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Compiling Lisp to Z80.I am doing some thought experiments on this. Here is an example of a Lisp program. It adds two numbers together. [code] (define (add x y) (if (= …
... ld a,b ; endvalue to testregister
or a ; the test on zero
ld a,c ... original registers
dec b ; counter 1 down
B and C?
And ... is this closer to what a ... -
Checksum routine wantedI wish to make a program that verify integrity of a Multiface 1 ROM. It is possible to compare each byte of the ROM against a binary dump, but this i…
...
xor h ; XOR with memory content
ld h,a
ld b,8
ld a,h ; XOR with polynomial $1021
xor $10
ld h,a
ld a,l ... -
Thinking of modding an Atari paddle controller for games like Arkanoid...Hello, Was thinking of trying out a controller mod using an Atari 2600 paddle controller to use with games like arkanoid, Batty, etc... The paddle c…
... a,c
ld h,Table/256
ld l,a
ld a,b
ld (OldValue),a
ld b ... -
CODE SCREEN$ in MCIs there any way of determining what character is displayed at a certain co-ordinate from machine code like the 'IF CODE SCREEN$=' arrangement in bas…
... ;fetch string from stack
ld a,b ;string length in BC. DE ... do:
[code]
ld c,12
ld b,15
call Screens ... -
Hardware description - DivIDE interface[B][U]DIVIDE interface / DivIDE 2k11[/U][/B] [B][U]The main description[/U][/B] DIVIDE is IDE interface with own external memory. Thanks to very goo…
... /> ld a,b
out ($ab),a
ld a,e
out ($af),a
ld a,d ...
out ($b3),a
ld a,c
out ($b7),a
ld a ... -
RND cyclical behaviourGood evening. I'm playing with RND function to show its cyclical behaviour, i.e. after 65536 calls to it, the next one will return the same value of …
... c,RNDFUN
ld (23677),bc ;(COORDS)
call $22aa ;PIXEL_ADD
ld b,a ... nz
ld a,b
or (hl)
ld (hl),a ;update display byte ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... for blue
xor a
ld (.border_instruction),a
endm
ld a,0xa1 ; AND C
ld (.border_instruction),a
ld a,7 ; ... -
Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... Z and NZ
ld a,(ms_cmp) ;13T
xor $08 ; 8T Swap ... jp nz opcodes
ld (ms_cmp),a ;13T
ld a,b ; 4T
ret ... -
melbourne drawIt could be said I am easly pleased,:grin: Very nice peice of software. I was realy impressed by its ease of use. I think a lot of time and effort w…
... using DJNZ for the loop so the screens display ... s a little bit of setup needed before the loop starts ... /> LOOP1: push bc
ld a,b
cp $0d ;screen 13 ... this number
LD ($7F77), A
LD L, (IX+$01 ... -
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…
... ld c,l
ld b,h
lp dec l
ld a,(bc)
ld b ... ,(hl)
ld (hl),a
ld a,b
ld b,h
ld (bc),a
inc c ...
bit 4,c ... -
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…
...
ld a,(de)
ld b,(hl)
ld (hl),a
ld a,b
ld (de),a
ld c,a
ld a,(bc)
ld c,(hl)
ld (hl),a
ld a,(bc)
jamorski
September 2013
Development
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RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
... /> loop ld a,h
xor l
and $F8
xor l
ld d,a ... )
ld bc,offset
loop ld a,h
xor l
and ... $F8
xor l
ld d,a ... -
RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
... ]loop ld bc,offset
ld a,h
xor l
and $F8
xor ... l
ld d,a ...
xor h
xor l
ld a,d
cp $58
jr nz,loop
ld bc ... -
RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
... ,$4000
loop ld bc,rcs_source_addr-$4000
ld a,h
xor l
and $F8
xor l
ld d,a ...
xor h
xor l
ld a,d
cp $58
jr nz,loop
... -
RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
... ,$4000
loop ld bc,rcs_source_addr-$4000
ld a,h
xor l
and $F8
xor l
ld d,a ...
xor h
xor l
ld a,d
cp $58
jr nz,loop
... -
Copying data between memory banks in USR0 modeI am experimenting with Funky Fungus to load the majority of its data (levels, screens, music etc.) into memory banks 1, 3, 4, 6 and (partly) 7 by sw…
... destination
LD HL,49152
LOOP: OUT (C),D ;reads from ... source bank
LD A,(HL)
OUT (C),E ;writes to ... -
RCS (Reverse Computer Screen)[B]RCS[/B] ("Reverse Computer Screen", or simply SCR written backwards) is a small utility I'm about to release, that reorders bytes from the ZX-Spec…
[QUOTE=Einar Saukas;722758]Good work! But I suppose label "loop" should be at instruction "inc hl" instead of "ld a,b"?[/QUOTE]
Yes, just noticed that and its been corrected as such. Thanks Mr S. -
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…
... ld h,a ;H =010ssppp
1005 LET a=b: REM ld a,b
1006 LET a=a ... LET a=a+c: REM or c ;C =column
1011 LET l=a: REM ld l,a ... -
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…
... ;(HL)=ATTR(B,C)
ld b,a
ret
GETDISP:ld a,%01000000 ;calculate ... /> ld b,8
PRINTAB:ld a,(hl) ;copy graphic to display AT B,C
ld ... -
filled shape creating codeDevelopment is continuing well on a resurrected project of mine from about 20 years ago. Speed and size optimizations are going well along with displ…
... /> ld a, d
sub c
ld d, a
REPT 7
ld a ... drcs_next_row_or_col
ld b, 32
ld e, 0
ld a, d
cp ... -
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…
... ]
You could US A'F' as well as AF ... , use I: pop bc, ld A,B, LD I,A, LD A,C, pop BC to make flag ... -
filled shape creating codeDevelopment is continuing well on a resurrected project of mine from about 20 years ago. Speed and size optimizations are going well along with displ…
... with XOR.
Drawing line in linear buffer, inner loop:
add hl,bc
ld d,h
ld a,(de)
xor ... pixel
ld (de),a
xor e
ld (hl),a
inc h
xor d
ld (hl),a ... -
Troublesome routine, help needed!Having problems with this routine, it basically fires a rocket up the screen, but refuses to detect collisions. I'm using attribute blocks for detect…
... /> ld b,17 ;countdown from 17
loop
ld a,b ;load a with value of b ...
dec a ;decrease by ... -
Z80: ABS(HL) functionI must be very tired but I cannot get my head around whether this function provides a correct implementation of a ABS function for a signed 16-bit va…
... nz, loop
rst 0
ABS ld a, h
xor $ff ...
ret m
ld h, a
xor a
Code to test if a rectangle is in a rectangle[SIZE=3][FONT=Calibri]I am looking to write some code that will check if a rectangular shape is outside or overlapping a second rectangle. If the sma…
... )
;d b
ld a,b
cp h
jr c,no_coll0 ;too ... left
ld a ... /> no_coll1
ld hl,(rect2_yy)
;e c
ld a,c
cp h ...Help with File Compressor by Mladen PopovicHi, I'm trying to compress BombJack (MCM) and transfer it to a +3 disk (Yes I own the original game :) ). I'm unsure about the addresses to enter in…
... inc b
jr m1
x6 add a,c
n2 ld bc ... c
rl b
add a,a
jr nz,n6
ld a ... /> ld l,c
ld h,b
add hl,de
ld c,a
ld b,0 ...Help with File Compressor by Mladen PopovicHi, I'm trying to compress BombJack (MCM) and transfer it to a +3 disk (Yes I own the original game :) ). I'm unsure about the addresses to enter in…
... inc b
jr m1
x6 add a,c
n2 ld bc ... c
rl b
add a,a
jr nz,n6
ld a ... /> ld l,c
ld h,b
add hl,de
ld c,a
ld b,0 ...
