
  double temp;
  for (j = 0; j < n; j++) {
    temp = 0;
    for (i = j; i < tn; i += n)
      temp += u[i] * u[i];
    temp = sqrt(temp);
    if (temp > fabs(v[j])) {
      t[j] = (temp + v[j]) / 2;
      for (i = j; i < tn; i += n)
        x[i] = t[j] / temp * u[i];
    } else if (temp <= v[j]) {
      t[j] = v[j];
      for (i = j; i < tn; i += n)
        x[i] = u[i];
    } else {
      t[j] = 0;
      for (i = j; i < tn; i += n)
        x[i] = 0;
    }
  }
}
```