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Assembly - Loops bigger than 255Hi, It looks like it's a bit difficult to make loops with more than 255 cycles on Z80 machine code, since the 16-bit decrements (DEC) do not alter a…
... a FOR example
LD HL,16384 ; Beginning of the ... graphic memory
LD DE,1024 ; Loop length ... B, for DJNZ
LD C,D ; Load the ... loop_high
loop:
LD (HL),62 ; Fill the video ... with this number
INC HL
DJNZ loop
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)
z88dk and im2I set up a minimal IM2 mode so I can draw sprites for a laff [code] #include <string.h> #include <stdio.h> #include <im2.h> #include <stdlib.h> #in…
... br />
LD BC,255
LD DE,04000h
LD HL,37000
push bc
push hl
push de
... />
LD BC,255
LD DE,04000h
LD HL,37000
pop de
pop hl
pop bc
...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 ...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 …
... data from the address HL is set to 55143, ... level number
ld b,a
ld hl,udg-32 ;start of ... /> ld b,32 ;8 x 4
loopa inc hl ;increase ... /> djnz loop
ld b,32 ;hl should now point to ... level x 32
ld de ...Converting an integer arbitrary large binary number into a printable decimal formThis was asked a long ago at the comp.sys.sinclair newsgroup. At that time, I came up with a solution by extrapolating the classic algorithm of suces…
... /> Add4Block proc
ld hl,BCD
BucAdd ld a,(hl)
cp 50h ... leading zeros
ld hl,BCD
BucPrint2Dig ld a,(hl)
srl a ...A "generic" loader for +3(e)I've made this loader for 128k games in +3DOS. [CODE]dos_open equ 262 dos_close equ 265 dos_abandon equ 268 dos_read equ 274 dos_write equ 277 dos_s…
... /> ; disable cache
ld de,0
ld hl,128
call dos_set1346 ... file
ld bc,$0501
ld de,$0002
ld hl,fichero
cerrar:
ld b,5
call dos_close ...
; return to BASIC
ld iy,23610 ; restoring iy so ...About how z88dk generates code and makes room for variables.When you attempt to code games for the 128K models using z88dk in C you need to somewhat control where variables are stored in memory. I thought tha…
... />
[code]ld A, $06
ld ($5EF1), A
ld A, $07 ...
ld ($5EF2), A
ld HL, $0008
ld ($C729), HL
ld HL ... , $0009
ld ($C77D), HL ...Ghosts n' Goblins loaderI'm trying to put Ghosts n' Goblins onto a +3 disk but struggling to understand the mc loader. Basic loader [code] ink 7 : clear 25000 : load "" cod…
... : LD SP, HL
65253: POP HL
65254: LD SP, HL
65255: LD HL, 60016 ...
65258: PUSH HL
65259: PUSH HL ...Venturespeak Helplooking at the code from ZX Computing, October, November & December 1986. How do I make the code do more then 3 letters say 5. and could it be made …
...
60108 219EEB LD HL,START
60111 1600 LD D,000
60117 19 ADD HL,DE
60118 77 LD (HL),A
60119 ... DEC A
60266 329BEB LD (COUNT),A
60269 C378EA ...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 +…
...
ld hl,48640
ld de,48641
ld (hl),191
ld bc,256 ... = y*32
ld hl,22528
add hl,bc ;hl = address of start ... /> ld hl,char_address
add hl,bc ;hl = row in table
ld e,(hl)
4294967296 pseudo output portsIn an effort to avoid any hardware conflicts with the clashbasher interface I've been looking for an alternative to using the spectrum's ports for ou…
... use of the instructions LD (HL),n LD(IX+i),n and ... ie: for LD(HL),n :-
pointing HL at the address ... If you execute LD(HL),n with HL pointing to n the ... to detect when a LD (HL),n is being executed ... can be written to using LD (HL),n
Does this addressing technique have a name?Hi All, Bit of a weird/unnecessary question, but can anyone help build on my knowledge of asm terminology by telling me what the *second* method of …
... ,21
LD (PlyrY), A
LD A,15
LD (PlyrX), A ... Method:
LD HL, 3861
LD (PlyrY), HL
DEFB:
EXX ProblemsWondering if any other coders have had problems using the EXX instruction in FUSE... I am calling the BEEP routine from within my own code and prese…
... ]
EXX
ld hl,497 ;pitch
ld de,10 ;duration
ld, hl ld,de and call, so that ...misunderstanding screen addressingHi I am just reading mastering machine code Toni Baker: [url]ftp://ftp.worldofspectrum.org/pub/sinclair/books/MasteringMachineCodeOnYourZXSpectrum…
... code program:
21A440 LD HL,40A4
36FF LD (HL),FF
C9 ...DJNZ displacementHi I had a question about DJNZ operation. Just running through this code in MMCOYZXS by Toni Baker page's 87-88 [QUOTE]21A440 LD HL,40A4 11083F …
... br /> [QUOTE]21A440 LD HL,40A4
11083F LD DE,3F08
... /> 1A LOOP LD A,(DE)
77 LD (HL),A
... [QUOTE]fa00: 21 a4 40 ld hl, $40a4
fa03: 11 ... 08 3f ld de, $3f08
fa06 ... ld b, $08
fa08: 1a ld a, (de)
fa09: 77 ld (hl ...byte to screen eventI have another question regarding assembly routine in MMCOYZXS by Toni Baker page's 87-88 [QUOTE]21A440 LD HL,40A4 11083F LD DE,3F08 0608 LD B,08…
... />
[QUOTE]21A440 LD HL,40A4
11083F LD DE,3F08
0608 ...
1A LOOP LD A,(DE)
77 LD (HL),A
[QUOTE]fa00: 21 a4 40 ld hl, $40a4
fa03: 11 08 ... would happen at:
77 LD (HL),A
But when ...Double-Buffer ScreenFor my Alien Breed Speccy re-write I decided to use a Double Buffer (DB) or 'Back Screen' to draw all the game action onto, before shuffling the whol…
... br /> .org 31144
ld hl, 25000 ;Start of DB Screen ... Counter
loop1:
ld bc,32 ;BC is counter ...
ld e,a
ld a,(dreg)
ld d,a ... 3
ld (cfield),a
ld a,80
ld (dreg),a ...SBC or ADDIs this dangerous/bad practice thing to do..... I want to subtract 64 from a number, but to save a few bytes can I just add (65536-64) 65472 to the…
... LD HL,32768
LD BC,65472
ADD HL,BC
LD (test),HL
LD HL,32768
LD BC,64
SBC ... HL,BC
CCF ; ... sometimes it need this....
LD (test),HL
RET
Unusual custom turbo loaders - with sourcesI have always been fascinated by turbo loaders; my games all feature a TZX version with one of such schemes implemented, and I have been experimentin…
...
LD HL,01045
DJNZ 65380
DEC HL
LD A,H ... 003
LD C,A
LD H,000
LD B,208 ...
JR NC, 65371
LD HL, 1045
DJNZ 65380
DEC HL
LD A, H
OR L ...Problem with DivIDEHi There is a problem on ZX-Spectrum +2 (Grey Model) + DivIDE 2k14 here is video with problem [URL="http://www.youtube.com/watch?v=nIQboFo7Epc"]h…
... />
[CODE] ld de,#3808
i_04
ld hl,#5818
i_02 ...
ld bc,#001f
i_03
ld (hl),d
add a,a< ...
ld (hl),e
inc hl
djnz i_03
ld bc,#0018 ...Fuse bug? Strange T state countingI was testing delay routine presented [URL="http://www.worldofspectrum.org/forums/showthread.php?p=214851"]here[/URL]. I'm reproducing its listing: …
... hl
DELAY: ld hl,-141
add hl,bc
ld ... bc,-23
.loop add hl ... ,bc
jr c,.loop
ld a, ...Currah ?Speech channelIt seems to me that it would be nice to be able to send words to the ?Speech with PRINT #5;"Speak English to me, Jimmy" or some such. There really i…
... /> new_word:
ld hl, 65362 ; if zero
ld (hl), $51 ; make it ... add hl, de ; allophone
ld a, (hl) ; get allophone
ld hl, ( ... 65362) ; address buffer
ld (hl), ...Hooky - hook ZX ROM and rewire RST and NMI to RAM - rantThis is a rather long rant. Not for short tempered. :) The objective is to hook into RST "vectors" and NMI on a Spectrum without affecting the normal…
... /> 0x11DC LD (HL),#0x02 ; mem. 0xffff is 2
0x11DE DEC HL ; HL=HL-1 ... 5cb2
0x1222 LD HL,(5CB2) ; FF57
0x1225 LD (HL),#0x3e ; write 3e ... there
0x1227 DEC HL ; hl=ff56
0x1228 LD ...Help with Manic Miner tweaksPlease. :) This is the Software Projects version, simply as I had it to hand. [B]Problem 1:[/B] I've learned a bit (actually quite a bit) and manag…
... 37107 24 202
L_90F5: LD (HL), 48 ; 37109 54 48
DEC HL ; 37111 43
LD A, L ; 37112 ... 50 87 132
L_9109: LD A, (HL) ; 37129 126
... :
[code]L_8FD0: LD HL, (L32944) ; 36816 42 176 128 ...analysing program variable usageIf I wanted to count the number of times each variable is referenced while a program is running (not the number of times each variable is referenced …
... correct value for (VARS) in HL. The problem then is how ... /> Oh, hang on, reset (ERR_NR), LD HL,[true (VARS)], CALL (not JP ...Problem Reading the KeyboardHi Folks, I'm working my way through Toni Baker's rather good book and thought I'd write some code to scan the keyboard and store the results so tha…
... copy
LD DE,_oldKeyStates ;Destination
LD HL,_currentKeyStates ;Source< ... the keyboard segments
LD HL,_currentKeyStates ;Where to store ... keyboard segment number
LD HL,_keyboardSegments ;Calculate the keyboard ...Simple text scrolling routine...I'm having trouble writing a very simple text scroller, the idea is to use the ROM printer routine to print 32 characters each time the routine is ca…
... inc a ;increase
ld (counter),a ;update counter with ... new number
ld (point+2),a ; ... />
print1
ld a,2
call 5633 ...
attr
ld hl,23264
ld b,64
loop ... inc a
ld (hl),a
inc hl
djnz loop ...Help needed with a bit of code...My minds gone blank again I'm afraid, I'm having trouble with this routine that loads variables into memory then calls the corresponding routine. Th…
... ld b,3
ld hl, cor
ld de,adds
loop
ld ... a,(de)
ld ... inc de
ld a,(de)
ld (caller+2),a; loads ... inc de
;ld a,(hl) ;hl stores variables
;now i ...Return to basic from sna created by Z80 compilerHow can I go back to basic when running sna created using Z80 Assembler ([url] http://www.worldofspectrum.org/utilities.html#crossass [/url])? For e…
... />
ld hl,16384
ld de,16385
ld bc,6143
ld a ... ,255
ld (hl),a ...
ldir
skok: ld a ...
