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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 …
... -b has 2's complement overflow
PO => If a ... hasn't 2's complement overflow
You shouldn't ... -
TZX format updateHi folks. Following the private communication with Andy I would like to start a discussion on changing the TZX format to reflect new needs and improv…
... byte present
bit 1 parity byte present
bit 2 ... parity XOR/ADD
12+2N ... -
TZX format updateHi folks. Following the private communication with Andy I would like to start a discussion on changing the TZX format to reflect new needs and improv…
... higher-level concepts such as "parity byte" in the mix here ... -
TZX format updateHi folks. Following the private communication with Andy I would like to start a discussion on changing the TZX format to reflect new needs and improv…
... of the data (flag-data-parity), or the data would be ... that the flag and the parity are always present, which is ... how to show the right parity status etc. (For now some ... a red block because the parity byte is either not present ... -
TZX format updateHi folks. Following the private communication with Andy I would like to start a discussion on changing the TZX format to reflect new needs and improv…
... others.
About the parity flags, I'm still not ... -
TZX format updateHi folks. Following the private communication with Andy I would like to start a discussion on changing the TZX format to reflect new needs and improv…
... of the data - the flags, parity etc, as well as some ... -
TZX format updateHi folks. Following the private communication with Andy I would like to start a discussion on changing the TZX format to reflect new needs and improv…
... say that the flag or parity have this or that value ... -
How to program Machine Code on a PC, and then run it on a speccy?Well, I've been looking into MC a bit more deeply recently - I reckon I could get my head round MC now. Back when I was a teenager, I couldn't see th…
... party. It looks like the parity byte is wrong as it ... -
How to program Machine Code on a PC, and then run it on a speccy?Well, I've been looking into MC a bit more deeply recently - I reckon I could get my head round MC now. Back when I was a teenager, I couldn't see th…
[quote]It looks like the parity byte is wrong as it ... page is broken, because the parity byte is fixed, so it ... -
My first attempt at Gigascreen interlacingWonderful. Did some research on the port which controls memory paging and wrote a short BASIC programme to switch pages 5 and 7 in and out of the scr…
... alt.binaries.sinclair (with par2 parity recovery files using quickPar2) and ... -
Another Z80 processor questionOK, this time this isn't clearly covered in the FAQ, as far as I can see.... Suppose we have the CB instruction "SET b,r" (b=bit, r=register (differ…
... /> Z80 docs say that an overflow occurs when the two's ... following algorithm for determining the overflow status of "A ADC/SUB ... , not 8-bit arithmetic
- overflow has occured if only if ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... is the case - does the overflow flag (flagP/V) change to ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... is the case - does the overflow flag (flagP/V) change to ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... ]
With regards to the overflow flag - would it be set ... ? For instance, 255 + 5 = 5 + ?overflow + ?carry
i.e ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... both a carry and an overflow flag. Carry is somewhat meaningless ... two's complement arithmetic, likewise overflow is meaningless if you're ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... is struggling with carry and overflow.
I guess there ... -
I would like to write emulatorHi guys, I'm new to this forum but I realise that you must get loads of posts from people asking "how do I write an emulator" so I'll try and be spe…
... is struggling with carry and overflow.
I guess there ... -
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 …
... P/V flag - the V (oVerflow) aspect of it, to be ... -
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 …
... P/V flag - the V (oVerflow) aspect of it, to be ... magic circuit that computes the overflow flag xors the carry out ... -
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 …
... -126 minus -126, so no overflow.
Thinking about these ... -
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 …
My P flag pops up when the bladder is nearly full.
I rarely have Overflow problems because if it gets that bad that I can feel the gargle in the back of my throat I go and relieve the pressure.
Skarpo
:) -
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 …
... P/V flag - the V (oVerflow) aspect of it, to be ... -
ADCI'm a little confused about how the Z80 manages the ADC instruction. I'm assuming two ADD instructions are performed (am I wrong?!) I can think of 3 …
... how is the Overflow flag set?
If overflow is detected by ... -
ADCI'm a little confused about how the Z80 manages the ADC instruction. I'm assuming two ADD instructions are performed (am I wrong?!) I can think of 3 …
... 0xffffff00):(0)))!=s)
set overflow flag;
[/code]
set overflow;
[/code]
< ... addition there is no overflow, even if intermediate ... results would have caused an overflow.
... -
ADCI'm a little confused about how the Z80 manages the ADC instruction. I'm assuming two ADD instructions are performed (am I wrong?!) I can think of 3 …
... $ffffff80)!= $ffffff80))
set overflow;
end
[/code] -
ADCI'm a little confused about how the Z80 manages the ADC instruction. I'm assuming two ADD instructions are performed (am I wrong?!) I can think of 3 …
... bound to produce errors (my overflow flag emulation has been corrected ... -
TZX formatQuick question: What is the current pulse level at the start of a TZX file? Difficult question: Why does the format say that the final pulse shoul…
... the last bit of the parity byte. However the SA/LD ... -
Game being created with Platform Game DesignerBeen playing with this since yesterday when i bought it from Cronosoft. To someone like me who cant program its excellent to create a Manic Miner st…
... it's a question of overflow of some sorts ... I didn ...
