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Scrolling a mapCan someone explain in idiots terms how you scroll a map. I'm not after code as such, just an explanation of how it can be done. I'd like to scroll…
... . You can do this with byte (8 pixel) positioning horizontally, and ... precision vertically. Use a look-up table of the address of each ... each rotation onto the next byte in the line, so that ... -
Playing SID music on AY??Hello. Some time ago, with occasion of another thread, I was asking about possibility of making a very certain thing - a SID emulator for Spectrum …
... back), if the CPU is up to it. If you pick ... zero-page to a different 256-byte page, the rest of it ... -
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…
... you could consider a look up table (29 t-states) - but wasting ... /> [code]
LD H, lookup / 256 ; 7
LD A,(HL ... answers (put this on a 256 border)
[/code] -
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…
... you could consider a look up table (29 t-states) - but wasting ... /> [code]
LD H, lookupMSB / 256 ; 7
LD D, lookupLSB ... answers (if previous table is in
a 256 border, this will ... -
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 ... -
BRAND NEW VTX 5000 MODEMSI have for disposal a number of BRAND NEW BOXED PRISM VTX 5000 Modems If tou would like to add one or more VTX 5000 modems to your Sinclair ZX Colle…
... party lift the telephone handset up, switch the VTX
5000 ... switch off line (up position) and talk to your ... Detection: Data is transferred in 256 Byte blocks.
EXOR checksum is ... Shift D: Transmit "Please pick up your phone"Symbol Shift E ... -
Converting UDG to 2x2I've got a udg that I want to display in different sizes. Obviously I just print it for normal size, I can use the udg in bin format to display it ea…
... doesn't need a 1024-byte data table after all, a 512 ... -byte one will do - although it ... also tried it with a 256-byte table, but the 4th column lost ... a d$(128,4,2) table, so I could avoid doing ... -
Optimisations in Exomizer Z80 decrunch codeThis is the 163 bytes old code (simple and optimized): [CODE] ld iy, exo_mapbasebits ld a, 128 ld b, 52 push de exo…
... on having the exo_mapbasebits table on a 256 byte page boundary... I use ... allow you to place the table anywhere in memory, but am ... -
Optimisations in Exomizer Z80 decrunch codeThis is the 163 bytes old code (simple and optimized): [CODE] ld iy, exo_mapbasebits ld a, 128 ld b, 52 push de exo…
... :
so an extra 565 byte space have to be reserved ... ]
Yes. The table must be 256 byte-aligned. HL and DE ... -
Fastest redraw of screen from UDGsHere's a question for everyone, to generate a bit of code to be used in games: On a standard 48K Spectrum, what's the fastest way to redraw the scre…
[QUOTE=joefish;688062]Because then they're not a fixed size. You'd either need a look-up table to find the start of each character or store all your map data as 16-bit words.[/QUOTE]
Just align them on whatever boundary you require. -
The Great Escape disassemblyHi, Over the past few months I've been steadily chipping away at reverse engineering Denton Designs' classic 48K title, The Great Escape. I'm now a…
... 'd either need a look-up table in the program or a ... a full character set starting 256 bytes lower in memory. So ... -
Trailblazer - mapped?Anyone mapped Trailblazer yet? I'd kind of like to get hold of the maps. D.
... by fitting each tile on byte boundaries, I was going ... and save them, ending up with 255 tile permutations coded ... of each of the 14 byte maps in turn, POP ... that makes the pattern look-up table 48960 bytes, I couldn' ... t even fit the look-up table into RAM, let alone ... -
Fantasy Z80 instructions?This follows on from something catmeows said in another thread, and that I've been meaning to ask for a while. This may sound daft to people with mo…
... setting H=0 and L=256 byte index but you are not ... to just one page of 256 bytes. You're a little ... was no longer a 4-byte "extend" opcode to introduce the ... would not have been taken up in 1975. -
Storing strings in minimum spaceIn the game I am planning there will be a number of text strings. I am looking into different ways of encoding the strings so that they use the minim…
... the token technique and single byte values $A5-$FF to replace ... cross-reference to a look-up table when printing.
5 ... -
Where do you stick the stack?...OK, so I've got a fair chunk of ASM code assembled from 24000 mark. The stack shouldn't get very big, just a few PUSHes and POPs of the main regis…
... SP,$5BFF and use the 256 bytes in the unused area ... Jetset Willy use every single byte of the 48K including System ... 't need a 256 byte interrupt table as the low byte of the interrupt ... -
Where do you stick the stack?...OK, so I've got a fair chunk of ASM code assembled from 24000 mark. The stack shouldn't get very big, just a few PUSHes and POPs of the main regis…
... 't need a 256 byte interrupt table as the low byte of the interrupt ... -
Tape loading - blocks with checksumThese were sometimes used for 128K games and had a searching / loading message, ie. Loading Block 08, then if a block didn't load right one could rew…
... load memory in block of up to 256 bytes. If an unrecognised ... save the screen as 27 256-byte blocks, and load it back ... -
Spectaculator 8 vs REAL diskDoes Spectaculator 8 support real floppy drives? I want to use an external USB floppy drive to read/write +D and +3 floppy disks. I have Windows 7…
... +3, but TR-DOS uses 256 byte sectors and cannot be read ... . You may need to close up half of the index hole ... -
Spectaculator 8 vs REAL diskDoes Spectaculator 8 support real floppy drives? I want to use an external USB floppy drive to read/write +D and +3 floppy disks. I have Windows 7…
... +3, but TR-DOS uses 256 byte sectors and cannot be read ... . You may need to close up half of the index hole ... -
Mirroring UDG'sJust wondered is there a quick an easy way of mirroring UDGs (byte values)? i.e. BIN 11110000 becoming 00001111 etc.
The quickest way is to use a pre-calculated 256-byte flip table aligned to a page boundary, like the one at [url="http://pyskool.ca/disassemblies/contact_sam_cruise/asm/32256.html"]32256[/url] in Contact Sam Cruise. -
Movin And A Groovin Horizontal Flip improvementOn the left is the flip horizontal portion from Andy Pennell'S excellent Movin' & a Groovin' machine code screen routines from Your Spectrum #19 (Oct…
... , then using a lookup table method as follows, but ... z80 fast using a lookup table.
Scr_add ...
Create lookup table to 256 byte boundary (requires 256 bytes of free space ...
;17 bytes
256 byte table will look like this:
Clashbasher a new interface to reduce colour clashI've been working on this for a while now. [IMG]http://markamy.uwclub.net/cauldron.JPG[/IMG] Basicly its an add on for a 48k spectrum, which reinte…
... for a total palette of 256 colours. Also they are in ... drop the colour you get 256 grey shades.
[quote ... one of four color look-up tables (CLUTs). That's how ... chip to hold the look up table.[/QUOTE]
You only need ...display file addressing; screen slicingWhile working on this Compendium I'm updating or rewriting a lot of stuff. One thing I eventually came to appreciate was the simple & clever way in w…
... table will have 128 entries so will fit in a 256 byte page ... read a two-byte screen address out of the table.
256 byte page.
If you ... the high bytes in one 256-byte page and the low bytes ...SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
... ; add one for the inclusive byte
add hl, de ... HL points to first displaced byte
ret ; end of ... hl ; point to first data byte
ret ; end ... ld hl, op_str_lu ; address look up table
call indexer ; get offset ...128k gamesHi. I've come to World of Spectrum for advice. I'm a Commodore guy OK, please be nice to me, as I seek your wisdom! I love the Commodore 128, and I'…
... all in the same control byte.
Another problem is ... . But then they screwed it up by either giving you (a ... a data map or look-up table to save time interpolating or ... the copy was to end up at the same address in ...hash function permutation tableI'm using a simple Pearson hash function to generate keys for a $(103,6) array using a 256-byte permutation table. How do I arrange the entries in th…
A 256 byte hash table seems ideal for implementation in ... emulators already use a hash table to decode the opcodes (Zero ... optimize it to a jump table I've been told), but ...Math Quiz - MultiplicationThe topic is fast multiplication routines, from 8x8 to 32x32 and all points in between. These functions sit underneath floating point libraries, gen…
... , and use a small look up table for the result (and carry ... bit * 8 bit is four table lookups, and add the results ... , etc.
Yes, the table runs to a page.
byte?
In the end ...Is ESXDOS flexible enough to incorporate e.g. Spectranet commands?I was just discussing the idea with someone about the wish some people have to be able to combine interfaces such as DivIDE (Plus) / DivMMC EnJOY! wi…
... STDIO_MSG_EATC
;
; set-up: hl = state machine function address ...
I quite often end up rewriting stuff because I didn ... eg, which I think have 256 byte sectors; you could always do ... buffers and only give up the least-recently-used ...
