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JP (HL) confusionokay.... JP nn will jump to memory address nn. JP (HL) ,I assumed would read the contents of memory address HL and jump to the location and be a gre…
... to memory address nn.
JP (HL) ,I assumed would read the ... L,A
LD HL,jumptable
JP (HL) ; read/peek the contents ... do.
JP nn means PC=nn
JP (HL) means PC=nn ...
JP (IX) means PC ... -
LINE-routine and other nice pieces of codeThe line-topic came in the end with a nice piece of fast coding. I think that there might be more of these routines out there (where-ever-u-r). Isn…
... /> .......LD DE,0
.......JP MAIN
B2.....INC ... /> .......LD H,(HL) ; fetch highbyte (7)
.......JP (HL) ; jump indirect ... 00
JP I03
JP I06
...
JP IFF ; last ... 83 (#8301)
...
JP IFD ; last (#8300-#83FF)
Z80 Emulator Source?Found a link to this on comp.sys.amstrad.8bit. i havent been with the discussion long but supposedly this is the source for a Z80 emulator. Forgive m…
Urgent Help needed to fix this: calling all machine code gurusI am currently trying to write tutorials on the amazing Orfeus music composer by Proxima which allows you to do multi channel music through the beepe…
... hl
jp l8959
pop hl
ld a,(hl)
inc hl
hl
jp l8ac3
pop hl
ld a,(hl)
inc hl ... e,(hl)
inc hl
ld d,(hl)
ex de,hl
jp (hl ...The short blocks loaded in Jet Pac(Hope this have not been previously discussed. If so, my apologies) Is there any reason why Jet Pac loads three short blocks after the main block? I…
... but the opcode of the JP (HL) instruction, which is called from ...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 …
... br /> ld l,c
jp (hl) ;JP address
; ... a character
pop hl ;HL=string pointer
djnz ... max_length?
NOSPACE:pop hl ;HL=string pointer
jr ...BIT/RES/SET b,r where b is variableWhat's the best way to use the bit flag group of commands if it's not known in advance which bit should be referenced; ie. where it's dependent upon …
... particular one with either a "jp (hl)" or a series of "cp ...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…
... /> ;
l_0d09: inc hl
push hl
ld (iy+$00 ... br /> ld hl, $009f
ex (sp), hl
push hl
... , e
pop de
jp (hl)
;; hook-code- ... br /> ;
l_0d63: ld hl, ($5ce3)
jp (hl)
;
[/CODE]
Flood Fill IssueHi Folks, Came across the following Flood Fill routine by John Metcalf: [code]; scanline fill by John Metcalf ; call with d=x-coord, e=y-coo…
... 60004 2E FF
push hl 60006 E5
; ... 60039 28 0D
ld (hl),a 60041 77
inc ... 78
or (hl) 60083 B6
cp (hl) 60084 BE
push de 60101 D5
jp (hl) 60102 E9[/code]
Textured Scanline Flood Fill for ZX Spectrum 48KPity that it's quite hard to contribute code to WoS in a straightforward manner. Recently, I have created a textured/hatched fill M/C routine for the…
Pity that it's quite hard to contribute code to WoS in a straightforward manner. Recently, I have created a textured/hatched fill M/C routine for the ZX Spectrum 48K. It was for a text/graphic adventure I'm working on. The algorithm is based on [url="http ...Anyone for a hacking challenge ?I have to get the DSK version of Tomahawk to work. It uses the well-known Digital Integration "SECURITY CODE" lock just like in Bobsled, ATF, etc. Th…
... , E921
E91D JP C, E846
E920 JP (HL)
E921 CALL ... /> E92E POP HL
E92F POP DE
E930 JP 5DC0
JP (HL)... that's the end of ... again. Look again and the JP (HL) could mean that if we ...help in byte mirroring.I need some help. What is the best way to mirror the byte? (for ex. 10010011 -> 11001001) I mean, if there is a simple way to do it (may be with OR, …
...
000A C31200 10 JP Swap1
000D CB47 8 ...
0032 C33A00 10 JP Swap3
0035 CB57 8 ... If IX/IY or HL is available JP HL etc. would make the ... JP Swaps only 4 T ...help in byte mirroring.I need some help. What is the best way to mirror the byte? (for ex. 10010011 -> 11001001) I mean, if there is a simple way to do it (may be with OR, …
... . If IX/IY or HL is available JP HL etc. would make the ... JP Swaps only 4 T states ...Z80 register decoding document error?Hi, I've been working on a disassembler using the following document written by Cristian Dinu (aka GOC?). [url="http://www.z80.info/decoding.htm…
... is suppose to decode to JP (HL), but according to your algorithm ... decodes to JP HL. If I force it to be JP (HL) how does ... code is (HL) then DDE9 works out to be JP (IX+d ... ) instead of JP (IX) (what it ...Z80 register decoding document error?Hi, I've been working on a disassembler using the following document written by Cristian Dinu (aka GOC?). [url="http://www.z80.info/decoding.htm…
... is suppose to decode to JP (HL), but according to your algorithm ... decodes to JP HL. If I force it to be JP (HL) how does ... the Z80 instruction set. The "JP (HL)" notation is an error that ... am using the correct notation, JP HL, which corresponds to what the ...Z80 register decoding document error?Hi, I've been working on a disassembler using the following document written by Cristian Dinu (aka GOC?). [url="http://www.z80.info/decoding.htm…
... />
E9 is JP HL
DDE9 is JP IX
FDE9 is ... JP IY
The ... [/url]
uses JP(HL), JP(IX), JP(IY), but describe their behaviour ...Z80 register decoding document error?Hi, I've been working on a disassembler using the following document written by Cristian Dinu (aka GOC?). [url="http://www.z80.info/decoding.htm…
... />
E9 is JP HL
DDE9 is JP IX
FDE9 is ... JP IY
The ... [/url]
uses JP(HL), JP(IX), JP(IY), but describe their behaviour ...Z80 register decoding document error?Hi, I've been working on a disassembler using the following document written by Cristian Dinu (aka GOC?). [url="http://www.z80.info/decoding.htm…
... :48, GOC wrote:
The "JP (HL)" notation is an error that ... /> "Somehow" of course being because JP (HL) is the official notation used ...Programming MC challengeIn the 80-ies I got the following assignment for a programming course. 2 16-bit values stored in #8000 and #8002 must be added together and stored i…
... />
[code]
ex (sp),hl
ld sp,#8000
.skip
push bc
jp (hl)
[/code]
Which ...The incredible shrinking screendumpIn this topic I stated that I would be impressed if the screendump could be smaller than 37 bytes. [url="http://www.worldofspectrum.org/forums/viewt…
... c,0
ld hl,table
jp (hl)
[/code]
ld hl,table
jp (hl)
[/code]
ld hl,table
jp (hl)
[/code]
ZX Spectrum BogoMipsBogoMips value gives some indication of the processor speed, and is one of the most used way of comparing diferent systems. The definition of BogoMi…
In that case:
org 60000
ld hl, loop
loop:
jp (hl) ;4 tstates
0.875 bogomips
DerekROM paging questionAssuming the Spectrum 128 memory map and port addresses, but two custom ROMs in place of the normal Editor and BASIC, what is the most efficient way …
... E,(HL)
INC HL
LD D,(HL)
INC HL
PUSH HL ... : save RET Address after call address
EX DE,HL
JP (HL ...What do you think.Do you think if you went back in time and made a Sudoku game for the spectrum you would be a millionaire now? (all my get rich quick schemes invole …
... ,(HL) ; save HL on stack
LD HL,(SYSVARJUMP) ; Fetch JUMP-address
JP (HL ...What do you think.Do you think if you went back in time and made a Sudoku game for the spectrum you would be a millionaire now? (all my get rich quick schemes invole …
... ,(HL) ; save HL on stack
LD HL,(SYSVARJUMP) ; Fetch JUMP-address
JP (HL ...ANN: SP1 for Z88DK (aka splib3, Sprite Pack v3.0)Well it's finally arrived, after a month of "a few days from now" release deadlines. SP1 is the lastest version of splib, a flicker-free software sp…
...
uchar res3; // +14 "JP (HL)" opcode
struct sp1_cs * ...ANN: SP1 for Z88DK (aka splib3, Sprite Pack v3.0)Well it's finally arrived, after a month of "a few days from now" release deadlines. SP1 is the lastest version of splib, a flicker-free software sp…
... res0; // +10 typically "LD HL,nn" opcode
uchar *def ... in the struct sp1_cs). HL is loaded with the ... character belongs to. Then a JP(HL) is executed.
HL; JP(HL)" in the struct sp1_ss ...Galaksija emulator for ZX Spectrum +3/+2A(black)This is a NEW program/utility/game pack for ZX Spectrum. It is basically an emulator of an ex-Yugoslav computer "Galaksija" which is also Z80 based. …
... h,b
ld h,(hl)
jp (hl)
org #a000 ... ,#ae,#af
i00 jp b1
defb 0
exx
jp b1
defw 0
