user: 请从给定的汇编指令推导出C源代码:

```asm
<main>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x618,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x608(%rsp)
  xor    %eax,%eax
  lea    0x10(%rsp),%rbp
  mov    $0x0,%r12d
  jmp    L51
L188:
  movb   $0x0,(%rcx)
  mov    %r10d,%r8d
L258:
  mov    %r9d,%eax
  sub    %edx,%eax
  sub    $0x1,%rdx
  add    $0x1,%rcx
  test   %dx,%dx
  js     L264
L192:
  movsbl (%rdx,%rbp,1),%eax
  sub    $0x30,%eax
  imul   %esi,%eax
  add    %r8d,%eax
  cmp    $0xa,%ax
  je     L188
  movswl %ax,%r8d
  imul   $0x6667,%r8d,%r8d
  sar    $0x12,%r8d
  mov    %eax,%edi
  sar    $0xf,%di
  sub    %edi,%r8d
  lea    (%r8,%r8,4),%edi
  add    %edi,%edi
  sub    %edi,%eax
  mov    %al,(%rcx)
  jmp    L258
L264:
  cmpw   $0xffff,0xe(%rsp)
  mov    %r10d,%edi
  cmovge %r13d,%edi
  test   %r8w,%r8w
  je     L232
  movswq %di,%rdi
  mov    %r8b,0x210(%rsp,%rdi,1)
  lea    0x2(%rax),%edi
L232:
  mov    %r14d,%ebx
  sub    %r11d,%ebx
  movswl %bx,%r8d
  movswl %di,%edi
  add    %r8d,%edi
  cmp    %edi,%r8d
  jge    L59
  mov    %r8d,%ecx
  mov    %r12d,%esi
  jmp    L160
L243:
  movslq %ecx,%rcx
  mov    %al,0x410(%rsp,%rcx,1)
  mov    %ebx,%edx
  add    $0x1,%ebx
  movswl %bx,%ecx
  cmp    %edi,%ecx
  jge    L185
L160:
  mov    %ecx,%eax
  sub    %r8d,%eax
  cltq
  movsbw 0x210(%rsp,%rax,1),%ax
  movslq %ecx,%rdx
  movsbw 0x410(%rsp,%rdx,1),%dx
  add    %eax,%edx
  lea    (%rdx,%rsi,1),%eax
  mov    %r12d,%esi
  cmp    $0x9,%ax
  jle    L243
  sub    $0xa,%eax
  mov    %r10d,%esi
  jmp    L243
L185:
  test   %si,%si
  je     L59
  lea    0x2(%rdx),%ebx
  movslq %ecx,%rcx
  movb   $0x1,0x410(%rsp,%rcx,1)
L59:
  sub    $0x1,%r11
  test   %r11w,%r11w
  js     L276
L179:
  test   %r9w,%r9w
  js     L29
  movsbl (%r11,%r15,1),%esi
  sub    $0x30,%esi
  movswq %r9w,%rdx
  lea    0x210(%rsp),%rcx
  mov    %r12d,%r8d
  jmp    L192
L276:
  mov    %ebx,%r13d
  sub    $0x1,%r13w
  js     L12
  movswq %r13w,%r13
  mov    %r12d,%edx
  mov    $0x1,%r14d
  jmp    L130
L93:
  add    $0x30,%edi
  movsbl %dil,%edi
  call   <putchar@plt>
  mov    %r14d,%edx
L210:
  sub    $0x1,%r13
  test   %r13w,%r13w
  js     L30
L130:
  movzbl 0x410(%rsp,%r13,1),%edi
  test   %dil,%dil
  jne    L93
  test   %dx,%dx
  je     L210
  jmp    L93
L30:
  test   %dx,%dx
  je     L12
L184:
  mov    $0xa,%edi
  call   <putchar@plt>
L51:
  mov    %rbp,%rdi
  call   <gets@plt>
  test   %rax,%rax
  je     L104
  lea    0x110(%rsp),%r14
  mov    %r14,%rdi
  call   <gets@plt>
  mov    %rbp,%rdi
  call   <strlen@plt>
  mov    %eax,%r13d
  mov    %r14,%rdi
  call   <strlen@plt>
  mov    %eax,%r14d
  movswl %r13w,%esi
  cwtl
  add    %eax,%esi
  test   %esi,%esi
  jle    L135
  mov    $0x0,%ecx
  mov    $0x0,%edx
L25:
  movslq %edx,%rdx
  movb   $0x0,0x210(%rsp,%rdx,1)
  movb   $0x0,0x410(%rsp,%rdx,1)
  add    $0x1,%ecx
  movswl %cx,%edx
  cmp    %esi,%edx
  jl     L25
L135:
  sub    $0x1,%r14w
  js     L276
  movswq %r14w,%r11
  lea    -0x1(%r13),%r9d
  lea    0x110(%rsp),%r15
  mov    $0x1,%r10d
  lea    -0x2(%r13),%eax
  mov    %ax,0xe(%rsp)
  jmp    L179
L12:
  mov    $0x30,%edi
  call   <putchar@plt>
  jmp    L184
L29:
  mov    %r14d,%ebx
  sub    %r11d,%ebx
  jmp    L59
L104:
  mov    0x608(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L111
  add    $0x618,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L111:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void main() {
  char a[251], b[251], m[502], ra[502];
  short la, lb, i, j, max, ml, ad, carry, lt, dif;
  while (gets(a)) {
    gets(b);
    la = strlen(a);
    lb = strlen(b);
    for (i = 0; i < la + lb; i++) {
      m[i] = 0;
      ra[i] = 0;
    }
    lt = 0;
    for (i = lb - 1; i >= 0; i--) {
      carry = 0;
      lt = 0;
      for (j = la - 1; j >= 0; j--) {
        ml = (b[i] - '0') * (a[j] - '0') + carry;
        if (ml == 10) {
          m[lt] = 0;
          carry = 1;
        } else {
          m[lt] = ml % 10;
          carry = ml / 10;
        }
        lt++;
      }
      if (carry) {
        m[lt++] = carry;
        carry = 0;
      }
      dif = lb - i - 1;
      for (j = dif; j < lt + dif; j++) {
        ad = ra[j] + m[j - dif] + carry;
        if (ad > 9) {
          ra[j] = ad - 10;
          carry = 1;
        } else {
          ra[j] = ad;
          carry = 0;
        }
      }
      if (carry)
        ra[j++] = carry;
    }
    lt = 0;
    for (i = j - 1; i >= 0; i--) {
      if (ra[i] != 0)
        lt = 1;
      if (lt)
        putchar(ra[i] + '0');
    }
    if (!lt)
      putchar('0');
    putchar('\n');
  }
}
```