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<1234567…34>
  • LDIR timings in contended RAM?The 48K Spectrum technical reference page ([URL="http://www.worldofspectrum.org/faq/reference/48kreference.htm"]here[/URL]) describes the detailed ti…

    ... loops, is:
    [code]Contended: LDIR LDI

    Only (DE) 24 ... bytes more quickly than [b]ldi[/b] writes one. They're ...
    ajmoss ajmoss June 2010 Development
  • Assembly game programming on ZX how-to?Hi. I'm planning to build and release new software for the Speccy but I'm pretty lame as to handle its hardware despite a good mastery of Z80 assembl…

    ... sequence of LDI commands (faster than LDIR)

    LDI
    LDI
    LDI
    Ralf Ralf September 2012 Development
  • [Asm] Is this nested loop faster than LDIR or a bunch of unrolled LDI's?Hi all. I'm learning Z80 asm on Speccy 48K, and to start with I decided to write my own "CLS" routine (without relying on ROM calls or LDIR) as a lea…

    ... go then (or settle for LDIR/LDI's). It is harder to ...
    ST1 ST1 November 2018 Development
  • [Asm] Is this nested loop faster than LDIR or a bunch of unrolled LDI's?Hi all. I'm learning Z80 asm on Speccy 48K, and to start with I decided to write my own "CLS" routine (without relying on ROM calls or LDIR) as a lea…

    ... relying on ROM calls or LDIR) as a learning exercise. What ... this code is faster than LDIR because that is operating on ... a partially unrolled set of LDI's (let's say 5 ...
    ST1 ST1 November 2018 Development
  • Z80 core testing ?OK, my z80 core is almost finished (apart from RRD, RLD, and block instructions except LDI,LDIR,LDD,LDDR). I run the 48K rom and hurray, it resets co…

    ... , RLD, and block instructions except LDI,LDIR,LDD,LDDR). I run the ...
    GOC GOC July 2004 Development
  • Smooth Color Masked Sprites using fast page flip on 48kHere is a quick demo of using char based sprites using the Page flip method: a) Background is copied to buffer b) Sprites drawn on buffer c) Buffer …

    ... ]

    Instead of LDIR or multiple LDI's I have used ...
    LD (HL),%01000111
    LDIR


    MAIN:
    robpearmain robpearmain September 2004 Development
  • Mode 2 Tile Editor SourceA Timex Mode 2 Tile Editor incorporating a byte mirror table. The compiled version is available in the CSSCGC 2008 collection from the WoS archive. …

    ... block)

    cp2b_a:
    ldi ; copy contents of hl to ... )
    ; increment both pointers
    ldi ; copy contents of hl to ... remaining bytes to clear
    ldir ; wipe screen
    ret ; done ...
    chev chev January 2007 Development
  • Rainbow Generator for 48K Spectrum using PUSHThis is what I came up with from [B]gasman[/B]'s suggestions. It's stable in ZXSpin and ZX32 simulating a 48K Speccy. Anyone like to try it on the …

    ... , 256 ;Make 256 copies
    ldir ;Thusly

    ;Interrupts will ... go (253*256 + 253)
    ldi ;Copy the 3-byte jump ... instruction
    ldi
    ldi

    ;Install interrupts ...
    joefish joefish May 2009 Development
  • CPI emulationI'm currently writing Sinclairean's emulation assembly for the CPI/CPD/CPIR/CPDR instruction group. Does anybody know what exactly the behavior of th…

    ... [/B] cycle, just like the LDI/LDD/LDIR/LDDR group (!)

    Madonna Mk 2 Madonna Mk 2 March 2010 Emulators
  • LDIR timings in contended RAM?The 48K Spectrum technical reference page ([URL="http://www.worldofspectrum.org/faq/reference/48kreference.htm"]here[/URL]) describes the detailed ti…

    ... /> My program will have the LDIR instruction in non-contended memory ... to the duration of a LDIR instruction (normally 21T) means ... that when LDIR synchronises with the gaps in ... per byte.

    Using LDIR to scroll the full screen ...
    ajmoss ajmoss June 2010 Development
  • Contention: LDI vs LD (ss), rAccording c.s.s. FAQ: instruction LD (ss),r breakdowns as pc:4,[b]ss:3[/b] and LDI as pc:4,pc+1:4,hl:3,[b]de:3,de:1 x 2[/b] can anyone explain why …

    ... ]ss:3[/b]
    and LDI as pc:4,pc+1 ... explain why WRITE operation in LDI introduces two delays? or that ...
    Fikee Fikee February 2011 Development
  • Push/Pop data copyingWe all know that stack pointer cheese and push/pop is faster to move data than LDIR - which in turn is slower than unrolled LDI's anyway. I rewrote …

    ... data than LDIR - which in turn is slower than unrolled LDI's ...
    Gedlion Gedlion March 2011 Development
  • Jet Set Willy Turbo edition!Improve the speed of the game with just a few pokes! Do the standard CLEAR 32767 : LOAD "" CODE to get at the BASIC loader (see Your Spectrum issue …

    ... ]
    It replaces the two LDIR instructions at $89C4 and $89FE ... screen with a series of LDI instructions. The game now moves ... kept in contended memory) The LDI instructions are stored at $FEC0 ...
    Jimmy Jimmy May 2011 Sinclair Miscellaneous
  • Rambo (improved BUGFIX)An improved BUGFIX was provided for game [URL="http://www.worldofspectrum.org/infoseekid.cgi?id=0004010"]Rambo[/URL], please replace the "known error…

    ... instruction LDIR (setting BC to zero), then instruction LDI twice ... (setting BC to $FFFE), then another instruction LDIR ... LD D,HX
    LDI
    LDI
    INC HL
    LDIR ; Fixed using POKE 41642 ...
    Einar Saukas Einar Saukas June 2011 Infoseek database
  • Fairlight's use of LDIRYS, comparing Fairlight and Nightshade, said: [quote]Fairlight is much more interesting even though the techniques that Bo Jangeborg uses for screen…

    ... long time that uses an LDIR instruction to move the screen ...
    mjwilson mjwilson January 2012 Sinclair Miscellaneous
  • Quickest way to fill the attributes using LDIRI'm looking for a small routine to fill the entire attribute area of the memory with a single value, I've used LDIR in the past, but forgotten how to…

    I'm looking for a small routine to fill the entire attribute area of the memory with a single value, I've used LDIR in the past, but forgotten how to do it... :confused:
    daveysludge daveysludge August 2012 Development
  • 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…

    ... de
    exo_literalcopy:
    ldi
    exo_mainloop:
    call ... bc ;bc=lenght
    ldir
    pop hl ;Keep ... de
    exo_literalcopy:
    ldi
    exo_mainloop:
    add ...
    antoniovillena antoniovillena November 2012 Development
  • 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…

    ... solution is to use [B]LDIR[/B]:
    [CODE]
    ... br /> ld bc,4096
    ldir[/CODE]

    The ... better, simpler solution using [B]LDI[/B]:
    [CODE]
    ... loop:
    REPT 32
    ldi
    ENDR
    djnz loop ...
    Einar Saukas Einar Saukas October 2013 Development
  • LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …

    When using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store it?
    MatGubbins MatGubbins March 2014 Development
  • Scrolling Bi-Colour Engine for 4-Player GamesJust putting this code up for people to have a look at. Far from finished. Should simply compile and run a bit of a demo. Only good for 128K and +…

    ...
    ld bc,256
    ldir

    ;Copy main ... /> ld bc,interrupt_main_end-interrupt_main
    ldir

    ;Point interrupts ... X to address

    ldi
    ld a,(hl)
    inc l
    ldi
    ldi ;draw two pixel rows
    joefish joefish March 2014 Development
  • Tinkering with DMASo, some afternoon tinkering... [img]http://photo.alioth.net/tmp/dma_small.jpg[/img] The purpose of this all is to see what's possible using the Xi…

    ... transfers
    On the Z80, LDI takes 16 T-states per ... />
    A better comparison is LDIR which is something like 21 ... 't be modifying registers like LDI/LDIR or PUSH.

    The ...
    Winston Winston November 2014 Hardware
  • Addressing mode of LDIR and LDDRWhat addressing mode would the instructions LDIR and LDDR be classed as using? Would I correct in thinking that they're register indirect, as both t…

    What addressing mode would the instructions LDIR and LDDR be classed as using?

    Would I correct in thinking that they're register indirect, as both the source (HL) and destination (DE) registers are pointing into memory?
    cmonkey cmonkey January 2015 Development
  • Let's copy buffers!Figured I'd do some double buffered graphics, so I can render for several frames before displaying stuff. Yes, I mean on a 48k speccy, so no 128k spe…

    ... is to replace the ldir with 24 ldi instructions..
    [code]
    ldi
    ldi
    ldi
    ldi
    ldi
    ldi
    ldi
    ldi
    ldi
    ldi
    ldi ...
    Sol_HSA Sol_HSA April 2016 Development
  • Console frameworkStill working on Specotron, but at the point where working out the diagonal lines collision is not good at beer o'clock. In the meantime I've knoc…

    ...
    ld bc, 32
    ldir
    pop bc
    ENDM ...
    ld bc, 32
    ldir
    pop bc
    ENDM ...
    ld hl, scr_out_row
    ldi
    ldi
    ret

    ld (hl), a
    ldir
    ex af, af'
    Paradigm Shifter Paradigm Shifter August 2022 Development
  • Advice about drawing sprites on spectrum I've coded sprite drawing before and know all the theory about masks from a long time ago (microhobby rules! ;), but since I did it on Amiga with ha…

    ... a hidden screen, and then LDIR to real screen at interrupt ... , but at a cost: an LDI'd screen takes more than ...
    Alcoholics Anonymous Alcoholics Anonymous July 2003 Games
  • Rambo First Blood Part 1Greetings. I was just wondering if anyone knows of a version of this game that doesn't crash when you hit the enemy chopper. It's getting on my nerve…

    ... piece of code
    ...............
    LDIR
    LD (IY+0),8 ... /> LD D,HX
    LDI
    LDI
    INC HL
    INC ...
    LD C,6
    LDIR
    ...........

    Try find ...
    g00db0y g00db0y June 2004 Games
  • Game loop design?Having some thoughts on how to design the game loop and could do with some hints and tips from folks who have done it before! It's all about how to …

    Multiple LDI opcodes execute far faster than LDIR.
    Woody Woody September 2004 Development
  • Speccy 128k Double Buffering.If I understand this right, you display either of the screens, and draw to the one that is not being displayed. Am i right in thinking that the Non …

    ...
    ld bc, width
    ldir
    [/CODE]
    Which would ... /> ld de, window_top_line
    ldi
    ldi
    ldi
    ...
    [/CODE]
    LDIR is incredibly slow). The space ...
    icabod icabod May 2006 Development
  • Pimp my code...Erm, this is just the result of a mental exercise - I wanted to repeatedly display a UDG but decided against using a ROM routine and UDGs! Any sugges…

    ... ]

    :-)

    LDIR (and LDI) is fast for copying bytes ... , but not fast. A single "LDI" step takes 16 cycles whereas ... : INC HL" takes 13 cycles. LDI does supply a byte counter ... LDIR takes close to 21 cycles per byte and an unrolled LDI ...
    Alcoholics Anonymous Alcoholics Anonymous August 2006 Development
<1234567…34>

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Related Threads

  • [Asm] Is this nested loop faster than LDIR or a bunch of unrolled LDI's?Hi all. I'm learning Z80 asm on Speccy 48K, and to start with I decided to write my own "CLS" routine (without relying on ROM calls or LDIR) as a lea…
  • LDIR timings in contended RAM?The 48K Spectrum technical reference page ([URL="http://www.worldofspectrum.org/faq/reference/48kreference.htm"]here[/URL]) describes the detailed ti…
  • Contention: LDI vs LD (ss), rAccording c.s.s. FAQ:<br /> <br /> instruction LD (ss),r breakdowns as pc:4,[b]ss:3[/b]<br /> and LDI as pc:4,pc+1:4,hl:3,[b]de:3,de:1 x 2[/b]<br /> …
  • Fairlight's use of LDIRYS, comparing Fairlight and Nightshade, said:<br /> <br /> [quote]Fairlight is much more interesting even though the techniques that Bo Jangeborg use…
  • Quickest way to fill the attributes using LDIRI'm looking for a small routine to fill the entire attribute area of the memory with a single value, I've used LDIR in the past, but forgotten how to…
  • LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
  • Addressing mode of LDIR and LDDRWhat addressing mode would the instructions LDIR and LDDR be classed as using?<br /> <br /> Would I correct in thinking that they're register indirec…

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