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Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... br /> DEC IY Decrement IY.
DEC ss Decrement register pair ss ... Disable interrupts.
DJNZ e Decrement B and jump relative if ... operand s and accumulator.
OTDR Perform an OUTD and repeat ... -
IND/INDR/INI/INIR/OUTD/OTDR/OUTI/OTIRI'm looking for confirmation that the official Z80 User Guide from Zilog is wrong and that these composite instructions actually change the value of …
... decremented before first use in OTDR, as the common way to ... /> ld bc,&10f8
otdr[/code]
Looking at the ... from xz80), the OUT instructions decrement B before use, the IN ... instructions decrement after use. What do the ... -
IND/INDR/INI/INIR/OUTD/OTDR/OUTI/OTIRI'm looking for confirmation that the official Z80 User Guide from Zilog is wrong and that these composite instructions actually change the value of …
... decremented before first use in OTDR, as the common way to ... /> ld bc,&10f8
otdr[/code]
Looking at the ... from xz80), the OUT instructions decrement B before use, the IN ... instructions decrement after use. What do the ... -
InterruptsA small piece intended for the FAQ. Comments, corrections, additions welcome. Notably: * How long does the 48K ULA hold /INT low? * What happens i…
... tstates: acknowledge the interrupt and decrement SP.
* M2: ... 7 tstates: acknowledge interrupt and decrement SP.
* M2: 3 ... 6 tstates: acknowledge interrupt and decrement SP.
* M2: 3 ... tstates: acknowledge the NMI and decrement SP.
* M2: ... -
Codies help? Werewolves of LondonHi All, never one for shying away from the deep end, having only just dipped my toe in to the world of machine code I find myself trying to find out …
... register = 1, If yes then decrement to 00 and carry on ... -
unused assembler commands?Z80 processor has commands like OUTI OUTD OTIR OTDR INI IND INIR INDR.They deal with sending /reading bolcks ofinformation to ports. The problem is, …
... commands like OUTI OUTD OTIR OTDR INI IND INIR INDR.They ... -
Well I'm excited, but I guess you might not beHehe this is as far as I got today, a silly little border program: [PHP] ORG 32768 PROGGY: LD C,255 ; We loo…
... the border
DEC A ; Decrement register A
DJNZ BORDERDOWN ... into A
DEC A ; Decrement it
LD C,A ... -
Graphic equalizer m.c. program neededBack in the 90's I had a full-screen attribute equalizer that was simple, yet very impressive. We used to listen to Vangelis or Jean M Jarre by conne…
... counter is different from zero, decrement that counter by one. This ... -
DJNZ e ProblemI'm trying to write the DJNZ e instruction as part of the development of my emulator and can't get it to work. Here is the in and out states of Phil…
... />
[code] // Get regB and decrement it by one
dim ... -
Tutorial - learn machine code in 30mins[B][I]Message from the moderators[/I] - bigjon has requested that readers' attention be drawn to a better version of this tutorial, one which is easi…
... , djnz.
djnz stands for Decrement then Jump if Not Zero ... over the instruction to increment / decrement the car position.
Replace ... for LoaD ((hl) to (de)),Decrement (hl and de) and Repeat ... -
Static vs stacked local variables in z88dkHello everyone. I'm doing a program for Spectrum 48KB with z88dk v1.8 (XX Mar 2008), and I eventually discovered that if your local variables in fun…
... on.
b) the decrement control static local variable bug ... -
iXpectum 1.2 HD (iPad enabled) is out!iXpectrum now supports iPad on jailbroken devices ;) Thanks to Ryosaebaa for his support... You can download by now at: [url]http://code.google.co…
... flags in OUTI,OTIR,OUTD,OTDR instructions.
- Improved port contention ... -
Kiwi OS for z80 computerHi everyone, Nearly made my z80 computer with 2K ROM 32K RAM. It has an OS im still writing called Kiwi (apple, blackberry, you get the idea ;D) he…
...
DEL
DJNZ DEL ;DECREMENT B AND KEEP LOOPING UNTIL ... /> ;*********************************
MULTIPLY
DEC B ;DECREMENT B
MULTI
ADD ... -
Difficult to find upper RAM fault.I've recently repaired an issue 3B 48K Spectrum that had a tricky to diagnose upper RAM fault, so I thought I'd post a report of what I found here. …
... of this test did not decrement a value to zero, the ... -
Inefficient code in ROM, from ram-check to RAM-DONEHere is the inefficient code: [CODE] ;; ram-check L11DA: LD H,D ; Transfer the top value to the HL register LD L,E …
... .
DEC HL ; Decrement memory address.
CP ...
DEC (HL) ; decrement to zero.
JR Z ... .
DEC HL ; Decrement memory address.
CP ... -
IND/INDR/INI/INIR/OUTD/OTDR/OUTI/OTIRI'm looking for confirmation that the official Z80 User Guide from Zilog is wrong and that these composite instructions actually change the value of …
I'm looking for confirmation that the official Z80 User Guide from Zilog is wrong and that these composite instructions actually change the value of B first. You'd only notice this when reading or writing from a 16-bit I/O address using one of these ... -
MGT MOUSE - exist really ?I read disassembly of +D rom/ram code and from address #2249 is routine for read MGT MOUSE ports. I can't find any info about "MGT MOUSE". Exist real…
... .
226D DEC (HL) Otherwise decrement x-coordinate.
226E RET ... -
Routine for handling large scores?[FONT=Calibri][SIZE=3]I want to store various numbers for scores and levels etc. Some of these can be very large so will need to be held in multiple …
... be able to increment and decrement these values. Anyone got some ... -
Tinkering with DMASo, some afternoon tinkering... [img]http://photo.alioth.net/tmp/dma_small.jpg[/img] The purpose of this all is to see what's possible using the Xi…
... time (the limit of OTIR/OTDR) and it can be designed ... -
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…
... LINE COUNTER
DJNZ LOOP2 ; DECREMENT THE LINE COUNTER AND LOOP ... BC the DJNZ doesn't decrement it by one, it suddenly ... -
A sped up pixel-shift routine for 1-byte–wide spritesHere’s an optimized (for speed) real-time sprite shifting routine for sprites that are one byte wide. It uses no memory variables for storage of inte…
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. …
... name...
DEC A ; ...otherwise decrement A until it is 0 ...No-tearing (“vsync”) Full Screen FadeSeeing as most screen fades exhibit visible tearing, I wrote my own routine which does away with that problem. Simple, effective, short, and fully re…
... 0
dec c ;else, decrement INK
f1 ld a ... 0
sub 8 ;else, decrement PAPER
f2 or c ...Printing text, part MMXIIXI'm pretty sure there's been a zillion threads about this already, and I don't think it's the first one by myself either, but here goes. Proportiona…
... /> jr NC, prewidthloop
; pre-decrement target space
ld a ...
rl b
; Decrement pixels that fit in target ... /> inc hl
bytefull:
; Decrement width, loop if not done ...Machine Code ChallengeHere's a challenge for all you Z80 programmers. Points to be awarded for elegance and brevity. (I haven't got the solution either) HL addresses the …
... /> CALL Process_byte
DEC B ; Decrement quantity.
RET Z ; Return ...Machine Code ChallengeHere's a challenge for all you Z80 programmers. Points to be awarded for elegance and brevity. (I haven't got the solution either) HL addresses the …
... B=0
DJNZ Next_byte ; Decrement quantity.
; Fix ...Anyone for a hacking challenge ?I have to get the DSK version of Tomahawk to work. It uses the well-known Digital Integration "SECURITY CODE" lock just like in Bobsled, ATF, etc. Th…
... first pass
DEC A ; Decrement contents of Accumulator ie. subtract ...ZX81 and ZX80 emulator on Spectrum 128KA couple of weeks ago we were talking about a new ZX81 emulator for the 128K. Someone beat me. More details at [url="http://www.fruitcake.plus.com/S…
... /> ;; COUNTER
L038A: DEC E ; decrement the measuring timer.
IN ...
