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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…
... : LET L=0: : REM SBC HL,HL ; RESULT BITS 32..47 = 0 ... : LET L=0: : REM SBC HL,HL ; RESULT BITS 48..63 = 0 ... /> 1120 LET I=0 : REM ADD HL,DE ; RESULT += MPD
1121 ... : LET I=0 : REM ADC HL,DE
1141 LET L ... -
How to write self-relocating code using Pasmo?With z80asm, I can write code like this: [CODE] org 0 ; a total lie, but makes the reloc sums work .dest: equ …
... ; ...and now it is in HL
ld de,.dest ; target ... to 0...
add hl,bc ; ...but now in HL relative to entry ... -
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…
... /> ; 16224T
ADD HL,HL ; extra delay
... /> ; 16282T
ADD HL,HL ; extra delay
... /> ; 16285T
ADD HL,HL ; extra delay
... -
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…
... byte
ADD HL,DE ADD HL,DE
ADD IX,DE ADD IX,DE
ADD HL,DE ADD HL,DE
ADD IX,DE ADD IX,DE
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…
... hl
jr z,ScrDone
ld a,(de)
add ...
pop hl ;HL=$000D
ex (sp),hl ;HL=$106E
... /> ld bc,10
add hl,bc
call $33b4 ; ...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…
... push de
push hl
exx
... br /> ld hl,counter_addr
ld (hl),204
... hl,SOURCE-TARGET-16
add hl,sp
ld sp,hl
ld hl ... ,counter_addr
dec (hl ...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…
... /> ADD HL, HL
ADD HL, HL
ADD HL, HL
ADD HL, HL
ADD HL, HL
LD DE, 22528
ADD HL, DE ...
LD DE, (bv1)
ADD HL, DE
LD A, (HL)
cp 1 ...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…
...
add hl,de
loop_12:
add hl,hl
jr ...
add hl,de
loop_13:
add hl,hl
jr ... add hl,de
loop_17:
add hl,hl
ret nc
add 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…
... /> 65250: POP BC
65251: ADD HL, DE
65252: LD SP ... , HL
65255: LD HL, 60016
65258: PUSH HL
65259: PUSH HL ... /> 65528: AND (HL)
65529: RST 56
65530: ADD A, L ...
65531: RST 56
65532: LD (HL), 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 …
... ,WAIT
60108 219EEB LD HL,START
60111 1600 LD ... A,(CHR)
60117 19 ADD HL,DE
60118 77 LD ... (HL),A
60119 13 INC ...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 +…
... hl,22528
add hl,bc ;hl = address of start of row
add hl,de ;hl ... 2
ld hl,char_address
add hl,bc ;hl = row in ... table
ld e,(hl)
inc hl ... ex de,hl
add hl,bc
ex de,hl ;de = ...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…
... 3808
i_04
ld hl,#5818
i_02
ld ... br /> i_03
ld (hl),d
add a,a
jr ... c,$+3
ld (hl),e ...
inc hl
djnz i_03
ld bc,#0018
add hl,bc
ld a,h ...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: …
... : af, bc, hl
DELAY: ld hl,-141
add hl,bc
ld bc,-23
.loop add hl,bc ...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…
... push de ; the
push hl ; registers
ld ... /> ld e, a
add hl, de ; allophone
ld ... a, (hl) ; get allophone
ld hl, (65362) ; address ... put in buffer
dec hl ; reduce address
ld ...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…
... 2
0x11DE DEC HL ; HL=HL-1
0x11DF CP ... DE>HL)
0x11E5 ADD HL,DE ; restore HL
0x11E6 INC HL ; HL=HL+1 ... test_2:
0x11EF DEC HL ; HL=HL-1 (hl back to 0xffff)
0x11F0 ... 0x120C EX DE, HL
0x120D INC HL ; hl back to 0xff58
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…
... _oldKeyStates ;Destination
LD HL,_currentKeyStates ;Source
LDIR ... keyboard segment number
ADD HL,BC ;Calculate the keyboard ... number
DEC HL ;Calculate the keyboard segment ...Multiplying. Again.Is there a faster way of hl=a*32 than doing add hl,hl 6 times?<div><br></div><div>I get the feeling that working with 8 bit registers for most of it …
Is there a faster way of hl=a*32 than doing add hl,hl 6 times?
I get the feeling that working with 8 bit registers for most of it would be faster, but can't quite see the route...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…
... (iy)
ex de,hl
add hl, bc ; add x offset
ex ... de,hl
ld a ... h, 3 (iy)
add hl, bc ; add x offset
ld ...Mr. Jido makes some noiseA little something to analyse and discuss for you. [code] ORG 60000 ; RND Generator: RND LD HL,EARTH LD A,(WIND) ADD A,L LD …
... A,(WIND)
ADD HL,DE
LD A,(HL)
LD (FIRE ... HL,WIND
INC (HL)
LD E,(HL)
LD HL,EARTH
ADD HL ... ,DE
LD A,(HL)
Problem with BC corrupting after DJNZJust for fun, I'm messing around trying to get the level maps from Lemmings to display on the screen with machine code. It's been ages since I did an…
... screen I have to add 32 to the map ... br /> MAIN LD HL,50213 ; MAP START ADD
LD ... DE,16384 ; SCREEN START ADD
LOOP1 LD ... CHARS
INC E ; ADD 256 TO SCREEN ADDRESS TO ... MAP ADDRESS
ADD HL,BC ; ADD 32 TO THE MAP ...Let's copy buffers!Figured I'd do some double buffered graphics, so I can render for several frames before displaying stuff. Yes, I mean on a 48k speccy, so no 128k spe…
... scanline start + 12)
push hl
push de
... bc, #12
add hl, bc
ld sp, hl
pop af ...
ld bc, #12
add hl, bc
[/code]
[img ...sdcc inline assembly wtf..So, I'm trying to get division to work. By googling I've found one division algorithm that's quoted in several places, but can't seem to get it to wo…
... br /> pop iy
pop hl
pop bc
push ... b, #16
_loop:
add hl, hl
rla
cp c ... br /> pop iy
pop hl
pop bc
push ...Copying a single character from one place to another?[code] ORG 33000 LD A,8 LD HL,16384 LD BC,256 LD DE, 18432 LOOP: PUSH AF LD A,(HL) LD (DE),A ADD HL, BC POP AF DEC A JR NZ,LOOP REST […
... /> LD A,8
LD HL,16384
LD BC,256 ... /> LD (DE),A
ADD HL, BC
POP AF
...Mojon Twins MK2 and lighting effectsDoes anyone have any experience in getting the overlay.h working in the MK2 engine. There were several games written in the churro that used the ove…
... push hl
add hl, hl ; hl = ovl_y * 8
add hl, hl ; hl = ovl_y * 16
add hl, hl ; hl = ... push hl
add hl, hl ; hl = ovl_y * 8
add hl, hl ;
andydansby
June 2017
Development
how does this multiplication routine work?taken from chuntey wordpress: imul ld e,d ; HL = H * D ld a,h ; make accumulator first multiplier. ld …
... accumulator first multiplier.
ld hl,0 ; zeroise total.
ld ... ,imul2 ; wasn't set.
add hl,de ; bit was set, so ... add de.
and a ; reset ...High score table routineI wrote this general purpose high score table routine. It stores 5 scores and displays them alongside the player names, which are 8 characters long. …
... ---------
LD HL,(SCORE) ; final score
...
INC HL ; increment HL...
LD (TEMP),HL ; ...and store ... LD A,13
ADD A,D ; DE now ... is zero
SHWDG0 ADD HL,DE ; restore total
Other than using attributes what other ways to detect collisions, when using char based movement?So I'm slowly working out the bits and pieces to write a game completely in assembly. I've been using attributes when writing in BASIC to detect whet…
... think?
[code]
ld hl,22528
ld a,10 ... bc,32
LOOP:
add hl,bc
dec a
pop bc
add hl,bc
ld a,(hl) ; a now holds ...INC not working as expected in LoopHi, i have been working on this for around 2 weeks now and Ive read myself into a hole. I am trying to increment HL. HL is referencing a display …
... /> I am trying to increment HL. HL is referencing a display attribute ... de,1
add hl,de
---
inc hl
---
inc ...Prportional Ascii text scrollerA couple of years ago I wrote a little scroller that nestles at the top of RAM (FFCA - 65482) and scrolls standard Ascii encoded text from anywhere y…
... =FF
and (hl) ;apply (HL)
pop hl ;restore chr set ... address
inc (hl) ;inc counter
add a,a ;get bit ...
