-
Scrolling loader counter in 85 T-States?Would it be possible to write a scrolling loader counter in 85 T-States? I have a custom screen load routine that loads attribute first, then the …
... /> and 7
jr nz,loop1 ; jr if not 8 pixels
cp $5b
jr nz,loop2 ;
ret ... dlyloop: dec a ; 04ts
jr nz, dlyloop ; 07/12ts
; ... scrolling load counter in 85 t-states. Should be possible to ... -
How many T-states takes PUSH DE ?Hi. Just a quick one. According to z80.info docs, a PUSH DE should take 11 T-States to be executed. But WHAT if SP is pointing to Contended Memory,…
... PUSH DE should take 11 T-States to be executed.
T states looks OK, but shouldn't it take longer ... interrupts disabled but that shouldn't change the fact that the ... />
I think this 11 T states info is normal situation and ... -
Why doesn't my loop work?Can anyone help me understand why my loop doesn't work? Is it to do with how DEC HL affects the flags? [code] ; Read 32k bytes from port 191 as fa…
... understand why my loop doesn't work?
Is it to ... DE
DEC HL
JR NZ,loop
RET
28-character wide multicolour(ish) on 48k SpectrumLong-time lurker here... I've always been interested in rainbow effects on the 48k Spectrum, mainly from a perspective of "Just what [I]would [/I]ha…
... ,B
OR C
JR NZ,DELAY
ld bc ... here at 14238+0*224 t-states, just at the start of ... here at 14238+1*224 t-states, just at the start of ... here at 14238+2*224 t-states, just at the start of ... here at 14238+3*224 t-states, just at the start of ...Movin And A Groovin Horizontal Flip improvementOn the left is the flip horizontal portion from Andy Pennell'S excellent Movin' & a Groovin' machine code screen routines from Your Spectrum #19 (Oct…
... as those JR NC's ate away the t-states.
... C
JR NZ,FLIPH ;do all the columns JR NZ,fliph
... BC
DEC C
JR NZ,fliph
RET
...Problem Reading the KeyboardHi Folks, I'm working my way through Toni Baker's rather good book and thought I'd write some code to scan the keyboard and store the results so tha…
... ,(0xFE) ;Read the key states for this segment
... then the key wasn't pressed so move to ... key in segment
JR NZ,_storeKey3 ;If the bit is ... then the key wasn't pressed so move to ... then the key wasn't pressed so move to ...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…
... hl[/b], which is two T states slower.
Note the ... a ;is it zero?
jr z,msl_skip_shift ;okay, no shifting ... will be 0 then
jr nz,msl_shift_done ;if not, we're ... it back in L
jr c,msl_shift_done ;if ADD A ...help in byte mirroring.I need some help. What is the best way to mirror the byte? (for ex. 10010011 -> 11001001) I mean, if there is a simple way to do it (may be with OR, …
... br /> 0002 C20D00 10 JP NZ,Set1
0005 CB47 ... br /> 0016 C22100 10 JP NZ,Set2
0019 CB4F ... br /> 0037 C23C00 10 JP NZ,Next3
003A EE24 ... used JR cc,e to shave off 0.5 T states each ...Delay routineAs some people are aware, I have recently starting writing a [url=http://fuse-emulator.svn.sourceforge.net/viewvc/fuse-emulator/trunk/fusetest/]autom…
... possible to reduce the minimal T-states. My program has a shortest ... run of 54 T-states, with CALL, RET and NOP ... added it becomes 89 T-states
[code]
org ... h
dec h
jr nz,no-exit ; test on H ...Preferred way of determining Y co-ord in assembly?I know of 2 ways of calculating the y-cord of a pixel row for the speccy in assembly. One is to calculate the address by ways of shifting and masking…
... the Min Size version (83 T States; no table) as although I ... \ LD A,H\ AND 7\ JR NZ,$+12\ LD A,L\
JR C,$+6\ LD A,H ...Clearing the Carry flagI'm reading that sometimes I may want to clear the carry before using ADC or SBC. A simple AND A or OR B will do. However, as I see it, for 8-bit ar…
... of two, and in four T-states instead of 7. So even ... in code where performance isn't all that important, you see ... , b
cp 0
jr nz, nonzero
ld a, c ...Tips on optimizing some newbie assembly routinesI'm starting to learn some assembly language. The best way to learn is to actually code something you are going to use, so I'm creating a very simple…
... the character index. I don't think it will render fast ... , and save 13*7+8 states from djnz.
----
t unroll the loop yet) from ...
inc e
jr nz,_b1a
[/code]
Has any programmers recently pushed the spectrum to the limits?Hi there. Ive just discovered this great forum and I was brought up with the speccy 16,48 and then 128k. Im just wanting to know if there are any re…
... arbitrary characters if you don't mind storing the attributes directly ... instructions holding the attributes aren't next to each other ... B
OR C
JR NZ,DELAY
nop
; Hit here at 14164 t-states
LD SP, 5820H ; Load ...The Goldfinch updates thread([url=http://www.worldofspectrum.org/forums/showthread.php?t=25034]original announcement thread here[/url] - I figured it was worth starting a new to…
... paging within a few thousand t-states of a reset, or ... /> #0007 JR NZ,#0004
You can't on real ZX ... ZX keys (software can't detect break/space buttons from ... ,B
OR C
JR NZ,ABC
-------------------------------
(*) - ...The incredible shrinking screendumpIn this topic I stated that I would be impressed if the screendump could be smaller than 37 bytes. [url="http://www.worldofspectrum.org/forums/viewt…
... of PIX from
[B] jr nz,pix [/B]
[/QUOTE]
is possible but Toni Baker states in her machinecode tutorial a ... this adress??[/QUOTE]
Don't know, I always use 48K ...Help fix this keyboard read program?This code runs in an interrupt routine with DI. What would be the simplest way of making it so it doesn't auto repeat a keypress? [code]keys: ld a…
... were pressed and you wouldn't bother reading the keys ... />
I numbered the states that way so that masking ... last read and you don't want to register it ... read and you don't want to register it ... ,c ; check right key
jr nz, setstate
ld ...Help fix this keyboard read program?This code runs in an interrupt routine with DI. What would be the simplest way of making it so it doesn't auto repeat a keypress? [code]keys: ld a…
... switch position so probably haven't gained anything speed or code ... ,c ; check right key
jr nz, setstate
ld a ...
... etc for all states
.setstate
states, eg) and the routine ...Spectrum 128K RS232 to PC serial cableIf you have read some of my recent posts then you will know that I am eager to link my Spectrum +3 to a PC. This will be done by wiring a standard PC…
... )
and 1
jr nz,wait ; Space?
jr nz,sync ; d = 0
ld e,8 ; 123.15 T-states ... /> delay dec a
jr nz,delay ; 43
dec e ; 4
jr nz,bit ; 12
... br /> inc hl
jr byte
...Spectrum 128K RS232 to PC serial cableIf you have read some of my recent posts then you will know that I am eager to link my Spectrum +3 to a PC. This will be done by wiring a standard PC…
... )
and 1
jr nz,wait ; Space?
jr nz,sync ; d = 0
ld e,8 ; 92.36 T-states ... br /> dec e ; 4
jr nz,bit ; 12
...
inc hl
jr byte
... written to keep the T-states to a specific value ...Spectrum 128K RS232 to PC serial cableIf you have read some of my recent posts then you will know that I am eager to link my Spectrum +3 to a PC. This will be done by wiring a standard PC…
... /> and a,d ; RxD
jr nz,wait
; ------------
jr nz,sync ; d = 0
ld e,8 ; 92.36 T-states ... />
dec e ; 4
jr nz,bit ; 12
exx ...
or a,d
jr nz,byte
done ei ...Spectrum 128K RS232 to PC serial cableIf you have read some of my recent posts then you will know that I am eager to link my Spectrum +3 to a PC. This will be done by wiring a standard PC…
... /> jr nz,poll
; ------------
exx ; 57600 BAUD (61.57 T-states ... /> dec e ; 4
jp nz,bit ; 10
exx ... /> or a,d
jp nz,read
ret
[/code ...Optimization for this codeHello, I have done and submitted a small program for the CSS Crap Game Compo which involves a machine code routine. The z80 with BASIC and MC is av…
... difference in the amount of states between INC (hl) and< ... now with a JR NZ?[/QUOTE]
INC HL - 11 t-states
LD A,(HL) - 7 t-states
INC A - 6 t-states ...
LD (HL),A - 7 t-statesOptimization for this codeHello, I have done and submitted a small program for the CSS Crap Game Compo which involves a machine code routine. The z80 with BASIC and MC is av…
... does, so you don't have to read it back ... br /> ld (hl),a
jr nz, kontroll1[/CODE]
... jr nz, kontroll1[/CODE]
That would be going from 20 states ... , or size? I don't seem to get it: If ... , so maximum speed doesn't really make much sense. ...Spectrum 128K RS232 to PC serial cableIf you have read some of my recent posts then you will know that I am eager to link my Spectrum +3 to a PC. This will be done by wiring a standard PC…
... ,(hl) ; 57600 BAUD (61.57 T-states)
exx
ld d ... /> dec e ; 4
jp nz,txd ; 10
ld ... /> and a,a ; 4
jr nz,write ; 12
ret
Recent talk of developing new SpectrumsHi all, I can see from a few threads on here that some Wossers like Vasil and Aien 8 are interested in developing more powerful Spectrums or improvi…
... ,h
and 7
jr nz, cont
ld a,l ... br /> ld l,a
jr c,cont
ld a ... /> No. It's only 25 T-states in 7 cases out of ... is used instead of jr (or even 4 T-states if expanded)
[/CODE]
(which takes 30 T-states) [B]OR[/B] (if you ...Recent talk of developing new SpectrumsHi all, I can see from a few threads on here that some Wossers like Vasil and Aien 8 are interested in developing more powerful Spectrums or improvi…
... ]
taking 27/26 states. And the advantage goes clearly ... ld l,a
jr c,othersegbranch
ld a ... 3,h
jp nz,forward
ld a, ... ]
taking just 21 states. And wasting a whole register ... average) only about 8 T-states per line with NO extra ...Your Views on... GhostbustersI dusted off the Master System version of this and inspired me to try out the Speccy version. It's a good game with it's strong and weak points. I …
... /> LDIR of 6816 bytes = 143131 T-states (cripes, that's 2 entire ... T-states (including DEC A and JR NZ)
Speed increase = 30662 T-states per ...
