... problem easily by reading the screen byte, ORing it with the ... /> ld (de), a ; write UDG pixel byte to screen
[/code]
< ... /> ld b, (de) ; read existing screen pixel byte
or b ... a
ld (de), a ; write new screen byte back
[/code]

... it's a bit wasteful to have two buffers, but clearing ... the interrupt and the copy-to-screen.

I'm not ... , even if mine does have to re-write the SP a lot ... . Is it going to copy 2/3 ... of the screen ahead of the ...

... the interrupt and the copy-to-screen.[/quote]
With a ... even if mine does have to re-write the SP a lot ... . Is it going to copy 2/ ... 3 of the screen ahead of ... time from "ld ix,copy_addr_table" to the next op after "jp ...

... I have been trying to write some code like Cobra. ... modified level code to push these to the screen.
It ... ; Load screen address to push to
; Self modified push to screen
... buffer: defs 15 ;
;
ld hl,sp ; Move to ...

... , and the CPU can write to video RAM at full speed ... a PUSH instruction can write two bytes in 11T if ... line, you can only write one byte every 8T. ... or write occurs. It's all very hard to predict.< ... the top line of the screen; synchronising itself with memory ...

... say, when there's a write to the screen, update your bitmap in ... of screen according to the T-States elapsed since the last write. Assuming ... method you can use is to synchronise to the sound output. Traditionally ...

... program does not read or write to this area of RAM, ... bottom right of the screen and the next access, ... . And to add the logic for a shadow screen. It ... market, the development needs to start about 12 months ... ...

To be fair to Amstrad, they did put ...

... 7, write to it, switch in page 4, swap to the shadow screen. It ... was an exercise to see how ... like whether a screen had to be switched in to be shown. All ...

... to screen is only 7 t-states. Perfectly acceptable, no need to write gfx to ... a buffer, do it on the fly straight to screen ... ago, abandoned it due to my character (3 x ... as bitmaps. I need to re-draw all my ... by mid day. Off to have a drink and ...

... to 4 frames to check a single byte and write on screen ... quote="Crisis;975699"]
[quote]to get a grasp of the ... its much more easy to stick to writing C instead ... learn C. If you want to learn Z80, learn Z80. ... learn how to write Z80, you're going to be very ...

... needed would be to load from tape and write to Microdrive and even ... the chips to deliver... If it included a buffered write capability ... have been possible to deliver writes to the screen at high bus ... wait states by buffering the write in hardware, and then ...

... that the I/O writes to the bank switching register switches ... game will not (normally) try to write to the bank switching register. But ... the computer even got to the ‘start-up’ screen, 48K games would ... br />
You really need to load in a diagnostic/RAM ...

... point it to an off screen buffer and copy that to screen if ... br /> ld h, a ; write it back
; stash column ... /> ; blit 8 pixel row to screen
ld a, (de)< ... br /> ld h, a ; write it back
ld l ... br /> ld h, a ; write it back
ld l ...

... point it to an off screen buffer and copy that to screen if ... write it back
ld l, b
; look up screen address ...
ld h, a ; write it back
ld l ... br /> ld h, a ; write it back
ld l ... br /> ld h, a ; write it back
ld l ...

... this requires tbl_scraddr be aligned to a 256 byte boundary< ... write it back
ld l, b
; look up screen ... /> ; blit 8 pixel row to screen
ld a, (de)< ... line. Too many beers to explain why ;) An 8 ... like that are safe to change as well (but ...

... ]
; de pointer to 8 bytes graphic data
to a 256 byte boundary< ... write it back
ld l, b
; look up screen ... hl)
; copy this to HL but add col onto ... /> ; blit 8 pixel row to screen
ld a, (de ...

... on the screen (must be entirely on screen again).
ld h, a ; write it back
; push ...
; look up screen address from the table
to screen in cells at column C ... blit 16 pixel rowdata to screen in cells at column C ...

... flag
ld h, a ; write it back
ld l ... /> push hl
; look up screen address from the table
; blit 16 pixel rowdata to screen in cells at column C ... :
; blit 16 pixel rowdata to screen in cells at column C ...

... ; This is way too slow to draw to screen every frame
BOX_TEST ... ; write it back
ld l, b
; look up screen address ... ; write it back
ld l, b
; look up screen address ... flag
ld h, a ; write it back
; push table ...

... is way too slow to draw to screen every frame
BOX_TEST ... write it back
ld l, b
; look up screen ... br /> ld h, a ; write it back
ld l ... /> ld h, a ; write it back
ld l ... br /> ld h, a ; write it back
; push table ...

... ; This is way too slow to draw to screen every frame
ATTRIBS ... ; write it back
ld l, b
; look up screen address ... ; write it back
ld l, b
; look up screen address ... flag
ld h, a ; write it back
; push table ...

... /> ; A -> attrib to set when clearing screen
cls:
di ... #A000 if you want to draw directly to the screen
; (not recommended ... that), but drawing to the screen is easiest thing to do
; so ...

... hl ; hl points to high byte of screen address
ld d ... ; write it back
ld l, b
; look up screen address ... :
; blit 8 pixel row to screen
ld a, (de)
to get the screen row starting address and ...

... hl ; hl points to high byte of screen address
ld d ... ; write it back
ld l, b
; look up screen address ... :
; blit 8 pixel row to screen
ld a, (de)
to get the screen row starting address and ...

... it to an off screen buffer and copy that to screen if ... br /> ld h, a ; write it back
; push ... ; blit 16 pixel rowdata to screen in cells at column C ... br /> ld h, a ; write it back
; push ... ; blit 16 pixel rowdata to screen in cells at column C ...

... ; This is way too slow to draw to screen every frame
ATTRIBS ... ; write it back
ld l, b
; look up screen address ... ; write it back
ld l, b
; look up screen address ... flag
ld h, a ; write it back
; push table ...

... br /> ld h, a ; write it back
; push ... ; blit 16 pixel rowdata to screen in cells at column C ... ; blit 16 pixel rowdata to screen in cells at column C ... br /> ld h, a ; write it back
; push ... ; blit 16 pixel rowdata to screen in cells at column C ...