-
help sought with first foray into machine code - pixel scrolldownI have started to code my first machine code program, a simple roadrace game. I've based it around the pixel scrolldown routine in 40 Best Machine Co…
... /> savscrpos
push hl ;save road left side posn ... copy byte. . .
ld (hl),a ;. . .to next pixel line ... right, 1line up
ex (sp),hl ;?? load posn of byte ... up
ex de, hl ;put 224 into hl, byte to ... to be copied
ex de,hl ;?? but now it' ... -
help sought with first foray into machine code - pixel scrolldownI have started to code my first machine code program, a simple roadrace game. I've based it around the pixel scrolldown routine in 40 Best Machine Co…
... 't I need some horrible 'ex(sp), hl'-type instructions to get the ... know how many cycles an ex instruction takes? -
help sought with first foray into machine code - pixel scrolldownI have started to code my first machine code program, a simple roadrace game. I've based it around the pixel scrolldown routine in 40 Best Machine Co…
... t I need some horrible 'ex(sp), hl'-type instructions to get the ... takes?[/QUOTE]
ex (sp),hl takes 19 cycles but this ... pop ix
ld hl,-32
add hl,sp
ld (source ... pop). The "ld sp,hl; ld sp,ix; ld sp,iy" instructions need ... -
Understanding the StackSorry folks. I guess I'm going to be a pain for a little while. Hope it's ok with everyone. I'm currently studying the stack and wrote the little pr…
... you did 'ld hl, 0; add hl, sp', then hl would contain the address ... /> pop ix ; my_addr structure
ex (sp), hl ; restore return addr, fd now ... here is the last instruction, EX (SP), HL. This just swaps whatever value ... -
Understanding the StackSorry folks. I guess I'm going to be a pain for a little while. Hope it's ok with everyone. I'm currently studying the stack and wrote the little pr…
... QUOTE=rahtgaz;328421]LD SP seems one heck of ... somewhere convenient, and LD SP,nnnn is the way ...
In fact, LD SP,nnnn does come in useful ... methods like LD (HL),A. But abusing SP like that is ... learning :-)
Now, EX (SP),HL is the instruction *I've ... -
128 ROM paging alternativeWould this work (with the appropriate code in each ROM)? [code] ; 128 rom paging routine ; use rst 28h with call address stored after restart ;;rom…
... registers):
[CODE]
ex (sp),hl
ld (SaveDE),de
hl)
inc hl
ld d,(hl)
inc hl
ex (sp),hl
Interface One - New FunctionalityAs you may (or may not) be aware the Interface One is a pretty powerful piece of kit. One of it's greatest features is being able to easily extended …
... c1 $0ats
ld (hl), c ; 049f 71 $07ts< ... f5 $0bts
ld hl, $3de5 ; 04c6 21 e5 ... /> cp (hl) ; 04ce be $07ts
ex de, hl ; 04cf eb ... ; 04d6 f1 $0ats
ex (sp), hl ; 04d7 e3 $13ts
... 00 $0ats
push hl ; 04e3 e5 $0bts
AY programming and notes frequencyHello everybody, I'm Targhan from the french CPC group Arkos, perhaps you've heard of us. I'm currently working on a music tool and I'd like to k…
... l,a
add hl,sp
ld sp,hl
ld a,b ...
add hl,sp
ld sp,hl
pop hl
add hl,de
csp_
ld sp,03131h
ex (sp),hl
xor a
sp
ld sp,hl
pop hl
add hl,de
AY programming and notes frequencyHello everybody, I'm Targhan from the french CPC group Arkos, perhaps you've heard of us. I'm currently working on a music tool and I'd like to k…
... l,a
add hl,sp
ld sp,hl
ld a,b ...
add hl,sp
ld sp,hl
pop hl
add hl,de
csp_
ld sp,03131h
ex (sp),hl
xor a
sp
ld sp,hl
pop hl
add hl,de
Z80 'EXX' ConfusionI was working on a little Z80 routine last evening, and, having run out of registers, resorted to sticking one of the values into a memory location a…
And we still have
EX DE,HL
EX (SP),HL
Always nice to use....Z80 'EXX' ConfusionI was working on a little Z80 routine last evening, and, having run out of registers, resorted to sticking one of the values into a memory location a…
Ah, yes, the DE/HL one kind of makes up ... able to add BC onto HL, not DE. So you can ... swap DE/HL, add an address offset onto ... HL, then swap them back again. ... I've used EX (SP),HL yet though. If it was EX SP,HL I might ...Z80 'EXX' ConfusionI was working on a little Z80 routine last evening, and, having run out of registers, resorted to sticking one of the values into a memory location a…
... saw what the point of EX (SP),HL was - until I started work ... means that you can POP HL to pick the return address ... parameters, then finish off with EX (SP),HL to pick up the last ...Z80 'EXX' ConfusionI was working on a little Z80 routine last evening, and, having run out of registers, resorted to sticking one of the values into a memory location a…
... will be intimately familiar with EX (SP), HL :-)
Also I use ... store HL while setting the return address, and swap them with EX (SP), HL.Z80 'EXX' ConfusionI was working on a little Z80 routine last evening, and, having run out of registers, resorted to sticking one of the values into a memory location a…
... saw what the point of EX (SP),HL was - until I started work ... means that you can POP HL to pick the return address ... parameters, then finish off with EX (SP),HL to pick up the last ...Z80 'EXX' ConfusionI was working on a little Z80 routine last evening, and, having run out of registers, resorted to sticking one of the values into a memory location a…
... saw what the point of EX (SP),HL was ...[/QUOTE]
[code]
.PrText
EX (SP),HL
.PrTextLp
LD A ... ,(HL)
INC HL
AND A
.PrTextEnd
EX (SP),HL
RET
CALL ...tricks to simplify codingWhen i started with programming in assembler i had very simple approach to do things. Just shifting bytes around, doing simple tests and so... Later …
... l,a ; hl = function address
ex (sp),hl ; hl = message ... /> uchar res2; // +13 "EX DE,HL" opcode
uchar res3; ... frame
ex de,hl
jp (hl)
[/ ...New member here. And a spider! :)Hello everyone. My name is Sekrets. I'm quite a lonely individual, searching for a digital home where I might find fellow speccy enthusiasts to adopt…
... hl,line
ld b,(hl)
ld hl, col
ld c,(hl ... /> 10 pop de
11 ex (sp),hl
12 ld h,e ... 0..191
18 ; exit : hl = screen address
19 ; uses ... : af, hl
20
21 srl ...Spectrum 128K RS232 to PC serial cableIf you have read some of my recent posts then you will know that I am eager to link my Spectrum +3 to a PC. This will be done by wiring a standard PC…
... ;
ex (sp),hl
ld (r_pc),hl
ex (sp),hl
ld sp,r_r
ex af ... /> push de
push hl
ex af,af'
exx
exx
ex af,af'
pop hl
pop de ... br /> exx
ex af,af'
ld sp,(r_sp)
yeah - unix for zx spectrumI started a new hobby project. An operating system for ZX Spectrum. A unix clone. Talked to my friend about it and he asked me what if after I'm done…
... absolute addresses, loading up SP and performing a task switch ... .pushreg
75
76 ex (sp),hl
77 push af
...
92 jp (hl)
[/code]
... on stack
; save SP in task structure
; perhaps ...AY Magic version for ZX81 was bornModified Ay magic ,my previous interface for zx48. On board, ay chip based on Zonx interface but with stereo output and rampack 16 or 32 kilo on boa…
... l, a
add hl, sp
ld sp, hl
ld a, ... /> add hl, sp
ld sp, hl
pop hl
add hl, de
csp_:
ld sp, 03131h
ex (sp), hl
xor a
sp
ld sp, hl
pop hl
add hl, de
RAND USR that doesn't work in emulators and clonesEons ago, I "discovered" a strange RANDOMIZE USR. This is it: [b]RANDOMIZE USR 46578[/b] Using it on a genuine ZX Spectrum rubber key or Plus model,…
... EXX instruction followed by PUSH HL. There's more places in ... that performs EXX followed by EX (SP),HLKobrahsoft DB1 - doesn't work?Hi, I've tried loading [URL="http://www.worldofspectrum.org/infoseek.cgi?regexp=^DB1$&pub=^Kobrahsoft$&loadpics=3"]DB1 by Kobrahsoft[/URL] into two …
... B ; 8007 A8
EX (SP), HL ; 8008 E3
XOR ... L ; 800A AD
EX (SP), HL ; 800B E3
XOR ... 00 00
ADD HL, SP ; 803A 39
...Kobrahsoft DB1 - doesn't work?Hi, I've tried loading [URL="http://www.worldofspectrum.org/infoseek.cgi?regexp=^DB1$&pub=^Kobrahsoft$&loadpics=3"]DB1 by Kobrahsoft[/URL] into two …
... & off the top with "EX (SP), HL".
The explanation for ...writing an emulator-newbie needs helpHi, this is my first post here. I decided to write a minimalistic emulator of ZX Spectrum-no emulation of advanced peripherals, no emulation of sound…
... placed on a stack? Would SP be decremented by 2 regardless ... br />
Another example: EX (SP),HL. What if SP points to an address ... H and (SP) gets loaded into L, but (SP) and (SP+1) remain ... H, L and (SP+1) changed accordingly and (SP) remains unaffected?
line, plot and circle in whole 256x192 displayhi! are there some way to draw lines, or whatever, in the whole 256x192 display, than just the above 256x176 part? (this is the msx1 version i made o…
... /> ;-- SUBs --------------------------------------------
dodraw LD HL,(oldxy) ;draw a line between ... counter
dostep EX (SP),HL ;save HL, fetch oldxy
... /> POP BC
EX (SP),HL ;fetch counter, save new ...Need help with tzxingI recently got a copy of this Polish text game: [url]http://www.worldofspectrum.org/infoseekid.cgi?id=0006622[/url] I can't make a tzx of it howeve…
... LD DE,16384
EX DE,HL
EX (SP),HL
DI
...
PUSH HL
LD HL,L49650
EX (SP),HL
JR ... JR NC,L49579
EX (SP),HL
LD A,D
EX (SP),HL
DEC HL
LD A,H ...Need help with tzxingI recently got a copy of this Polish text game: [url]http://www.worldofspectrum.org/infoseekid.cgi?id=0006622[/url] I can't make a tzx of it howeve…
... ; C1EC 21 F2 C1
EX (SP), HL ; C1EF E3
JR L_C195 ...Fastest way to mirror a byte?I.E. turning 01100000 into 00000110, in assembly. I'm trying but I suck at stuff with rotation and the carry bit. Any pointers?
... interrupts.
EX (SP),HL Exchange the location (SP) and HL.
EX (SP),IX Exchange the ... location (SP) and IX.
EX (SP),IY ...
