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Optimize this assembly?Aiming for Variable*192 -> HL In the first case, I came up with the obvious method - *128 +*64: [code] ld a, (variable) ;13 ld h,0 ; 7 ld l,…
... /> ld l, a ; 4
add hl, hl ;11
add hl, hl ;11 ... />
[code]
LD A,(variable) 13
LD h,a ; A ... * 256 4
LD L,0 ; L=0 7 ... *128 10
ADD HL,BC ; HL=A*192 11
--
+3 assembler questionI was wondering if anyone could give any suggestions as to how to get this bit of code working on the +2A/+3 in 128k mode. It works on the +128k/+2 i…
... ;in LAST_K
LD BC,9000 ;new line number ... to jump to
LD (23662),BC ;OLDPPC - CONTINUE line ... - CONTINUE statement number
LD HL,(23641) ;E_LINE - address of ...
EX DE,HL
LD (HL),$e8 ;insert code for ...Common pitfalls and solutionsLet's discuss some of the common problems in Speccy programming, and the methods we use to avoid them. For an example, here is a piece of code that …
... /> LD HL,#1303
PUSH HL
LD (#5C3D),SP
LD HL,#1BB0
PUSH HL ...
LD HL,(#5C4F)
LD ... /> ADD HL,DE
LD DE,#1B5E
EX DE,HL
LD BC,4 ...Z80 Machine Code Question...Hi Folks, I know not strictly a BASIC question but I have started to learn Z80 machine code - 25 years too late! :smile: I have been reading a book…
... ][FONT="Courier New"]LD BC,1400h
LD HL,4000h
LD(HL),FFh
DEC ... BC
JR NZ,F9h ... the [FONT="Courier New"]DEC BC[/FONT].
Am I ...Using the stack to copy memory blocksA [b]PUSH[/b] and a [b]POP[/b] instruction together take less time than two [b]LDI[/b], so long [b]POP/PUSH[/b] sequences are sometimes used to copy …
... /> ld ix, source
ld hl, dest
ld de, 8 ; stepsize
ld a ...
exx ; 4
pop bc ; 10
pop de ; 10 ...Machine code issue...Hi Folks, My trials with MCODE continue and I am stuck. I wrote the following program in BASIC to simply POKE an attribute byte in to a "box" on th…
... LD BC,22528 ;BC=ATTR Address
09 ADD HL,BC ;HL=HL+ATTR Address
ED4B01FA LD BC ... ,(64001) ;BC=X
09 ADD HL,BC ;HL=HL ...Help needed with simple MCode routineI'm trying to code a routine to clear the screen and I can't figure out why it's not working: ld hl,16384 ld bc, 6144 loop:ld (hl),0 inc hl dec bc l…
... /> ld hl,16384
ld bc, 6144
loop:ld (hl),0
inc hl
dec bc ...
ld a ...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…
... to do with how DEC HL affects the flags?
LD BC,191 ; Port to IN from
LD HL,32767 ; Number ... of bytes to read
LD DE, ... loop: IN A,(C)
LD (DE),A
INC ... DE
DEC HL
JR NZ,loop < ...A fast DRAW routineI was investigating how to speed up the line drawing for the [URL="http://www.worldofspectrum.org/forums/showthread.php?t=20225"]BASIC compiler[/URL]…
... (hl)
__DRAW_START:
ld (__PLOTOVER), a
exx
ld bc ... Address of pixel
ld bc, (COORDS) ; B,C = y1, x1 ...
add hl, bc ; error += dY
exx
ld a, e ...Help?Hi All, I wonder if anyone has a few minutes to look at this bit of code I'm working on. I'm trying to move to sprites and want to do it with a scr…
... /> [CODE]org 33000
keys ld bc,63486 ;press 1 and the ... ;repeat 8 times
ld hl,bits ;reset bits (lines of ... from top
ld (point),hl
ld hl,seed ;screen address table ... halt
ret
sprite ld hl,(point) ;address of current line ...Small Machine Code Routines Which Maybe UsefulAs part of creating Flynn's Adventure in Bombland I created a lot of little routines to do all sorts of things. A lot of these I created based on inp…
... /> add hl,hl ; 11t - x4
add hl,hl ; 11t - x8
ld bc,$3C00 ; ... 11t - ROM font mem location ($3C00)
add hl,bc ; ... 11t - move hl to correct position in ... with previous plot byte
ld (hl),a ; 7t - plot ...Frank N SteinThis is an improved bugfix for [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0001849"]Frank N Stein[/URL] as discussed recently in [URL="htt…
... $C472 ; 50290
PATCH1: POP BC ; 193
CALL $81A4 ; 205 ...
DEC HL ; 43
DEC HL ; 43
LD SP, HL ; 249
Shadow ROM partial decoding not implemented in emulatorsOr at least, not implemented in Spectaculator, and it seems that not in Fuse too. [URL="http://www.speccy.org/foro/viewtopic.php?f=8&t=408&start=53"…
... di
ld hl,StartCopy
ld (5cedh),hl
rst ... /> StartCopy ld hl,0
ld de,32768
ld bc,16384
(part of) screen to UDGHere is a routine to copy a Y,X-position on screen to a UDG. 0<=y<=23 0<=x<=31 144<=udg<=165 (UDG "A" to UDG "U") [code] ; start code with ; PRINT …
Here is a routine to copy a Y,X-position on screen to a UDG.
0automatic relocating of non-relocatable codeI was pondering upon the problem of changing absolute addresses used by CALL, JP, etc. when code is moved, without reassembling at the new location; …
... : ld (STACKP),sp ;save stack pointer
ld hl,CHANGE
add hl,bc
ld ... sp,hl ;point SP to ...machine code loadercan someone have a look at this loader and break down what its actually doing and also how i can stop it from executing the 2 loads of headerless blo…
... [CODE]
5B00 LD SP,5BFF
5B03 LD A,(5C48)
LD (5C48),A
5B0B LD HL,5800
5B0E LD BC,02FF
5B11 XOR A
5B12 LD (HL ... ),A
5B13 INC HL
5B14 DEC BC
5B15 LD ...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…
... print_message
ld hl,key_left_port
call get_defined_key
ld hl,msg_right
; -----------------------------------------------
delay: ld bc,32768
ld a,0
d_loop ...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…
... hl,hl ; ASCII code * 8
add hl,hl
add hl,hl
ld de ...
push bc
push af
ld (32859),sp ; Preserve ... af
pop bc
pop de
pop hl ;
Lord Of The Rings; Files skipped ?Hi folks, Does anyone know what blocks 8~13 are for in the Lord of The Rings: [url]http://www.worldofspectrum.org/infoseekid.cgi?id=0006601[/url] I…
... 61440 LD HL,61440
61443 LD DE,23296
61446 LD BC,00144< ... 61584 ADD HL,BC
61585 JR 61520
61587 LD H,(IX ... HL
61671 POP DE
61672 INC DE
61673 LD BC ... ,00012
61676 LD (HL),000
61678 ...AND,XOR,OR,BIT,RES,SET,CPL,NEG,RLC,RRC,SLA,SRL,RL, RR,SRA for BASICAs this was drifting away from the original INKEY$ thread I thought that I'd create a new one. So here's a routine to provide all of the above mentio…
...
rst $20
ld bc,15
ld hl,OPTIONS+14
cpdr ... af
ld hl,OPCODES
add hl,bc
add hl,bc
ld de,OPERATE ...Is it possible to access the +3 disk drive via m/c in USR0 mode?Is it possible to access the disk drive of the +3 via m/c +3DOS calls when running in USR0 mode? I ask because I'm having an awful lot of trouble ge…
... /> ld ($9000),sp ; 36864
ld bc,$7ffd
ld a,($ ... ld e,1
ld hl,filename
call 262
ld bc ... ld bc,1
here push bc
di
ld bc, $7ffd
ld ... /> di
ld bc,$7ffd
ld a,($5b5c)
set ...BREAK from GOSUBHere's another one. Just in case you wanted to break out of multiple GOSUB levels with a single command, here's a routine to do it, tested on all mod…
... [code]
RETSUB: LD HL, 20 ; 33 20 0 ... BC ; 193
POP HL ; 225
POP DE ; 209
LD ... ;reset ERR_SP
LD BC,$1B76 ; 1 118 ...Procrustean PrintingHere's a short routine to manage printing of text with command tokens, to avoid messing up the screen when they are expanded. It just prints as many …
... ;
STACK: ld hl,14
add hl,sp
ld sp,hl ;undo USR ... ;BC=addr
ld h,b
ld l,c
jp (hl) ;JP ...Indirect Variable AssignmentHere's another wacky routine. This allows assignment of values to variables where the source & destination variables can themselves be defined in var…
Here's another wacky routine. This allows assignment of values to variables where the source & destination variables can themselves be defined in variables (or expressions which evaluate to variables). Some of this can already be done with VAL or VAL$, ...Undefine functionHere's a routine to selectively remove variables from the VARS area and reclaim the space. This can be done partially from BASIC already by assigning…
... de,hl
add hl,bc
ld b,h
ld c,l ;BC=(length ... /> STRARR: inc hl
ld c,(hl)
inc hl
ld b,(hl) ;BC=length of ...Loading the display with data from memoryTrying to load part of the screen(4k's worth) with data from memory location 53000, I've written this routine, but it doesnt work... [I]ld b,4000 ld…
... ]ld b,4000
ld de, 16384
ld hl, 55000
loop ld a,(hl ... )
ld (de ... ),a
inc de
inc hl
bc instead but that wont work ...S-S-Sample black borderI'm wanting the 'S-S-Sample' routine from YS to play the sounds without the flashing border effects. A plain black border is required. Heres the rou…
... /> ld hl, (32768 )
ld de, (32770)
ld bc, 2048
ld c, (hl)
ld a ... , c
rlca
ld c ...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…
... de,hl
add hl,bc ;HL=joined length
ex de,hl
ld (hl),e ...
inc hl
ld (hl ...The INPUT command routine ($2089)I was looking at the INPUT routine with a view to modifying the intro so that I could pre-load the workspace and edit an existing value, rather than …
... .
2161 IN-VAR-4 LD (K-CUR-hi),+00 The ... is copied to[/color]
LD BC,(ECHO-E) [color=red]the ... .
2174 IN-VAR-5 LD HL,+5C71 This is FLAGX.
editing strings with INPUT LINEHere's the latest in my unpredictable series of utility routines. This one I needed for the SAGE game editor; it emulates INPUT LINE l$ but with the …
... hl
ld c,(hl)
inc hl
ld b,(hl) ;BC=l$ length
inc hl ...
push hl ...
