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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?
... 16-bit port space
"Both types of interrupts increase the R register by ... one, when accepted..."
This is incorrect. IM0 executes the ... instructions.
"The Z80 responds to the change of the line from +5 ... -
MEMPTR: Is it worth emulating?Some advice if you will :) The only info I have on MEMPTR is this document here: [url]http://zx.pk.ru/showpost.php?p=43800[/url] I notice SpecEmu h…
... 5+3 of the flags register after a BIT n,(HL). The rest of the instruction set ... on BIT 7,x setting the sign bit which is undocumented in the Z80 manuals. The ... code does something like:
BIT 7,(HL ... -
Routine for clearing screenI was looking for a 'nice' way of clearing a screen of graphics in Z80. After a ridiculous amount of time mucking around, this is the best and most …
...
; DE is the LFSR register, seeded at 1
LD ... will "process" the value of DE through a 16bit register with a defined ... }
; Input: DE contains 16-bit register to "shift"
; Output: DE ... as we will be putting bit 7 of D to zero as we ... -
Low level microdrive programmingSo I'm on my lunch break trying to find out about low level microdrive programming (without using IF1 ROM). I see one can use port 0xe7 to read and w…
... set the r/w bit to r first?).
2) The purpose of the ... ) stop motor
7) To erase microdrive/create a ... /> a) start the motor
b) set the r/w bit
c ... anything (like the SYNC bit or the GAP bit) without seting the R/W bit?
ULA bug and snowI am tryng to improve the snow emulation in FBZX wii but I do not have a real spectrum to test the results. I used the information taken from Harele…
... read the lower 7 bits address of the previous reading which is the register R in the case of the ... first pair and the lower 7 bits address of the first ...Video generation using a CPUWe know it is possible to generate a video signal using a CPU, and this technique was often used on low-end computers in the early 1980's (for exampl…
... internal 3 bit register in the ULA which tells it which line of the character ... we're on (it can hold 0 to 7) and the ... i register which normally points to ...MC LPRINT 23681Having problems with this routine to print large on the screen using LPRINT, it works ok in BASIC, but cant seem to get it to loop for some reason in…
... from masking the r register with 0x5. This limites the number of colours to ... 7 (after adding 1).
The 'r' register is sensitive to the length of the ... loop too. With the current code, the ink ...display file addressing; screen slicingWhile working on this Compendium I'm updating or rewriting a lot of stuff. One thing I eventually came to appreciate was the simple & clever way in w…
... /> display file addressing bit patterns (using the HL register pair):
H =010ssppp ... -7, ccccc=char.col 0-31
That's the kernel of ... segment has 8 rows of characters numbered 0-7 (bits rrr in ... has 8 lines of pixels numbered 0-7 (bits ppp in H ...Issue 3 board with strange piggy-back boardIn case you are interested. I?ve never seen something like this before. I have an Issue 3 board here. When I opened the case and found a strange pig…
Agreed that it can't be OUT.
Could bit 7 of register 'R' be detected?
Sometimes you find LS158 instead of 157SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
...
ret ; end of subroutine
; THE 'INT-FETCH' SUBROUTINE
; THE 'FLOATING-POINT TO BC' SUBROUTINE ...
set 7, d ; set bit 7 of D'
exx ; main register set
SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
... ; main register set
ret ; end of subroutine
; THE 'SUBTRACTION ... ; restore pointers
; THE 'ADDITION' OPERATION
org 0x3014 ... /> exx ; alternate register set
bit 7, d ; test bit 7 of D'
exx ...SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
[code]; THE SCANNING VARIABLE ROUTINE
org ... if so
res 7, c ; clear bit 7 of C
org ... 6, (hl) ; assume numeric
bit 7, e ; is it?
jr ... until done
; THE TABLE OF OPERATORS
org 0x2795
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…
How about just using IX for referencing SP and just SET or RES bit 7 of IXH. Then IY can be the additional register pair to allow 16 bytes at a time, this solving the leftovers issue?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…
... or RES bit 7 of IXH. Then IY can be the additional register pair to ... allow 16 bytes at a time, this solving the ... , this would work in case of 16384 and 49152 but it ... /> [QUOTE]The downside is that the more faffing you do, the slower it ...Which Emulator supports Betadisk48?Hi out there and happy new year, I'm looking for an emulator to run with my vision1.7 trdos-rom in 48 mode. Unfortunately most emus only support Bet…
... OF ENTRY AND EXIT:
31 (1FH) - Register commands from the controller ... at 1.
Bit 4 - SELECT SIDE of the drive. If = 1 ... the ROM entry routines, so no need for patch traps.
Bit 7 of ... FCh determines whether the disk I/O ...ULA snow effectIt's wintertime, you know. [quote="http://ramsoft.bbk.org.omegahg.com/floatingbus.html"]when the I register falls in the range 0x40-0x7F then the UL…
... describe in your post with the alternate columns.
cool ... see where the r register only incrementing through the lower 7 bits is ... making the scrolling image ... character cell for part of the scroll then it jumps ...ULA snow effectIt's wintertime, you know. [quote="http://ramsoft.bbk.org.omegahg.com/floatingbus.html"]when the I register falls in the range 0x40-0x7F then the UL…
... see where the r register only incrementing through the lower 7 bits is ... register, which is then copied to R at the beginning of ... two types of R overflow situations over the course of the NOP ... Generally manifests as part of the scrolling columns being offset ...Sorting BusinessThis is a little bit different from the usual game-related fare but I know there are a few people here who like this sort of thing. This is about so…
... to be sure the savings are there. The cost of the extra swaps is ... a single bit because you can never be out of balance by ... is already an item at the top of the stack, and I do ... want to go to the exchange set. The R register is there, but I ...ZX Spectrum CartridgesI have been thinking of "cloning" ZX Cartridges for a while (case, board and silicon skirt), to be able to make new releases or replace damaged cartr…
... we can control I and R register, it's possible to ... can FORCE the I and R register to become ZERO.
The R register is ... a fetch at #0000 instead of a read.
... special bit (R7), that doesn't change, even after R register increment ...Graphics program in AssemblyHi so I think I'm getting the hang of this so I've done this program. It writes directly to the screen. I'm using ZX Spin. [code] LD HL,16384 LD B,…
... the r register?[/quote]
Basically, its a 7-bit (technically 8, but the most-significant bit ... never changes) register that's ... #RRegister"]Z80 Technical Information about the R register[/url]Two different versions of Bruce Lee?There's a possible MIA here, I think. I sat down at lunchtime to play a bit of Bruce Lee and discovered that the version I'd downloaded from WOS (th…
... around in the Erbe TZX you can see the remnants of BASIC ... />
Just a couple of notes for the snapshot and TZX
the R register, and the POKE above in the listing enables copy ... the TZX just do LOAD "" CODE, and then INK 7 to see the ...Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…
... it does at the end of that function, finds the first bit set in ... through the carry (9 bit rotate) just check what is left in the register ... />
I also set the bit 7 of C register on exit if you are ...The name of the gameDoes anyone knows the name of the following game: You have to take your girlfriend to a show, but someone as trashed your bike and splitted all the …
Does anyone knows the name of the following game:
You ... your bike and splitted all the parts across town.
You have to fight for the motorcycle parts
You ... need a spanner.
The game was all in black ...
