Spectrum Computing

If you run PRINT USR "a" you should get a number that's identical to the number at 23675, this is where the DE needs to sit right before the LDIR is executed. Normally this is 65368. i went through the code and found a few bugs. its kind of mostly working now, i think. if you press the r ...

If you run PRINT USR "a" you should get a number that's identical to the number at 23675, this is where the DE needs to sit right before the LDIR is executed. Normally this is 65368. ive managed to get the sprite to move around the screen but it crashes when i press any of the other keys....

It's got to be said, that's a horrible book for trying to learn assembly from. And the embedded machine code in REMs was never going to play well with typed in code. I wonder if it originally came with a cassette copy of all the listings or if it just never worked? Even the assembly examples are pr...

That's good, because now you're able to observe something that can be worked on, instead of experiencing a crash. The UDGs are defined right at the start. Check why this is not done. Set a breakpoint at the first instruction and go step by step. The first LDIR is supposed to copy the graphic bytes ...

I think you can omit the call. Instead do this: ;call 23760 ld a,2 call 5633 ; open channel 'S' and give it a go. ok, the abc characters come up now but they are not udg's. and when i try and press a key the screen shows artefacts and eventually crashes. it also looks like some of the machine code ...

The author of this book uses a special assembler (McGraw-Hill as stated in the preface). And that's why all examples in this book use this 'org 23760' which is causing trouble in ZX Spin. Try a higher ORG address and adjust the calls. In the book's example there's a line 1 REM >? STEP ....etc which...

Hi! Right at the start there's a call to 23760, and that's right into the first line of your Basic program. 500 DATA 24,79,5,2,"STOP THE TAPE" ^ here is 23760, which is garbage to call at hi, im not sure how to do that. there are so many calls to addresses around 23xxx in the code that im...

i decided to type it out anyway, here: org 30001 di call 23760 jr START DATA1 defb 0,0,15,24,49,226,255,224 dEfb 24,60,255,255,153,255,231 defb 60,0,0,240,24,140,71,135,7 START ld de,(23675) ld hl,DATA1 ld bc,24 ldir jr BEGIN DATA2 defb 22,0,0,16,8,17,8,144,145 defb 146 BEGIN ld de,DATA2 ld bc,10 ca...

sn3j wrote: ↑Sat Dec 31, 2022 2:41 pm ORG address 23760 is very low. On a ZX 48 the program area starts at 23755.
Perhaps a higher value like 32000 and issuing a CLEAR 31999 statement helps.

yeah, it works. thank you

How do you compile and start the code? Make sure you didn't run an old binary. Sorry for asking this kind of stuff but I don't use compilers myself and don't know how you do it over there. Yep according to what I've read that's fixed so far. Issue 2-4 isn't that critical. i just used spin assembler...

sn3j wrote: ↑Sat Dec 31, 2022 2:09 pm This could be an emulator issue. Try it without the DI instruction.

no, still does the same thing

sn3j wrote: ↑Sat Dec 31, 2022 10:49 am With all fixes applied the code should do ok.
Does it clear the screen and do you see the spaceship?

Ink value should be 8 btw:

Code: Select all

defb 22,0,0,16,  8,  17,8

no, it does nothing

sn3j wrote: ↑Sat Dec 31, 2022 5:53 am

tried all of these still the same result

it tried typing this in and the code does absolutely nothing. its supposed to move a spaceship around. ive double checked the code and cant find any errors: org 23760 ;disable keyboard di jr start ;udg data data1 ;chr$ 144 defb 0,0,15,24,49,226,255,224 ;chr$ 145 defb 24,60,255,255,153,255,231,60 ;ch...

Have you got a TL866II PLUS USB Minipro Programmer EEPROM FLASH or have you got the complete kit to make up, I was going to buy one. Was thinking to do a ZX Dandanator Mini 2.1 and program the eeproms. I'm having to build it myself. So I will need the programmer at some point. I think you program i...

im building a finalgrom for the ti99 with surface mount devices

WhatHoSnorkers wrote: ↑Mon Dec 26, 2022 6:41 pm This has been fun, and I can't get it working fully yet... but at least it doesn't crash any more. A lot of the problems were of my own making, and interoperation with the BASIC Assembly.

could you send me a sna of it?

@azesmbog,

ive found this program, which does the same thing, although it works in a different way according to the basic listing. unfortunately its in german.

https://spectrumcomputing.co.uk/entry/8 ... Plot-Print

Edited by PJ

azesmbog wrote: ↑Wed Dec 21, 2022 8:42 am Well, let's have the full program. Preferably in TAP.
As a last resort, the BASIC part is in text format. Well, at least in the SNA.
Let's take a look at the patterns.
By the way, I compiled it in SJAsm assembler.

heres a sna of the offending code:

https://easyupload.io/r9f8lv

azesmbog wrote: ↑Tue Dec 20, 2022 5:16 pm
exactly 265 bytes, try

it doesnt crash but it doesnt work either. just starts to flood the screen then leave weird patterns on it

https://cdn3.emoji.gg/emojis/4718_chad_yes.png Yes. The BASIC listing has no dodgy USR calls - it only ever starts at 32393, and the code is not doing what it says in the text. And while I may cast doubt on 777's ability to type in a listing accurately, there is a noticeable amount of slop in the o...

@TMD2003
where is jr -4 and jr 11 in the code?

Removed quoting - PJ

Morkin wrote: ↑Tue Dec 20, 2022 3:33 pm I'm not sure, whenever I've used SPIN I tend to use JR with labels rather than offsets.

Maybe instead of 'JR Z, -7' try 'JR Z, $-7'?

(Just a guess!)

ok, that assembles, ok. weird, i thought id already tried that...

but now it crashes when i run the program

There are several "jr' instructions, but I only noticed 2 "jr z" instructions, at addresses 32363 and 32373. The only problems you mentioned were "jr z" with negative offsets, and removing + from "jp z" which is odd since all "jp" in the listing use labe...

I'm going to type this in myself and see if I can get what's happening. I'll uploaded a snapshot when I'm done. One thing I have found with Spin's assembler is that sometimes it will not accept a label - usually if it's interpreted as a command. The JR L1 and JR L2 in this listing might throw it. U...