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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…
... ]inc (hl)[/B] sets the zero flag and if [B]ld (hl ... -
Games in machine codeHi everyone, How do go about doing multiple shots like a machine gun, do you have to store every x and y position of each bullet? When you kill som…
... idea to have a 'kill' flag and process all the removes ... that have a count of zero. You need one array entry ... (non signed)
MOVZX = Move zero extended (Clears upper bits of ... not equal (uses zero flag)
JE = Jump equal (uses zero flag)
RESD ... -
Games in machine codeHi everyone, How do go about doing multiple shots like a machine gun, do you have to store every x and y position of each bullet? When you kill som…
designing a computerHi everyone! I am designing a 4 bit computer and i need some advice, is this a good instruction set? [CODE] BINARY OPCODE DESCRIPTION 00000 nop…
...
1001 JPZ - Jump if zero flag on
1010 JPN - Jump ... if not zero flag on
1011 RSV - Set ... flags, Z and NZ, zero and not zero
I think i ...designing a computerHi everyone! I am designing a 4 bit computer and i need some advice, is this a good instruction set? [CODE] BINARY OPCODE DESCRIPTION 00000 nop…
... start, you only need one zero flag - It is either set or ... the target CPU. The carry flag is easy as the sum ... be copied to the carry flag. Greater than or equal to ... of the carry flag (CF) and zero flag (ZF). The sign flag (SF) can ...Learning Assembly LanguageHow easy would it be to learn assembly language for someone who has a decent grasp of Basic? I mean how long do you think it would take before I coul…
... /> ld bc,0 ; Set to zero
ld hl,16384 ; Screen ... tip is to learn the zero flag (ZF) as soon as you ... '1' when a result is zero, otherwise it is set to ... '1' when a result is zero. There are enough comments in ...Move objectHi again, I am using paper colors to represent game objects. I have a "paddle" that is 4 pixels wide. I save its position as a 2 byte word in memory…
... 0.. XOR A will set zero flag for every value of A...Saving and Loading from tape in MC?I'm actually having problems with saving and loading from the ROM routines for the interpreter... I'm currently using the following codes for saving…
... /> L0556: INC D ; reset the zero flag without disturbing carry.
EX ... ]
INC D ; reset the zero flag without disturbing carry.
EX ...MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
... faster and sets the zero flag when it reaches zero again (avoiding the ...MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
... a register, and simplifying the zero check
[*]With A no ... needed to check DE for zero, we can keep the fill ... 256 (currently E). For the zero flag to be set at the ...MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
... 8-bit INC sets the zero flag when you INC from 255 ...MCODE problem...Hi Folks, Trying to write a simple machine code program to hatch the screen. So far I have the following but even this is not working - it does not…
... faster and sets the zero flag when it reaches zero again (avoiding the ...New WIP underway - 'Dingo'.Hi, Prepare for a long post. Perhaps I can even challenge ewgf here. :razz: Anyway, I've been meaning to get into Z80 programming and making a game…
New WIP underway - 'Dingo'.Hi, Prepare for a long post. Perhaps I can even challenge ewgf here. :razz: Anyway, I've been meaning to get into Z80 programming and making a game…
... bit is 0 so the zero flag is raised (I think?).
flag NZ is correct.
Up/Down Left/Right scrollCan anybody give a newbie some pointer to simple one char scrolling by pixel? I've looked at a lot of resources, but as you can imagine, it's all a …
... put down. It starts at zero, has 1 added to it ...
;ahhh....a check for zero...what does that mean? It ... it it now holds zero - so the zero flag is set) and need ...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…
... br /> INC B ;reset Zero flag
SETRET: LD BC ... AND A ;error if not zero
JP NZ, $1F36 ... br /> inc a ;reset Zero flag
push de ;restore ...Loading the display with data from memoryTrying to load part of the screen(4k's worth) with data from memory location 53000, I've written this routine, but it doesnt work... [I]ld b,4000 ld…
... is supposed to set the zero flag to exit the loop? The ... don't affect the Z flag.
Are you simply ...2nd OpCode question.... pretty please...Whats 0xED 0x70 please? Sean's doc says: IN F,(C)* / IN (C)* That doesn't mean much to me :( Lower down in Sean's doc it says: ED 70 is IN F,(n) so…
... A,(n) but with the flag register?
Is (C ... is set accordingly (so the Zero flag is set if the value ... read is zero, and Sign, 3, and 5 ...2nd OpCode question.... pretty please...Whats 0xED 0x70 please? Sean's doc says: IN F,(C)* / IN (C)* That doesn't mean much to me :( Lower down in Sean's doc it says: ED 70 is IN F,(n) so…
... is set accordingly (so the Zero flag is set if the value ... read is zero, and Sign, 3, and 5 ...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 …
... ; back to RAM-READ if zero flag was set.
;; RAM ...What's going on during a reset?Always wanted to know this. Why does the screen fill with garbage then white lines on black then just a totally black screen? What is happening?
Using CP and JR Z commandI have been trying to [URL="http://www.worldofspectrum.org/forums/showthread.php?t=40011"]convert a BASIC routine to machine code[/URL], but to no av…
... 5 = 5-5 means 0, Zero flag will be set; but A ... CP 5 = 6-5, not zero, Z will be not set ...Oops, wrong flag!North Korean women's football team have reacted angrily to the South Korean flag being shown by accident on stadium screens during the warm-up. Not …
I often get the test for the zero flag and carry flag mixed up. :DTutorial - learn machine code in 30mins[B][I]Message from the moderators[/I] - bigjon has requested that readers' attention be drawn to a better version of this tutorial, one which is easi…
... for jump relative if not zero. It skips over the ... carry, and set the carry flag to zero.
'or' compares ... all the digits are zero, then the zero flag will be set, ... and Repeat (until bc is zero).
Replace line 53 ... bit and sets the zero flag if it is 0)< ...Using R as a loop counterThis is just something silly I've found a while back. xD [b][How-to][/b] Setup your routine like this:[code] ld a,X ;see below ld r,a loop ;your …
How does ld a,r set the zero flag?
I thought load was flag free?Using R as a loop counterThis is just something silly I've found a while back. xD [b][How-to][/b] Setup your routine like this:[code] ld a,X ;see below ld r,a loop ;your …
... ld a,r set the zero flag?
I thought load ... was flag free?[/QUOTE]
Idk ... does. Same with the sign flag. P/V is different, it ...Getting PC into HLHello, here's a conundrum for you... Is there a way to obtain the value of the PC register (say into HL) without using absolute addressing such as C…
... avoid faffing about with the Zero flag, somewhere that $e1,$e9 occurs ...Machine code loopsDear all, 30 years too late I know, but I'm finally starting to get to grips with Machine Code - something I could never manage back in my early tee…
... also equal 0, affecting the zero flag accordingly?
Can't ...
