Wiki editing discussion

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By msxholder

Champion (382)

msxholder's picture

06-07-2021, 09:28

Make me an offer !

By gdx

Enlighted (4628)

gdx's picture

06-07-2021, 11:54

No thank. I will find otherwise. I participate in the wiki to help the developers, users and those who are looking to acquire equipment. This allows the community to grow and everyone wins even me because I learned a lot. And in this way, the MSX is more fun since we can avoid a lot of problems.

By Pentarou

Champion (389)

Pentarou's picture

21-07-2021, 01:58

I've noticed that there are two NMS 1205 Wiki pages:
https://www.msx.org/wiki/Philips_NMS_1205
and
https://www.msx.org/wiki/Philips_NMS-1205

Content of the pages seems identical, is this intentional?

By Grauw

Ascended (10005)

Grauw's picture

21-07-2021, 02:24

That is normal, Philips_NMS-1205 is a redirect to Philips_NMS_1205, notice that if you click the “Page” tab on the former page it takes you to the URL of the latter. This happens when pages are renamed, the old URL is preserved (aliased) in order to not break links.

By mars2000you

Enlighted (5954)

mars2000you's picture

24-07-2021, 07:40

Concerning wiki pages about MSX-DOS1/2 Tools, i remember to gdx his own words on 20/04/20:

gdx wrote:
mars2000you wrote:

There's a big difference between the advanced tools you mention (and it can also include MemMan) and the more simple tools that look like external commands.

The only difference is the complexity of the programs. Simple tools look like external commands but are not really. It's as ambiguous as that because basically DOS (CP/M) was created only to manage the disks. This ambiguity was removed from MS-DOS using EXE files. External commands are commands made with the MSX-DOS and together. The rest are programs some of which can be also called external commands or tools for MSX commander, M, Multimente, etc. but in the wiki, it makes more sense to stay general.

Because the MSX community does not like the 'external commands' terminology, we need to use the 'tools' terminology, even for very simple external commands.

It explains why I use the word 'tool' in the general description before coming to a 'Command' section including subsections (Effect, Syntax, Parameters, etc...), just like for the MSX-DOS Internal Commands.

The coherency of the wiki requires to respect that.

By Briqunullus

Champion (391)

Briqunullus's picture

27-07-2021, 18:31

I have found some Danish, English, Finnish and German magazines on archive.org and I have created some Wiki pages for them.

My bad, I thought there were 2 Danish magazines, while in fact there is only one. MSX Bruger Bladet later changed its name to SYNTAX. For now I have added all editions to the SYNTAX page, just because that name already was in the Wiki list (just without a page). The MSX Bruger Bladet page could be removed. Or should it be the other way around?

MSX Bruger Bladet created, could be removed
SYNTAX created
MSX Magazin (Germany) created
PTC Print 2 editions added
MSX User editions added (were already known on issuu.com)
MSX uutiset created

The newly created pages still need intros added to them.

By mars2000you

Enlighted (5954)

mars2000you's picture

27-07-2021, 18:39

I will redirect to a page whose name will combine both Danish names, just like it has been made for the French magazine Standard MSX / Micros MSX.

https://www.msx.org/wiki/MSX_Bruger_Bladet_/_SYNTAX

By Briqunullus

Champion (391)

Briqunullus's picture

27-07-2021, 18:46

Even better!

(Maybe the other ones can still be removed. They are so short lived that links will not exist yet. I don't know what the policy is on this. Ehhh, wait, I just created links in my previous post. Lol.)

By Bengalack

Champion (394)

Bengalack's picture

30-07-2021, 19:32

This page, section, and the P/V-flag: https://www.msx.org/wiki/Z80_Assembler_for_Dummies#Flags

I just flipped the information about the meaning of PE and PO on that page. Normally I don't want to modify anything more than necessary. But in this case, I'd like to hear you guys out:

  1. I'm unsure about the current line "This is copy of the results least significant bit". I can't see how that works.
  2. The section with the flags, seems to be a short, quick reference "for dummies", but I believe this flag actually requires "a certain amount of text" if we want it to be accurate.

About 2) If we look at the manual here, http://www.zilog.com/docs/z80/um0080.pdf, at page 67, the flag can actually mean all these things:

Quote:

The Parity/Overflow (P/V) Flag is set to a specific state depending on the operation being performed. For arithmetic operations, this flag indicates an overflow condition when the result in the Accumulator is greater than the maximum possible number (+127) or is less than the minimum possible number (–128). This overflow condition is determined by examining the sign bits of the operands.

For addition, operands with different signs never cause overflow. When adding operands with similar signs and the result contains a different sign, the Overflow Flag is set, as shown in the following example.

***EXAMPLE***

The two numbers added together result in a number that exceeds +127 and the two positive operands result in a negative number (–95), which is incorrect. The Overflow Flag is therefore set. For subtraction, overflow can occur for operands of unalike signs. Operands of alike signs never cause overflow, as shown in the following example.

***EXAMPLE***

The minuend sign has changed from a positive to a negative, resulting in an incorrect difference; the Overflow Flag is set. Another method for identifying an overflow is to observe the Carry to and out of the sign bit. If there is a Carry in and no Carry out, or if there is no Carry in and a Carry out, then an Overflow has occurred.

This flag is also used with logical operations and rotate instructions to indicate the resulting parity is even. The number of 1 bits in a byte are counted. If the total is Odd, ODD parity is flagged (i.e., P = 0). If the total is even, even parity is flagged (i.e., P = 1).

During the CPI, CPIR, CPD, and CPDR search instructions and the LDI, LDIR, LDD, and LDDR block transfer instructions, the P/V Flag monitors the state of the Byte Count (BC) Register. When decrementing, if the byte counter decrements to 0, the flag is cleared to 0; otherwise the flag is set to1.

During the LD A, I and LD A, R instructions, the P/V Flag is set with the value of the interrupt enable flip-flop (IFF2) for storage or testing.

When inputting a byte from an I/O device with an IN r, (C) instruction, the P/V Flag is adjusted to indicate data parity.

This is a lot of info. I think we could remove the examples in the text below, and include this instead:

Quote:

The Parity/Overflow (P/V) Flag is set to a specific state depending on the operation being performed. For arithmetic operations, this flag indicates an overflow condition when the result in the Accumulator is greater than the maximum possible number (+127) or is less than the minimum possible number (–128). This overflow condition is determined by examining the sign bits of the operands.

This flag is also used with logical operations and rotate instructions to indicate the resulting parity is even. The number of 1 bits in a byte are counted. If the total is Odd, ODD parity is flagged (i.e., P = 0). If the total is even, even parity is flagged (i.e., P = 1).

During the CPI, CPIR, CPD, and CPDR search instructions and the LDI, LDIR, LDD, and LDDR block transfer instructions, the P/V Flag monitors the state of the Byte Count (BC) Register. When decrementing, if the byte counter decrements to 0, the flag is cleared to 0; otherwise the flag is set to1.

During the LD A, I and LD A, R instructions, the P/V Flag is set with the value of the interrupt enable flip-flop (IFF2) for storage or testing.

When inputting a byte from an I/O device with an IN r, (C) instruction, the P/V Flag is adjusted to indicate data parity.

Before bombing in such an amount of text, I'd like to make sure there isn't anything special about this page that I should know about. (like "keep it super simple" and such) :-)

By Grauw

Ascended (10005)

Grauw's picture

30-07-2021, 21:40

A simple explanation is no good if it is incorrect. If the intent is to keep the page simple it could just not elaborate on it at all, and rather state that it is used for parity, overflow and some other things, and refer to other more elaborate documentation. It’s not an important flag for a beginner to know about.

Some comments on your text, because the syntax for the flags is PE/PO (parity even/odd) I would consider parity the primary function of the flag, and start with that description rather than overflow.

Also when the flag is not used for parity I never remember whether PE or PO means that the flag is set. So I would indicate whether PE or PO refers to the flag being set, and additionally, explicitly mention whether PE or PO indicates overflow and BC reaching zero.

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