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Moving a line down the display in assembler?...It's not a "[I]how can I do it[/I]" question, it's more a "am I missing something in trying to do it a new way" kinda question. What I've been doing…
... First I'm generating a table of screenaddresses. I [URL ... that generates a 512 byte table (128 bytes of it ... on the start of a 256 byte page.
...
ld h,SCRTABLE/256
add a,(hl)< ... 512 bytes on a table might earn me a ... -
CMWC random number generator for Z80Seeing the interest regarding the [URL="http://www.worldofspectrum.org/forums/showthread.php?t=23070"]Xor-Shift random number generator for Z80[/URL]…
... c,e
ld hl,table
add hl,bc< ... br />
ret
table
db 82,97,120 ... /> As you can see, the table access is quite expensive compared ... computation itself. Having the table aligned to 256 byte boundary could be used ... -
Rendering clipped glyphSometimes you need to render a glyph of arbitrary size to the screen. And clip it. For example: drawing a mouse cursor means combining drawing of a…
... glyph_t *glyph,
byte x,
byte y,
rectangle_t *clip_rect ... address table (using standard trick with two tables on 256 byte boundary ... point 12 then first byte mask will be 11111110 ... and end byte mask will be 00000111. ... -
Scrolling Bi-Colour Engine for 4-Player GamesJust putting this code up for people to have a look at. Far from finished. Should simply compile and run a bit of a demo. Only good for 128K and +…
... br /> ;Use interrupt table at 48640 (190*256) and point to 191 ... />
;Interrupt vector table to go at 190*256 = 48640..48896
;Point interrupts to the table:
ld a,190
table
REPT 8,int_sprite_attr_loop
Optimal shifting for set pixel?Hi, I'm optimizing my set pixel code. For speed. But without using partitioned memory (i.e. a table on 256 byte boundary) I have optimal memory addr…
... memory (i.e. a table on 256 byte boundary) I have optimal memory ...Mirror tableCan anyone help with a byte mirror table? e.g. so you can look up a byte of a left-facing sprite and return the correct right-facing value. There …
Can anyone help with a byte mirror table? e.g. so you can ... look up a byte of a ... up a byte and returning its mirrored value from the table using ... if anyone's got a byte mirror table to hand, please point ...Horizontal scrollDoes anyone know how to do a 2 or 4 pixel left or right horizontal scroll of the spectrum screen. I can make a 1 one pixel scroll with: ... rl (hl…
... supposed you could create a table of values relating to multiple ... say you would have a 256 byte table and do something like:
LD H,table ; point to a 256 boundary table
LD A ... ,(HL) ; get shifted value from table ...Advice about drawing sprites on spectrum I've coded sprite drawing before and know all the theory about masks from a long time ago (microhobby rules! ;), but since I did it on Amiga with ha…
... /> 2. Having a shifting table, along these lines:
... hl is base of shifting table
; ix is ... The rotation table is pointed at by h*256 and ... not hl if we are being pedantic. The table ... must start on a 256-byte boundary.
Sync-buzzer, interrupts and general confusionBeen wittering on about this in the Misc group, but thought it was best discussed here. Basically been trying to recreate the Sid-Sound effect from A…
...
Effectively I*256 points at a 256 byte table containing interrupt service routine ... *256+255,I*256+256. So the Spectrum needs a 257 byte table ... every byte of the 257-byte table pointed at by I*256 ... 0xf100 inclusive. Every byte in this table is set to ...An MC question (sorry, there's no MC forum to post to!)Ok, still struggling with learning MC - but am getting there. I just can't find anywhere on the web / in books that explains how to do arrays in MC.…
...
add a,MyArray%256
ld l,a< ... you align MyArray to the
; start of a 256-byte page ... evenly
; divisible by 256 so that, in 16
ld h,MyArray/256
ld a,(hl)< ... example above, sz=1 byte so no multiplication was necessary ...Pixel setting / general speccy codingi just started doing some cross-coding with the [url="http://www.bigfatpanda.fsnet.co.uk/z80.html"]Z80 SNA assembler[/url] and an emulator, and this …
... br /> LD H,LINEPTRS/256
ADD A,(HL ... assumes the pixel table doesn't cross a 256 byte boundary.
If you place the pixel table ... right at the beginning of a 256 byte page, ...
LD D,PIXELTAB/256
LD E,A
need help with speed optimization. this procedure draws a sprite with mask from memory onto the screen with x-coordinate in pixels. it doesn't shift sprites in realtime, it just uses …
... to look up the table for every byte, which is fairly time ... dealing with only 256 bytes. Each of this 256 byte tables is organized ... 4 more registers for storing table address)
Unfortunately, I ...need help with speed optimization. this procedure draws a sprite with mask from memory onto the screen with x-coordinate in pixels. it doesn't shift sprites in realtime, it just uses …
... ;placing table at the beginning of
;a 256 byte page ... br /> LD H,C0H ;table with preshifted mask bytes for ... B0H ;there is a table with all bytes preshifted ... form:
;mask byte, sprite byte, mask byte, sprite byte... and so on.) ...need help with speed optimization. this procedure draws a sprite with mask from memory onto the screen with x-coordinate in pixels. it doesn't shift sprites in realtime, it just uses …
... ADD A,BYTETAB/256 ; there is a table with all bytes preshifted ... address table
* SCRTAB must be at the start of a 256 byte ... start of the next
* 256 byte page.
SCRTAB ... shifted each byte takes two bytes
* The table is divided ...InterruptsCan someone help with providing some info or a link about IM 2. I know I need to create a vector table and want to store this as high in memory as po…
... *256. The peripheral supplies a single byte identifier that indexes into this table ... a table lookup at address I*256+255/I*256+256, meaning the table must ... same byte in the entire table. Eg: from i*256 through i*256+256 inclusive ...Map to screen address problemCan anyone help me out with what I guess is a screen address calculation problem. I need to calculate the screen address of a tile based on a number…
... 'd definitely use a lookup table for speed instead of the ... at the start of the table (with interrupts disabled of course ... SP here, and if your table contains 256 entries or less (this ... ), it's worth using separate 256-byte blocks for all the entries ...Convert x,y to Attribute Address in AssemblyWhat is the fastest way, given x,y (in hl) to return the attribute address?
... the expense of a 512 byte lookup table, you might want to ... has to be on a 256-byte boundary, of course.
ANN: SP1 for Z88DK (aka splib3, Sprite Pack v3.0)Well it's finally arrived, after a month of "a few days from now" release deadlines. SP1 is the lastest version of splib, a flicker-free software sp…
... in the default configuration the table occupies addresses $f200-$ffff ... t need the rotation table. The rotation table is not used ... tile array is a 512-byte table of pointers. Each entry ... is actually two 256 byte arrays, with the first 256 bytes containing ...ANN: SP1 for Z88DK (aka splib3, Sprite Pack v3.0)Well it's finally arrived, after a month of "a few days from now" release deadlines. SP1 is the lastest version of splib, a flicker-free software sp…
... vector table. The interrupt vector table must begin on an exact 256-byte page ... table with the same byte. This way the z80 will always read byte*256+byte ... want a 257-byte table. A "0" would make a 256-byte table, which is ...Biotoxins redumping projectI've been spending quite a bit of time between dumping STP / MIA titles at looking at the titles flagged by Biotoxin as possibly needing a redump... …
... BYTE number of symbols in the alphabet (interpret 0 as 256 ... )
SYMREC [..] alphabet table (rows=alphabet symbols)
BYTE ... 256)
SYMREC [..] alphabet table (rows=alphabet symbols)
BYTE ... of repetitions
BYTE symbol
...Delay routineAs some people are aware, I have recently starting writing a [url=http://fuse-emulator.svn.sourceforge.net/viewvc/fuse-emulator/trunk/fusetest/]autom…
Anyone care to write a version that doesn't require a table aligned to 256 byte boundaries (and has the table directly following the code)? Thought I'd ask in case someone does so that I can avoid a little work :-)Delay routineAs some people are aware, I have recently starting writing a [url=http://fuse-emulator.svn.sourceforge.net/viewvc/fuse-emulator/trunk/fusetest/]autom…
... require a table aligned to 256 byte boundaries (and has the table directly ... [CODE]overhead2 EQU 21 + (LOW table)[/CODE]
The 16 is ... that as long as the table and the "remainder" routines ... ] ASSERT (HIGH t_ret = HIGH table)[/CODE], which will fail if ...Preferred way of determining Y co-ord in assembly?I know of 2 ways of calculating the y-cord of a pixel row for the speccy in assembly. One is to calculate the address by ways of shifting and masking…
... HL
FAST: LD H,TABLE/256 ; 2 / 7
... a 192 bytes table, aligned to a 256 byte boundary, and ... followed by another 192 bytes table ... bytes table, aligned to a 256 byte boundary, and this table is ...Preferred way of determining Y co-ord in assembly?I know of 2 ways of calculating the y-cord of a pixel row for the speccy in assembly. One is to calculate the address by ways of shifting and masking…
... HL
FAST: LD H,TABLE/256 ; 2 / 7
ADD A ... to a 192 bytes table, aligned to a 256 byte boundary, and followed ... by another 192 bytes table 64 ...He's back......and he's got a new trick! AY Chip here. I've been away far too long. I would like to announce 'HatStand': for no adequately explored reason, I h…
... as the high byte for a look-up table of addresses. The ... hardware supplies the low byte (depends ...
In practice the low byte could be anything so programmers ... then filled the entire 256-byte block with that byte to make sure ...Disappearing/appearing effectI remember doing a small routine in BASIC which could be used to cover the attributes section randomly, until all 704 characters were filled with the…
... a saving! Place your 'bit table' on a page boundry for ... register to access the bit table as you say. I thought ... a constant, aligned at a 256-byte boundary and C L or ... suggestion can be optimised. The 256-byte boundary can be a bit ...Channels and streamsSo I've put some thought into channels and streams, and read the dead (and presumably rotting corpse) of the CSS FAQ which contains some information …
... are accessed via a jump table. So long as the jump ... table exists and points to the ... gets updated. The jump table (in the 256 byte block starting at 0x3E00 ...VIC 20 emulation on the SpectrumI'm sure most people are aware of the my attempt at bringing the full Commodore experience to Sinclair users with the "Twenty Commodes" program. It e…
...
; PTR2 points to 256 byte table of worm segment positions
LDA #SPRITES%256
STA PTR1
... WORMPOS data
LDA #WORMPOS%256
STA PTR2
... position in A & WORMPOS TABLE
TYA
LDY ...I just learnt that Spectrum has 1kB of unused ROMWell, man learns through all his life. I have just discovered that Spectrum has over 1 kilobyte of unused ROM memory, from address 14446 to 15615. Al…
... trap (a 256 byte area) for the Spectranet indirect call table. Then I ... (with a very small 8 byte entry point area right at ...
