AArch64 wrong register access read/write flags on "cmp" instruction

[cyanpencil]

First of all, thank you for your work, this is an amazing library.
Unfortunately, I found a bug when I used the code from the doc page to test register read/write flags here: https://www.capstone-engine.org/op_access.html

The code outputs:

cmp     x1, x2
Registers read: x2
Registers modified: nzcv x1

which is wrong, as x1 is read, not modified.

I'll paste here the exact code I used for easier reproduction:

#include <stdio.h>

#include "include/capstone/capstone.h"

#define CODE "\x3F\x00\x02\xEB" // cmp x1, x2

int main(void)
{
  csh handle;
  cs_insn *insn;
  size_t count, j;
  cs_regs regs_read, regs_write;
  uint8_t read_count, write_count, i;
  
  if (cs_open(CS_ARCH_ARM64, CS_MODE_ARM, &handle) != CS_ERR_OK)
    return -1;
  
  cs_option(handle, CS_OPT_DETAIL, CS_OPT_ON);
  
  count = cs_disasm(handle, CODE, sizeof(CODE)-1, 0x1000, 0, &insn);
  if (count > 0) {
    for (j = 0; j < count; j++) {
      // Print assembly
      printf("%s\t%s\n", insn[j].mnemonic, insn[j].op_str);

      // Print all registers accessed by this instruction.
      if (cs_regs_access(handle, &insn[j],
            regs_read, &read_count,
            regs_write, &write_count) == 0) {
        if (read_count > 0) {
          printf("\n\tRegisters read:");
          for (i = 0; i < read_count; i++) {
            printf(" %s", cs_reg_name(handle, regs_read[i]));
          }
          printf("\n");
        }

        if (write_count > 0) {
          printf("\n\tRegisters modified:");
          for (i = 0; i < write_count; i++) {
            printf(" %s", cs_reg_name(handle, regs_write[i]));
          }
          printf("\n");
        }
      }
    }

    cs_free(insn, count);
  } else
    printf("ERROR: Failed to disassemble given code!\n");

  cs_close(&handle);

  return 0;
}

Thank you!

[kabeor]

Merged in #1655