Writing ARM assembly on RISC OS

https://www.youtube.com/watch?v=_w4FS7aC82s

RISC OS C Development Tutorial 4 - First WIMP App
https://www.youtube.com/watch?v=SsPBvpN0nXo

NetSurf is an open source web browser for RISC OS, licensed under the GPL. Its aim is to bring the HTML 4 and CSS standards to the RISC OS platform.

Compared to other RISC OS browsers, NetSurf is notable for its speed and comprehensive support of CSS, as well as novel handling of history. The main feature missing from NetSurf is JavaScript

The main feature missing from NetSurf is JavaScript

The main feature missing from NetSurf is JavaScript

The main feature missing from NetSurf is JavaScript

The main feature missing from NetSurf is JavaScript

The main feature missing from NetSurf is JavaScript

https://www.youtube.com/watch?v=4zxUHicG6qY

Sophie Wilson tells about ARM
https://www.youtube.com/watch?v=Rc5i6tA3dH0

RISC OS on modern ARM computers:
https://www.youtube.com/watch?v=Mu-s2EV8FrY

>>5
tell us more, Sophie

I was curious where the RISC OS `device.path.leads.to.file` style path format came from.
Apparently it came from the classic IBM OSes.

Multics >device>path>leads>to>file.ext
Unix /device/path/leads/to/file.ext
MIT ITS device:path;leads;to;file ext extension is separate from filename
Amiga device:path/leads/to/ext.file extension comes first
CP/M device:\path\leads\to\file.ext
DOS device:\path\leads\to\file.ext yes, MS "borrowed" a lot from CP/M
MacOS device:path:leads:to:file.txt System 1 to Mac OS9
VMS device:[path.leads.to]file.ext also allows ext.gen - versioning
TOPS-20 device:<path.leads.to>file.ext also allows ext.gen - versioning
TENEX device:<path.leads.to>file.ext
IBM zOS device.path.leads.to.file.ext
RISC OS device.path.leads.to.file extension is separate from filename
DOS files .ext is renamed to /ext
while ROS files get ,HEXCODE suffix
when transferred to DOS or over
network, without MIME types.

Note that VMS/TOPS-20/zOS/RISC OS allow several named root dirs for a device.
I.e. single device could have several filesystems.

Typically they are specified as DEVICE$FILESYSTEM

So basically, the `.` format comes from IBM. Unsure if the `.` in C based language was also based on it.

>>8
MIT ITS apparently too allowed referencing separate partitions of the device
https://github.com/PDP-10/its/blob/master/doc/NITS.md
:MIDAS DSK0:.;NITS BIN_SYSTEM; ITS

file:///D:/GUIDES/USERGUIDE/MANUAL/BOOK3B/BOOK3_2.HTML
Command and Obey file types
There are two types of file you can use for command scripts: Command files, and Obey files. The differences between these two file types are:

- An Obey file is always passed to the command line interpreter, whereas a Command file is passed to the current input.
- An Obey file is read directly, whereas a Command file is treated as if it were typed at the keyboard (and hence usually appears on the screen).
- An Obey file sets the system variable Obey$Dir to the directory it is in.
- An Obey file can have parameters passed to it.

>>10

These example files illustrate some of the differences between Command and Obey files:

Example 1
*BASIC

AUTO

FOR J= 1 TO 10

PRINT "Hello"

NEXT J

END

If this is a command file, it will enter the BASIC interpreter, and input the file shown. The command script will end with the BASIC interpreter waiting for another line of input. You can then press Esc to get a prompt, type RUN to run the program, and then type QUIT to leave BASIC. This script shows how a command file is passed to the input, and can change what is accepting its input (in this case to the BASIC interpreter).

On the other hand, if this is an Obey file it will be passed to the command line interpreter, and an attempt will be made to run these commands:

*BASIC

*AUTO

*FOR I = 1 TO 10

* PRINT "Hello"

*NEXT I

*END

Only the first command is valid, as an Obey file all this does is to leave you in the BASIC interpreter. Type QUIT to leave BASIC; you will then get an error message saying File 'AUTO' not found, generated by the second line in the file.

memset in your fav christian/muslim arch:
...

memset in ARM:
void memset(int value, int count) {
-- register lr holds return value
mov r0, value
mov r3, count
loop:
movle pc,lr -- return if r3 is below or equal zero
str r0,[r12],#0x4 -- store r0 at address r12, increment r12 by 4
subs r3,r3,#0x4 -- signed subtract 4 from r3 and store into r3
b loop -- jump to loop
}

interesting.
Are you a racis?

>>13
I got beaten by muslims and by christians.

>>12
Note: each ARM opcode could be suffixed with s, telling it to set flags based of the result (carry, negative, zero, etc). That is compared to x86 where all opcodes mess the flags, even if you don't want them to. So there are `add` and `adds` mnemonics, and then there are `addsle` and `addle`, which execute only of flags are set. That allows avoiding a large portion of branches and also makes code more readable. `if` reads like an Python if, just with a FORCED FLAG SUFFIX instead of Python's FIOC.

ARM also discourages the use of big immediate values, compared to the unaligned x86 opcodes. But the existing immediate mechanism is very powerful, since they can be applied to any place in a register. For example you can elegantly load a byte at any place in a register or xor any any byte. Yet when you need a large immediate you just load it from the function's header (using PC+offset). Base ARM allows loading 4 registers at once, so it has some SIMD capabilities built into the core architecture.

>>15
Also, because flags are so easily accessible, one ARM calling convention uses the carry flag to return boolean value.

>>14
You in france? Or russia etc (I say russia etc because eastern europe / russians seem to be the only ones who actually study the foundations of computing these days)?

>>17

I study ARM because it is elegant and designed by a trans woman.
Transphobes made x86.

>>18
You're not >>14. It's evident by the pantameter of your wrighting.

>>18
Nope, guy wasn't a eunich when he worked on it decades ago. Just as Quake isn't a tranny OS just because some guy that worked on it after John Carmack, and then abandoned the thing, joined google and chopped his dick and balls off.

That doesn't back-flush to the versions that pre-date the defection and dick-sawing; and doesn't back-flush to John Carmack.

>>18
That's like saying Paul was still an active murderer of christians after he chopped his genitals off, became a "new organism" not male not female, and mellowed out. No: Saul was the active murderer when he was an intact man; then he had his "conversion" (dick and balls chopped off like Jesus said to in Matthew 19): then after that there's "no male nor female"

That doesn't back-wash to the Old Testament that Saul was enforcing prior to chop chop saw saw.

>>21
A devilishly cheap way to get good cassette tapes: Tape over the Bible!
The reason why those tapes are in such good shape is the same reason why you bought the set so cheap: No one played them.

https://www.youtube.com/watch?v=TtNmiZphYik