-
A new Apple 1 emulator for the SpectrumHi all, I'm happy to announce a new Apple 1 emulator for the Sinclair ZX Spectrum! It's a port of Simon Owen's Apple 1 emulator for the SAM coupe to…
... main ld a,(de)
ld l,a
ld h,table/256
ld h,(hl)
jp (hl)
org $7000
table ... : defb $71,$73,$72 repeat until 256 bytes filled ... you can change the LD H,N in LD H,B reaching every ... -
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…
... =L; output HL
FAST: LD H,TABLE/256 ; 2 / 7
ADD A ... bytes table 64 bytes later, at TABLE+256.
The first table is ... =A; output HL
HIBRI2: LD H,SMALLTAB/256 ; 2 / 7
RLCA ... -
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…
... =L; output HL
FAST: LD H,TABLE/256 ; 2 / 7
ADD A ... bytes table 64 bytes later, at TABLE+256.
The first table is ... -
rotating HL left through CarryI've tried this several ways, and it works for a while, then a particular value has a bit set in an inconvenient place and it all goes to pot. Eg: "…
... only need to fill a table with 256 bytes with a function ... , $84->$48. So the table is:
[CODE ... />
If you consider the table so long, you can generate ... br />
[CODE]
ld h, table/256
ld b, 0
here inc ... -
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…
... in DE. table should be aligned on a 256-bytes boundary, first ... 24 bytes of the table are ... /> [code];H=X L=Y
ld a,h
ld h,table/256
ld d,(hl ... room for larger table - first half is at 256-bytes boundary, next ... -
Thinking of modding an Atari paddle controller for games like Arkanoid...Hello, Was thinking of trying out a controller mod using an Atari 2600 paddle controller to use with games like arkanoid, Batty, etc... The paddle c…
... /> ld h,Table/256
ld l,a
ld a,b
ld (OldValue),a
ld ... -
Help with 1-bit sampled soundHi all, I've been sent over this way from the CPC Wiki forums as you guys may be able to help me more specifically with a programming query. Firstly…
... [CODE]
ld de,sample
ld h,table/256
ld c,254
ld a,(de) ... . You could lengthen the table entries, or repeat them, ... sample rate. Maybe the table could be tweaked for ... -
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…
LD A,#x;
AND #7;
LD H, table/256; # locate table in such manner that L=0
LD L,A;
LD A,(HL);
table defb #80,#40,#20,#10,#08,#04,#02,#01;
-----
It's untested, but you should get the idea. -
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…
... ;
AND #7;
LD H, table/256; # locate table in such manner that L ... =0
LD L,A;
LD ... A,(HL);
table defb #80 ... like:
[CODE]
ld h,bw/256
ld l,X; X is ... -
IX+n and self modifying code and pasmoI'm using pasmo and if I wanted to use ix+n like this: (ix holds the position to a sinus table) ld (symbol), a LD a, (ix+symbol) What I want to do…
... of 256, ie $xx00) you can use:
[code]LD HL,table ; Point ... to start of table at $xx00
LD L ... :
[code]LD H,table/256 ; Point to table at $xx??
LD L,A ; Index ... -
Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …
... have used a look up table for the char address, and ... ;BUILDING UP A TABLE WITH
LD BC,0FDH ;253*256+253, I ... , EG. L=10
LD H,SCREENTABLE/256 ; POINT H TO FA00H, SO HL ... -
Smooth Masked Sprites using fast page flip on 48k Part 2Ok, After all the suggestions in Part 1, which were all excellent (Thankyou), I opted on the following: I have 2 x 6k Offscreen areas (Yes, that's …
... ;BUILDING UP A TABLE WITH
LD BC,0FDH ;253*256+253, I ... , EG. L=10
LD H,SCREENTABLE/256 ; POINT H TO FA00H, SO HL ... H ; INCREASE H, THUS MOVING 256 BYTES FORWARD IN MEMORY TO FB0AH
LD H ... -
Pixel Explosion CodeJust a little snippet to cause explosive effects. It uses table lookups for the screen address, and can handle up to 32 pixel particles. A particle…
... -255)
ld h,screen_xpos_table/256 ; point h to beginning of xpos table
; so ... of screen
ld h,(hl) ; h now = screen address (left hand ... -
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="http ... that generates a 512 byte table (128 bytes of it ... /> ld h,SCRTABLE/256
add a,(hl)
inc h
ld h,(hl)
ld ... -
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
table:
ld a,190
ld i,a
ld h,colour_address_A/256
ld l,a
ld sp,hl
Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…
... /> ld de, (scr_out_row)
ld h, tbl_rows/256 ; address of the screen rows table page ... font
ld h, 0
ld d, FONTBASE/256
ld e, h ; zero E ... /> ld de, (cursor_row)
ld h, tbl_rows/256 ; address of the screen rows table page ...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 ... a 256 byte table and do something like:
LD L ... shift
LD H,table ; point to a 256 boundary table
LD A,(HL) ; ... get shifted value from table< ...help in byte mirroring.I need some help. What is the best way to mirror the byte? (for ex. 10010011 -> 11001001) I mean, if there is a simple way to do it (may be with OR, …
need a Table of 256 bytes stored on a 256byte boundary
on entry: a=byte to mirror
FlipByte:
ld h,TableAdress/256
ld l,a
ld a,(hl)
retPixel 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 …
... /> LD H,LINEPTRS/256
ADD A,(HL)
INC H
LD H,(HL)
LD ... 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 ...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,A
LD H,C0H ;table with preshifted mask bytes for ... a table with all bytes preshifted to all steps.
LD H,A ... /> LD H,SCRTAB/256
ADD A,(HL)
INC H
LD H,(HL)
LD ...Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …
... ;BUILDING UP A TABLE WITH
LD BC,0FDH ;253*256+253, I ... , EG. L=10
LD H,SCREENTABLE/256 ; POINT H TO FA00H, SO HL ... H ; INCREASE H, THUS MOVING 256 BYTES FORWARD IN MEMORY TO FB0AH
LD H ...Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …
... ;BUILDING UP A TABLE WITH
LD BC,0FDH ;253*256+253, I ... , EG. L=10
LD H,SCREENTABLE/256 ; POINT H TO FA00H, SO HL ... H ; INCREASE H, THUS MOVING 256 BYTES FORWARD IN MEMORY TO FB0AH
LD H ...Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …
... ;BUILDING UP A TABLE WITH
LD BC,0FDH ;253*256+253, I ... , EG. L=10
LD H,SCREENTABLE/256 ; POINT H TO FA00H, SO HL ... H ; INCREASE H, THUS MOVING 256 BYTES FORWARD IN MEMORY TO FB0AH
LD H ...Pixel Explosion CodeJust a little snippet to cause explosive effects. It uses table lookups for the screen address, and can handle up to 32 pixel particles. A particle…
... )
ld h,screen_xpos_table/256 ; point h to beginning of xpos table
... )
ld h,screen_xpos_table/256 ; point h to beginning of xpos table
...Pixel Explosion CodeJust a little snippet to cause explosive effects. It uses table lookups for the screen address, and can handle up to 32 pixel particles. A particle…
... -255)
ld h,screen_xpos_table/256 ; point h to beginning of xpos table
; so ... hl=address in xpos table
ld a,(hl) ; a = x ...Pixel Explosion CodeJust a little snippet to cause explosive effects. It uses table lookups for the screen address, and can handle up to 32 pixel particles. A particle…
... -255)
ld h,screen_xpos_table/256 ; point h to beginning of xpos table
; so ... hl=address in xpos table
ld a,(hl) ; a = x ...My little first set of routines.Hi all, I just coded a little set of routines just to draw a screen on video mem and a fade out. I could have just copied the screen rendering rout…
... /> LD H,TABLE>>8 Table must start on address divided by 256
LOOP:
LD ... .
[/code]
Table is 256 bytes long. If you don ...My little first set of routines.Hi all, I just coded a little set of routines just to draw a screen on video mem and a fade out. I could have just copied the screen rendering rout…
... /> LD H,TABLE>>8 Table must start on address divided by 256
LOOP:
LD ... .
[/code]
Table is 256 bytes long. If you don ...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…
... byte
LD H,'PRT_RND ;256-byte table
CURND LD A,0
INC A
LD (CURND ... +1),A
LD L,A
LD B,(HL ...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…
... code for the pre-shift table sprites demo. To save space ... to see if the shift table approach would be fast enough ... ld h,a
ld a,b
and 7
add h
ld h ... /> ;
build_tables ld h,shiftbyte/256
ld l,255
ld b,255
