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Screen access in assemblerI am again troubled by the unusal screen design of the Spectrum. :) If I want to do something with, say, a 16x16 bit block of the screen (in the sam…
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If you'll align table on 256 bytes boundary and make it ... 512 bytes long, with 256 LSB first (192 actual and ... 64 dummy values) and 256 HSB next, you could fetch ... /> [code] ld h, HSB of table address
ld l, Y ... -
Screen access in assemblerI am again troubled by the unusal screen design of the Spectrum. :) If I want to do something with, say, a 16x16 bit block of the screen (in the sam…
... =Shiru;315883]If you'll align table on 256 bytes boundary and make ... it 512 bytes long, with 256 LSB first (192 actual and ... ]64 dummy values[/B]) and 256 HSB next, you could fetch ... />
also, sometimes is the table used for sprite clipping in ... -
Skool Daze disassemblyWhile developing [url="http://pyskool.wordpress.com/"]Pyskool[/url], I've also been putting together a disassembly of Skool Daze and Back to Skool, m…
... in memory (using a 256-byte "mirror" lookup table) to obtain the right ... bits as nibbles: two per byte. The INK always defaulted to ... Skool also used a lookup table to access text strings, which ... text strings at 32-byte or 16-byte intervals, and used arithmetic ... -
So you want to make a cardgame......but you haven't got a good deck to display. Well here is a fully relocatable routine that will do the job for you. Place the code anywhere in me…
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LD H,'PRT_RND ;256-byte table
CURND LD A,0< ... -
how to reflect a byte's bit-pattern in assembly?I'm trying to use 16 pixel-wide graphics which are symmetrical around the vertical, i.e. if the left byte is 01001110 the right byte will be 01110010…
Use a lookup table aligned on a 256 byte boundary. Then you have a fixed high byte address and the byte you're reflecting becomes the offset into the table.
Of course you still need to build this table with ugly rotate opcodes first! -
Fastest Block Drawing Code?Following on from my scrolling thread [URL="http://www.worldofspectrum.org/forums/showthread.php?p=351304#post351304"](http://www.worldofspectrum.org…
... . the end of one 32 byte (or bigger/smaller) line goes ... will be faster as no 256 byte boundries to worry about.
table. It's far simpler to ... start of the sceen address table and use POP to read ... -
many scr files to tap fileguys, I know that threads like this have existed in the past, but i'm gonna try to get a video onto speccy. The +3e to be exact. figured i'd use full…
... all rather timing-critical and error checking was one of the ... to the screen or a 256-byte sound buffer, and stopping periodically ... -
Games not compatible with real grey +2There are many threads about Spectrum+3/2A incompatibility issues but what about grey +2? I've found that games like Marauder and Skate Crazy don't w…
... with an incomplete IM2 vector table. A number of games depend ... end of the IM2 table at address (I+256) / (I+257) to ... Twins use a full 257-byte IM2 table so this wouldn't ... -
Games not compatible with real grey +2There are many threads about Spectrum+3/2A incompatibility issues but what about grey +2? I've found that games like Marauder and Skate Crazy don't w…
... with an incomplete IM2 vector table. A number of games depend ... end of the IM2 table at address (I+256) / (I+257) to ... Twins use a full 257-byte IM2 table so this wouldn't ... -
Question on copying screen bufferHi, Al my prevoius games were copying graphics directly to screen memory starting at 16384. Now I'm experimenting with screen buffer where I could d…
... buffer. I keep a 96 byte buffer (1 bit/character cell ... (257 bytes of interrupt vector table to force screen refresh to ... to screen I use a 256 byte buffer with screen addresses to ... more than 128 cells (256 bytes = 128 * 2 byte data) I flag ... -
Please test my Manic Miner remake!Thanks to everyone who downloaded my sneak preview of Manic Miner Turbo. Thanks especially to na_th_an who is the only person so far to give feedback…
... up SP. If you align copybuf on a 256-byte boundary, you could ... -
Please test my Manic Miner remake!Thanks to everyone who downloaded my sneak preview of Manic Miner Turbo. Thanks especially to na_th_an who is the only person so far to give feedback…
copybuff is aligned on a 256 byte boundary ;)
I align nearly everything. The sprite records and guardian instances are the only buffers that aren't aligned I think (would need to check). -
OptimisationI've participated in several thread hijacks about this, so perhaps I should open a new thread. Et VIOLA! Here it is! Knuth, who was earlier reporte…
... it silly to waste a byte and 3 T-states even ... is always in the same 256 byte page - instead of using the ... actually need to use a table.
So apologies to ... -
Double Dragon 128k - The graphicsAs you are all probably aware, I tried gathering a team of people together a few years back to make a totally re-programmed version of Double Dragon …
... a 256 byte lookup tables for mirroring and maybe a 512 byte table for ... a nibble shifted table for allowing sprite ... -
'Hello World' in ASM ?Can someone show how to make the classic 'Hello World' print with ASM code ? I cant figure at this moment how to insert and handle strings with the s…
... from address (60*256) instead of from (61*256).
The ... the screen. The less-significant byte is the number of character ... the bottom third. (The attribute table is at 88-90, but ... bitmap in ROM crosses a 256-byte boundary.
inc l ... -
Help! Reverse engineering a Spectrum game[deleted]
... takes advantage of code being 256 byte aligned or position dependent code ... build a table that stored a flag for each byte in the ... -
Sprites masterclassHi All, You guys are probably tired of explaining sprites but I'd like to clarify a few things if possible. I've sorted the vertical aspect of scro…
... not the usual 256 x 8 table though, it's 256 x 16 ... right halves of each shifted byte.
Unfortunately, since the ... -
Copying a SCREEN$ in ZX BASIC in 1 second?!Following on from the revived "[thread=20207]Saving a complete SCREEN$ in BASIC[/thread]" thread (although Arjun really only needed a suitable POKE i…
... me is, instead of CLEARing RAMTOP down for workspace, extend VARS ... for a full rotation in 256 byte steps. Using this trick for ... -
Kobrahsoft DB1 - doesn't work?Hi, I've tried loading [URL="http://www.worldofspectrum.org/infoseek.cgi?regexp=^DB1$&pub=^Kobrahsoft$&loadpics=3"]DB1 by Kobrahsoft[/URL] into two …
... indicate data CRC error in ST1+ST2
[*]first byte of data ... a data CRC error. The 9th sector is only 256 bytes, and ... sector (512 bytes from the 256-byte data field). I've yet ... , such as sector positions, multiple error copies and data fields for ... -
Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... table and do a lookup when required
2: Invert the byte ... nicer but after running the table generation routine you can ... a 256 byte table of reversed values
; hl = base of 256 byte table (try ... 't need to create this table
; 20/20 hindsight ... -
playing sound samples from Boriel's zxbasic-compilerfirst of all, sorry if it sounds confusing if i'm posting this thread here instead instead of at Discussions:SinclarBasic it's because this is more …
... hl = noptable on an exact 256 byte boundary
; bc = sample ... be at beginning of 256-byte page
defs LEVELS ... />
noptable contains a table of NOP instructions into which ... 1 and then the table places an OUT ... of 0 into the table depending on the ... -
Up/Down Left/Right scrollCan anybody give a newbie some pointer to simple one char scrolling by pixel? I've looked at a lot of resources, but as you can imagine, it's all a …
... each other. The 'remnant table' takes a byte GGGGGGGG and returns GGG00000 ... the right). The 'current table' takes a byte GGGGGGGG and returns 000GGGGG ... are aligned to a 256-byte boundary then each table occupies an address ... -
A new multicolor engine called BIFROST*I'm glad to announce the release of a new multicolor engine implemented by yours truly, including high quality 16x16 tiles designed by R-Tape: [IMG]…
... can believe in 256 byte alignments (there's an align compiler directive for ... -
A new multicolor engine called BIFROST*I'm glad to announce the release of a new multicolor engine implemented by yours truly, including high quality 16x16 tiles designed by R-Tape: [IMG]…
... can believe in 256 byte alignments (there's an align compiler directive for ... -
General purpose full screen input routineHi Folks, One of the things that annoyed me back in the 1980s with most BASICs was the lack of a full screen "formatted" input function. You could …
... then overwrites eight bytes in 256 byte steps from 22783 to 24575 ... I was using the 96-byte validation table idea, then at line ... -
assembly optimization: times tenDecimal numbers are not computer friendly :) Anyway, short of saying "sod it - I'll multiply by 8" - and another part of the program does indeed div…
... 256 border)
lookupLSB: precalculate LSB of all answers (if previous table ... is in
a 256 border, ... will already be at 256 border)
[/code ... in successive 256-byte tables, aligned on a 256-byte boundary. ... -
Work out attribute location in MCHow do I go about writing a MC routine which calculates the attribute address from a set of PRINT co-ordinates. I know you in basic you multiply the…
A lookup table of the address of the first byte in each row ... to start it on a 256-byte boundary. Then you just load ... it as the lower byte of the table address, then read off ... and after the actual screen table that divert drawing to somewhere ...
