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Why doesn't my routine work?I have a "level" defined by 504 bytes (28 squares across x 18 squares down) I'm trying to write a routine that will take an X,Y coordinate in pixels…
... HL
add hl, hl
add hl, hl ;x4 original value
ld de, hl ... -
How the spectrum generates the video from ramHi everyon, I know that most people here allready know this but i think i found out how the spectrum acctually dispalys stuff and why the LD x, (HL)…
... dispalys stuff and why the LD x, (HL) is used to display ... using the instruction LD x, (HL), you look at address HL (which would ... -
Help?Hi All, I wonder if anyone has a few minutes to look at this bit of code I'm working on. I'm trying to move to sprites and want to do it with a scr…
... +0) ;low byte
ld (hl),a ;a, the screen address ... ;repeat 8 times
ld hl,bits ;reset bits (lines of ... next from top
ld (point),hl
ld hl,seed ;screen address table ... /> halt
ret
sprite ld hl,(point) ;address of current line ... -
Small Machine Code Routines Which Maybe UsefulAs part of creating Flynn's Adventure in Bombland I created a lot of little routines to do all sorts of things. A lot of these I created based on inp…
... /> ld l,a ; 4t - hl=char to plot
add hl,hl ; ... add hl,hl ; 11t - x4
add hl,hl ; 11t - x8
ld bc ... previous plot byte
ld (hl),a ; 7t - plot ... 4t - down one
ld (hl),a ; 7t - plot line ... previous plot byte
ld (hl),a ; 7t - plot ... -
quick - Zx80 ASM questionWhile I am ploughing through lots of ASM listings, one of my earlier adaptation attempts surprised me [B][asm code][/B] [code] org 32768 start: ld…
... ROM
[B]ld hl,text1 ; set HL with text1 data
ld hl,text2 ; set HL with text2 data
ld a,(hl) ; get character to print ... -
Frank N SteinThis is an improved bugfix for [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0001849"]Frank N Stein[/URL] as discussed recently in [URL="htt…
... : equ $5C3D ; 23613
PATCH2: LD HL, (ERR_SP) ; 42 61 92
DEC HL ; 43
DEC HL ; 43
LD SP, HL ; 249
Back to BASIC[U][B]Archaeology guide to programs compiled used MCODERII.d[/B][/U] After various people have been talking about "Frank'n'stein" I decided to finis…
...
+1 LD HL,0
+4 LD (59346),HL
+7 LD HL,LINES
+10 LD A,NVARS
+12 LD ...Shadow ROM partial decoding not implemented in emulatorsOr at least, not implemented in Spectaculator, and it seems that not in Fuse too. [URL="http://www.speccy.org/foro/viewtopic.php?f=8&t=408&start=53"…
... di
ld hl,StartCopy
ld (5cedh),hl
rst ... StartCopy ld hl,0
ld de,32768
ld bc,16384 ...(part of) screen to UDGHere is a routine to copy a Y,X-position on screen to a UDG. 0<=y<=23 0<=x<=31 144<=udg<=165 (UDG "A" to UDG "U") [code] ; start code with ; PRINT …
Here is a routine to copy a Y,X-position on screen to a UDG.
0Nemesis the Warlock (BUGFIX)This is a bugfix for game [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0003387"]Nemesis the Warlock[/URL], please add the following "known …
... :
[CODE]
77ff: ld a,($caf3) ; exit: 0=horizontal ... jp z,$7825
7806: ld hl,($ca56) ; oops! may reach " ... when moving up
7809: ld ($caf4),hl
780c: jp $7825 ... 194
7806: ld hl,($ca56)
7809: ld ($caf4),hl
780c: jp ...Thanos (improved BUGFIX)This is an improved BUGFIX for game [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0005221"]Thanos[/URL], please replace the "known errors" d…
... :
658c 216b65 ld hl,$656b
658f 7e ld a,(hl)
6590 ...
65a3 218400 ld hl,$0084
65a6 226e65 ld ($656e),hl
65a9 ...
65f7 211800 ld hl,$0018
65fa 226e65 ld ($656e),hl
65fd ...automatic relocating of non-relocatable codeI was pondering upon the problem of changing absolute addresses used by CALL, JP, etc. when code is moved, without reassembling at the new location; …
... pointer
ld hl,CHANGE
add hl,bc
ld sp,hl ;point SP ...
ld (hl),e ;DE=new value
inc hl
ld (hl),d
Kiwi OS for z80 computerHi everyone, Nearly made my z80 computer with 2K ROM 32K RAM. It has an OS im still writing called Kiwi (apple, blackberry, you get the idea ;D) he…
... LD HL, 32800 ;LOAD HL WITH STACK POINT LOCATION
LD SP, HL ... br />
LD HL, 33000 ;LOAD HL WITH STARTING ADDRESS
HL ;REMEMBER HL
LD HL, 1527 ;LOAD HL WITH ...Keys redefine routine and key check.I have written some asm code which allows me to redefine keys (for a game etc.), and also allows me to be able to check any keypresses for the redefi…
... print_message
ld hl,key_left_port
call get_defined_key
ld hl,msg_right
ld hl,key_right_port
call get_defined_key
ld hl,msg_fire
Tile based graphics and scrolling thingy...Here's my best attempt so far at a tile based rendering and scrolling routine. It draws in 22 8*8 graphics tiles along the top of the screen (junk i…
... ld hl,tile_base ; tile_base
ld (next_tile_line),hl
start ld b ... hl,hl ; ASCII code * 8
add hl,hl
add hl,hl
ld ... />
ld hl,16385
ld (position_var),hl ; Reset print ...AND,XOR,OR,BIT,RES,SET,CPL,NEG,RLC,RRC,SLA,SRL,RL, RR,SRA for BASICAs this was drifting away from the original INKEY$ thread I thought that I'd create a new one. So here's a routine to provide all of the above mentio…
... /> LOGIC: ld hl,12
add hl,sp
ld sp,hl ;undo USR ... ld hl,OPCODES
add hl,bc
add hl,bc
ld ... bc
ld hl,OPERATE+1
ld a,(hl)
jr ...probably a stupid question about RST16I'm using the 'hello world' code borrowed from [url=http://equant-retrochallenge.blogspot.com/2008/07/zx-spectrum-assembly-programming-under.html]her…
... />
[code]
ld hl,line ; Print line
call ... out a line
ld a,(hl) ; Get character to ... in 'A'
inc hl ; Move onto the next ...
you can load HL and call it again immediately ...tiny routine to shift RAMTOP & stackCompressing some data areas above RAMTOP and wanting to make the released space available for BASIC arrays, I needed to move RAMTOP without using CLE…
... /> LD HL, 18 ; 33 18 0
ADD HL, SP ; 57
LD SP, HL ...BREAK from GOSUBHere's another one. Just in case you wanted to break out of multiple GOSUB levels with a single command, here's a routine to do it, tested on all mod…
... br /> [code]
RETSUB: LD HL, 20 ; 33 20 0 ;Discard ... & (ERR_SP)
LD SP, HL ; 249 ;from m/c ... )
EX DE, HL ; 235
LD (23613), SP ; 237 ...Procrustean PrintingHere's a short routine to manage printing of text with command tokens, to avoid messing up the screen when they are expanded. It just prints as many …
... ;
STACK: ld hl,14
add hl,sp
ld sp,hl ;undo USR ... ,hl ;HL=string pointer
ld b,a ;B =max_length
SSNEXT1:ld a,(hl ...Invalid combination of operands and opcodesIt says the error in the title, why is this?? [CODE] ORG 0000 LD HL, 63000 ;LOAD HL WITH STACK LOCATION LD SP, HL ;SET STACK POINTER TO HL LD A, …
... br /> LD HL, 63000 ;LOAD HL WITH STACK LOCATION
LD SP, HL ;SET ... STACK POINTER TO HL
LD ... DISPLAY
LD HL, 0000 ;LOAD HL WITH THE STARTING ... DISPLAY
LD HL, 0000 ;LOAD HL WITH Z80 POWERED ...Indirect Variable AssignmentHere's another wacky routine. This allows assignment of values to variables where the source & destination variables can themselves be defined in var…
Here's another wacky routine. This allows assignment of values to variables where the source & destination variables can themselves be defined in variables (or expressions which evaluate to variables). Some of this can already be done with VAL or VAL$, ...Amazonia (BUGFIX)This is a bugfix for game [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0027280"]Amazonia[/URL], please add the following "known errors" des…
... /> 9ec1 210000 ld hl,0000h
9ec4 22c89b ld (9bc8h),hl ; reset time ... ret
9ee0 3600 ld (hl),00h ; reset minutes/hours/ ... already zero)
9ec5 21e99b ld hl,9be9h ; clock address
...Loading the display with data from memoryTrying to load part of the screen(4k's worth) with data from memory location 53000, I've written this routine, but it doesnt work... [I]ld b,4000 ld…
... ]ld b,4000
ld de, 16384
ld hl, 55000
loop ld a,(hl ... )
ld (de ... ),a
inc de
inc hl
S-S-Sample black borderI'm wanting the 'S-S-Sample' routine from YS to play the sounds without the flashing border effects. A plain black border is required. Heres the rou…
... /> ld hl, (32768 )
ld de, (32770)
ld bc, 2048
ld c, (hl)
ld ... a, c
rlca
ld ...editing strings with INPUT LINEHere's the latest in my unpredictable series of utility routines. This one I needed for the SAGE game editor; it emulates INPUT LINE l$ but with the …
... />
inc hl
ld c,(hl)
inc hl
ld b,(hl) ;BC=l ... de,hl
ld (hl),$0d ;followed by ENTER
ld (K_CUR),hl
ld de ...Routine for clearing screenI was looking for a 'nice' way of clearing a screen of graphics in Z80. After a ridiculous amount of time mucking around, this is the best and most …
...
ld hl,16384
ld bc,6144
ld de,(PRT_CHR ... ld a,(hl)
and e
ld (hl),a
inc hl ...
dec bc
ld a ... ,SCREEN_CLEAR_LOOP
ld a,(PRT_CHR)
sla a ... ret nc
ld (PRT_CHR),a
jr ...28-character wide multicolour(ish) on 48k SpectrumLong-time lurker here... I've always been interested in rainbow effects on the 48k Spectrum, mainly from a perspective of "Just what [I]would [/I]ha…
... /> LD H,A
LD A,24
LD (DEPTH),A
LD (HIATT),HL ... ; Some more attribute data
ld hl,5566H ; Some more attribute data ... /> LD L,C
LD D,A
LD E,B
LD (HL),0FDH ...Byte-order backbufferThis is a tool for Z80 coders who wish the Spectrum screen had a serial layout. It runs as an interrupt mode 2 service routine and uses POP and PUSH …
... byte of the screen
ld hl, $ + 9 ; set return location (no ... stack available)
ld (endcall), hl
jp blit ; call ... ) - (chunk * 2048)
ld hl, $ + 9
ld (endcall), hl
jp blit
