Forem: Matheus

ISO Pascal is love

Matheus — Thu, 05 Mar 2026 02:33:21 +0000

I finished the ISO Pascal book, and I found the language very interesting. I'm in love with this language!

Unlike other Pascal implementations, ISO Pascal is minimalist. The language features thirty-five keywords, thirteen built-in procedures, and seventeen built-in functions. The language is proposed for teaching structured programming, but may do very well for other tasks. At first glance, the language may seem unusable or uneasy. However, once mastered, there's no going back! The language is excellent!

The following is a program I wrote. The program reads from a file, constructs a circular linked list from the contents, and prints the contents.

program Index(Input, Output, Pipe);

const
        MaxArg = 1000;
        MaxStr = 1000;
        EndOfStr = Chr(0);
type
        PStrbuf = ^Strbuf;
        Strbuf = record
                Length: Integer;
                Buffer: Array[1..MaxStr] of Char;
                Next: PStrbuf;
                Prev: PStrbuf;
        end;
var
        BufArg: PStrbuf;
        Pipe: Text;

procedure Print(Str: PStrbuf);
var
        I: Integer;
begin
        I := 1;
        while Str^.Buffer[I] <> EndOfStr do
        begin
                Write(Str^.Buffer[I]);
                I := I + 1;
        end;
        Writeln
end;

procedure AllocStr(Str: PStrbuf; var Overflow: Boolean); { The var declaration here means to pass by reference. }
var
        I: Integer;
        C: Char;
begin
        Str^.Length := 0;
        I := 1;
        while (not Overflow) and (not Eoln(Pipe)) do
                if I < MaxStr then
                begin
                        Read(Pipe, C);
                        Str^.Buffer[I] := C;
                        Str^.Length := I;
                        I := I + 1;
                end
                else
                        Overflow := True;
        if not Overflow then
                Str^.Buffer[I] := EndOfStr
end;

procedure AllocArg(Last: PStrbuf; Str: PStrbuf);
begin
        Last^.Next := Str;
        BufArg^.Prev := Str;
        Str^.Next := BufArg;
        Str^.Prev := Last
end;

procedure Main;
var
        BufPtr: PStrbuf;
        Str: PStrbuf;
        Overflow: Boolean;
begin
        Reset(Pipe);
        New(BufArg);
        BufArg^.Next := BufArg;
        BufArg^.Prev := BufArg;
        BufArg^.Length := 0;
        BufArg^.Buffer[1] := EndOfStr;
        Overflow := False;
        while (not Overflow) and (not Eof(Pipe)) do
        begin
                New(Str);
                AllocStr(Str, Overflow);
                AllocArg(BufArg^.Prev, Str);
                if Overflow then
                begin
                        Writeln('Overflow!');
                end
                else
                        Get(Pipe);
        end;
        if not Overflow then
        begin
                BufPtr := BufArg^.Next;
                while BufPtr <> BufArg do
                begin
                        Print(BufPtr);
                        BufPtr := BufPtr^.Next;
                end
        end
end;

begin
        Main
end.

The language is very different from C. Such a small language, yet so much can be done. Really cool, and, at the same time, odd. It doesn't have return. It doesn't have break. It doesn't have continue. It doesn't have a sizeof operator. It doesn't have an address-of operator. Even then, it does excellently!

GUI for OpenSoldat

Matheus — Mon, 29 Dec 2025 01:26:29 +0000

This is a WIP GUI implementation for OpenSoldat, an exciting unique side-view multiplayer action game. The GUI is written in C, making use of OpenGL.

GLtron 0.53 was used as base to develop the GUI. The entire work was relicensed under the 0BSD license.

Contributions are very much appreciated.

The sources are found here.

[G530BT] Devuan GNU/Linux installer

Matheus — Mon, 29 Sep 2025 14:02:26 +0000

This is an Odin package for installing Devuan GNU/Linux on the G530BT. Note this is only for G530BT. Other versions of the Galaxy Grand Prime may have a different partition layout. Therefore, the installation on devices other than G530BT is discouraged. However, you're welcome to adapt the scripts for different versions of the Galaxy Grand Prime.

Note this will erase ALL your data. Back up your data before proceeding.

Download the TAR file, run Odin, select the file from AP/PDA, and start flashing.

Note there's no progress status for the installation. If everything did right, you should be able to use ADB. Note ADBD takes about 2 minutes to load and run. Be patient.

If something did wrong, you can always boot into recovery mode and use ADB from there.

The sources for the Linux kernel can be found here.

Noteworthy files are /etc/inittab, /etc/boot, /etc/fstab, /sbin/adbd. These files are present in the devuan.tgz file, present in the cache.img.ext4 file. Out of these files, the most interesting is /etc/boot. You can tune and set up the boot sequence in this file.

Tools used to create this package include simg2img, Android Image Kitchen, Busybox, adbd, gcc-linaro-4.9.

Menu written in Objective-C, for GLtron.

Matheus — Mon, 28 Jul 2025 01:09:40 +0000

I'm developing a small GUI for GLtron, in Objective-C. Objective-C is an amazing language. Initially, this was only a GUI for selecting the audio driver. However, I decided to expand to rewrite the entire OpenGL-designed menu in Objective-C.

Although I'm not a front-end developer, I'm loving this.

The sources are found here. Contributions are welcome!

ADBD: binary size-reduced version

Matheus — Mon, 10 Mar 2025 17:08:55 +0000

Following my previous post on ADB access from stock recovery, I implemented a static version based on lollipop-release.

root@Digitron:~/adbd-lollipop-release/adb# wc -c < adbd
552296

root@Digitron:~/adbd-lollipop-release/adb# file adbd
adbd: ELF 32-bit LSB executable, ARM, EABI5 version 1 (GNU/Linux), statically linked, BuildID[sha1]=b3c3b7ad245a3bec2e40df678fd1a70bc9db0198, for GNU/Linux 3.2.0, stripped

The work provides an ADBD binary worth of reduced size. The original, marshmallow implementation holds 3 Mbytes if statically linked + stripped. The lollipop-release implementation holds half a Mbyte if statically linked + stripped.

Those who have limited mobile storage might find interesting running the lollipop-release version.

My Galaxy Gran Prime is successfully running Devuan GNU/Linux. Sadly, some apps don't work, due to dated kernel. Still a great solution to those owning an unused Android device.

Control your PlayStation 3 remotely

Matheus — Sun, 23 Feb 2025 20:51:47 +0000

This is an app I developed in the spare time to simulate a PlayStation 3 controller from a computer. Currently, isn't possible to remap controls, but work is on the way.

Note webMAN MOD is required for this to work.

Only tested on FreeBSD, and only with Clang compiler.

How to use

Install webMAN MOD, build pad.c and run the following:
./a.out <PlayStation 3 ip>

Key bindings

Up arrow - D-pad up;
Down arrow - D-pad down;
Right arrow - D-pad right;
Left arrow - D-pad left;
W - Triangle;
Z - Cross;
S - Circle;
A - Square;
E - R1;
Q - L1;
C - R2;
X - L2;
1 - START;
2 - SELECT;
H (lowercase) - Home;
H (uppercase) - Home (hold).

sm64coopdx ported to FreeBSD

Matheus — Sun, 23 Feb 2025 13:42:28 +0000

I managed to port sm64coopdx to FreeBSD. I made some small adjustments in the Makefile and Python scripts. The hard parts were Lua and optimization level. Optimization level 2 rendered SIGSEGV at times. Optimization level Z (for aggressive size optimization) solved the issue. As for Lua, the release 5.3.5 rendered SIGABRT. Updating to 5.4.7 solved the issue.

There also are input issues regarding external inputs. I couldn't get my Microntek gamepad working. Haven't managed to investigate.

I'm not confident SIGSEGV shall be fixed changing the optimization level. There might be some wrong code somewhere I couldn't find. Had no luck tracing with LLDB.

(lldb) bt
* thread #1, name = 'sm64coopdx', stop reason = signal SIGSEGV: address not mapped to object (fault address: 0xffffffff02b5cdb0)
  * frame #0: 0x000000000274e369 sm64coopdx`vec3f_get_dist_and_angle [inlined] atan2s(y=0, x=<unavailable>) at math_util.c:856:41
    frame #1: 0x000000000274e337 sm64coopdx`vec3f_get_dist_and_angle(from=0x000034ba8cbb2f44, to=0x0000000822eba9ec, dist=<unavailable>, pitch=<unavailable>, yaw=0x000000000346af2a) at math_util.c:765:12
    frame #2: 0x0000000002781a74 sm64coopdx`next_lakitu_state(newPos=0x0000000822ebaa68, newFoc=0x0000000822ebaa78, curPos=0x000034ba8cbb2f50, curFoc=0x000034ba8cbb2f44, oldPos=0x000000000346b4d8, oldFoc=0x000000000346b4e4, yaw=0) at camera.c:5656:9
    frame #3: 0x00000000027814b2 sm64coopdx`update_lakitu(c=0x000034ba8cbb2f40) at camera.c:3024:22
    frame #4: 0x0000000002782f34 sm64coopdx`update_camera(c=0x000034ba8cbb2f40) at camera.c:3352:5
    frame #5: 0x00000000027b315f sm64coopdx`play_mode_normal at level_update.c:1305:9
    frame #6: 0x00000000027b392e sm64coopdx`update_level at level_update.c:0
    frame #7: 0x000000000274a728 sm64coopdx`level_cmd_call_loop at level_script.c:287:17
    frame #8: 0x000000000274a040 sm64coopdx`level_script_execute(cmd=<unavailable>) at level_script.c:1146:13
    frame #9: 0x000000000279f2d6 sm64coopdx`game_loop_one_iteration at game_init.c:603:24
    frame #10: 0x000000000287c077 sm64coopdx`produce_one_frame at pc_main.c:312:5
    frame #11: 0x000000000287c76a sm64coopdx`main(argc=<unavailable>, argv=<unavailable>) at pc_main.c:538:9
    frame #12: 0x0000000828634c3a libc.so.7`__libc_start1 + 298
    frame #13: 0x0000000002745240 sm64coopdx`_start at crt1_s.S:83

ADB access from stock recovery

Matheus — Fri, 21 Feb 2025 17:24:34 +0000

ADB has issues from TWRP on the Samsung Galaxy Gran Prime. I modified the stock recovery so that ADB can be used as in TWRP. This is composed of a modified RAM disk + kernel. The modifications introduced in the RAM disk are for allowing ADB to be used as in TWRP. For that, I rebuilt adbd from this source, as well as modified default.prop with the following parameters.

ro.secure=0
ro.debuggable=1
persist.sys.usb.config=adb
ro.adb.secure=0

As for the kernel, I introduced a minimal modification so that SELinux remains permissive. Having SELinux in permissive mode is vital for allowing third-party utilities to run, as well as to have full privileges on the system.

Use Android Image Kitchen for extracting the RAM disk.

All requires one to root is set SELinux to permissive.

[Boost]

Matheus — Fri, 21 Feb 2025 00:16:24 +0000

etcsh: an enhanced version of the original tcsh

Matheus ・ Jun 15 '24

#c #shell

E-commerce management system

Matheus — Mon, 10 Feb 2025 02:21:56 +0000

Written in Objective-C. SQL integration is in progress! Source code is found here. Contributions are welcome!

etcsh: an enhanced version of the original tcsh

Matheus — Sat, 15 Jun 2024 05:15:12 +0000

etcsh is an enhanced version of the original tcsh, which is a version of the original Berkeley C shell implementing file name completion and command line editing.

etcsh features the following enhancements and fixes over the original tcsh.
• Function declarations;
• variable assignment from pipes and redirections;
• comments on interactive sessions;
• tell whether stdin is empty or not;
• variable expansion on expressions corrected;
• piped built-ins are forked;
• missing test built-in implemented;
• read-write variable flag;
• exit shall cancel lists.

More is to come. Feedbacks and contributions are much appreciated.

Modifications on [T]csh

Matheus — Sun, 18 Feb 2024 18:07:31 +0000

I've introduced some modifications on [T]csh.

Functions (only for scripts)
Read files into a variable
Comments on interactive sessions
Tell whether stdin is empty

I'd appreciate for any feedback, suggestion or contribution. Contributions of any kind are very welcome.

A key [T]csh developer asked me to create documentation and tests for my functions invention. I've written some tests, but I'm afraid they aren't enough.

The source code is here. The modifications are separated in branches.

I've a repository for the original Csh, but only functions are there, and isn't up-to-date.