-
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…
... /> ld hl, rtable ; base address of table
ld h, d ; DE
ld l, e ... -
SCREEN$ bug fixI've been using the SCREEN$() function recently for reading data off the screen rather than taking up space with an array and I got fed up with the s…
... I incorporated a little parameter table for CHARS, UDG and BLOCK ... -byte = base address adjustment = (256-offset)/256 = 0 or 1
; 5 ...
ld l,(ix-20)
ld h,(ix-19)
ld e,(hl ... -
How to print logo onto screen at chosen coordinates?Hi, I've just got back into zx spectrum games after all these years and after seeing some of the great games on here I would like to start learning p…
... the block graphics table) is at PEEK org+256*PEEK (org+ ... /> ld l,a
ld a,h
or $58
ld h,a ... and %11111000
ld h,a ;H =010ssppp
ld a,b
and ... -
Multiply by 48Is there a 'cheat' to multiply by 48 in Z80? I have a table of sprites 48 bytes each entry, and I want to be able to offset my pointer with a simpl…
... memory, put the sprites at 256 byte boundaries and just add ... =$0B
add a,h
ld h,a
HL ... 't clarify is that the table will hold 4 frames for ... consider:
Having a table of pointers to your sprites ... -
JP (HL) confusionokay.... JP nn will jump to memory address nn. JP (HL) ,I assumed would read the contents of memory address HL and jump to the location and be a gre…
... ; to next byte
LD H,(HL) ; H store 'H' of jumptable data
jumptable ; aligned to a 256 boundery
DEFW donothing ; 0 ... requirement is that the jump table is high-byte aligned. However ... -
Optimal shifting for set pixel?Hi, I'm optimizing my set pixel code. For speed. But without using partitioned memory (i.e. a table on 256 byte boundary) I have optimal memory addr…
... be made (if placing shift table on 256-byte boundary) by using ... />
[CODE]
LD H,$HIGH(SHIFTS)
LD L,#nrshifts
JP ... -
Snowfall effectHow do you go about creating a snowfall effect like the one in Yeti? Now don't laugh, I'm currently printing 32 UDG's of dots OVER the top of my gam…
... table
djnz snowloop
ret
;
snowtab ;x (0-256 ... of screen display.
ld h,a ; line * 256.
; Find which third ... give segment start address.
ld h,a
; Find character cell ... -
Snowfall effectHow do you go about creating a snowfall effect like the one in Yeti? Now don't laugh, I'm currently printing 32 UDG's of dots OVER the top of my gam…
... IX to next entry in table
djnz snowloop
ret ... of screen display.
ld h,a ; line * 256.
; Find which third ... give segment start address.
ld h,a
; Find character cell ... -
Snowfall effectHow do you go about creating a snowfall effect like the one in Yeti? Now don't laugh, I'm currently printing 32 UDG's of dots OVER the top of my gam…
... IX to next entry in table
djnz snowloop
ret ... of screen display.
ld h,a ; line * 256.
; Find which third ... give segment start address.
ld h,a
; Find character cell ... -
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]…
... + 1 ) & 7
ld hl,table
add hl,bc
[CODE]rnd:
ld de,table ; i
ld a,e
inc ... ]
ld b,0
ld h,c ; t = 256 * y
ld l,b ... -
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]…
... ]rnd:
ld bc,0 ; i
ld hl,table
add hl ... ,bc
ld a,c ... de,hl
ld h,c ; t = 256 * y
ld l,b
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]…
... version? Put reference to table at the beginning, making ... ]rnd:
ld hl,table
idx:
ld bc,0 ; i ... hl
ld h,c ; t = 256 * y
ld l,b< ... x
ld (de),a
ret
table:
db ...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]…
... />
ld h,c ; t = 256 * y
rnd_cy ld l,0 ; t = 256 * y ... table%256
db 15
if (table/256)-((table+15)/256)
error "whole table ...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]…
... = &cy
ld b,h ; bc = &q[i]
256 byte block:
rnd ld hl,table
ld a ... = &cy
ld b,h ; bc = &q[i]
Code structureHi all, I'd be interested in opinions on the neatest way to do this. I've got a print string routine in which 0-31 are reserved for control codes, …
... can implement jump table with SMC, using a 256-aligned "jump_table ... br /> My JP table was already 256 aligned, but was ... /> inc hl
ld h,(hl)
ld l,a
jp ... that style of jump table to redraw the screen, ...Game development guidesHello all, I want to get into game development for the ZX Spectrum and would like to know where I can find some helpful guides. I've looked around t…
... /> ld h, (sineTable >> 8) & $FF ; Get MSB of table
ld ... )
add a,sineTable%256
ld l,a
adc a ... ,sineTable/256
sub l
ld h,a[/code]Game development guidesHello all, I want to get into game development for the ZX Spectrum and would like to know where I can find some helpful guides. I've looked around t…
... also applies to the vector table example previously mentioned:
[code ... /> ld l,a
adc a,VectorTable/256
sub l
ld h ... ,a
ld a,(hl ...Fixed point math lib?Is there a liberally licensed fixed point math lib for z80 somewhere? When searching, I expected to find a bunch of GPL'd ones and perhaps one or two…
... course the table of squares has to be on a 256 byte ...
mect2
ld l,a
ld h,>squares_lo
h
ld l,b
ld a,(hl)
inc h
ld h,(hl ... /> ld l,a
ld a,0
sbc a,h
ld h,a ...Printing text, part MMXIIXI'm pretty sure there's been a zillion threads about this already, and I don't think it's the first one by myself either, but here goes. Proportiona…
... table
ld bc,#_yofs+0
ld l,7 (ix)
ld h ...
ld l,a
ld h,#0x00
... pre-shifted
ld h,#0x00
add hl ... so simple +256 is enough)
ld de, ( ...im looking for other games like the muncher that use double height and width graphics with colouri havent come across this type of graphics mode on the spectrum before and would like to know if there are any other games that use it.
... away with just a 256 byte table for the flip ... /> but is smaller than regular 256 bytes table + code
table can be much smaller - ... L = sprite cellwidth
ld h, 0
ld (keep_spr_width), hl
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... also better using a table for your level pointers, ... read 2 bytes from a table into a register).
... in the table must not cross a 256 byte boundary ... /> inc l
ld h, (hl)
ld l, a
[/ ... from location from a table of 16 bit pointers ...LINE-routine and other nice pieces of codeThe line-topic came in the end with a nice piece of fast coding. I think that there might be more of these routines out there (where-ever-u-r). Isn…
... LD A,(DE) ; fetch code to be emulated (7)
.......LD H ... ,B ; point H to table (4)
.......LD L,A ... ; HL points to highbyte (4)
.......LD H ...
Total memory for table 1K. Minimum required = 512 ...Z80 Emulator Source?Found a link to this on comp.sys.amstrad.8bit. i havent been with the discussion long but supposedly this is the source for a Z80 emulator. Forgive m…
... />
fetch: ld a,(de)
ld l,a
ld h,21h
;instruction jump table
jumpb .equ 0c3h ...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 …
... a table with all bytes preshifted to all steps.
LD H,A ... ;| finding a suitable part of preshifted bytes table to ... C
LD A,H
SUB 8
LD H,A
...Machine Code Sprites Example Code Using Char Based SystemBelow is my WIP code to do smooth screen wrapping sprites using char positions and offsets, as opposed to writing direct to a line (0-191) and shifti…
... /> INC H ; *256 to get next line
LD A,(DE)
LD (HL ... H ; Increase H, thus moving 256 bytes forward in memory to FB0Ah
LD H ...Smooth Screen Scrolling RoutineHi everyone, this is a follow up to the thread on smooth screen scrolling. As promised here is the code for the routine. It's pretty long and fairl…
... INC H
LD (HL),B
LD H,D
LD L,E ... INC H
LD (HL),B
LD H,D
LD L,E ... INC H
LD (HL),B
LD H,D
LD L,E ... table
SUB 12
LD L,A
INC H
LD ...The incredible shrinking screendumpIn this topic I stated that I would be impressed if the screendump could be smaller than 37 bytes. [url="http://www.worldofspectrum.org/forums/viewt…
... B 0
nline ld hl,table-1 ; Use JR value ... ; B becomes 0 after 256 times
ld b,(hl) ; B = ... ; Goto next byte in table
ld e,(hl) ; Fetch ' ... last' byte in table
prbyte ld a,(hl) ; Fetch byte ...Programming MC : first stepsIsn't nice to collect all kinds of short routines to help making the first steps into MC for everyone who never touched MC? What I mean is mostly th…
... /> Reading a value from a table in MC
When ... next number
ld a,h
and #3f
ld h,a ; but ... keep it in ROM
ld (seed),hl ...
