-
joining lines of BASICDue to overwhelming demand - well, one demand - well, more of a suggestion, really - here's a routine to join together lines of BASIC. The vertical c…
... hl
inc hl
push hl
ld e,(hl)
inc hl
ld d,(hl) ;DE ... -
editing strings with INPUT LINEHere's the latest in my unpredictable series of utility routines. This one I needed for the SAGE game editor; it emulates INPUT LINE l$ but with the …
... de,hl
ld (hl),$0d ;followed by ENTER
ld (K_CUR),hl
ld de,LNAME
ld ... -
AZIMUT / Frecuency spectrum[code]start DI LD HL,#7F40 LD D,#58 loop LD B,#00 bucle1 LD A,H IN A,[#FE] XOR A,C AND A,L J…
... DI
LD HL,#7F40
LD D,#58
loop LD B,#00 ... /> AND A,H
LD [DE],A
LD C,#FF
bucle2 ... ,H
LD [DE],A
LD C,#00
LD A,H
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 …
... /> START
ld hl,16384
ld bc,6144
ld de,(PRT_CHR)
SCREEN_CLEAR_LOOP
ld a,(hl)
and e
ld (hl ...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…
... /> push de
push hl
PUSH AF
LD (VALSP),SP ... data
ld de,3344H ; Some more attribute data
ld hl,5566H ; ... LD SP,(VALSP)
POP AF
POP HL
POP DE
LD L,C
LD D,A
LD E,B
LD (HL),0FDH ...Inefficient code in ROM, from ram-check to RAM-DONEHere is the inefficient code: [CODE] ;; ram-check L11DA: LD H,D ; Transfer the top value to the HL register LD L,E …
... br /> ;; RAM-FILL
L11DC: LD (HL),$02 ; Load memory with $02 ... prepare to subtract.
SBC HL,DE ; subtract and add back ... /> EX DE,HL
;; RAM-FILL
L11DA: LD (HL),$01 ; ...Help pleeease "Proving Emulator OpCode flags are correct"So I had a cunning plan... I wanted to write a test harness for Emulators that could "prove" that all opcode flags were correct. I wanted something m…
... :
LD HL,0x7000 //mcAddr, lAddr
LD IX,0x8000 //xAddr ...
LD B,0 //aAddr
LD C,0 //fAddr ...
LD D,0 //dAddr ... AF
POP DE
LD (HL),D
LD (IX+0),E
Byte-order backbufferThis is a tool for Z80 coders who wish the Spectrum screen had a serial layout. It runs as an interrupt mode 2 service routine and uses POP and PUSH …
... byte of the screen
ld hl, $ + 9 ; set ... chunk * 2048)
ld hl, $ + 9
ld (endcall), hl
jp blit< ... pop de
pop hl
ld sp, iy
push hl ... ; write 16 bytes
push de ...Moving a line down the display in assembler?...It's not a "[I]how can I do it[/I]" question, it's more a "am I missing something in trying to do it a new way" kinda question. What I've been doing…
... /> ld b,16 ;
ld de,(xpos)
loop1: ld a,d
ld ... ,(hl)
inc h
ld h,(hl)
ld l,a
ld (hl ...CMWC random number generator for Z80Seeing the interest regarding the [URL="http://www.worldofspectrum.org/forums/showthread.php?t=23070"]Xor-Shift random number generator for Z80[/URL]…
...
ret
rnd ld de,0 ; c,i
ld c,e
ld hl,table
add hl,bc
ld c,(hl ... / 256
ld (rnd+1),de
ld a,l ; x ...Jelly-Vision!As threatened in the "'Spectrum Play' Error" thread, here's a ruff'n'reddy interrupt driven full screen wobbling routine which has no practical use w…
... ,MOVEUP
MOVEDOWN: ld hl,16384+256
ld de,16384
ldir
MOVEUP: ld de,16384+6143
ld hl,16384+6143-256
assembly optimization: times tenDecimal numbers are not computer friendly :) Anyway, short of saying "sod it - I'll multiply by 8" - and another part of the program does indeed div…
... /> LD D,0
ADD HL,HL
ADD HL,HL
ADD HL,HL
ADD HL,DE ...
ADD HL,DE
LD D,H
ADD HL,HL
ADD HL,HL
ADD HL,DEHep needed with a bit of code...I've written a bit of code to make a character move across the screen, but the counter stops at 29 when the 3 lines to delete the characters trail ar…
... ; ????
ld hl, 63289
dec (hl)
dec (hl)
ld a,(63289 ... /> call 5633
ld bc, 10
ld de, 63290
call 8252 ...
ret
prb: ld a ...40 Column Printing RoutineI've written a 40 column printing routine, which I'd like to share... It's my first piece of 'public' code so go easy on me! I don't think it is a…
... /> ld (hl),a
inc hl
inc de
ld a,(de)
and (hl)
ld (hl ...merging bytesPicturing three bytes with their bits identified by letters to make the visualisation easier, what's the best way to perform this transformation? [co…
... pop de ;D=ABCDEFGH
ld e,0
ld B ... ld (hl),a
inc hl
[color=red] ld a,(hl) ;ld a ... d ;A=FGHlmnop
ld (hl),a
ret
...next pixelI searched the "Discussions" groups for the phrase "next pixel" and got no matches - and removing the quotes it discards the "next" and just searches…
... ld hl,$4000
ld de,$4000
ld bc,0
pixrow: ld (hl),$ ... jr z,set_hl
ld d,%01000000
inc c ... b ;B =segment
ld a,b
cp 3 ...Any ideas on speeding up this assembler segment?It copies a pixel column of a rectangle which may be anywhere in the display file to a pixel column in d$. The source column may start at any bit pos…
... 1->8
ld a,(hl) ; 7
rotbit0 ... br /> ex de,hl ; 4
or (hl) ; 7
ld (hl),a ; 7 ... set selected bit in d$()
ex de,hl ; ...BeepFX ProblemHi All, I'm currently trying to integrate the BeepFX engine in my 100% Assembler Game and it plays the sound fine, but then plays the sound again, a…
... bc
SFXRTl1: add hl,de
ld a,h
SFXRTDUTY: cp ... /> ld b,(ix+8)
ex de,hl
add hl,bc
ex de,hl ...multi-scroll m/c subroutine for BASICArising from recent posts, here's a scrolling routine that will manage multiple left/right scrollings for any (sensible) line width or step; (ie. whe…
Arising from recent posts, here's a scrolling routine that will manage multiple left/right scrollings for any (sensible) line width or step; (ie. where width isGraph Plothi! please, help with code: [PHP]For x=-100 To 100 For y=-100 To 100 If (x/2-25)*(x/2-25)+(y-50)*(y-50)<200 Or (x/2+25)*(x/2+25)+(y-50)*(y-50)<200 th…
hi! please, help with code:
[PHP]For x=-100 To 100
For y=-100 To 100
If (x/2-25)*(x/2-25)+(y-50)*(y-50)Optimisations in Exomizer Z80 decrunch codeThis is the 163 bytes old code (simple and optimized): [CODE] ld iy, exo_mapbasebits ld a, 128 ld b, 52 push de exo…
... /> ld (iy+104), d ;base[i]=b2
add hl, de
ex de, hl ... /> ld (iy+104), d ;base[i]=b2
add hl, de
ex de, hl ...Elliptical ChallengeSubsequent to the recent "Graph Plot" thread, I wrote this general purpose ellipse drawing routine which will plot (although it doesn't actually use …
...
ld hl,(STKENDO)
ld de,STKSTOR
ld bc,20< ... br /> ld hl,STKSTOR
ld de,(STKENDO)
ld bc,20< ... calculator stack
ld (23653),de ;STKEND
call ...Machine code RST10 problemHello! After 27 years of playing with Spectrums I'm starting to look into doing assembly language properly. All went swimmingly well until I wrote …
... ex de,hl ; remember HL as it points to the message
ld hl,msgctl ... ld b,$10 ; messages are always 16 characters long
ex de,hl ... ; recall hl pointing to message
.msgpch ld a,(hl) ; load ..."Chronos": how fast should it really be?I was reading [URL="http://timfollin.pwp.blueyonder.co.uk/Archive.htm"]Tim Follin's webpage[/URL] the other day and came across a curious remark abou…
... /> 58426: ld hl, 64484
58429: ld de, 3
58432: ld b, 128 ...
58552: sbc hl, de
58554: djnz 58434
hl, de, if one thinks carefully, ... :
[CODE]
ld hl, 64484
ld b, 128
Chronos (BUGFIX)Please add the following "known errors" entry to [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0000951"]Chronos[/URL]: [QUOTE]Bugfix provid…
... : ld hl, 64484 ; off-screen buffer
ld de, 3
ld b ...
rld
sbc hl,de ; next pixel line address
[CODE]58426: ld hl, 64484 ; off-screen buffer ...Works in Fuse & SpecEmu, not ZXSpinI decided that I wanted to change the scroll routine which I was using for compiling the Trailblazer maps, as I'd just copied it out of Andrew Hewson…
... /> call CHARSCROLL
ld hl,23296
ld de,16394 ;HL=(DF_CC) for line 0 ...
call PATTERN
ld de,16426 ;HL=(DF_CC) for line 1,column ...Some thoughs about fast scrolling on 128 modelPlease, consider this article as technically interesting concept not a proven algorithm. ONE The fastest scrollers use long sequence of PUSH inst…
...
[CODE]
ld hl, (register_x)
push hl
[/CODE]
... generates
[CODE]
; ld hl, (register_x) - it is same pattern ... we skip loading
push hl
[/CODE]
Do ... registers to common patterns like DE for empty tile and ...Idk>le me browsing through some game's code >..... [code]61A8 F5 push af 61A9 3EFF ld a,FF 61AB D37F out (7F),a 61AD D33F ou…
... ld (62FA),hl
61CA 31F862 ld sp,62F8
61CD D5 push de ... 22BE62 ld (62BE),hl
620F 2100CD ld hl,CD00
6212 22BC62 ld (62BC),hl ... D1 pop de
62B7 E1 pop hl
62B8 ED7BFC62 ld sp ...Rotronics Wafadrive v.1.80 ROM - Corrupt or purposely broken?I've been digging around the Wafadrive v1.80 ROM (from [URL="http://zxspectrum.it.omegahg.com/_RO.htm"]here[/URL]) and can't decide if the ROM is cor…
... /> push de
ld hl, $009f
ex (sp), hl
push hl
ld e ... /> ld hl, $0cf7 ; address the hook-code table!? WTF?
add hl, de
ld ... e, (hl)
inc hl
ld h, (hl)
ld l, e ...
