-
Screen2StringFurther to writing that BASIC one-liner to redirect CAT to a string I thought that I'd do a general redirection routine for anything which normally p…
... code
REM ld hl,(ptr) : ld (hl),a : inc hl : ld (ptr),hl : ret
DATA ... -
What's wrong with this code ?OK, working my way through Jonathan Cauldwells 'How To' tome and I can't get the following to run in either spin or basin. ( iused the assembler in b…
... graphics.
ld hl,blocks ; address of user ... ld hl,21+15*256 ; load hl pair with starting coords.
ld (plx),hl ... br />
mpl ld hl,ply ; remember, y ... br />
mpr ld hl,ply ; remember, y ... -
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…
... /> [CODE]
ld hl,16384
ld b,8
loop1: ld (hl),255
hl)
inc h
ld h,(hl)
ld l,a
ld (hl ... -
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 b,0
ld c,e
ld hl,table
add hl,bc ...
ld c,(hl ... = ~x
pop hl
ld (hl),a ; q[i] = x ... -
Jelly-Vision!As threatened in the "'Spectrum Play' Error" thread, here's a ruff'n'reddy interrupt driven full screen wobbling routine which has no practical use w…
... : push hl
ld hl,0005
add hl,sp
ld a,(hl)
cp ... ,MOVEUP
MOVEDOWN: ld hl,16384+256
ld de,16384
ldir ... -
40 Column Printing RoutineI've written a 40 column printing routine, which I'd like to share... It's my first piece of 'public' code so go easy on me! I don't think it is a…
... /> ld hl,overscratch
overpopulate ld (hl),%00000011
inc hl
ld (hl),255
inc hl ... -
merging bytesPicturing three bytes with their bits identified by letters to make the visualisation easier, what's the best way to perform this transformation? [co…
...
ld (hl),a
inc hl
[color=red] ld a,(hl) ;ld a,b ... /> or d ;A=FGHlmnop
ld (hl),a
ret
[/code ... -
Any ideas on speeding up this assembler segment?It copies a pixel column of a rectangle which may be anywhere in the display file to a pixel column in d$. The source column may start at any bit pos…
... position 1->8
ld a,(hl) ; 7
rotbit0: ... br /> ex de,hl ; 4
or (hl) ; 7
ld (hl),a ; 7 ... set selected bit in d$()
ex de,hl ... -
BeepFX ProblemHi All, I'm currently trying to integrate the BeepFX engine in my 100% Assembler Game and it plays the sound fine, but then plays the sound again, a…
... /> add hl,bc
ld a,(hl)
inc hl
ld h,(hl)
ld l ... ,a
push hl ... -
multi-scroll m/c subroutine for BASICArising from recent posts, here's a scrolling routine that will manage multiple left/right scrollings for any (sensible) line width or step; (ie. whe…
Arising from recent posts, here's a scrolling routine that will manage multiple left/right scrollings for any (sensible) line width or step; (ie. where width is -
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…
... /> [I]Eg
ld z,(hl) ;if condition met load accumulator ... with (hl)
or
Graph Plothi! please, help with code: [PHP]For x=-100 To 100 For y=-100 To 100 If (x/2-25)*(x/2-25)+(y-50)*(y-50)<200 Or (x/2+25)*(x/2+25)+(y-50)*(y-50)<200 th…
hi! please, help with code:
[PHP]For x=-100 To 100
For y=-100 To 100
If (x/2-25)*(x/2-25)+(y-50)*(y-50)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…
... [i]=b1
push hl
ld hl, 1
defb 210 ... hl
ld h, d
ld l, e
sbc hl, bc ;hl ... hl
ld d, h
ld e, l
sbc hl, bc ;hl= ...Omitting LETAn untested thought. Changing: [code]1B34 SUB $CE ; Reduce command code by $CE to ; give 00 to 31 for comman…
... ,TRYLET
...
TRYLET LD HL,(CHADD) ; Step CHADD back to ... statment
DEC HL
LD (CHADD),HL
LD A,'LET'-$CE ; Set ...Machine code RST10 problemHello! After 27 years of playing with Spectrums I'm starting to look into doing assembly language properly. All went swimmingly well until I wrote …
... de,hl ; remember HL as it points to the message
ld hl, ... control codes
.msgpcc ld a,(hl) ; load character into A ... ; print it
inc hl ; point to next control character ... ex de,hl ; recall hl pointing to message
.msgpch ld a,(hl) ; load ...How do you restrict this routines actions?I'm trying to plagiarise a piece of code I came across in the 80's, but seem to be banging my head against a brick wall! The routine fades the scree…
...
l_b798: ld hl, 22528+32
l_b79b: ld a, (hl)
ld b, a ... , b
l_b7ca: ld (hl), a
inc hl
ld a, h
ret
fader: ld b, 16
l_b7d5: push ...
jr l_b798
l_b7d8: ld bc, 511
l_b7db: dec ...Printing textThis is probably quite a basic question, or there might be something obvious I'm missing. I'm looking for an economical way of printing formatted te…
...
ld hl,text_to_print
print_text
ld a,(hl)
or ...
rst 16
inc hl
jr print_text
Idk>le me browsing through some game's code >..... [code]61A8 F5 push af 61A9 3EFF ld a,FF 61AB D37F out (7F),a 61AD D33F ou…
...
61BF 22F862 ld (62F8),hl
61C2 ED73FC62 ld (62FC),sp
61C6 E1 pop hl
61C7 22FA62 ld (62FA),hl
61CA 31F862 ... 22BE62 ld (62BE),hl
620F 2100CD ld hl,CD00
6212 22BC62 ld (62BC),hl ...Struggling with this routine... Any ideas?I'm trying to write a routine that plots 3 pixels to decrease the energy bar in the top right corner by 5 units, but it just wont have it! There mus…
... /> [CODE]org 30000
ld b,5 ;decrease energy by ... push bc
loop1 ld hl,51993 ;address energy level is ... stored
dec (hl) ;decrease energy level(5 ... br /> ld (23695),a ;set colour
ld a,(hl) ; ... load a with energy level
ld b ...Rotronics Wafadrive v.1.80 ROM - Corrupt or purposely broken?I've been digging around the Wafadrive v1.80 ROM (from [URL="http://zxspectrum.it.omegahg.com/_RO.htm"]here[/URL]) and can't decide if the ROM is cor…
... /> ld hl, $009f
ex (sp), hl
push hl
ld e, a
ld ... d, $00
ld hl, $0cf7 ... /> add hl, de
ld e, (hl)
inc hl
ld h, (hl)
ld l ...30-column 8x2 multicolor (even in 48K)I don't recall any 8x2 multicolor routine for 30 columns that would work on all Spectrum models (including the Spectrum 48K), so I decided to write i…
... LD HL,nn
LD DE,nn
LD BC,nn
EXX
LD HL ... PUSH HL ; columns 21 and 22
LD HL,nn
LD (nn),HL ; ... columns 29 and 30
ADD HL,HL ...Movin And A Groovin Horizontal Flip improvementOn the left is the flip horizontal portion from Andy Pennell'S excellent Movin' & a Groovin' machine code screen routines from Your Spectrum #19 (Oct…
... /> LD B,24 LD B,24
FLATTR LD A,(HL) flattr LD A,(HL)
flattr LD A,(HL)
LD C,(IX+0)
LD (HL),C
LD (IX ...Routine for Currah speechI'm currently writing a routine for the Currah that will provide speech during a game. A timer is set to initiate the speech every 50 cycles of the …
... />
Start: ld hl, Dat1
ld de, 65361
ld b, 15 ;load ... with 4
Loop: ld a, (hl)
ld (de), a ;load allophone ... last byte in buffer
ld (65364), hl ;update pointer
ret ...MC LPRINT 23681Having problems with this routine to print large on the screen using LPRINT, it works ok in BASIC, but cant seem to get it to loop for some reason in…
... call cols ;fill attributes
ld hl,72 ;start of address to ... br /> loop ld (23681),hl ;poke address with hl
push hl
... cols ld hl,22816 ;random colours
ld b,159
lp2 ld a ... inc a
ld (hl),a
inc hl
djnz lp2
128 BASIC-compatible way of loading BASIC as code?On a 48K Speccy (or from 48 BASIC or USR 0 mode on a 128K machine), one can do a silly trick like this: [code];; load a 4000 byte BASIC program ld i…
... byte BASIC program
ld ix,23552 ; start address ... of system variables
ld de,4000
call ... line 100
ld hl,100
ld (23618),hl
ld a,1 ; ... statement 1
ld (23620), ...SCREEN$ 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…
... discard
ld hl,(23606) ;HL=(CHARS)
ld (23680),hl
ld hl,(23675) ;HL=(UDG)
dec h
ld ...LZ4 decoderI encountered the [URL="http://code.google.com/p/lz4/"]LZ4 compressor[/URL] a few weeks ago. Reading the [URL="http://fastcompression.blogspot.co.uk…
... =0
.mainloop:
ld a,(hl) ; place token into accumulator
ld e,(hl) ; read the low byte of ... (4T)
.getlength_nocarry:
ld a,(hl) ; re-read the byte (7T ...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…
... [CODE]
ld hl,counter_addr
ld (hl),204
ld sp,SOURCE+4096 ... ld hl,SOURCE-TARGET-16
add hl,sp
ld sp,hl
ld hl, ... counter_addr
dec (hl)
Nasty 'Gotcha' for multicolour timingI thought I would be better developing my multicolour routine on the 48K first, being the slowest, so it would then be sure to work on the 128K varia…
... the +2A. I've used LD (nn),HL , then I've used ... prefix byte longer than using HL. There's even a ... duplicate of the command using HL, again with the prefix ... I can do LD (nn),IX followed by LD (nn),HL since the ... . POP IX and POP Hl to refill those registers with ...Troublesome routine, help needed!Having problems with this routine, it basically fires a rocket up the screen, but refuses to detect collisions. I'm using attribute blocks for detect…
... /> LD L, A
ADD HL, HL
ADD HL, HL
ADD HL, HL
ADD HL, HL ...
ADD HL, HL
LD DE ...
