user: 这段汇编代码用C语言表示是什么样的:

```asm
<calculate_fg>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x28,%rsp
  movsd  %xmm0,-0x68(%rsp)
  movsd  %xmm1,-0x20(%rsp)
  movsd  %xmm2,-0x18(%rsp)
  movsd  %xmm3,-0x30(%rsp)
  movsd  %xmm4,-0x28(%rsp)
  movapd %xmm5,%xmm15
  movsd  %xmm6,-0x38(%rsp)
  mov    %edi,0xc(%rsp)
  mov    %esi,0x8(%rsp)
  mov    %rdx,0x10(%rsp)
  mov    %rcx,%r11
  mov    %r9,%r12
  test   %esi,%esi
  jle    L76
  movslq %edi,%rcx
  shl    $0x3,%rcx
  mov    %rdx,%r9
  lea    (%rdx,%rcx,1),%rdi
  add    %r8,%rcx
  lea    0x1(%rsi),%esi
  shl    $0x3,%rsi
  mov    $0x8,%eax
L109:
  mov    (%r9),%rdx
  movsd  (%rdx,%rax,1),%xmm0
  mov    (%r8),%rdx
  movsd  %xmm0,(%rdx,%rax,1)
  mov    (%rdi),%rdx
  movsd  (%rdx,%rax,1),%xmm0
  mov    (%rcx),%rdx
  movsd  %xmm0,(%rdx,%rax,1)
  add    $0x8,%rax
  cmp    %rsi,%rax
  jne    L109
L76:
  mov    0xc(%rsp),%eax
  test   %eax,%eax
  jle    L25
  movslq 0x8(%rsp),%rdx
  shl    $0x3,%rdx
  lea    0x1(%rax),%edi
  mov    $0x1,%eax
L106:
  mov    (%r12,%rax,8),%rcx
  mov    (%r11,%rax,8),%rsi
  movsd  (%rsi),%xmm0
  movsd  %xmm0,(%rcx)
  mov    (%r11,%rax,8),%rcx
  movsd  (%rcx,%rdx,1),%xmm0
  mov    (%r12,%rax,8),%rcx
  movsd  %xmm0,(%rcx,%rdx,1)
  add    $0x1,%rax
  cmp    %rdi,%rax
  jne    L106
L25:
  mov    0xc(%rsp),%ecx
  cmp    $0x1,%ecx
  jle    L108
  mov    0x8(%rsp),%ebx
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%r10
  lea    0x8(%r10),%rax
  mov    %rax,-0x8(%rsp)
  lea    -0x8(%r10),%rsi
  mov    0x10(%rsp),%rdi
  mov    %r11,%r13
  add    $0x8,%r8
  lea    0x8(%r12),%rbp
  lea    -0x2(%rcx),%eax
  lea    0x8(%rdi,%rax,8),%rax
  mov    %rax,(%rsp)
  lea    -0x2(%rbx),%eax
  lea    0x10(,%rax,8),%rbx
  movsd  D165(%rip),%xmm3
  movq   D91(%rip),%xmm8
  mov    %r10,%r15
  mov    %rsi,%r10
  movapd %xmm15,%xmm13
  mov    %r11,0x18(%rsp)
  mov    %rbp,%r11
  mov    %rbx,%rbp
  mov    %rdi,%rbx
  mov    %r8,%r14
  mov    %r12,0x20(%rsp)
  jmp    L38
L26:
  movapd %xmm13,%xmm4
  mulsd  %xmm13,%xmm4
  movsd  %xmm4,-0x60(%rsp)
  movsd  -0x38(%rsp),%xmm7
  movapd %xmm7,%xmm4
  mulsd  %xmm7,%xmm4
  movsd  %xmm4,-0x10(%rsp)
  mov    $0x8,%ecx
  mov    %r10,%r12
  mov    %rbp,%r9
  mov    %r14,%r10
  mov    %rcx,%r14
  mov    %r15,%rcx
  movsd  %xmm13,-0x78(%rsp)
L117:
  mov    0x8(%rbx),%rdx
  movsd  (%rdx,%r14,1),%xmm7
  mov    0x10(%rbx),%rax
  mov    (%rax,%r14,1),%rsi
  movq   %rsi,%xmm5
  addsd  %xmm7,%xmm5
  mulsd  %xmm3,%xmm5
  movsd  %xmm5,-0x70(%rsp)
  mov    %r14,%rax
  add    $0x8,%r14
  movsd  (%rdx,%r14,1),%xmm13
  movapd %xmm7,%xmm1
  addsd  %xmm13,%xmm1
  mulsd  %xmm3,%xmm1
  movapd %xmm1,%xmm0
  mov    (%rbx),%rdi
  movsd  (%rdi,%rax,1),%xmm15
  movapd %xmm7,%xmm14
  addsd  %xmm15,%xmm14
  mulsd  %xmm3,%xmm14
  movsd  -0x8(%rdx,%rax,1),%xmm1
  mov    0x8(%r13),%rdx
  movsd  (%rdx,%rax,1),%xmm9
  mov    0x10(%r13),%rbp
  movsd  0x0(%rbp,%rax,1),%xmm6
  movsd  %xmm6,-0x58(%rsp)
  movapd %xmm6,%xmm2
  addsd  %xmm9,%xmm2
  mulsd  %xmm3,%xmm2
  mov    (%rdx,%r14,1),%r15
  movq   %r15,%xmm6
  addsd  %xmm9,%xmm6
  mulsd  %xmm3,%xmm6
  movsd  %xmm6,-0x40(%rsp)
  mov    0x0(%r13),%r8
  movsd  (%r8,%rax,1),%xmm4
  movsd  -0x8(%rdx,%rax,1),%xmm11
  movapd %xmm9,%xmm10
  addsd  %xmm11,%xmm10
  mulsd  %xmm3,%xmm10
  movapd %xmm7,%xmm5
  addsd  %xmm7,%xmm5
  movapd %xmm5,%xmm12
  movsd  %xmm0,-0x48(%rsp)
  mulsd  %xmm2,%xmm0
  movq   %xmm0,%r8
  movapd %xmm11,%xmm5
  addsd  -0x8(%rbp,%rax,1),%xmm5
  movq   %xmm5,%rbp
  movapd %xmm9,%xmm5
  addsd  %xmm9,%xmm5
  movsd  %xmm5,-0x50(%rsp)
  movapd %xmm15,%xmm0
  addsd  (%rdi,%r14,1),%xmm0
  movq   %xmm0,%rdi
  mov    (%r10),%rdx
  movapd %xmm15,%xmm0
  subsd  %xmm12,%xmm0
  movq   %rsi,%xmm6
  addsd  %xmm6,%xmm0
  divsd  -0x60(%rsp),%xmm0
  movapd %xmm1,%xmm6
  subsd  %xmm12,%xmm6
  addsd  %xmm6,%xmm13
  movsd  -0x10(%rsp),%xmm6
  divsd  %xmm6,%xmm13
  addsd  %xmm13,%xmm0
  divsd  -0x68(%rsp),%xmm0
  movsd  -0x70(%rsp),%xmm13
  andpd  %xmm8,%xmm13
  movapd %xmm7,%xmm5
  movq   %rsi,%xmm12
  subsd  %xmm12,%xmm5
  mulsd  %xmm5,%xmm13
  mulsd  %xmm3,%xmm13
  movq   %xmm13,%rsi
  movapd %xmm14,%xmm13
  andpd  %xmm8,%xmm13
  subsd  %xmm7,%xmm15
  mulsd  %xmm13,%xmm15
  mulsd  %xmm3,%xmm15
  movq   %rsi,%xmm13
  subsd  %xmm15,%xmm13
  movsd  -0x30(%rsp),%xmm15
  mulsd  %xmm15,%xmm13
  movsd  -0x78(%rsp),%xmm12
  divsd  %xmm12,%xmm13
  movsd  -0x70(%rsp),%xmm5
  mulsd  %xmm5,%xmm5
  mulsd  %xmm14,%xmm14
  subsd  %xmm14,%xmm5
  divsd  %xmm12,%xmm5
  addsd  %xmm5,%xmm13
  subsd  %xmm13,%xmm0
  andpd  %xmm8,%xmm2
  movapd %xmm7,%xmm14
  subsd  %xmm1,%xmm14
  mulsd  %xmm14,%xmm2
  mulsd  %xmm3,%xmm2
  movq   %rbp,%xmm14
  andpd  %xmm8,%xmm14
  movapd %xmm14,%xmm13
  movapd %xmm1,%xmm14
  subsd  %xmm7,%xmm14
  mulsd  %xmm14,%xmm13
  mulsd  D5(%rip),%xmm13
  subsd  %xmm13,%xmm2
  movapd %xmm15,%xmm14
  mulsd  %xmm15,%xmm2
  movsd  -0x38(%rsp),%xmm15
  divsd  %xmm15,%xmm2
  addsd  %xmm7,%xmm1
  movapd %xmm1,%xmm13
  mulsd  %xmm3,%xmm13
  movq   %rbp,%xmm1
  mulsd  %xmm3,%xmm1
  mulsd  %xmm1,%xmm13
  movq   %r8,%xmm1
  subsd  %xmm13,%xmm1
  movapd %xmm1,%xmm5
  divsd  %xmm15,%xmm5
  addsd  %xmm5,%xmm2
  subsd  %xmm2,%xmm0
  addsd  -0x20(%rsp),%xmm0
  movsd  -0x28(%rsp),%xmm12
  mulsd  %xmm12,%xmm0
  addsd  %xmm7,%xmm0
  movsd  %xmm0,(%rdx,%rax,1)
  mov    (%r11),%rsi
  movapd %xmm4,%xmm7
  movsd  -0x50(%rsp),%xmm5
  subsd  %xmm5,%xmm7
  movapd %xmm7,%xmm0
  movsd  -0x58(%rsp),%xmm7
  addsd  %xmm7,%xmm0
  divsd  -0x60(%rsp),%xmm0
  movapd %xmm11,%xmm2
  subsd  %xmm5,%xmm2
  movq   %r15,%xmm5
  addsd  %xmm5,%xmm2
  divsd  %xmm6,%xmm2
  addsd  %xmm2,%xmm0
  divsd  -0x68(%rsp),%xmm0
  movsd  -0x48(%rsp),%xmm1
  andpd  %xmm8,%xmm1
  movapd %xmm9,%xmm2
  subsd  %xmm7,%xmm2
  mulsd  %xmm2,%xmm1
  mulsd  %xmm3,%xmm1
  movq   %rdi,%xmm2
  andpd  %xmm8,%xmm2
  movapd %xmm4,%xmm5
  subsd  %xmm9,%xmm5
  mulsd  %xmm5,%xmm2
  mulsd  D5(%rip),%xmm2
  subsd  %xmm2,%xmm1
  mulsd  %xmm14,%xmm1
  movsd  -0x78(%rsp),%xmm5
  divsd  %xmm5,%xmm1
  addsd  %xmm9,%xmm4
  mulsd  %xmm3,%xmm4
  movq   %rdi,%xmm2
  mulsd  %xmm3,%xmm2
  mulsd  %xmm2,%xmm4
  movq   %r8,%xmm2
  subsd  %xmm4,%xmm2
  divsd  %xmm5,%xmm2
  addsd  %xmm2,%xmm1
  subsd  %xmm1,%xmm0
  movsd  -0x40(%rsp),%xmm7
  movapd %xmm7,%xmm6
  andpd  %xmm8,%xmm6
  movapd %xmm6,%xmm1
  movapd %xmm9,%xmm2
  movq   %r15,%xmm4
  subsd  %xmm4,%xmm2
  mulsd  %xmm2,%xmm1
  mulsd  %xmm3,%xmm1
  movapd %xmm10,%xmm2
  andpd  %xmm8,%xmm2
  movapd %xmm11,%xmm4
  subsd  %xmm9,%xmm4
  mulsd  %xmm4,%xmm2
  mulsd  %xmm3,%xmm2
  subsd  %xmm2,%xmm1
  mulsd  %xmm14,%xmm1
  divsd  %xmm15,%xmm1
  movapd %xmm7,%xmm6
  mulsd  %xmm7,%xmm6
  mulsd  %xmm10,%xmm10
  subsd  %xmm10,%xmm6
  divsd  %xmm15,%xmm6
  addsd  %xmm6,%xmm1
  subsd  %xmm1,%xmm0
  addsd  -0x18(%rsp),%xmm0
  mulsd  %xmm12,%xmm0
  mov    0x8(%r13),%rdx
  addsd  (%rdx,%rax,1),%xmm0
  movsd  %xmm0,(%rsi,%rax,1)
  cmp    %r9,%r14
  jne    L117
  mov    %rcx,%r15
  mov    %r9,%rbp
  mov    %r10,%r14
  mov    %r12,%r10
  movapd %xmm5,%xmm13
L70:
  mov    0x8(%rbx),%rax
  movsd  (%rax,%r15,1),%xmm2
  mov    0x10(%rbx),%rdx
  movsd  (%rdx,%r15,1),%xmm15
  movapd %xmm2,%xmm1
  addsd  %xmm15,%xmm1
  mulsd  D165(%rip),%xmm1
  mov    -0x8(%rsp),%rcx
  movsd  (%rax,%rcx,1),%xmm10
  mov    (%rbx),%rdx
  movsd  (%rdx,%r15,1),%xmm9
  movapd %xmm2,%xmm5
  addsd  %xmm9,%xmm5
  mulsd  D165(%rip),%xmm5
  movsd  (%rax,%r10,1),%xmm11
  mov    0x8(%r13),%rdx
  mov    0x10(%r13),%rax
  movsd  (%rdx,%r15,1),%xmm6
  addsd  (%rax,%r15,1),%xmm6
  mulsd  D165(%rip),%xmm6
  movapd %xmm2,%xmm7
  addsd  %xmm2,%xmm7
  movsd  (%rdx,%r10,1),%xmm14
  addsd  (%rax,%r10,1),%xmm14
  mov    (%r14),%rax
  movapd %xmm9,%xmm0
  subsd  %xmm7,%xmm0
  addsd  %xmm15,%xmm0
  movapd %xmm13,%xmm4
  mulsd  %xmm13,%xmm4
  divsd  %xmm4,%xmm0
  movapd %xmm11,%xmm4
  subsd  %xmm7,%xmm4
  addsd  %xmm10,%xmm4
  movsd  -0x38(%rsp),%xmm12
  movapd %xmm12,%xmm7
  mulsd  %xmm12,%xmm7
  divsd  %xmm7,%xmm4
  addsd  %xmm4,%xmm0
  divsd  -0x68(%rsp),%xmm0
  movapd %xmm1,%xmm4
  andpd  D91(%rip),%xmm4
  movapd %xmm2,%xmm7
  subsd  %xmm15,%xmm7
  mulsd  %xmm7,%xmm4
  mulsd  D165(%rip),%xmm4
  movapd %xmm5,%xmm7
  andpd  D91(%rip),%xmm7
  subsd  %xmm2,%xmm9
  mulsd  %xmm9,%xmm7
  mulsd  D165(%rip),%xmm7
  subsd  %xmm7,%xmm4
  movsd  -0x30(%rsp),%xmm7
  mulsd  %xmm7,%xmm4
  divsd  %xmm13,%xmm4
  mulsd  %xmm1,%xmm1
  mulsd  %xmm5,%xmm5
  subsd  %xmm5,%xmm1
  divsd  %xmm13,%xmm1
  addsd  %xmm4,%xmm1
  subsd  %xmm1,%xmm0
  movapd %xmm6,%xmm1
  andpd  D91(%rip),%xmm1
  movapd %xmm2,%xmm4
  subsd  %xmm11,%xmm4
  mulsd  %xmm4,%xmm1
  mulsd  D165(%rip),%xmm1
  movapd %xmm14,%xmm4
  andpd  D91(%rip),%xmm4
  movapd %xmm11,%xmm5
  subsd  %xmm2,%xmm5
  mulsd  %xmm5,%xmm4
  mulsd  D5(%rip),%xmm4
  subsd  %xmm4,%xmm1
  mulsd  %xmm7,%xmm1
  divsd  %xmm12,%xmm1
  addsd  %xmm2,%xmm10
  mulsd  D165(%rip),%xmm10
  mulsd  %xmm6,%xmm10
  addsd  %xmm2,%xmm11
  mulsd  D165(%rip),%xmm11
  mulsd  D165(%rip),%xmm14
  mulsd  %xmm14,%xmm11
  subsd  %xmm11,%xmm10
  divsd  %xmm12,%xmm10
  addsd  %xmm10,%xmm1
  subsd  %xmm1,%xmm0
  addsd  -0x20(%rsp),%xmm0
  mulsd  -0x28(%rsp),%xmm0
  addsd  %xmm2,%xmm0
  movsd  %xmm0,(%rax,%r15,1)
  add    $0x8,%rbx
  add    $0x8,%r13
  add    $0x8,%r14
  add    $0x8,%r11
  cmp    (%rsp),%rbx
  je     L60
L38:
  cmpl   $0x1,0x8(%rsp)
  jg     L26
  jmp    L70
L60:
  movapd %xmm13,%xmm15
  mov    0x18(%rsp),%r11
  mov    0x20(%rsp),%r12
L108:
  mov    0x8(%rsp),%ecx
  cmp    $0x1,%ecx
  jle    L32
  movslq 0xc(%rsp),%rax
  shl    $0x3,%rax
  mov    0x10(%rsp),%rdi
  lea    (%rdi,%rax,1),%rbp
  lea    (%r11,%rax,1),%rbx
  lea    0x8(%r11,%rax,1),%r8
  lea    -0x8(%rax),%r9
  lea    (%r11,%r9,1),%r10
  movapd %xmm15,%xmm3
  mulsd  %xmm15,%xmm3
  movsd  %xmm3,-0x70(%rsp)
  movsd  -0x38(%rsp),%xmm4
  movapd %xmm4,%xmm3
  mulsd  %xmm4,%xmm3
  movsd  %xmm3,-0x60(%rsp)
  add    %rdi,%r9
  add    %rax,%r12
  mov    %ecx,%eax
  lea    0x0(,%rax,8),%r13
  mov    $0x8,%eax
  movsd  D165(%rip),%xmm4
  movq   D91(%rip),%xmm7
  movsd  D5(%rip),%xmm14
  mov    %rbp,%r15
  movsd  %xmm15,-0x78(%rsp)
L1:
  mov    (%r15),%rdx
  movsd  (%rdx,%rax,1),%xmm6
  mov    %rax,%rcx
  add    $0x8,%rax
  addsd  (%rdx,%rax,1),%xmm6
  mulsd  %xmm4,%xmm6
  mov    (%rbx),%rdx
  movsd  (%rdx,%rcx,1),%xmm2
  mov    (%r8),%rsi
  movsd  (%rsi,%rcx,1),%xmm9
  movsd  (%rdx,%rax,1),%xmm10
  movapd %xmm2,%xmm3
  addsd  %xmm10,%xmm3
  mulsd  %xmm4,%xmm3
  mov    (%r10),%rsi
  movsd  (%rsi,%rcx,1),%xmm13
  movsd  -0x8(%rdx,%rcx,1),%xmm11
  movapd %xmm2,%xmm5
  addsd  %xmm11,%xmm5
  mulsd  %xmm4,%xmm5
  movapd %xmm2,%xmm1
  addsd  %xmm2,%xmm1
  mov    (%r9),%rdx
  movsd  (%rdx,%rcx,1),%xmm0
  addsd  (%rdx,%rax,1),%xmm0
  movapd %xmm0,%xmm8
  mov    (%r12),%r14
  movapd %xmm13,%xmm0
  subsd  %xmm1,%xmm0
  addsd  %xmm9,%xmm0
  divsd  -0x70(%rsp),%xmm0
  movapd %xmm11,%xmm12
  subsd  %xmm1,%xmm12
  movapd %xmm12,%xmm1
  addsd  %xmm10,%xmm1
  divsd  -0x60(%rsp),%xmm1
  addsd  %xmm1,%xmm0
  divsd  -0x68(%rsp),%xmm0
  movapd %xmm0,%xmm12
  movapd %xmm6,%xmm1
  andpd  %xmm7,%xmm1
  movapd %xmm2,%xmm0
  subsd  %xmm9,%xmm0
  mulsd  %xmm1,%xmm0
  mulsd  %xmm4,%xmm0
  movapd %xmm8,%xmm1
  andpd  %xmm7,%xmm1
  movapd %xmm13,%xmm15
  subsd  %xmm2,%xmm15
  mulsd  %xmm15,%xmm1
  mulsd  %xmm14,%xmm1
  subsd  %xmm1,%xmm0
  movsd  -0x30(%rsp),%xmm15
  mulsd  %xmm15,%xmm0
  divsd  -0x78(%rsp),%xmm0
  addsd  %xmm2,%xmm9
  movapd %xmm9,%xmm1
  mulsd  %xmm4,%xmm1
  mulsd  %xmm6,%xmm1
  addsd  %xmm2,%xmm13
  mulsd  %xmm4,%xmm13
  mulsd  %xmm4,%xmm8
  movapd %xmm8,%xmm6
  mulsd  %xmm13,%xmm6
  subsd  %xmm6,%xmm1
  divsd  -0x78(%rsp),%xmm1
  addsd  %xmm0,%xmm1
  movapd %xmm12,%xmm0
  subsd  %xmm1,%xmm0
  movapd %xmm3,%xmm1
  andpd  %xmm7,%xmm1
  movapd %xmm2,%xmm6
  subsd  %xmm10,%xmm6
  mulsd  %xmm6,%xmm1
  mulsd  %xmm4,%xmm1
  movapd %xmm1,%xmm10
  movapd %xmm5,%xmm6
  andpd  %xmm7,%xmm6
  movapd %xmm11,%xmm1
  subsd  %xmm2,%xmm1
  mulsd  %xmm1,%xmm6
  mulsd  %xmm4,%xmm6
  movapd %xmm10,%xmm1
  subsd  %xmm6,%xmm1
  mulsd  %xmm15,%xmm1
  movsd  -0x38(%rsp),%xmm6
  divsd  %xmm6,%xmm1
  mulsd  %xmm3,%xmm3
  mulsd  %xmm5,%xmm5
  subsd  %xmm5,%xmm3
  divsd  %xmm6,%xmm3
  addsd  %xmm3,%xmm1
  subsd  %xmm1,%xmm0
  addsd  -0x18(%rsp),%xmm0
  mulsd  -0x28(%rsp),%xmm0
  addsd  %xmm2,%xmm0
  movsd  %xmm0,(%r14,%rcx,1)
  cmp    %rax,%r13
  jne    L1
L32:
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

tool_calls: name: disassemble_data
arguments: label: D165
type_guessed: byte[8]
name: disassemble_data
arguments: label: D91
type_guessed: qword[2]
name: disassemble_data
arguments: label: D5
type_guessed: byte[8]

tool: {"D165": [0x00,0x00,0x00,0x00,0x00,0x00,0xe0,0x3f]}

tool: {"D91": [0x7fffffffffffffff,0x0000000000000000]}

tool: {"D5": [0x00,0x00,0x00,0x00,0x00,0x00,0xd0,0x3f]}

assistant: ```c
void calculate_fg(double Re, double GX, double GY, double alpha, double dt, double dx, double dy, int imax, int jmax, double **U, double **V, double **F, double **G) {
  int i;
  int j;
  double u_frd_sum_i;
  double u_bkd_sum_i;
  double v_frd_sum_i;
  double v_bkd_sum_i;
  double u_frd_sum_j;
  double u_bkd_sum_j;
  double v_frd_sum_j;
  double v_bkd_sum_j;
  double d2ux;
  double d2uy;
  double du2x;
  double duvy;
  double d2vx;
  double d2vy;
  double duvx;
  double dv2y;
  for (j = 1; j < jmax + 1; j++) {
    F[0][j] = U[0][j];
    F[imax][j] = U[imax][j];
  }
  for (i = 1; i < imax + 1; i++) {
    G[i][0] = V[i][0];
    G[i][jmax] = V[i][jmax];
  }
  for (i = 1; i < imax; i++) {
    for (j = 1; j < jmax; j++) {
      u_frd_sum_i = (U[i][j] + U[i + 1][j]) / 2;
      u_frd_sum_j = (U[i][j] + U[i][j + 1]) / 2;
      u_bkd_sum_i = (U[i][j] + U[i - 1][j]) / 2;
      u_bkd_sum_j = (U[i][j] + U[i][j - 1]) / 2;
      v_frd_sum_i = (V[i][j] + V[i + 1][j]) / 2;
      v_frd_sum_j = (V[i][j] + V[i][j + 1]) / 2;
      v_bkd_sum_i = (V[i][j] + V[i - 1][j]) / 2;
      v_bkd_sum_j = (V[i][j] + V[i][j - 1]) / 2;
      d2ux = (U[i - 1][j] - 2 * U[i][j] + U[i + 1][j]) / (dx * dx);
      d2uy = (U[i][j - 1] - 2 * U[i][j] + U[i][j + 1]) / (dy * dy);
      du2x = (u_frd_sum_i * u_frd_sum_i - u_bkd_sum_i * u_bkd_sum_i) / dx + alpha * (fabs(u_frd_sum_i) * (U[i][j] - U[i + 1][j]) / 2 - fabs(u_bkd_sum_i) * (U[i - 1][j] - U[i][j]) / 2) / dx;
      duvy = (v_frd_sum_i * u_frd_sum_j - (V[i][j - 1] + V[i + 1][j - 1]) / 2 * u_bkd_sum_j) / dy + alpha * (fabs(v_frd_sum_i) * (U[i][j] - U[i][j - 1]) / 2 - fabs(V[i][j - 1] + V[i + 1][j - 1]) * (U[i][j - 1] - U[i][j]) / 4) / dy;
      d2vx = (V[i - 1][j] - 2 * V[i][j] + V[i + 1][j]) / (dx * dx);
      d2vy = (V[i][j - 1] - 2 * V[i][j] + V[i][j + 1]) / (dy * dy);
      dv2y = (v_frd_sum_j * v_frd_sum_j - v_bkd_sum_j * v_bkd_sum_j) / dy + alpha * (fabs(v_frd_sum_j) * (V[i][j] - V[i][j + 1]) / 2 - fabs(v_bkd_sum_j) * (V[i][j - 1] - V[i][j]) / 2) / dy;
      duvx = (u_frd_sum_j * v_frd_sum_i - (U[i - 1][j] + U[i - 1][j + 1]) / 2 * v_bkd_sum_i) / dx + alpha * (fabs(u_frd_sum_j) * (V[i][j] - V[i + 1][j]) / 2 - fabs(U[i - 1][j] + U[i - 1][j + 1]) * (V[i - 1][j] - V[i][j]) / 4) / dx;
      F[i][j] = U[i][j] + dt * ((d2ux + d2uy) / Re - du2x - duvy + GX);
      G[i][j] = V[i][j] + dt * ((d2vx + d2vy) / Re - duvx - dv2y + GY);
    }
    j = jmax;
    u_frd_sum_i = (U[i][j] + U[i + 1][j]) / 2;
    u_frd_sum_j = (U[i][j] + U[i][j + 1]) / 2;
    u_bkd_sum_i = (U[i][j] + U[i - 1][j]) / 2;
    u_bkd_sum_j = (U[i][j] + U[i][j - 1]) / 2;
    v_frd_sum_i = (V[i][j] + V[i + 1][j]) / 2;
    d2ux = (U[i - 1][j] - 2 * U[i][j] + U[i + 1][j]) / (dx * dx);
    d2uy = (U[i][j - 1] - 2 * U[i][j] + U[i][j + 1]) / (dy * dy);
    du2x = (u_frd_sum_i * u_frd_sum_i - u_bkd_sum_i * u_bkd_sum_i) / dx + alpha * (fabs(u_frd_sum_i) * (U[i][j] - U[i + 1][j]) / 2 - fabs(u_bkd_sum_i) * (U[i - 1][j] - U[i][j]) / 2) / dx;
    duvy = (v_frd_sum_i * u_frd_sum_j - (V[i][j - 1] + V[i + 1][j - 1]) / 2 * u_bkd_sum_j) / dy + alpha * (fabs(v_frd_sum_i) * (U[i][j] - U[i][j - 1]) / 2 - fabs(V[i][j - 1] + V[i + 1][j - 1]) * (U[i][j - 1] - U[i][j]) / 4) / dy;
    F[i][j] = U[i][j] + dt * ((d2ux + d2uy) / Re - du2x - duvy + GX);
  }
  i = imax;
  for (j = 1; j < jmax; j++) {
    u_frd_sum_j = (U[i][j] + U[i][j + 1]) / 2;
    v_frd_sum_i = (V[i][j] + V[i + 1][j]) / 2;
    v_frd_sum_j = (V[i][j] + V[i][j + 1]) / 2;
    v_bkd_sum_i = (V[i][j] + V[i - 1][j]) / 2;
    v_bkd_sum_j = (V[i][j] + V[i][j - 1]) / 2;
    d2vx = (V[i - 1][j] - 2 * V[i][j] + V[i + 1][j]) / (dx * dx);
    d2vy = (V[i][j - 1] - 2 * V[i][j] + V[i][j + 1]) / (dy * dy);
    dv2y = (v_frd_sum_j * v_frd_sum_j - v_bkd_sum_j * v_bkd_sum_j) / dy + alpha * (fabs(v_frd_sum_j) * (V[i][j] - V[i][j + 1]) / 2 - fabs(v_bkd_sum_j) * (V[i][j - 1] - V[i][j]) / 2) / dy;
    duvx = (u_frd_sum_j * v_frd_sum_i - (U[i - 1][j] + U[i - 1][j + 1]) / 2 * v_bkd_sum_i) / dx + alpha * (fabs(u_frd_sum_j) * (V[i][j] - V[i + 1][j]) / 2 - fabs(U[i - 1][j] + U[i - 1][j + 1]) * (V[i - 1][j] - V[i][j]) / 4) / dx;
    G[i][j] = V[i][j] + dt * ((d2vx + d2vy) / Re - duvx - dv2y + GY);
  }
}
```