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writing an emulator-newbie needs helpHi, this is my first post here. I decided to write a minimalistic emulator of ZX Spectrum-no emulation of advanced peripherals, no emulation of sound…
... . Two highest bits of last byte in header indicate the type ... the manner described when loaded back into an emulator with no ... -
BUZZSAW+ Demo No. 3Right, another demo of BUZZSAW+. [URL="http://www.joefish.co.uk/speccy/Joefish_Buzzsaw_Demo_3.tap"]Joefish_Buzzsaw_Demo_3.tap[/URL] The default con…
... . In between is a 176 byte buffer which contained my border ... an OUT 254 with one byte from a buffer, so I ... to pick from and play back. And the noise banks would ... , I've had to cut back to four banks (704 bytes ... -
+3 Copy ProtectionHi all, I've been looking at copy protection and I've realised that, as a kid, I thought things like speedlock were there to stop you poking the gam…
... limit what can be written back, often requiring specific knowledge on ... couldn't just do a byte for byte disk image?[/quote]Most ... FDC supports, and bit or byte-level reading or writing is ... the Atari ST does support byte-level reading and writing of ... -
At the Carboot sale today.Today at the carboot sale I picked up An Acorn Electron -I see these all the time, An Official Branded BBC Micro Datacassete Recorder - I'v…
... i got sent back from software projects / bug byte from 1984 tho ... -
At the Carboot sale today.Today at the carboot sale I picked up An Acorn Electron -I see these all the time, An Official Branded BBC Micro Datacassete Recorder - I'v…
... i got sent back from software projects / bug byte from 1984 tho ... -
Unlisted game - The Battle of MaidaI've just moved back the the UK and unearthed a game called "The Battle of Maida". I really loved this game back in the 80s and I believe a friend of…
... "development" copy? Line 870 (from byte offset 0x1542 onwards) reads like ... some numbers, that the 5-byte binary version following the decimal ... (rather rare) cases, the 5th byte is ok, though (0x00)
But coming back to the header. The 2nd ... -
Unlisted game - The Battle of MaidaI've just moved back the the UK and unearthed a game called "The Battle of Maida". I really loved this game back in the 80s and I believe a friend of…
... "development" copy? Line 870 (from byte offset 0x1542 onwards) reads like ... some numbers, that the 5-byte binary version following the decimal ... (rather rare) cases, the 5th byte is ok, though (0x00)
But coming back to the header. The 2nd ... -
File size in 128K RAM diskHi Folks, Is there a way to get the size of a file stored in the 128K RAM disk from within a BASIC program? Many thanks Paddy
... file sizes include a 9-byte header.
[code]
10 ... this a test and report back.
Many thanks
INSTR function...Hi Folks, Another little program that people might find useful: [CODE]100 DIM i(4) 110 LET a$="This is some sample text" 120 LET b$="text" 130 GO S…
... ed52 SBC HL,DE ; go back to the beginning
5b6f ... ))+FN n(h$(2)): REM Byte hex conversion
1000 DATA ...Where to start?..Hello, First off, sorry if this is in the wrong and sorry if the questions I'm about to ask have been asked and answered numerous time! Little back…
... will never want to go back to Basic.
[QUOTE ... simple operations like copy one byte from one place to another ...Where to start?..Hello, First off, sorry if this is in the wrong and sorry if the questions I'm about to ask have been asked and answered numerous time! Little back…
... will never want to go back to Basic.
byte from one place to another ...Opcode QuestionsHi all, I am an experienced LabVIEW progammer and also have fond memories of the spectrum. Thus I started to think about writing my own emulator an…
... to DJNZ (i.e. the byte at PC+1) is a ... single byte signed offset, giving the jump ... of 1 would skip one byte; and a parameter of 254 ... to minus 2) would jump back to the DJNZ instruction, effectively ...Where to start?..Hello, First off, sorry if this is in the wrong and sorry if the questions I'm about to ask have been asked and answered numerous time! Little back…
... codes for those mnemonics, the back of the original 48K Spectrum ... />
The 'XX' represents a byte of data. So if the ... -bit number, with the low byte first. The fiddly ones are ... /IY offset instructions, where the byte is treated as a signed ...Where to start?..Hello, First off, sorry if this is in the wrong and sorry if the questions I'm about to ask have been asked and answered numerous time! Little back…
... codes for those mnemonics, the back of the original 48K Spectrum ... ;564533]The 'XX' represents a byte of data. So if the ... -bit number, with the low byte first. The fiddly ones are ... /IY offset instructions, where the byte is treated as a signed ...Keys redefine routine and key check.I have written some asm code which allows me to redefine keys (for a game etc.), and also allows me to be able to check any keypresses for the redefi…
... hl ; get the message address back
;call pm_do_it ; ... hl ; point to the key_xxx_pattern byte
ld (hl),a ... save the pattern byte
dec hl ; go back to the key_xxx_port ... byte
ld a,( ...Tile based graphics and scrolling thingy...Here's my best attempt so far at a tile based rendering and scrolling routine. It draws in 22 8*8 graphics tiles along the top of the screen (junk i…
... draw_tile_bytes ld a,(de) ; Get byte... (7)
ld (hl),a ... /> ld (hl),a ; ... draw last byte here
...
dec sp ; Point SP back one scanline for next time ... ; Using LDI, 16 ticks per byte * 22 = 352
ldi ...Tile based graphics and scrolling thingy...Here's my best attempt so far at a tile based rendering and scrolling routine. It draws in 22 8*8 graphics tiles along the top of the screen (junk i…
... />
dec sp ; Point SP back one scanline for next time ... ; Using LDI, 16 ticks per byte * 22 = 352
ldi
Tile based graphics and scrolling thingy...Here's my best attempt so far at a tile based rendering and scrolling routine. It draws in 22 8*8 graphics tiles along the top of the screen (junk i…
... />
dec sp ; Point SP back one scanline for next time ... ; Using LDI, 16 ticks per byte * 22 = 352
ldi
Tile based graphics and scrolling thingy...Here's my best attempt so far at a tile based rendering and scrolling routine. It draws in 22 8*8 graphics tiles along the top of the screen (junk i…
... be D that needs changed back. Very elegant! . As i'm ... 4 words = 17.75 per byte!
jp loop[/CODE ...Placing a switch over a jumper?Hi Guys, Rich from RWAP has kindly provided me with a replacement DivIDE Plus after problems with my original. The new one however has the two (woul…
... power cycle thankfully returns me back to the currentl installed FATware ... installer. It is a 43 byte routine stored in a REM ...Gauging interest: ZX EvolutionHi everyone. First of all I would like to introduce myself, since this is my first post. My name is Conrad, I'm from Vancouver, BC, Canada, and I hav…
... style module playing in the back ground!!!!.. It is even stranger ... made a copy of the byte header file you used on ... your file, but changed the byte length to show the size ...MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
[I]JR NZ,07h [/I]is doing a 7 byte forward jump, you need to do a 6 byte backward jump (ie a minus number) to go back into your loop.
Are you using labels in your assembler or are you doing everything by hand?MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
... [/I]is doing a 7 byte forward jump, you need to ... 6 byte backward jump (ie a minus number) to go back into ...MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
... we know that the low-byte (L) pointing to memory changes ... we use the 8-bit (byte) INC mnemonic because 8-bit ... do something when L trips back to 0 then we get ...Surely not Buzzsaw+ Already..?But this game has had such a short development time, how can this be? Free version of [I]Buzzsaw+ (Foxton Locks Mix)[/I] available here: [url]http:…
... of an object, the same byte would require 3 different colors ... bottom eight rows would revert back to their proper green, as ...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?
[QUOTE=obo;569684]Reading back what I wrote, I didn' ... manipulates some bits within a byte rather than all of them ...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?
... hl,&4000 ; first display byte
ld de,&57ff ... ; last display byte
ld b,revtab/256 ...
defs (-$)%256 ; 256-byte align
revtab:
defb ... IRC a year or two back)Requesting a little help to identify the purpose of this 'add-on' to my Issue 2Hi everyone First of all it's my first post here so please go easy on me! I'm grateful to be accepted into your fine little club :smile: I probabl…
... asm routine which fills each byte from 32768 to 65535 with ... to 255 and then reads back the value that it's ...Requesting a little help to identify the purpose of this 'add-on' to my Issue 2Hi everyone First of all it's my first post here so please go easy on me! I'm grateful to be accepted into your fine little club :smile: I probabl…
... /> ld a,(hl) ;and PEEK back
cp b ;equal?
byte requested by the cpu. Is ... wanted to put the socket back.
