-
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... :
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... /> ldir
pop hl ; restore source address ... -
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... :
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... /> ldir
pop hl ; restore source address ... -
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... :
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... /> ldir
pop hl ; restore source address ... -
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... :
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... /> ldir
pop hl ; restore source address ... -
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... :
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... /> ldir
pop hl ; restore source address ... -
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... copy_byte_loop:
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... - offset - 1
pop de ; DE = destination
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... copy_byte_loop:
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... - offset - 1
pop de ; DE = destination
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... copy_byte_loop:
ldi ; copy literal byte
push hl ; store destination< ... offset - 1
pop de ; DE = destination
ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... ,$c000
push de
call dzx7
pop hl
ld ... /> ex de,hl
ldir ; copy attributes
ret
[/CODE ... ,rcs_buffer
push de
call dzx7
pop de
[/CODE ...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…
So how do you use RCS in practice? It's quite simple:
[LIST]
[*]First transform a regular ZX-Spectrum screen file (such as "Cobra.scr") into the RCS format (producing "Cobra.scr.rcs") using the command-line utility RCS;
[*] ...RAM used / corrupted by +3DOSAs I said previously, [url=http://www.worldofspectrum.org/forums/showthread.php?t=41775]I'm trying to put some games in hard disk[/url] so they can b…
...
push de
call $1820 ; initialise RAMdisk
pop de
copy in various routines, including its ... level loader, a copy of which resides in high ...ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
... copy_byte_loop:
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... - offset - 1
pop de ; DE = destination
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…
... br /> ; Preserve initial address
push de
; First step ... br /> ; Recover initial address
pop de
; Second step ... : for each column, copy all bytes from screen ... to this buffer, then copy them again to the screen ...ZX7: an "optimal" LZ77 packerAbout 20 years ago, I started a M.Sc. in Computing, planning to work on data compression. Although I quickly changed to another subject for a number …
...
copy_byte_loop:
call copy_byte ; copy literal byte
main_loop:
; copy previous sequence
ex (sp ... EX AF,AF' with PUSH AF/POP AF if you want 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…
... copy_byte_loop:
ldi ; copy literal byte
... restore destination
push hl ; store destination< ... - offset - 1
pop de ; DE = destination
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…
89 bytes (-1 byte):
C cruncher code:
[CODE]
#define MAX_OFFSET 2160 /* range 1..2160 */
...
void write_elias_gamma(int value) {
int bits= 0, rvalue= 0;
while ( value>1 )
++bits,
Z80 internal compressionThis isn't exactly a ZX Spectrum problem, but since WOS probably has some of the best Z80 coders in the world, I thought I might ask anyway. For my …
... JR NC,UM4 ; "1" means "copy an uncompressed byte"
LDD ... /> LD B,0
LDDR ; copy the string from the already ...
DEC HL
PUSH BC
PUSH HL
LD L ... /> JR NZ,UM10
POP HL
POP BC
RET
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…
... those PUSH instructions. It's not doing a copy.
When you copy data, you POP as ... many registers as you can, then PUSH ... about which registers you PUSH and in what order ... />
Also a PUSH takes 11 cycles, or 16 ...Full 16*16-digit BASIC multiplicationI liked Andre Adrian's 32-bit long multiplication routine so much that I decided to a decimal version. After all, 2^63 is only 9223372036854775808, a…
... digit
push de
exx
pop hl
... br /> ;16 bytes copy area
COPY: equ WORKSP+24< ... Z
ld de,COPY
ld bc,12 ... ldir
ld hl,COPY
ld de,Ba< ...Confounded DEF FNCan anyone see why this is going wrong? I've been tinkering with it since tea time and got nowhere. [code] 2 DEF FN t$(n,t,d) =STR$ INT (n/t)…
... pop hl ;HL=$000D
ex (sp),hl ;HL=$106E
push ... hl
push de
push bc
ld ... exx
ld d,0 ;copy denominator to 'D'E'
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…
... /> ld a,c ; copy working value into accumulator
push hl ; at this point, HL ... /> ld (.border_routine_addr),hl
pop hl
endm
...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…
... counter (past byte)
push bc ; save byte counter ... :
ld (de),a ; copy byte
inc de ; advance ... run is complete
pop bc ; restore byte counter ...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…
... />
push bc
exx
pop bc
call ... br /> push de
exx
push ix
pop hl< ... a ;copy attributes for graphic
push ix
pop hl
SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
... :
ld hl, (ch_add) ; copy address of current character
push bc ; stack BC
call keyboard ; read keypress
pop ... (iy + _err_nr), l ; then copy to err_nr
ld sp ... /> ld a, (hl) ; copy character at current address to ...SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
... _mode) ; mode to C
push hl ; stack pointer
call ... for meta and control
pop hl ; unstack pointer
... :
ld b, d ; copy shift byte
ld a ... k_decode:
ld a, e ; copy main code
k_decode_1 ...SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
...
me_ent_3:
pop bc ; unstack length
pop de ; unstack prog ... pointers
push hl ; stack new pointer
ldir ; copy the new ... new pointer
pop bc ; unstack length
push de ; stack old ...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…
... /> LDIR
;proper copy routine
LD IX,49152 ... /> POP AF
LD SP,IY
PUSH AF
PUSH BC
PUSH ... [/B] tstates for a byte copy, easily beating LDI. The routine ...SE Basic IV Buffy v4.1 source (WIP)I've been doing a major refactor on the SE Basic source and I'd appreciate a code review from anyone who has time to look at it. I've almost certainl…
... fce ; stack
push de ; stack both
push hl ; pointers
push hl ; stack HL'
exx ... /> pf_save:
push de ; copy
exx ; DE
pop de ; to
