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Change JPs by JRsIs there any (easy) way to replace all long jumps with relative ones in assembler code? Of course, I can replace all in text editor, and then place …
... takes 10 T-states and a regular JR takes 12 T-states (if there ... -
Proportional fontsI've been doing some proportional font drawing, purely on C level at the moment, but it's orders of magnitude slower than I'd want it to be. It's sti…
... /> Then again, that's 11 T-States to get the two shifted ... that's only 2*4 T-States to get the values.
Proportional fontsI've been doing some proportional font drawing, purely on C level at the moment, but it's orders of magnitude slower than I'd want it to be. It's sti…
... to fit within the available t-states while the loader takes a ... /> Hopefully the whole thing won't increase in size too much ...Cool BASIC tricks and tips!Following on from Dunny's excellent suggestion of a compendium of BASIC tips + tricks, I believe it would be better to have a topic dedicated to it. …
... using integer addresses there isn't much point in using a ... 10101010 will save you 548 t-states per loop.
Try ...Why doesnt this work???Simple piece of code wont do as it should, just want to fill the top 22 lines of screen with an attribute value (150) but it wont have any of it. Som…
... " - ld sp, (nn) is 20 t states compared to just 10 for ...Why doesnt this work???Simple piece of code wont do as it should, just want to fill the top 22 lines of screen with an attribute value (150) but it wont have any of it. Som…
... " - ld sp, (nn) is 20 t states compared to just 10 for ... . On the spectrum you don't often care about these two ... his main code and couldn't figure out why he was ...Graphics program in AssemblyHi so I think I'm getting the hang of this so I've done this program. It writes directly to the screen. I'm using ZX Spin. [code] LD HL,16384 LD B,…
ld hl,(xx) uses 20 T-States. POP uses 10 and PUSH ... involve using up even more T-States and would require extra code ...The state of source level debuggingI was just wondering if we can put on a table everything we collectively know about source level debugging for ZX Spectrum to get an overview of curr…
... /> sprintf(buffer + strlen(buffer), "%04X\t", addr); /* Addr. */
if ... feel better). I included t-states into the decoding tables. ... { opcode, opcode mask, mnemonic, size, t-states, t-states fail }
{ 0x00000001, 0x00040301, "LD ...How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
... /> POP HL
}
;; 46 t-states[/code]
Is there ... first time. I need 46 t-states for 2 bytes. Or 736 ... scan lines hence 29.440 t-states. If I can spend the ... rest up to 60k t-states filling emptied column and drawing ...How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
[code]
rlc (hl)
dec l
[/code]
Should be only 19 t-states per byte, as opposed to your 23 per byte? Unless I'm missing something.How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
... ]
Should be only 19 t-states per byte, as opposed to ... /> RL (HL) ; 15 t-states
DEC HL ; 6 t-states
32 times ... faster.
Timings are 21 t-states x 32 cols = 672 per ... be 40 scan lines ... 26880 t-states.
As for pre ...How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
... ]
Should be only 19 t-states per byte, as opposed to ... affects flags. DEC HL doesn't. But it is still the ... as it only adds 2 t-states.[/quote]
Nope. DEC ... L doesn't affect the carry flag!How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
... /> Should be only 19 t-states per byte, as opposed to ... flags. DEC HL doesn't. But it is still ... as it only adds 2 t-states.[/quote]
Nope. ... DEC L doesn't affect the carry flag![/quote ...
You just saved 2650 t-states in one scroll pass. That ...How would you approach parallax?So ... there is this trick by Joffa that we all know...of waiting for the ULA to reach certain pattern on the screen using the IN command. And then s…
... it does it in 18 t-states. So if I store a ...How feasible is it to add a second CPU to the ZX Spectrum?Today with IDE, and USB, and TCP/IP and other wonderful technologies arriving on the ZX Spectrum, I'm beginning to wonder if we'll run out of CPU tim…
... anything from 4 T states (clock cycles) up to 23 T states (clock cycles ...How feasible is it to add a second CPU to the ZX Spectrum?Today with IDE, and USB, and TCP/IP and other wonderful technologies arriving on the ZX Spectrum, I'm beginning to wonder if we'll run out of CPU tim…
... anything from 4 T states (clock cycles) up to 23 T states (clock cycles ...How feasible is it to add a second CPU to the ZX Spectrum?Today with IDE, and USB, and TCP/IP and other wonderful technologies arriving on the ZX Spectrum, I'm beginning to wonder if we'll run out of CPU tim…
... anything from 4 T states (clock cycles) up to 23 T states (clock cycles ...New Game - Pietro Bros [z88dk/Nirvana+][b]PIETRO BROS[/b] Pietro and Luizo were transported to pipe world after eating some rancid mushrooms on his pizza. Help them to escape from th…
... drawn for you. Sprites don't interfere with interrupts and they ... don't take any CPU time from ... reduced it from 6500 t-states to 130 t-states. [b]LITERALLY 50x FASTER ...New Game - Pietro Bros [z88dk/Nirvana+][b]PIETRO BROS[/b] Pietro and Luizo were transported to pipe world after eating some rancid mushrooms on his pizza. Help them to escape from th…
... drawn for you. Sprites don't interfere with interrupts and they ... don't take any CPU time from ... reduced it from 6500 t-states to 130 t-states. [b]LITERALLY 50x FASTER ...What should your speccy have come with ?:) I was thinking about this earlier. What changes should of been made to the Speccy when you purchased yours ? Realistically this topic really…
... , unless the programmer knew their t-states intimately (I'm looking at ...HELP!I'm trying to replace a bit in a byte as follows, but having some sort of brain freeze trying to get it to do what I want. A=00 if bit to replace …
... . And all this in 29 t-states. Not bad. Not bad at ...HELP!I'm trying to replace a bit in a byte as follows, but having some sort of brain freeze trying to get it to do what I want. A=00 if bit to replace …
... . And all this in 29 t-states. Not bad. Not bad at ...HELP!I'm trying to replace a bit in a byte as follows, but having some sort of brain freeze trying to get it to do what I want. A=00 if bit to replace …
And if you align your sprite data (i.e. make sure it doesn’t cross the 256-byte boundary), you can use INC L instead of INC HL, which is two T states faster.Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... only possible in about 180 t-states.
I'm now ...Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... ROM), this gets you 358 T states 'for free' according to [url ... difference of few tens of T states is tiny compared to actual ...Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... worked out I have 366 t-states in the delay loop of ...Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... longest route down to 122 t-states, with printing the whole counter ... get it to under 85 t-states if I store only the ... x rra, then I don't need to mask off the ... , printing in two passes. Saving t-states and memory.Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... the counter down to 85 t-states. Storing the bytes to be ...Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
[quote="FrankT;897326"]I've got the printing of the counter down to 85 t-states[/quote]
Congratulations!New Game: A Yankee in Iraq (2017). A shoot-em-up.Last year, I [url="https://www.worldofspectrum.org/forums/discussion/53207/new-game-2016-revival-a-yankee-in-iraq-1992"]resurrected my old shoot-em-u…
... . I might sacrifice a few T states for that.
[quote ...
