Lowyat.NET: Latest topics by FlierMate4

The Making of My x86 Disassembler - Part 1

FlierMate4 — Mon, 13 Mar 2023 14:31:32 +0800

In 2020, I expressed my intention to do compiler, disassembler and QR code generator in Compiler and Disassembler, does anyone want to join? thread started by my previous user account.

Despite the criticism, e.g.

QUOTE

Indeed, without analyzing the code flow, a disassembler, even one that decodes every byte sequence correctly, will produce a result that leaves something to be desired.

...I still plan to go ahead with a x86 disassembler.

While I am still studying the decoding of CPU opcodes, I have finished the program to read EXE file and dump it code section.

In part 1 (I hope there will part 2 in coming weeks or months), I will share how to find the code section in EXE file.

In the mean time, you can find my code repo "exedump" on GitHub:

You may also refer to PE Format

1. Open file, read the beginning of file
2. If 'MZ', go to next step, if not quit
3. Set file position to 0x3C, read the DWORD offset value (start of PE)
4. Set file position to value read in previous step
5. If 'PE,0,0", go to next step, if not quit
6. Read adjacent WORD for machine type (optional)
7. Read next adjacent WORD for number of section
8. Set file position to 0x18 relative to 'start of PE'
9. Read magic number WORD value (for 32-bit or 64-bit PE)
10. Set file position to 0x2C relative to 'start of PE'
11. Read BaseOfCode DWORD value
12. If magic number (read in step 9) is 0x10B,
set file position to 0xF8 relative to 'start of PE', or else
set file position to 0x108 relative to 'start of PE'
13. Read section table (each table is 40 bytes long)
Its VirtualAddress, SizeOfRawData, PointerToRawData DWORD values
14. If VirtualAddress is equal to BaseOfCode (read in step 11) then go to print hexdump
If not match, then loop until 'number of section' (read in step 7)

You may ask why don't just use AddressOfEntryPoint? Well, because it is relative virtual address, not file offset on disk.
To set file position on disk, have to read section table (or section headers), I mean "code section", for its PointerToRawData.
But how we do know it is code section? I use a trick here, by comparing VirtualAddress found in each section table with BaseOfCode found in header.
For example: (Virtual address)

CODE

'.data' section: 0x1000
'.text' section: 0x2000
'.idata' section : 0x3000

The virtual address is unique for each section, so if my BaseOfCode is 0x2000, then I know the '.text' section is code section.

Until part 2!

Console App Development Service

FlierMate4 — Wed, 08 Mar 2023 21:37:28 +0800

I can write console app for you, specializing in file utility and system utility, for as low as RM 50 per program.

What I don't do:
- No database
- No multimedia, no graphics
- No networking

What I do:
- File read/write, directory read/write
- System info enumeration
- Basic cryptography

For example, I did a hexdump file utility as personal project, but no color highlighting. If you want, I can customize it for you to highlight certain hex values with certain colors.

I target Windows console and Linux terminal.

RM 50 is what I collect, to prevent misuse of my service.

Portfolio: https://github.com/fliermate

Or you can search "FilerMate", "FlierMate1" topics in Codemaster section. and Linux & Open Source Software section. I attach source code (and sometimes binary executable) for free download.

A clean and stylist webpage template for download

FlierMate4 — Tue, 07 Mar 2023 07:01:59 +0800

I designed it myself about two years ago. As seen in the screenshot below, it supports
*title styling
*subheadings styling
* button styling (with hover effect)

Click to download demo.txt, then after download, please change its extension to "html", e.g. "demo.html".
[attachmentid=11434514]

LICENSE: Public Domain (Unlicensed, you can freely use it and modify it without credits)

Definition: Mental disorder

FlierMate4 — Mon, 06 Mar 2023 17:56:51 +0800

What is mental health?

Good mental health is a state of well-being where you feel good and can function well. You can cope with normal stresses, work productively, and feel satisfied with life.

A mental disorder . . .

IS NOT the result of personal weakness.

IS a medical condition that causes significant distress and disrupts a person’s thinking, emotional control, and behavior.

Can often upset a person’s ability to relate to others and to handle the daily demands of life.

Can affect people of any age, culture, race, tribe, religion, educational background, or income level.

How difficult it is to create a game like this?

FlierMate4 — Sun, 05 Mar 2023 15:41:43 +0800

A alien space ship shooting game, someone did it using BASIC language, no game engine.

How easy or how difficult it is to create a game like this? Anyone attempted it before? Please share.

Convert to lower case and upper case manually

FlierMate4 — Sun, 05 Mar 2023 14:31:12 +0800

This is in C# , but also applicable in other languages:

QUOTE

AND,0xDF as to upper and OR,0x20 as lower, or XOR,0x20 for toggling.

CODE

static string UCase(string input)
{
string output=null;
for (int i = 0; i<input.Length; i++)
{
output += (char)(input[i] & 0xDF);
}
return output;
}

static string LCase(string input)
{
string output = null;
for (int i = 0; i < input.Length; i++)
{
output += (char)(input[i] | 0x20);
}
return output;
}

static string ToggleCase(string input)
{
string output=null;
for (int i = 0; i < input.Length; i++)
{
output += (char)(input[i] ^ 0x20);
}
return output;
}

static void Main(string[] args)
{
Console.WriteLine(UCase("Hello World"));
Console.WriteLine(LCase("Hello World"));
Console.WriteLine(ToggleCase("Hello World"));
Console.ReadKey();
}

Can you explain how it works?

Anyone heard of SoftCom by MoE about 25 years ago?

FlierMate4 — Sun, 19 Feb 2023 21:22:42 +0800

I can't find any info about SoftCom (software writing competition) organized by Ministry of Education in Malaysia about 25 years ago, completely disappeared.

Can someone help by giving link to news or article? I searched Wikipedia also can't find.

An idea of hobby project for the weekend

FlierMate4 — Fri, 10 Feb 2023 16:05:54 +0800

Anyone interested in a hobby project for the weekend?

A simple Unicode code point converter.

Available font style to choose from:

» Click to show Spoiler - click again to hide... «

CODE

ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
𝐀𝐁𝐂𝐃𝐄𝐅𝐆𝐇𝐈𝐉𝐊𝐋𝐌𝐍𝐎𝐏𝐐𝐑𝐒𝐓𝐔𝐕𝐖𝐗𝐘𝐙
𝐚𝐛𝐜𝐝𝐞𝐟𝐠𝐡𝐢𝐣𝐤𝐥𝐦𝐧𝐨𝐩𝐪𝐫𝐬𝐭𝐮𝐯𝐰𝐱𝐲𝐳
𝐴𝐵𝐶𝐷𝐸𝐹𝐺𝐻𝐼𝐽𝐾𝐿𝑀𝑁𝑂𝑃𝑄𝑅𝑆𝑇𝑈𝑉𝑊𝑋𝑌𝑍
𝑎𝑏𝑐𝑑𝑒𝑓𝑔𝑕𝑖𝑗𝑘𝑙𝑚𝑛𝑜𝑝𝑞𝑟𝑠𝑡𝑢𝑣𝑤𝑥𝑦𝑧
𝑨𝑩𝑪𝑫𝑬𝑭𝑮𝑯𝑰𝑱𝑲𝑳𝑴𝑵𝑶𝑷𝑸𝑹𝑺𝑻𝑼𝑽𝑾𝑿𝒀𝒁
𝒂𝒃𝒄𝒅𝒆𝒇𝒈𝒉𝒊𝒋𝒌𝒍𝒎𝒏𝒐𝒑𝒒𝒓𝒔𝒕𝒖𝒗𝒘𝒙𝒚𝒛
𝒜𝒝𝒞𝒟𝒠𝒡𝒢𝒣𝒤𝒥𝒦𝒧𝒨𝒩𝒪𝒫𝒬𝒭𝒮𝒯𝒰𝒱𝒲𝒳𝒴𝒵
𝒶𝒷𝒸𝒹𝒺𝒻𝒼𝒽𝒾𝒿𝓀𝓁𝓂𝓃𝓄𝓅𝓆𝓇𝓈𝓉𝓊𝓋𝓌𝓍𝓎𝓏
𝓐𝓑𝓒𝓓𝓔𝓕𝓖𝓗𝓘𝓙𝓚𝓛𝓜𝓝𝓞𝓟𝓠𝓡𝓢𝓣𝓤𝓥𝓦𝓧𝓨𝓩
𝓪𝓫𝓬𝓭𝓮𝓯𝓰𝓱𝓲𝓳𝓴𝓵𝓶𝓷𝓸𝓹𝓺𝓻𝓼𝓽𝓾𝓿𝔀𝔁𝔂𝔃
𝔄𝔅𝔆𝔇𝔈𝔉𝔊𝔋𝔌𝔍𝔎𝔏𝔐𝔑𝔒𝔓𝔔𝔕𝔖𝔗𝔘𝔙𝔚𝔛𝔜𝔝
𝔞𝔟𝔠𝔡𝔢𝔣𝔤𝔥𝔦𝔧𝔨𝔩𝔪𝔫𝔬𝔭𝔮𝔯𝔰𝔱𝔲𝔳𝔴𝔵𝔶𝔷
𝔸𝔹𝔺𝔻𝔼𝔽𝔾𝔿𝕀𝕁𝕂𝕃𝕄𝕅𝕆𝕇𝕈𝕉𝕊𝕋𝕌𝕍𝕎𝕏𝕐𝕑
𝕒𝕓𝕔𝕕𝕖𝕗𝕘𝕙𝕚𝕛𝕜𝕝𝕞𝕟𝕠𝕡𝕢𝕣𝕤𝕥𝕦𝕧𝕨𝕩𝕪𝕫
𝕬𝕭𝕮𝕯𝕰𝕱𝕲𝕳𝕴𝕵𝕶𝕷𝕸𝕹𝕺𝕻𝕼𝕽𝕾𝕿𝖀𝖁𝖂𝖃𝖄𝖅
𝖆𝖇𝖈𝖉𝖊𝖋𝖌𝖍𝖎𝖏𝖐𝖑𝖒𝖓𝖔𝖕𝖖𝖗𝖘𝖙𝖚𝖛𝖜𝖝𝖞𝖟
𝖠𝖡𝖢𝖣𝖤𝖥𝖦𝖧𝖨𝖩𝖪𝖫𝖬𝖭𝖮𝖯𝖰𝖱𝖲𝖳𝖴𝖵𝖶𝖷𝖸𝖹
𝖺𝖻𝖼𝖽𝖾𝖿𝗀𝗁𝗂𝗃𝗄𝗅𝗆𝗇𝗈𝗉𝗊𝗋𝗌𝗍𝗎𝗏𝗐𝗑𝗒𝗓
𝗔𝗕𝗖𝗗𝗘𝗙𝗚𝗛𝗜𝗝𝗞𝗟𝗠𝗡𝗢𝗣𝗤𝗥𝗦𝗧𝗨𝗩𝗪𝗫𝗬𝗭
𝗮𝗯𝗰𝗱𝗲𝗳𝗴𝗵𝗶𝗷𝗸𝗹𝗺𝗻𝗼𝗽𝗾𝗿𝘀𝘁𝘂𝘃𝘄𝘅𝘆𝘇
𝘈𝘉𝘊𝘋𝘌𝘍𝘎𝘏𝘐𝘑𝘒𝘓𝘔𝘕𝘖𝘗𝘘𝘙𝘚𝘛𝘜𝘝𝘞𝘟𝘠𝘡
𝘢𝘣𝘤𝘥𝘦𝘧𝘨𝘩𝘪𝘫𝘬𝘭𝘮𝘯𝘰𝘱𝘲𝘳𝘴𝘵𝘶𝘷𝘸𝘹𝘺𝘻
𝘼𝘽𝘾𝘿𝙀𝙁𝙂𝙃𝙄𝙅𝙆𝙇𝙈𝙉𝙊𝙋𝙌𝙍𝙎𝙏𝙐𝙑𝙒𝙓𝙔𝙕
𝙖𝙗𝙘𝙙𝙚𝙛𝙜𝙝𝙞𝙟𝙠𝙡𝙢𝙣𝙤𝙥𝙦𝙧𝙨𝙩𝙪𝙫𝙬𝙭𝙮𝙯
𝙰𝙱𝙲𝙳𝙴𝙵𝙶𝙷𝙸𝙹𝙺𝙻𝙼𝙽𝙾𝙿𝚀𝚁𝚂𝚃𝚄𝚅𝚆𝚇𝚈𝚉
𝚊𝚋𝚌𝚍𝚎𝚏𝚐𝚑𝚒𝚓𝚔𝚕𝚖𝚗𝚘𝚙𝚚𝚛𝚜𝚝𝚞𝚟𝚠𝚡𝚢𝚣
⒜⒝⒞⒟⒠⒡⒢⒣⒤⒥⒦⒧⒨⒩⒪⒫⒬⒭⒮⒯⒰⒱⒲⒳⒴⒵
ⒶⒷⒸⒹⒺⒻⒼⒽⒾⒿⓀⓁⓂⓃⓄⓅⓆⓇⓈⓉⓊⓋⓌⓍⓎⓏ
ⓐⓑⓒⓓⓔⓕⓖⓗⓘⓙⓚⓛⓜⓝⓞⓟⓠⓡⓢⓣⓤⓥⓦⓧⓨⓩ
ＡＢＣＤＥＦＧＨＩＪＫＬＭＮＯＰＱＲＳＴＵＶＷＸＹＺ
ａｂｃｄｅｆｇｈｉｊｋｌｍｎｏｐｑｒｓｔｕｖｗｘｙｚ
🄐🄑🄒🄓🄔🄕🄖🄗🄘🄙🄚🄛🄜🄝🄞🄟🄠🄡🄢🄣🄤🄥🄦🄧🄨🄩
🄰🄱🄲🄳🄴🄵🄶🄷🄸🄹🄺🄻🄼🄽🄾🄿🅀🅁🅂🅃🅄🅅🅆🅇🅈🅉
🅐🅑🅒🅓🅔🅕🅖🅗🅘🅙🅚🅛🅜🅝🅞🅟🅠🅡🅢🅣🅤🅥🅦🅧🅨🅩
🅰🅱🅲🅳🅴🅵🅶🅷🅸🅹🅺🅻🅼🅽🅾🅿🆀🆁🆂🆃🆄🆅🆆🆇🆈🆉

For example, user type the input and get the output:

QUOTE

This is something great!
Hopefully more is coming...

Output:

QUOTE

𝑻𝒉𝒊𝒔 𝒊𝒔 𝒔𝒐𝒎𝒆𝒕𝒉𝒊𝒏𝒈 𝒈𝒓𝒆𝒂𝒕!
𝑯𝒐𝒑𝒆𝒇𝒖𝒍𝒍𝒚 𝒎𝒐𝒓𝒆 𝒊𝒔 𝒄𝒐𝒎𝒊𝒏𝒈...

You can choose only one Unicode font style to try.
Of course there are already many similar tool on the Internet, like : https://texteditor.com/font-converter/

But treat this as a practise and learning process if you don't already know.

I tried it successfully yesterday.

You can let user type in text box and convert to another text box, or take in a input text file, and write to another output text file.
I hope it is fun.

Does using local name for app make it stand out?

FlierMate4 — Tue, 24 Jan 2023 19:40:41 +0800

For example, "Sambal".

I don't know who starts it first, there are at least three apps using "Sambal" as their app name.

www.sambalsos.com/

(Pengumpulan data bantuan orang ramai di seluruh negara)

There is this new application called SAMBAL SOS , initially called as the Bendera Putih app. This app is very helpful for people to locate food banks and ..

github.com/schemaorg/schemaorg/discussions/2968

Introducing Sambal - a linked data static site generator that uses schema.org json-ld as the content model.

And also my Sambal compiler.

---

As per title, does using local name to name after our apps make it more Malaysian? More stand out, or more productive?

First time using WinDbg

FlierMate4 — Tue, 17 Jan 2023 01:46:49 +0800

Hi, I have never really use a debugger /disassembler before (except online disassembler), so this is a new experience for me to try WinDbg!

Today I am going to disassemble my own program, called msgbox.exe, written also in fasm.

Example msgbox.exe to debug / disassemble

First, download the WinDbg and launch it:

Download debugging tools from Windows SDK

Start menu items of WinDbg after installation

Open WinDbg(x64)

Then, browse to msgbox.exe and open it.

Open executable (msgbox.exe)

But funny it didn't show a PE header analysis, I have to download a separate PEDump to find which memory to dump.

Run PEDump tool to find code section entry point

Finally, we got the address: 0x402000, so let's disassemble it.

View disassembly

Spot on!

It looks exactly like the source code!

CODE

start:

push 0x40
push title
push message
push 0
call [MessageBox]

push eax
call [ExitProcess]

I know quite a few sifu here, know better in anything disassembly, e.g. junyian, angch and cikelempadey.

I think I used the wrong tool to disassemble msgbox.exe, because it doesn't bring me directly to the code section of the executable.
Enlightenment please?

PEDump tool: forum.lazarus.freepascal.org/index.php?topic=46617.0

Windows SDK: developer.microsoft.com/en-us/windows/downloads/windows-sdk/

Anyone heard of DevEco Studio before?

FlierMate4 — Wed, 11 Jan 2023 04:26:10 +0800

Is it an Android Studio for Huawei?

Is there any codemaster here use DevEco Studio?

The attached pic is a "Hello, world" app developed in DevEco Studio which I downloaded from China's website.

"Return to Normal" Journal

FlierMate4 — Sun, 08 Jan 2023 01:53:53 +0800

Hi, I am new to this forum section. I pay more attention to my fitness now since I am getting old.

My ideal weight is 70~75 kg. Currently my body weight and personal particulars are as below:

Gender: Male
Age: 45
Height: 174cm
Weight: 90kg
BMI: 29.7 kg/m2 (Overweight)
Muscle Mass: 39.4 (was 39.9 three years ago)
No-Smoke & No Alcohol consumption

My workout plan is Walking.

5-Jan: 6000 steps (5-5:30PM, 7-7:30PM)

8-Jan: 3000 steps (12-12:30AM)

The mileage is low because I have no motivation to go to park.
Plus, I can walk anytime at home.

I plan to drink plenty of plain water, and at least a glass of full-cream milk everyday.

Currently the only medicine I am taking is for mental illness. No supplement.

Any good reference about muscle mass chart?

FlierMate4 — Sun, 08 Jan 2023 01:14:39 +0800

Hi, I am new to this forum section.

Where can I find reliable muscle mass chart on the Internet?

For example I found this, but....

According to another article:

QUOTE

There isn’t a lot of credible data on average muscle mass percentages. The only source with reliable information is a 2000 study in the Journal of Applied Physiology. In the study, researchers measured the muscle mass percentages of 468 men and women.

Their muscle mass chart is more oriented to age.

QUOTE

Muscle mass percentage averages for men

AgeMuscle mass percentage
18–35 40–44
36–55 36–40
56–75 32–35
76–85 < 31

Muscle mass percentage averages for women

AgeMuscle mass percentage
18–35 31–33
36–55 29–31
56–75 27–30
76–85 < 26

So let say a young man is 21 years old (not me) with 40% muscle mass, is he considered low in his age group (second chart), or high referring to the first chart?
It is confusing.