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Question about CP Z80 instructionSorry if this is the wrong folder, but it seems the most appropriate. When performing a CP instruction, is the P flag set when the compared values …
We're not talking PO/PE here, it's JP P ie. whether the sign flag is set or not.
Regards,
Jon. -
Question about CP Z80 instructionSorry if this is the wrong folder, but it seems the most appropriate. When performing a CP instruction, is the P flag set when the compared values …
Need help with my P flag!Not sure if I've emulated the P flag correctly when its comes to overflows. Here's what I've done: LD A,123 LD B,16 ADD A,B Twos Complement of 123 …
... are talking about P/V flag (tests PE/PO) but he ... was talking about S flag (tests P/M).
[/quote ... it, to be precise. The sign flag is easy - it just picks ...Need help with my P flag!Not sure if I've emulated the P flag correctly when its comes to overflows. Here's what I've done: LD A,123 LD B,16 ADD A,B Twos Complement of 123 …
... it, to be precise. The sign flag is easy - it just picks ... br />
For P/V flag, you can use the "if ... error so set P/V flag" as you've done. ... circuit that computes the overflow flag xors the carry out (borrow ... out on some P/V flag oddities. eg, block copy ...Need help with my P flag!Not sure if I've emulated the P flag correctly when its comes to overflows. Here's what I've done: LD A,123 LD B,16 ADD A,B Twos Complement of 123 …
Yeah, overflow is set when Carry out of the sign flag XOR Carry into the sign flag = 1.Need help with my P flag!Not sure if I've emulated the P flag correctly when its comes to overflows. Here's what I've done: LD A,123 LD B,16 ADD A,B Twos Complement of 123 …
... that somehow CHQ used a flag that none others did.< ... was right and that flag was the P flag.
... I had put:
Flag.P:=(TwoComp[DestinationByte]+SourceByte> ... whacked in is:
Flag.P:=(TwoComp[DestinationByte]+TwoComp[SourceByte ...Need help with my P flag!Not sure if I've emulated the P flag correctly when its comes to overflows. Here's what I've done: LD A,123 LD B,16 ADD A,B Twos Complement of 123 …
... are talking about P/V flag (tests PE/PO) but he ... was talking about S flag (tests P/M).
[/quote ... it, to be precise. The sign flag is easy - it just picks ...Collision detectionI understand the basic methods for testing for collisions but I have question about the trickier situation of testing for when shots hit the backgrou…
... to bit 7 - setting z80 sign flag
ret m ; return if ...Problem Wrapping SpritesHi, I am having an issue wrapping my sprites around the screen, Basically, I have a back buffer which is 24 chars (192 Pixels) by 28 chars (224 P…
... ;check, is it negative? (Set SIGN flag if >=128)
JP ...My emulator has a CPU bug, any ideas?.Hi all, I am writing a Speccy emulator in PureBASIC but have an odd bug. The spectrum interprets the odd numbers incorrectly whenever they are typed…
... got something setting the carry flag from the bottom bit by ... when you deal with the sign flag (and the undocumented bit-5 ...problem with DEFADD storageI have a function: DEF FN t(t$,m,t)=USR t which is called with, for an example: LET bc=FN t("t$()",mcworkspace,mcputt) where, at the time: mcworkspac…
... of byte 2 is the sign flag (which is reset here, indicating ...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…
... , 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 ...Machine Code Routine of the weekHow about a thread that has a routine each week that is in [B]assembly language[/B] and is also described in great detail what the hell is going on …
... A,R automatically sets the Sign flag according to the contents of ...Machine Code Routine of the weekHow about a thread that has a routine each week that is in [B]assembly language[/B] and is also described in great detail what the hell is going on …
... A,R automatically sets the Sign flag according to the contents of ...Help :) (FLAGS)ok a question about the 8080 so if anybody can help me. do the flags only change for the accumulator or are they affected for the other registers a…
... number is 1 but the sign flag is set to 1. ok ... so it becomes 1 the sign flag is set to 0...ok ...Help :) (FLAGS)ok a question about the 8080 so if anybody can help me. do the flags only change for the accumulator or are they affected for the other registers a…
... is 1 but the sign flag is set to 1. ... as -1, without considering the sign flag at all.
... Either way, the sign flag doesn't serve as an ... of the register. The sign flag is only set as ... The previous value of the sign flag doesn't have an effect ...Why doesn't my loop work?Can anyone help me understand why my loop doesn't work? Is it to do with how DEC HL affects the flags? [code] ; Read 32k bytes from port 191 as fa…
... : IN reg,(C) sets the sign flag (the "IN A,(port#)" doesn ... 7 read from (port) sets sign flag
JP P,trig ; wait ...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…
... then using some flags perhaps? sign flag might work but if hl ...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…
... then using some flags perhaps? sign flag might work but if hl ...28-character wide multicolour(ish) on 48k SpectrumLong-time lurker here... I've always been interested in rainbow effects on the 48k Spectrum, mainly from a perspective of "Just what [I]would [/I]ha…
... for a command involving the sign flag here, but there seems to ... found by the P/M flag what's the point of ... the S flag in the first place?28-character wide multicolour(ish) on 48k SpectrumLong-time lurker here... I've always been interested in rainbow effects on the 48k Spectrum, mainly from a perspective of "Just what [I]would [/I]ha…
... for a command involving the sign flag here, but there seems to ... the point of the S flag in the first place?[/ ... on the [B]S[/B] flag:
[LIST]
[*] [B ... "jump if minus sign", i.e. "jump if flag S is set ... "jump if plus sign", i.e. "jump if flag S is reset ...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 …
... a,r set the zero flag?
I thought load ... was flag free?[/QUOTE]
Idk ... just does. Same with the sign flag. P/V is different, it ...Checking for '+2e/+3e' ROMs via Sinclair BASICHi guys, I have a Spectrum +2A containing the '+e' ROMs (and a nice internal IDE interface with a CF card adaptor on it :) ) - If you are unsure wha…
... "DOS_VERSION" function and test the sign flag on return. If it's ...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…
... /> and %10000000 ; set sign
exx ; alternate register ... xor a ; clear carry flag
jp test_norm ; ... /> ccf ; complement carry flag
rra ; rotate ... p, oflw1_clr ; jump if sign flag cleared
jr nc, ...(Collected) Darkhog's noob question about z80 assemblySince when I'm learning new language or library, I tend to ask lots of stupid (for any advanced person) questions and I don't want it to have mess up…
... the [b]Z[/b]ero flag is set
jp c ... the [b]C[/b]arry flag is set
jp ... jp po and test the sign flag and parity flags.Mastering flagsI'm little lost when different flags are set/reset after logic operations, and what conditions must be met. For example, [code] ld a, MODE…
P/M is the sign flag, not parity. It is checking ... of #80 (like the carry flag in ADD/SUB when the ...Mastering flagsI'm little lost when different flags are set/reset after logic operations, and what conditions must be met. For example, [code] ld a, MODE…
... />
JP M/JP P: sign flag
JP PE/JP PO ... : parity flag
So if you ...Full-screen 32 columns bicolor engine NIRVANA+I'm glad to announce the release of [b]NIRVANA+ ENGINE[/b], providing support for bicolor graphics (multicolor 8x2) in 32 columns for all standard Sp…
... )
;
; Returns:
; F = Sign flag set if either 8x2 attribute ... />
; If no detections, S flag is automatically cleared
FLASH ...
