add dedicated variables such as prefix2e, prefix36, prefix66, prefix6…

[bughoho]

The ideas come from here:
#498

[aquynh]

with this we use less memory, but we have to sacrifice on performance.
can you run your benchmark and report the result with this change?

[bughoho]

ok,i use below test data:
00401000 > F3:A6 repe cmps byte ptr es:[edi],byte ptr ds:[esi]
00401002 F2:A6 repne cmps byte ptr es:[edi],byte ptr ds:[esi]
00401004 F0:0108 lock add dword ptr ds:[eax],ecx
00401007 2E:8B03 mov eax,dword ptr cs:[ebx]

#define X86_CODE32 "\xF3\xA6\xF2\xA6\xF0\x01\x08\x2E\x8B\x03"

and test case:

    err = cs_open(CS_ARCH_X86, CS_MODE_32, &handle);
    if (err) {
        printf("Failed on cs_open() with error returned: %u\n", err);
        return;
    }
    cs_option(handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_INTEL);
    cs_option(handle, CS_OPT_DETAIL, CS_OPT_ON);

    struct timespec time1, time2,time3;
    int temp;
    clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time1);
    int maxcount = 10000000;
    insn = cs_malloc(handle);
    for (i = 0; i < maxcount;) {
        code = (const uint8_t *)X86_CODE32;
        address = 0x1000;
        size = sizeof(X86_CODE32) - 1;
        while(cs_disasm_iter(handle, &code, &size, &address, insn)) {
            i++;
        }
    }
    cs_free(insn, 1);
    cs_close(&handle);
    clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time2);
    time3 = diff(time1,time2);
    printf("%ld.%ld\n",time3.tv_sec,time3.tv_nsec);

original version:
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
4.705734553
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.238786581
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.676539723
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.485251177
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.426390369
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.477414186

modified version:
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
4.503856648
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.870772781
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.755013231
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.506411565
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.514006102
bug@ubuntu:/capstone/suite/benchmark$ ./test_iter_benchmark
5.579528964

I don't think so.
The prefix instruction is very rare in real environment,
in fact,In this case,even though the instructions that I decode are the prefix instruction,the result is almost the same

[aquynh]

as spotted by @radare, above comment should be about true/false, but not 1/0

[aquynh]

merged, thanks!