-
"The Register" logo.What do those walking legs in the "The Register" logo represent? Is there a story behind them and why is it missing the rest of the body? Where is …
What do those walking legs in the "The Register" logo represent? Is there a story behind them and why is it missing the rest of the body? Where is it walking to?
[img]http://www.theregister.co.uk/Design/graphics/std/logo_414_80.png[/img] -
Machine code loopsDear all, 30 years too late I know, but I'm finally starting to get to grips with Machine Code - something I could never manage back in my early tee…
... back to if the b register isn't 0, but I ... ) Can I not just load BC with say 6912, dec it ... misunderstood this? Does the flag register only react to operations on ... -
Some thoughs about fast scrolling on 128 modelPlease, consider this article as technically interesting concept not a proven algorithm. ONE The fastest scrollers use long sequence of PUSH inst…
... DE for empty tile and BC for generic wall tile. And ... spend 256T by updating one register.
TEN
If ... -
Cobra (improved again BUGFIX)This is an improved BUGFIX for game [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0000996"]Cobra[/URL], that works better than the fix curre…
... loop:
[CODE]95fe: ld bc,$3f28
9601: ld a ...
9602: in a,($ff) ; register 'A' always set to $FF ... /> [CODE]95fe: ld bc,$0300
9601: dec bc
9602: ld ... -
MOVE_M Object Movement Manager for BASICAs moving things around on the screen is usually the slowest part of a game written in BASIC, I've been pottering around with this routine to handle …
... /> REM RESTORE USR DOINT : do stuff : RESTORE USR NOINT:
... REM replace USR labels with the ... /> 257 RESTORE USR DOINT: PAUSE 0: RESTORE USR NOINT: RETURN< ... $028e KEY_SCAN the DE register and the Zero flag
SCREEN$ bug fixI've been using the SCREEN$() function recently for reading data off the screen rather than taking up space with an array and I got fed up with the s…
... FN c$(r,c)=STR$ USR ScrDol0 .
[code]
ScrDol0 ... instead of BC
pop bc ;BC=$2d2b (discard)
pop bc ;BC=$3365
push de
push bc
ld de,(23653) ;DE ...that "listing variables during runtime" thingWell, I did eventually finish this, but with my meds playing up I don't have much time each day that I can spend at the computer, so it's taken rathe…
... FN s$(r,k)=STR$ USR ScrDol0
so if called ... contain r & k and BC=ScrDol0 prior to the call ...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…
... load "" code : ink usr 65477 : print usr 65040[/code]
65227: LD BC,236
... /> 65243: PUSH BC
65244: PUSH BC
65245: ... SP
65250: POP BC
65251: ADD HL ... , 23610
65441: POP BC
65442: RET
...dumping protected BASIC loadersI wrote this a few weeks ago but forgot to post it. It will load & list from tape/TAP/TZX any BASIC program which has been saved with SAVE, including…
... mc+5,0:
LET bc=USR mc: IF PEEK bytes THEN ... +5,PEEK (bytes+12): LET bc=USR mc
10 LET a ...SBC IX,DE/BCAlways wondered why there wasn't a SBC IX, DE/BC command.... so have to use PUSH HL ; save original HL PUSH IX ; IX on stack POP HL ; IX …
... 't a SBC IX, DE/BC command....
so have ... is the value to subtract, BC is the counter. Another note ...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…
... DB screen and then RANDOMIZE USR 31144 (or JP or CALL ...
loop1:
ld bc,32 ;BC is counter for block copy ...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: …
... GPL
; wait bc T (including call; bc>=141)
; ... ,-141
add hl,bc
ld bc,-23
.loop add ... /> [CODE] ORG 40000
LD BC,141
CALL DELAY
USR to "SCF + RET NC" or ...Machine Code in 30 minutes - car gameWotcha folks, 30 years on and I'm still struggling with Machine Code. I'm going through the 30-minute tutorial on the Chuntey blog and it's all made…
... this:
[code]
ld bc,65278 ;read keyboard caps to ... l
moveright
ld bc,32766 ;read keyboard space to ... why 65278 is loaded into BC, but what is 'IN A ... the contents of the C register ...which doesn't make sense ...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 de,16385
ld bc,6143
ld a,255 ... and run it with RANDOMIZE USR 31500 everything works well - screen ...Strange keyboard port reads on 48+Hi all, I don't know whether it was already discussed (I also searched forum, but there are too much of results searching "48k keyboard" so I didn't…
... /> 40 POKE 23692,255: PRINT USR 32768;" ";: GO TO 40
rept 3270
ld bc,+
ld a,239
Fuse tests - INC BC causes contention delayHi all, In the FUSE test suite it has the following for the output of opCode 0x3 (INC BC): 0 MC 0000 4 MR 0000 03 4 MC 0001 …
... output of opCode 0x3 (INC BC):
0 MC 0000 ... understand is why incrementing the BC pair should introduce two contentions ...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, since it has a somewhat usable debugger.
However I believe I found a few bugs, some in "zero" application, and some on emulation itself.
The following example ...The I register and IM 1Hi al! I've been doing some coding, replacing the BASIC ROM with my own code and upon examination of a few 16Kb cartridges, all the ones I've look…
... to say about the I register, apart from its use in ...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…
... />
LOOP1 LD BC,8 ; SET THE COUNTER FOR ... LINES
LOOP2 PUSH BC ; STORE THE LINE COUNTER ...
LD BC,32 ; SET THE COUNTER FOR ... NEXT LINE
POP BC ; RETRIEVE THE LINE COUNTER ... on screen, after popping BC the DJNZ doesn't ...Z88DK NOOB cplot INK colorHi I am a complete NOOB with Z88DK, I am trying to draw colored circles. How does ink, paper and border work with Z88DK. I started trying to wo…
... for CALLEE functions)
POP BC ; C = x, and remove x ... ; Move X to the proper register
; D = X and ...So it occurred to me; "Why bother with going into 48K BASIC when you can just....wrap the machine code calls inside a 'RST #28;DEFW addr:RET'?" Of course, you DO need a small M/C routine to do that, and ta-daaa, here it is: [cod…
... /> DEFW #2DA2 ; unstack BC from the calculator stack - ...
LD (addr),BC ; store the value at ... addr DEFW #0000 ; loaded from BC above ^^
RET
... Usage: RANDOMIZE addr AND USR 23764
3 ...RANDOMIZE USR, PRINT USR etcHello just wondering why is it called RANDOMIZE UsR what does randomising have to do with it ? When calling machine code routine from adress x you ty…
... why is it called RANDOMIZE UsR what does randomising have to ... you type RANDOMIZE USR x. Why not RUN USR x ? I just ... tried PRINT USR 65368 it resets the machine! ...Print (to screen) avalue held in a register pairHi guys, looking for a routine that will print any value from 0 to 65535 to the current position on the screen. I once heard that there was a PRIN…
... a value held in theBC register pair, to the current screen ...More basic assembly stuff!I've been figuring out some more stuff using CALL and DEFB but this has me a bit stumped. [code] ORG 33000 LD BC, 16384 PUSH BC CALL GO RET …
... 33000
LD BC, 16384
PUSH BC
CALL GO
BC
RET
[/code]
When I do PRINT USR ...New Windows Spectrum Emulator: CSpect V0.2 ZXSpectrum emulator by Mike DaillyNew Windows Spectrum Emulator: CSpect V0.2 ZXSpectrum emulator by Mike Dailly (Found on SpecNext Facebook-Page) Info and Download (=klick "CSpe…
... ===================
ld bc, $243B ; select the X scroll register
ld a ... ===================
ld bc, $243B ; select the Y scroll register
ld a ... as transparent
Register $20 ; Layer 2 transparency ...shadow regs musingIn the process of optimising some assembler, it occurred to me how great it would have been if the Z80's shadow reg opcodes had been a bit more fully…
... to exchange either AF or BC,DE,HL. Which makes them ... cumbersome to get shadow BC into regular BC without going via the ... .. originally intended for a quick register bank swap during interrupts, which ... up with:
ex bc, bc'
ex de, de'
Using BASIC from Machine CodeHi Folks, Came across a very interesting article by Toni Baker in Your Spectrum: http://www.users.globalnet.co.uk/~jg27paw4/yr11/yr11_66.htm …
... /> LD HL,(23641)
LD BC,130
CALL 5717
POP HL
LD BC,128
LDIR
SET ... 0
120 LET A=USR 62000[/code]
The ...Can't Get My Simple Code To RunHello again, I'm trying to run the following simple code: [code] org 32768 main ld b, 21 ; x coordinate is …
... ; string to print
ld bc, eostring-string ; length of string ... . I tried
[quote]Randomize USR 32768[/quote]
but I ...A Neat Redefine Keys RoutinePreviously, I’ve only shared this routine with a couple of people via PM, but I’ve now decided to make it public. I optimized it for size, so it uses…
...
2$ push bc ;remember counter
ld a ... ; otherwise, use a 16-bit register
;pair, such as ... ;table row
pop bc ;restore counter
djnz 2 ... up (HL will be incremented BC times)
cpir ;while ...
