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Math Quiz - MultiplicationThe topic is fast multiplication routines, from 8x8 to 32x32 and all points in between. These functions sit underneath floating point libraries, gen…
... br />
Surprisingly, a lot of optimizations I thought were going to ... come out even. So I thought I'd show what is being ... ,e
xor a
ld d,a
; eliminate ... /> ret
[/code]
I put in two tests.
Colission detection problems.G'ah...it's always the same (I've asked before too) - I'm always struggling when it comes to doing box colission checks, so I'm basically hoping you …
... always the same (I've asked before too) - I'm always struggling ... box colission checks, so I'm basically hoping you can ... /> ld a,h ; player's y coordinate.
inc a
ld b,a
ld a ...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…
... then I expected.
mc loader
[code]65040: LD A ... : LD A, D
65276: LD (65378), A
65279: LD A, E
65280: LD (65375), A ... : LD A, (DE)
65506: LD (HL), A
65507: LD (HL), A
65508: LD A, B ...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 …
... 1986.
How do I make the code do more ... 3E01 LD A,001
60175 32DFEB LD (TIME),A
60178 3A9BEB LD A,(COUNT ...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…
... address nn.
JP (HL) ,I assumed would read the contents ... the location
and be a great and cheap goto command ... instead of using a list of CP...JP nn ... /> LD A,bytetocheck ; Has to be a multiple of 2
LD L,A
LD ...Help needed with calculating screen addressesCan anyone help me finally crack Jonathan Cauldwell's screen addressing calculator and, more to the point, is the reason I'm struggling because this …
... point, is the reason I'm struggling because this ... Addresses[/B]
[I]The second method involves calculating ...
ld a,(ycoord) ; fetch vertical coordinate.
ld e,a ; store that ...understanding machine codeHi Quick question. Am not really sure if it fits development forum as its not really development per se its more a learners question about developm…
... START XOR A
323C5C LD (TVFLAG),A
... I use my monitor(using Zero emulator)
323c5c LD (TVFLAG), A ... I wonder if I am misunderstanding the expected result of LD (TVFLAG), A ...
A ...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 />
I had a question about DJNZ operation.
1A LOOP LD A,(DE)
77 LD (HL),A
I gather the displacement is ... negative 0x6 I think; which takes ...
I am unsure how it calculates ...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…
... LD HL,40A4
11083F LD DE,3F08
0608 LD ... /> 1A LOOP LD A,(DE)
77 LD (HL),A
ld hl, $40a4
fa03 ... ld b, $08
fa08: 1a ld a, (de)
fa09: 77 ld (hl), a ... I thought it would happen at:
77 LD (HL),A
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…
... use this approach, but I thought I'd share my version ... and quicker approaches, but I deliberately wrote this version as ... than making an SBC I reckon
dec a
jr ... a reg
add a,e
ld e,a
ld a,(dreg)
ld d,a ...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…
... such schemes implemented, and I have been experimenting with several ... of them.
I reverse engineered the loading routines ... orderly one associated with Biturbo I. The pilot tone colors ... 65491
LD A, C
CPL
LD C, A
LD A, B
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…
... what I came up with so far.
[CODE]
ld a ... ,#x ; symbolic. a is x (0-> ... a ; avoid special condition without shift / i.e. jr z
ld b,a ... ; our shift counter
xor a ; 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…
... very rough and ready code I wrote. I invite suggestions for ways ... /> ld a, (hl) ; get allophone
ld hl, (65362) ; address buffer
ld (hl), a ... />
xor a
ld (65362), a ; mark
ld (65363), a ; done
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…
... />
I've learned a bit (actually quite a bit) and managed ... out but there's a few things I'm struggling with ... 8
LD (L33880), A ; 37119 50 88 132
LD A, (L33879) ; ...
37113 / 37114 "CP 42" , I tried changing this but could ...Better arrangement for video memory?While doing some documentation work for the ZX-Uno project, I compared the advantages of the weird layout of the ZX Spectrum against a linear layout.…
...
XOR B
LD H,A
LD A,C
RLCA
LD L,A
[/code]
Then I remembered about the [I]hires[/I ... /> ld h,a
ld a,c
and $F8
ld l,a
ld a,b ...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…
I'm having trouble writing a very simple text scroller, the ... it to work though. Also I need to do an AT ... RST 16 or whatever, but I've forgot what to do ...
ld a,(counter)
inc a ;increase
ld (counter),a ;update counter ...LOAD "" CODE in machine code/store 128 bank dataHow do you LOAD "" CODE from machine code? I have written the following MC routine that fits into a REM statement in a basic program. I want to cal…
... machine code?
I have written the following MC ... into a REM statement in a basic program.
I want ... br />
How do I put the loaded 16K worth ... ld a,96
ld (23606),a
ld a,233
ld (23607),a ;chars
ld a ...Pixel level collision detection[SIZE=3][FONT=Calibri]I need to do some pixel level collision detection. Assuming I have a byte of my ?player? sprite in DE and a byte of screen to t…
... level collision detection. Assuming I have a byte of my ?player ... to test in HL I was thinking of something ... /> [CODE]
ld a, (de)
ld b, a
xor (hl)
I thought about on my ... only run when I know the player and a ?bad? ...IX+n and self modifying code and pasmoI'm using pasmo and if I wanted to use ix+n like this: (ix holds the position to a sinus table) ld (symbol), a LD a, (ix+symbol) What I want to do…
... position to a sinus table)
ld (symbol), a
LD a, (ix+ ... symbol)
What I want to ... do is to use LD a, (ix+n ... ), but declare n as a variable, and ...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…
How can I go back to basic ... ld bc,6143
ld a,255
ld (hl),a
ldir
skok: ld a ... restarts.
If I poke in the same code ... and after pressing "space" I am back to basic prompt ... .
I tried to put "ret" at ...Double height text...<p>Is here any good routines for printing a font double height?</p><p>I've concocted this ridiculous routine but I'm sure it can be done much better.…
... good routines for printing a font double height?I've concocted this ... ridiculous routine but I'm sure it can be ... loop ld a,(hl)
x1 ld (16384),a
x2 ld (16384+256),a inc ... hl
ld a,(hl ...Hardware damage due to software?<p>I'm not afraid to ask a stupid question, and I find it incredibly easy to do so in the hardware forum!</p><p>Is it possible to damage your Spectru…
... afraid to ask a stupid question, and I find it incredibly easy ... ), or make it break in a particular way, with software?For ... otherwise.Presumably the use of LD R,A as in Joffa's ...ZERO Emulator - BugsI have been using Zero emulator to experiment a few routines in assembly, since it has a somewhat usable debugger. However I believe I found a few b…
I have been using Zero emulator to experiment a few routines in assembly ... usable debugger.
However I believe I found a few bugs, some in ...Could use some help improving some controls.Back when Dingo was released many people said they had problems controlling it, so I've decided to improve the controls on it, so you no longer need …
... I'm using to test with).
[code]right: ld a ... Right2: ld a,(PlayerCoordX)
inc a
inc a
ld (PlayerCoordX),a
RightStop: ld a,232 ;Can't move further ...z80 assembly helpEver since I was a child I wanted to program my zx81 then my zx spectrum + 2. However, it was such a mystical beast and I only ever used BASIC not kn…
Ever since I was a child I wanted to program my ... as every time I read something I understood what was ... rst 16 ; print it.
ld a,(xcoord) ; vertical position.
rst ... The lines where I believe I fully understand i've put my ...Rom routine for pixel addressDear all, Having my bi-annual 'lets try machine code' project again and have come up with a problem with the pixel address rom routine at 8874. …
... and have come up with a problem with the pixel address ... the ZXSpectrum Rom Dissassembly book, I'm trying to do the ... ]ld b,175
ld c,0
call 8874
ld (hl),a ... HL, but when I attempt to LD (HL),A or investigate its contents ...Drawing some spritesI figured I want to draw some sprites. My target was to do a 16x16 masked sprite. There's no clearing here, just drawing the sprites. My first ite…
... one sprite a frame. I massaged the data a bit, interleaving ... /> inc de
ld a, (de) ;repeat
and (hl ... />
After that I pondered how to make it ... sprite data. That way I can get rid of ...Text scroller and custom fontYesterday I was testing this text scroll routine taken from Jonathan Cauldwell's Intro Maker (labels have been inserted to allow partial code relocab…
... standard ROM font, while I would like it to use ... at 64000.
I tried to peruse into the ... between them, but I was unable to find a solution. Could ... /> LD E,A
LD A,(PUNTO_A)
LD C,A
LD B,008
L_35459: LD A ...Function with push and popIm trying to see if I understand push and pop when it comes to using to pass parameters to functions: [code] LD HL,16384 LD A,5 Push AF Ld A…
... trying to see if I understand push and pop ... />
LD A,5
Push AF
Ld A,7
Push ... LD (16386),A
addfunc:
pop af
LD (16384),A
LD ... B,A
pop af
LD (16385),A
ADD A ...Add with Carry ExampleHi, I have been really struggling to understand this simple example from Mastering Machine Code and I wonder if anyone can help? I have include…
... can help?
I have included the op codes ... to what I think is happening:
[code]LD DE, ... /> LD A,L ;A = 7B
ADD A,E ;A = 7B + 33 = AE
LD L,A ... Therefore BC = 4CAE
I'm obviously getting confused because ...
