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Is there an SNA halt bug?Hello all, I noticed that some SNAs don't work on my emulator but they do work in almost everyone else's, SPUD fails with them too which is a tad sp…
... .
pop af
ld i,a
pop hl
pop de
pop bc
pop af
ld r,a
pop af
ld sp, (22B0h) ; SP
Is there an SNA halt bug?Hello all, I noticed that some SNAs don't work on my emulator but they do work in almost everyone else's, SPUD fails with them too which is a tad sp…
... .
pop af
ld i,a
pop hl
pop de
pop bc
pop af
ld r,a
pop af
ld sp, (22B0h) ; SP
generating a pre-defined list in an un-defined sequenceI've decided to become a drunkard, to which end I've been drinking a whole bottle of beer in one day (whereas normally I'd make it last 2 or 3 days).…
... 10 seconds to blank the screen ... but ... there's one sma ... were here
pop hl
pop bc
dec bc
ld a,b
Full 16*16-digit BASIC multiplicationI liked Andre Adrian's 32-bit long multiplication routine so much that I decided to a decimal version. After all, 2^63 is only 9223372036854775808, a…
... /> pop bc ;BC=$3365
pop de ;DE=$0000
inc sp
inc sp
pop hl ;HL ...Scrolling by 2 pixelsWhat is the fastest way of scrolling a Spectrum screen line by 2 pixels left or right? When thinking about it I've come to this simple solution: [C…
... /> pop hl
pop de
inc sp ;can't do "pop bc"
inc sp ; as ... one pixrow
ld hl,256-32
add hl,sp
ld sp,hl
dec ...Scrolling by 2 pixelsWhat is the fastest way of scrolling a Spectrum screen line by 2 pixels left or right? When thinking about it I've come to this simple solution: [C…
...
exx
pop hl
pop de
pop bc
rla
rr ... de
push hl
ld hl,10
add hl,sp
ld sp,hl
xor ...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…
... /> [CODE]Full screen flip
attrs ld hl,$5AF0
ld ix,$0000 ...
add ix,sp
ld sp,$FFF0 ...
ld a,(bc)
ld c,(hl)
ld (hl),a
ld a,(bc)
ld (de ...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…
... hl,sp
bit 3,h
jr nz, alp
screen ld b ... /> ld c,a
ld a,(bc)
ld c,(hl)
ld (hl),a
ld a,(bc ... )
ld (de ...128 BASIC-compatible way of loading BASIC as code?On a 48K Speccy (or from 48 BASIC or USR 0 mode on a 128K machine), one can do a silly trick like this: [code];; load a 4000 byte BASIC program ld i…
...
CALL $04C2 ;SA_BYTES
pop bc
ret
; ... ;LD-BYTES
ld hl,(23613) ;(ERR_SP)
ld sp,hl ;reset stack
ld hl ...SCREEN$ 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…
... codes $80-$87 match the screen character,
;if not use ... ,0
pop hl
ld bc,12
add hl,bc
ld c,(hl) ;C =col ...Copy 4Kb in Assembly?Here's an interesting problem: what's the best way to copy a block of 4Kb in assembly? The most obvious solution is to use [B]LDIR[/B]: [CODE] l…
... /> LD SP,IX
POP HL
POP DE
POP BC
EXX
POP HL
POP DE ...
POP BC
POP AF
LD SP,IY ...Copy 4Kb in Assembly?Here's an interesting problem: what's the best way to copy a block of 4Kb in assembly? The most obvious solution is to use [B]LDIR[/B]: [CODE] l…
... /> LD SP,IX
POP HL
POP DE
POP BC
EXX
POP HL
POP DE ...
POP BC
POP AF
LD SP,IY ...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…
... DE
pop bc ; error address to BC
ld (hl), 0x3e ; ... ld sp, hl ; SP to empty GOSUB stack
push bc ; stack error address
ld ... pop bc ; stmt-ret address to BC
pop hl ; error address to HL
pop ...Simple memory transfer routineI'm looking for a simple memory transfer routine that shifts 32 bytes of data from the address HL is set to 55143, I have tried using LDIR, but cant …
... /> ld hl, sp
push hl
ld hl, source + 32
ld sp, hl
pop af; 2
pop bc ... ; 4
pop ... de; 6
pop hl; ...Small demo to show my sprite engine for ZX Spectrum 48KThis demo shows 13 sprites moving at 50fps totally flicker free: 12 enemies bouncing in edges and the main character, controllable with OPSA (note S …
... , isn't using LD:PUSH in a flip screen game a bit ... ] ;...
pop de
ld a,(hl)
ld (bc),a
inc bc
and ... e
or d
ld (hl ...Small demo to show my sprite engine for ZX Spectrum 48KThis demo shows 13 sprites moving at 50fps totally flicker free: 12 enemies bouncing in edges and the main character, controllable with OPSA (note S …
... , isn't using LD:PUSH in a flip screen game a bit ... ] ;...
pop de
ld a,(hl)
ld (bc),a
inc bc
and ... observed) a 40000 cycles flip screen every frame. This is almost ... switch between normal a shadow screen at the begining of the ...What Spectrum projects (Software/Games/Utility)(Hardware)(Others) are you working on?So, basically that :) You dont have to give names or more clues if you dont want to ;) Also, if you are working on more than one, you can tell all of…
... ; uses : af, bc, de
ld a,b
or ... /> ld a,e
ld e,l
ld d,h ... ld (hl),a
inc de
dec bc
ld a ... />
pop hl
pop bc
pop de
ex (sp),hl
Elliptical ChallengeSubsequent to the recent "Graph Plot" thread, I wrote this general purpose ellipse drawing routine which will plot (although it doesn't actually use …
... /> ld (COORDS),bc
call $22aa ;PIXEL_ADD ;get x,y screen address
ld ...
ld (hl),a
pop hl
pop bc
djnz NextPoint
pop bc
...Help with File Compressor by Mladen PopovicHi, I'm trying to compress BombJack (MCM) and transfer it to a +3 disk (Yes I own the original game :) ). I'm unsure about the addresses to enter in…
... hl,de ;(RAMTOP)-SP
ld b,0
ld c,l
inc bc ;BC ... /> ld (23730),de
push hl
sbc hl,de ;old - new
pop hl ...How to print logo onto screen at chosen coordinates?Hi, I've just got back into zx spectrum games after all these years and after seeing some of the great games on here I would like to start learning p…
... it addresses the full screen, handles 96 characters, 16 ... ex de,hl ;DE=display file address
pop af
... :
ld hl,BlockData-SetBLOCK
add hl,bc
ld (23680),hl
...Animated attribute revealA new challenge to solve next. I would like to create an animated attribute reveal in machine code by having my 768 byte attributes held in ram whic…
... my second attempt at a screen attribute reveal routine ( [i]the ... nz,DELAY2
pop bc
pop hl
ld de,(L2R2L)
add ...Sorting BusinessThis is a little bit different from the usual game-related fare but I know there are a few people here who like this sort of thing. This is about so…
... />
begin_loop:
ex (sp),hl ; hl = array_lo
push de ... , size)
pop bc
ld e,l
ld d,h ; de ...Block RoutineHi Folks, I want to draw a block on the screen dependent on providing the X,Y,W,H values. I came up with the following: [CODE]100 LET l$=" …
... a filled rectangle on the screen. Whilst reading the "Step-by ... I came across the partical screen clear routine.
Here ... /> POP HL
POP BC
INC H
DJNZ 63061
POP HL
POP BC
LD ...Block RoutineHi Folks, I want to draw a block on the screen dependent on providing the X,Y,W,H values. I came up with the following: [CODE]100 LET l$=" …
... very pretty. The "out of screen" check is wrong, by the ... of screen
LD (a63092),DE ;unnecessary
add hl,bc
ld a,(hl ... /> POP HL
POP BC
INC H
DJNZ a63061
POP HL
POP BC
LD ...Why no PLOT, etc. on bottom two lines?I was pondering if there was any way to get PLOT, etc. to address the full screen from BASIC without having to write a few lines of assembler to bypa…
... /> [code]
;Full Screen PLOT
;Syntax: FLASH x ...
Plot191:ld bc,(23653) ;BC=(STKEND)
push bc
call ... or (hl)
ld (hl),a
pop bc
ld (23653),bc
...Why no PLOT, etc. on bottom two lines?I was pondering if there was any way to get PLOT, etc. to address the full screen from BASIC without having to write a few lines of assembler to bypa…
...
[code]
;Full Screen PLOT, Y=0 to +191 ...
Plot191:ld bc,(23653) ;BC=(STKEND)
push bc
call ... or (hl)
ld (hl),a
pop bc
ld (23653),bc
...TAP version of CrosswizeIs it possible to create a TAP version of Crosswize with all levels? On the tape or a TZX file, the levels are in the same block and a custom loader …
... bc
ld hl,49152
ld de,16384
ld bc,4096
ldir
pop bc ...
ld ... into 20480 (that part of screen is redrawn when playing, so ...Game of Life.Last year (I think) or maybe the year before, I entered a Game of Life simulator into the CSS CGC compo but for the Sinclair ZX81. I decided to port…
... phase shapes scattered around the screen; eg.:
[code]single phase ... /> SetGbyte:
pop hl
ld (hl),a
inc hl
pop bc
djnz LoopG1 ...
