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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 …
... pop de ; 10
pop hl ; 10 Subtotal = 54
... br /> ld sp, hl ; 6
push hl ; 11
push ... br />
add ix, de ; 15
add hl, de ; 11
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…
... =ATTR Address
09 ADD HL,BC ;HL=HL+ATTR Address
ED4B01FA LD ... ) ;BC=X
09 ADD HL,BC ;HL=HL+X
3A02FA LD A ... DE,32
19 ADD HL,DE ;Add 32 to Address
...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…
... />
ld de, 160
add hl, de
inc l ... the correct screen address into HL
; did not had ... /> call 0x1601
ld hl,text
loop ld a ...
rst 16
inc hl
jr loop
text ...Why doesn't my routine work?I have a "level" defined by 504 bytes (28 squares across x 18 squares down) I'm trying to write a routine that will take an X,Y coordinate in pixels…
... value for later
add hl, hl ;
add hl, hl ;
add hl, hl ;x8 (32x original value ...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]…
... br />
exx
add hl, bc ; error += dY
... While loop
exx
add hl, de ; error -= dY
exx
add hl, bc ; error += dX
add hl, de ;; Final screen addr ...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…
... plot
add hl,hl ; 11t - x2
add hl,hl ; 11t - x4
add hl,hl ; 11t - ... location ($3C00)
add hl,bc ; 11t - move hl to correct position in ... - convert to screen address
add a,l ; 4t
ld ... ; 4t
add a,32 ; 7t - add 32 or one char ...(part of) screen to UDGHere is a routine to copy a Y,X-position on screen to a UDG. 0<=y<=23 0<=x<=31 144<=udg<=165 (UDG "A" to UDG "U") [code] ; start code with ; PRINT …
Here is a routine to copy a Y,X-position on screen to a UDG.
0automatic relocating of non-relocatable codeI was pondering upon the problem of changing absolute addresses used by CALL, JP, etc. when code is moved, without reassembling at the new location; …
...
ld hl,CHANGE
add hl,bc
... /> add hl,bc
ex de,hl
pop hl
add hl,bc< ... br /> ex de,hl ;HL ...Tile based graphics and scrolling thingy...Here's my best attempt so far at a tile based rendering and scrolling routine. It draws in 22 8*8 graphics tiles along the top of the screen (junk i…
...
add hl,hl ; ASCII code * 8
add hl,hl
add hl,hl
... immediate value, faster!
add hl,de
ex de ... before POPing HL
inc (hl)
pop hl ; Restore HL and ...Lord Of The Rings; Files skipped ?Hi folks, Does anyone know what blocks 8~13 are for in the Lord of The Rings: [url]http://www.worldofspectrum.org/infoseekid.cgi?id=0006601[/url] I…
... [code]
61440 LD HL,61440
61443 LD DE ... JP 01366
61584 ADD HL,BC
61585 JR ... /> 61669 PUSH HL
61670 PUSH HL
61671 ... 61678 LDIR
61680 POP HL
61681 RET
61693 LD HL,(57149)
[/code]
AND,XOR,OR,BIT,RES,SET,CPL,NEG,RLC,RRC,SLA,SRL,RL, RR,SRA for BASICAs this was drifting away from the original INKEY$ thread I thought that I'd create a new one. So here's a routine to provide all of the above mentio…
... /> LOGIC: ld hl,12
add hl,sp
ld sp,hl ;undo USR ... af
ld hl,OPCODES
add hl,bc
add hl,bc
ld ... * 8
add a,c
LDOPC2: ld (hl),a
EVALOP ...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…
... ;Discard all but
ADD HL, SP ; 57 ;STMT_RET ... BC ; 193
POP HL ; 225
POP DE ... 217
NOGSUB: PUSH HL ; 229
PUSH DE ...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
GETARG: ... print a character
pop hl ;HL=string pointer
djnz SSNEXT1 ...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…
... "...,"argn"];
UNDEF: ld hl,14
add hl,sp
ld sp ... ,hl ;undo USR
ld ix ...
NOTFOR: ex de,hl
add hl,bc
ld b,h ...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…
...
inc hl
add hl,de
dec hl
ld (hl),":" ;replace ENTER ... de,hl
add hl,bc ;HL=joined length
ex de,hl
ld (hl ...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 …
... black paper.
DEC HL ; Decrement memory address.< ... SBC HL,DE ; subtract and add back setting
ADD HL,DE ... ; carry when back at start.
INC HL ...Optimize this: Distance CalculationBased on a taylor series expansion, suggested by NA_TH_AN, I've got this so far, which is far far faster than SQR(X^2+y^2) Formula is: in a right an…
... LD H,0
ADD A,B
LD ... LD B,A
SBC HL,BC ; take half our smallest ... from HL
SRL C ... Clear carry flag.
SBC HL,BC
SRL ... A ; Clear carry flag.
ADD HL,BC
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]…
... c,e
ld hl,table
add hl,bc
... ld c,(hl) ; y = q[i ... />
ld c,d
add hl,bc ; t = 253 * y + ...
pop hl
ld (hl),a ; q[i] = ...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…
... TESTSCROLL: push hl
ld hl,0005
add hl,sp
... ld a,(hl)
... bc
INSCROLL: pop hl
NOWOBBLE: pop af ...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…
...
Fastest way to do HL = HL x 10 ?
ADD HL,HL
ADD HL,HL
ADD HL,HL
ADD HL,DE
ADD HL,DE
ADD HL,HL
LD E,L
LD D,H
ADD HL,HL
ADD40 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,16384
add hl,de
... d
ld hl,uglifont
add hl,de
ret ... a
ld hl,coordslookup
add hl,de
...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…
... .
[code]
ld hl,$4000
ld de,$4000 ... ,0
pixrow: ld (hl),$ff
inc d ;D ... c
rrc c
add hl,bc
pop bc
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…
... add hl,bc
add hl,bc
ld a,(hl)
inc hl ...
ld h,(hl ... br /> ex de,hl
add hl,bc
ex ...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…
... (JP NC)
exo_setbit:
add hl, hl
dec c
jr ... /> ld h, (iy+104)
add hl, bc ;Always clear C flag ... (JP NC)
exo_setbit:
add hl, hl
dec c
jr ...A quick newbish questionI'm reading through 'mastering machine code on your spectrum',as kindly posted by Mr bert on this forum. Correct me if I'm wrong from what i read,bu…
... assuming the register pairs like Hl hold 2 bytes or a ... where it mentions that the add instruction you have to use ... register with it ie ADD A,C,ADD A,D but not ... C.Or you can use ADD HL,but it must be used ... another pair ie DE.
ADD Hl,DE together would still be ...
