user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<packforblock20>:
  endbr64
  push   %r15
  mov    %rdi,%rcx
  push   %r14
  mov    %rdx,%r14
  push   %r13
  mov    %rsi,%r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    (%rsi),%rax
  mov    (%rdx),%rdx
  mov    0x18(%rax),%esi
  mov    0x20(%rax),%r12d
  mov    0x38(%rax),%ebp
  mov    (%rax),%ebx
  sub    %edi,%esi
  sub    %edi,%r12d
  mov    0x70(%rax),%r11d
  mov    0x88(%rax),%r10d
  sar    $0x4,%esi
  shl    $0x10,%r12d
  sub    %edi,%ebp
  sub    %edi,%ebx
  or     %esi,%r12d
  mov    0x30(%rax),%esi
  shl    $0xc,%ebp
  mov    %ebx,-0x4(%rsp)
  mov    0x58(%rax),%ebx
  sub    %ecx,%r11d
  sub    %ecx,%r10d
  mov    0xa0(%rax),%r9d
  sub    %edi,%esi
  mov    0x48(%rax),%edi
  shl    $0x18,%r11d
  mov    0xb8(%rax),%r8d
  sar    $0x8,%esi
  sub    %ecx,%ebx
  shl    $0x14,%r10d
  mov    0xe8(%rax),%r15d
  or     %esi,%ebp
  mov    0x50(%rax),%esi
  sub    %ecx,%edi
  shl    $0x1c,%ebx
  sar    $0xc,%edi
  sub    %ecx,%esi
  shl    $0x8,%esi
  or     %edi,%esi
  mov    0x60(%rax),%edi
  or     %esi,%ebx
  mov    0x68(%rax),%esi
  sub    %ecx,%edi
  sub    %ecx,%esi
  sar    $0x10,%edi
  shl    $0x4,%esi
  or     %edi,%esi
  mov    0xc8(%rax),%edi
  or     %esi,%r11d
  mov    0x80(%rax),%esi
  sub    %ecx,%esi
  or     %esi,%r10d
  mov    0x98(%rax),%esi
  sub    %ecx,%esi
  sar    $0x4,%esi
  sub    %ecx,%r9d
  sub    %ecx,%r8d
  sub    %ecx,%edi
  shl    $0x10,%r9d
  sar    $0xc,%edi
  sub    %ecx,%r15d
  add    $0x100,%rax
  or     %esi,%r9d
  mov    -0x50(%rax),%esi
  shl    $0xc,%r8d
  add    $0x140,%rdx
  shl    $0x4,%r15d
  sub    %ecx,%esi
  sar    $0x8,%esi
  or     %esi,%r8d
  mov    -0x30(%rax),%esi
  sub    %ecx,%esi
  shl    $0x8,%esi
  or     %edi,%esi
  mov    -0x28(%rax),%edi
  sub    %ecx,%edi
  shl    $0x1c,%edi
  or     %esi,%edi
  mov    -0x20(%rax),%esi
  sub    %ecx,%esi
  sar    $0x10,%esi
  or     %esi,%r15d
  mov    -0x10(%rax),%esi
  sub    %ecx,%esi
  shl    $0x18,%esi
  or     %r15d,%esi
  mov    -0xf8(%rax),%r15d
  mov    %ebp,-0x138(%rdx)
  mov    %r12d,-0x13c(%rdx)
  sub    %ecx,%r15d
  mov    %ebx,-0x134(%rdx)
  shl    $0x14,%r15d
  or     -0x4(%rsp),%r15d
  mov    %r11d,-0x130(%rdx)
  mov    %r15d,-0x140(%rdx)
  mov    %r10d,-0x12c(%rdx)
  mov    %r9d,-0x128(%rdx)
  mov    %r8d,-0x124(%rdx)
  mov    %edi,-0x120(%rdx)
  mov    %esi,-0x11c(%rdx)
  pop    %rbx
  mov    %rax,0x0(%r13)
  pop    %rbp
  mov    %rdx,(%r14)
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void packforblock20(const uint32_t base, const uint32_t **pin, uint8_t **pw) {
  uint64_t *pw64 = *(uint64_t **)pw;
  const uint32_t *in = *pin;
  uint64_t w0;
  uint64_t w1;
  uint64_t w2;
  uint64_t w3;
  uint64_t w4;
  uint64_t w5;
  uint64_t w6;
  uint64_t w7;
  uint64_t w8;
  uint64_t w9;
  w0 = (uint64_t)(in[0] - base);
  w0 |= (uint64_t)(in[1] - base) << 20;
  w0 |= (uint64_t)(in[2] - base) << 40;
  w0 |= (uint64_t)(in[3] - base) << 60;
  w1 = (uint64_t)(in[3] - base) >> 4;
  w1 |= (uint64_t)(in[4] - base) << 16;
  w1 |= (uint64_t)(in[5] - base) << 36;
  w1 |= (uint64_t)(in[6] - base) << 56;
  w2 = (uint64_t)(in[6] - base) >> 8;
  w2 |= (uint64_t)(in[7] - base) << 12;
  w2 |= (uint64_t)(in[8] - base) << 32;
  w2 |= (uint64_t)(in[9] - base) << 52;
  w3 = (uint64_t)(in[9] - base) >> 12;
  w3 |= (uint64_t)(in[10] - base) << 8;
  w3 |= (uint64_t)(in[11] - base) << 28;
  w3 |= (uint64_t)(in[12] - base) << 48;
  w4 = (uint64_t)(in[12] - base) >> 16;
  w4 |= (uint64_t)(in[13] - base) << 4;
  w4 |= (uint64_t)(in[14] - base) << 24;
  w4 |= (uint64_t)(in[15] - base) << 44;
  w5 = (uint64_t)(in[16] - base);
  w5 |= (uint64_t)(in[17] - base) << 20;
  w5 |= (uint64_t)(in[18] - base) << 40;
  w5 |= (uint64_t)(in[19] - base) << 60;
  w6 = (uint64_t)(in[19] - base) >> 4;
  w6 |= (uint64_t)(in[20] - base) << 16;
  w6 |= (uint64_t)(in[21] - base) << 36;
  w6 |= (uint64_t)(in[22] - base) << 56;
  w7 = (uint64_t)(in[22] - base) >> 8;
  w7 |= (uint64_t)(in[23] - base) << 12;
  w7 |= (uint64_t)(in[24] - base) << 32;
  w7 |= (uint64_t)(in[25] - base) << 52;
  w8 = (uint64_t)(in[25] - base) >> 12;
  w8 |= (uint64_t)(in[26] - base) << 8;
  w8 |= (uint64_t)(in[27] - base) << 28;
  w8 |= (uint64_t)(in[28] - base) << 48;
  w9 = (uint64_t)(in[28] - base) >> 16;
  w9 |= (uint64_t)(in[29] - base) << 4;
  w9 |= (uint64_t)(in[30] - base) << 24;
  w9 |= (uint64_t)(in[31] - base) << 44;
  pw64[0] = w0;
  pw64[1] = w1;
  pw64[2] = w2;
  pw64[3] = w3;
  pw64[4] = w4;
  pw64[5] = w5;
  pw64[6] = w6;
  pw64[7] = w7;
  pw64[8] = w8;
  pw64[9] = w9;
  *pin += 32;
  *pw += 80;
}
```