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#91
avatar_HAL6128
Programming / Re: Rasm Z80 assembler
Last post by HAL6128 - 14:27, 16 May 24
Hello @roudoudou,

just two quick questions maybe I don't exactly understand your docu in RASM regarding calling a struct:

It says:

STRUCT nom_du_prototype, nom_de_la_variable / ENDSTRUCT

When STRUCT is used with 1 parameter (name), the following labels will be used to declare the structure, in particular its indexes 
When STRUCT is used with 2 parameters (type_name+struct_name), a structure is created of type_name and will be called structure_name

Although RASM allows you to put anything inside the declaration of a structure, the practical use is to declare labels and via the data definition instructions, a field size. It is not necessary to fill in a value in the DEF
struct st1
  ch1 defw
  ch2 defb
endstruct
struct metast1
  struct st1 pr1
  struct st1 pr2
endstruct
struct metast1 bigst ; instanciation de metast1 en bigst
ld hl,bigst.pr2.ch1 ; récupération de l'adresse absolue d'un membre de bigst
ld a,(hl)
ld a,(ix+metast1.pr2.ch1 ; utilisation de l'offset du champ via la définition de la structure (pas besoin d'instancier pour cet usage)

Q1: This part "ld hl,bigst.pr2.ch1" refers to second pointer (first struct) of the second pointer (second struct) included in the second struct? It's nested somehow, isn't it?

Q2: Is there also a D24 (3 byte member) within RASM struct available?
#92
Quote from: mmldrm on 12:23, 16 May 24Finally the 74LS02 has arrived!

I will try the above tests too, if I understand them.  :o

My oscilloscope is a Zoyi ZT-702S: https://zoyitools.com/product/zt-702s/

I found it for £43, and figured it's something I can use for years after this. This is true for the breadboard and components I bought for the tests - I like playing with electronics and would like to do more hardware projects in the future.

If these tests from @McArti0 can reduce the number of chips that I desolder and replace, I am less likely to destroy the motherboard in the process. Unorthodox, but I'm happy to proceed with caution on this.

Thanks for staying with me this far on the journey. I know there is a variety of opinions on the path we have taken. :)

The scope is ok for basic "signal present" checking, but only up to about 3MHz for proper diagnosis. That's a bit on the low side even for retro computer repair.

Bryce.
#93
Quote from: McArti0 on 13:26, 16 May 24Ok. Make OR Gate on breadbord. (From 2 NOR gate in 74Ls02). ;)
I could do this when I was 18. 😅 I'll go read up on it and get back to you. 🫡 
#94
Ok. Make OR Gate on breadbord. (From 2 NOR gate in 74Ls02). ;)
#95
Finally the 74LS02 has arrived!

I will try the above tests too, if I understand them.  :o

My oscilloscope is a Zoyi ZT-702S: https://zoyitools.com/product/zt-702s/

I found it for £43, and figured it's something I can use for years after this. This is true for the breadboard and components I bought for the tests - I like playing with electronics and would like to do more hardware projects in the future.

If these tests from @McArti0 can reduce the number of chips that I desolder and replace, I am less likely to destroy the motherboard in the process. Unorthodox, but I'm happy to proceed with caution on this.

Thanks for staying with me this far on the journey. I know there is a variety of opinions on the path we have taken. :)
#96
avatar_ervin
Games / Re: Adapting loading screens t...
Last post by ervin - 02:46, 16 May 24
I always really liked the original CPC loading screen, even if Trantor looks like David Lee Roth!  :laugh:
Your new version looks great.
#97
A
Games / Re: Bubble Quest - GX4000/CPC...
Last post by Anthony Flack - 01:53, 16 May 24
You really ought to hurry up and announce them so we can start being impatient.
#98
A
Programming / Re: Bootstrapping from FAT for...
Last post by andycadley - 22:49, 15 May 24
Quote from: Benedikt on 20:22, 15 May 24And is there any way to just read a specific sector in a file system agnostic way using Basic and to run it as machine code?
Putting a write-protected system file in a known sequence of sectors is solved problem.

The question is about bootstrapping, i.e a DOS with the relevant capabilities is not already running.
The only way from BASIC is |CPM which loads track 0, side 0 sector &41. It will only load 512 bytes though (whatever is booted is then expected to load the rest). 
#99
avatar_Prodatron
Programming / Re: Bootstrapping from FAT for...
Last post by Prodatron - 22:31, 15 May 24
There is

BPB_RsvdSecCnt

"Number of reserved sectors in the Reserved region of the volume
starting at the first sector of the volume. This field must not be 0.
For FAT12 and FAT16 volumes, this value should never be
anything other than 1. For FAT32 volumes, this value is typically
32."

So as all discs are FAT12, there is no chance for having additional reserved sectors at fixed LBAs beside the boot sector.
But you can always reserve clusters on a FAT device using the FAT itself without assigning them to a file (a PC then may want to repair the disc :) ). If you have always the same disc size, this could be done at fixed LBAs (tracks/sectors).
#100
@Benedikt
I didn't want to make an interface between the socket and the z80 at all costs. Fun for 80 pins.
Besides, in my micro fpga I have no free input left and only one gate.
I used SLG46826 because it has NVM configuration. I could probably fit everything in 46533 but there is OTP (PROM)

It is enough to confirm that OUT (C),0 is the only significant compatibility problem.
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