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The I register pointing to $40–$7f causes ULA snow and a crash. Or does it?I have heard it from numerous sources, including a few members of this forum, that 128K/+2 machines crash if the I register points to a range of $40–…
... /> LD A,#C0
LD I,A
LD A,#FE
LD I ... /> ld a,$10
out (c),a ; 48k rom selected, bank 00 ... area
ld ix,__LOADER_head
ld de,__LOADER_CODE_tail - __LOADER_head
How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... /> ALIGN 256
tbl_mirror db #00, #80, #40, #c0, #20, ... #5e, #de, #3e, #be, #7e, #fe ; 7
db #01, #81 ... , reg
ld h, tbl_mirror/256
ld l, bytetomirror
ld reg, (hl)
...LINE-routine and other nice pieces of codeThe line-topic came in the end with a nice piece of fast coding. I think that there might be more of these routines out there (where-ever-u-r). Isn…
... me..)
INIT...LD B,hightable ; B = constant through ... the program
.......LD DE,0
.......JP MAIN ... points to highbyte (4)
.......LD H,(HL) ; fetch highbyte ( ... br /> JP I00; jump instruction 00
JP I03
JP ...IM 2 interrupts and smooth scrolling - easy peasy!Okay, been fiddling around with IM 2 and have actually mastered (I think) how to use IM 2! Now I run my game Ragnar Revival in IM2 and use HALT to sy…
... intfunc
push hl
ld hl,16384
inc (hl ... br />
mainloop
ld a,07Fh ;Trap Space key ... handling
prepint
ld hl,58880 ;Building up a ... . Order: lsb,msb
ld (hl),0BAh
inc hl ... on 2004-07-27 00:40 ]IM2 Machine Code Sprites Example Code Using Char Based SystemFurther to my earlier post, here are sprites running using char method with IM2 driving it Note, for 48k spectrum using TASM [code] ; ***********…
... RIGHT
right:
LD A,(IX+2) ; x graphic ...
LD E,72
LD D,0
LD A,(IX ... br /> pp1:
ld (hl),C ; LD (0FE00h),FDh
...
ld a,0FEh
LD I,A ; I=FE
...Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …
... LD HL,BACKGROUND
LD DE,BACKGROUND+1
LD BC,1B00h
LD ...
PP1:
LD (HL),C ; LD (0FE00H),FDH
INC ... DI
LD A,0FEH
LD I,A ; I=FE
IM ...Smooth Masked Sprites using fast page flip on 48k Part 2Ok, After all the suggestions in Part 1, which were all excellent (Thankyou), I opted on the following: I have 2 x 6k Offscreen areas (Yes, that's …
... />
LD HL,BACKGROUND
LD DE,BACKBUFFER
LD BC,1800h ...
PP1:
LD (HL),C ; LD (0FE00H),FDH
INC ... DI
LD A,0FEH
LD I,A ; I=FE
IM ...Z80 register decoding document error?Hi, I've been working on a disassembler using the following document written by Cristian Dinu (aka GOC?). [url="http://www.z80.info/decoding.htm…
... following:
DDCB d 00
According to various ... this should work out to: LD B, RLC (IX+d)
DEC BC/LD A,B/OR C/JP NZ,loopyesterday i saw nice trick:[code] dec bc ld a, b or c jp nz, loop can be replaced (bc starts >255, short jump) by: dec bc inc b djnz loop [/code] …
yesterday i saw nice trick:[code]
dec bc
ld a, b
or c
jp nz, loop
can be replaced (bc starts >255, short jump) by:
dec bc
inc b
djnz loop
[/code]
..niceIN Port FE bit 6 confusionI know I've got this wrong. Tapes load fine but it all feels messy. Currently my emulator does this: Sets bit 6 of the result to 0. If (and only if…
... FAQ mentions something about OUT FE affected bit 6, is this ...Next Gen Console Games ?60.00 ?????I've just been reading on ch4 teletext that the price could be ?60.00. I wonder how many would pay that extortionate price for 1 game, not me, there …
... the price could be ?60.00.
I wonder how many ...Programming MC : first stepsIsn't nice to collect all kinds of short routines to help making the first steps into MC for everyone who never touched MC? What I mean is mostly th…
... />
start ld hl,(23672)
ld (seed),hl ; RANDOMIZE ... bc ; save registers
ld c,a ; marge to C ... /> and #3f
ld h,a ; but keep it ... -08-31 08:00 ]Problem with rotating procedureHi folks! I wrote a proc in z80 asm, based on: x' = x * cos (z) - y * sin (z) y' = x * sin (z) + y * cos (z) I used a precalculated table of sin a…
... ld h,a
ld a,c
ld ... ld d,l
ld l,h
ld ... br /> ;============================================================================
rotatez: ld bc,(anglez) ;xc=cos(anglez ... />
db $00,$00,$00,$00,$00,$00,$00,$00
db $20,$ ...Currah MicroSource emulationIt appears to be impossible to emualte the MicroSource in software on the ZX Spectrum SE as hardware polling is required. The following patch is not …
... br />
ld hl,uSource ; source
ld de,$2000 ; destination ... /> ; emulate polling
ld hl,$2bae ; insert the instruction ... /> ; emulate polling
ld hl,$2bab ; insert the instruction ...
zxROM:
defb $00;
[/code]Question on Z80 R/W cycles.Snipped from the complete spectrum ROM disassembly: [CODE] Now the memory is checked. 11DA RAM-CHECK LD H,D Transfer the value…
... the value in DE
LD L,E (START = +FFFF, ... RAMTOP).
11DC RAM-FILL LD (HL),+02 Enter the value ... DEC (HL) +01 goes to +00.
JR Z,11E2,RAM ...Paging MemoryAny idea why this short piece of code doesnt work, just crashes. I am just messing with paging memory in and out (not achived this yet) and reading t…
... .
01 FD 7F LD BC, NN Hardware Memory Switch ... ), A
06 00 LD B, N
4F LD C, A
A dual tuner PVR for ?15.00 not inc HDI have just recieved an email from Bigpockets saying they have dual tuner PVR's for sale at £8.99 but with postage its £15.00, u basically…
... but with postage its £15.00, u basically have to put ...Bizarre stuff in Interface 1's shadow ROMAccording to the Complete Shadow ROM disassembly, the function that exits back to the BASIC interpreter after interpreting IF1 commands is this: [co…
... br /> [code]
05C1 END1 LD SP,(ERR-SP) Clear machine ... stack.
05C5 LD (ERR-NR),+FF Clear error ... code.
05C9 LD HL,+1BF4 Return address ...
05D1 IN A,(+FE) during runtime.
05D3 ... RETAD-RUN
05D6 LD A,+FE
05D8 IN ...Speccy sound on tv show - againRemember the spectrum loading noise in two CSI shows? Well, fuzzix on c.s.s. has found what seems to be another clip of Speccy goodness: [url]http:/…
... 60 LBYTE LD A,#7F
70 IN A,(#FE)
80 ... RRA
90 RET NC
100 NBYTE LD ... L,1
110 LD BC,#B201
170 LD B,#B0
180 JR ...Bresenham's line algorithmHelp - I really am struggling to get my head around this algorithm. I don't know why, I coped with Cordic (SIN/COS) and integer divide routines (/10 …
... /> LD A,H
LD H,B
LD B,A
LD A ... ,L
LD L ... ,C
LD C ... dx is positive
LD A,$FE ;-2 as dx is negative ... dx is positive
LD A,$FE ;-2 as dx is negative ...So... you want to format your 3.5" as 720K eh?Well, i've been trying to get hold of an application to make proper use of my 3.5" +3 floppy disks but i haven't been able to find any. I stumbled up…
... RET ; Return
FERR LD A,2 ; Simple error handler ... Preserve registers
LD BC,32765
LD A,(23388)
... 2A,$52
DEFB $00,$00,$00,$00,$00,$00
[/code]BD Rom for ?57.00 @SVPIts only for today and with postage its ?63.00. Its a sony one as well [url]http://svp.co.uk/products-solo.php[/url]
Its only for today and with postage its ?63.00. Its a sony one as well
[url]http://svp.co.uk/products-solo.php[/url]FLASH EPROM programming on ZXExist any other software for rewriting FLASH EPROM or EEPROM chips on real ZX ? I know only: EEPROM flasher for original DivIDE [url]http://85.132.…
... /> ld b, $07 ;
ld a, b ;
and l ;
out ($fe ... ), a ; set border color
ld e, l ...Machine Code Microdrive File LoaderI've been experimenting with transferring games to run from microdrive. Typically I like to see a loading screen while things are happening, and I li…
... ;
main1 ld (err_sp),sp
ld hl,main2
ld (hd_11),hl ... br /> ld (attr_p),a
ld (_bordcr),a
out ($fe),a< ... br /> rst $10
defw $0d6b
;
ld ... a,"M"
ld (l_str1),a ; signify microdrive ...Tinkering with Quique Llar?a's Midi2Ay tool...Im tinkering with Quique Llar?a's Midi2Ay tool, found at: [url]ftp://ftp.worldofspectrum.org/pub/sinclair/tools/pc/midi2ay-0.1.zip[/url] Im not a v…
... ] xor a
in a, ($fe)
cpl
and %00011111 ... /> ld (R_PC),ix
ld ix,(R_IX)
ld (R_HL),hl
ld ... (R_DE),de
ld (R_BC),bc ... br />
ld (G_HL),hl
ld (G_DE),de
ld (G_BC),bc ...When would you use LD A,R ?Can anyone tell me a practical use of LD A,R and LD R,A I am confused when you would need to use it? Cheers
Can anyone tell me a practical use of LD A,R and LD R,A I am confused when you would need to use it?
CheersKeyboard Issues When Setting Border ColourWelcome to the next in my series of inane 'Z80 on the Spectrum' questions! ;) Here's a minimal snippet of code for polling the keyboard until any ke…
...
NOKEY: LD A,0
IN A,($FE)
CPL
[CODE]
LD A,0
OUT ($FE),A[/CODE]
LD A,0
OUT ($FE),A
NOKEY: LD A,0
IN A,($FE)
CPL
Z80 assemblerIf I do this [code] LD BC, 0002h [/code] is B=0 and C=2, or the other way around? does it disassemble to 01 00 02 does it disassemble to 01 02 00
If I do this
[code]
LD BC, 0002h
[/code]
is B=0 and C=2, or the other way around?
does it disassemble to 01 00 02
does it disassemble to 01 02 00
