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Integer RangesOK, I need a little help clarifying something. I am making good progress with the emulator so far - I've emulated most ADD, INC, DEC commands (as we…
... and I set the PV flag accordingly. The converse is true ... will interpreted this as a negative value.
A code between ... determine it's positive or negative value.
The overflow ... -
Interrupts - been a while !Not sure if this is the right place for this (1st post on WOS, but been a speccy user since Dec'84 :-o (yes I am that old ! :p) ), But I can't for …
... />
[CODE] ld a,0x80 ; flag the interrupt
ld r ... the refresh register as a flag. It never changes once set ... ,R ; auto triggers the negative/positive flag and you can "jump" instantly ... -
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…
Yeah, the carry flag seems to be the key. ... /> AND 128 ; check, is it negative?
JR NZ,MOVEX_NEG ; if ... so move to negative handler
LD A,(IX ...
SUB 80 ; we are negative so subract 80 to get ... -
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…
... AND 128 ;check, is it negative?
JR NZ,MOVEX_NEG ;if ... ADD A ;check, is it negative? (Shift BIT 7 to the ... ,MOVEX_NEG ;if so move to negative handler
[/code]
... ;check, is it negative? (Set SIGN flag if >=128)
Cis this a valid instruction? [code] A + B; [/code] If I assign 3 to A and 2 to B; and then "A + B;", then A should equal 5, and B equal 2. Correct?
... /> If the signs are both negative and the result is GREATER ... -bit registers but the carry flag gives you an easy way ...speccy + membranes group buyI am going to buy maybe 5-10 membranes for spectrum +'s... the prices have gone down for the more I buy.. wasn't sure if anyone else wanted them? a…
... want more feedback of the negative sort..
I have ... how many doubles of chequered flag I have.aggh!! haha
Machine code issue...Hi Folks, My trials with MCODE continue and I am stuck. I wrote the following program in BASIC to simply POKE an attribute byte in to a "box" on th…
... need to clear the carry flag. In your example you probably ... *) easier/faster to ADD the negative equivalent. For eample:
flag in any results!
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…
... and the world using the flag fields.
Displays all objects ... position. If the result is negative and greater than the display ...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 ... you... Also, adding a negative version of a number is ... target CPU. The carry flag is easy as the sum ... be copied to the carry flag. Greater than or equal ... the carry flag (CF) and zero flag (ZF). The sign flag (SF) ...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…
... the 'usual' way) correspond to negative numbers: 255 = -1, 254 = ... -1, without considering the sign flag at all.
... Either way, the sign flag doesn't serve as an ... the register. The sign flag is only set as ... value of the sign flag doesn't have an ...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…
... using some flags perhaps? sign flag might work but if hl ... it might interpret it as negative? is there a common way ...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…
... using some flags perhaps? sign flag might work but if hl ... it might interpret it as negative? is there a common way ...i am currently listening to........as i couldnt seem to find the old one, i didnt look that hard :P ive started a new one right after somebody asked me for some slayer ive rediscovere…
... die.
Blag Flag: Six Pack.
Negative Trend: How ya feelin ...Calculating percentage..or even calculating percentage. Maths and asm I find verryyy tricky. Can anyone suggest the easiest/best way to calculate a percentage from two 1…
... until we get a Carry Flag set in the
;High ... indicating that it has gone negative. Keep track of the loops ...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 …
... -9A-F
;
; z flag set indicates '0' digit
ld (de),a ; write negative sign
inc de
flag state (for m/c callers ... (zero or minus) and associated flag. However a lot of the ...Full 16*16-digit BASIC multiplicationI liked Andre Adrian's 32-bit long multiplication routine so much that I decided to a decimal version. After all, 2^63 is only 9223372036854775808, a…
... gets confusing.
For negative numbers it's only necessary ... /> I1: equ WORKSP+40 ;Carry flag#1 (1 byte, 0-9 ... /> I2: equ WORKSP+41 ;Carry flag#2 (1 byte, 0-9 ...Experimenting with turboloadersHello, My first post, having lurked here for a while. I'm a lifelong computer nerd, Spectrum fan since childhood in the eighties, and have recently…
... .
[*]Timings tweaked.
[*]Initial "flag" reinstated for use as a ... the loop starting value. If negative,
;; carry will be set ... b
;; (enough of this flag-juggling, let's learn from ...Can a guy that traveled on the short bus learn machine code...Hmmm So after some soul searching I figured it was time to finaly nail spectrum machine code. Its so frustrating to sit infront of a basic listing w…
... meant to say that negative numbers don't exist ... binary, isn't a negative number just the way that ... =99 (and a carry-flag).
The carryflag should ... can also have a min. negative score of -85
Relative JUMPs use also negative numbers but there bit 7 ...Can a guy that traveled on the short bus learn machine code...Hmmm So after some soul searching I figured it was time to finaly nail spectrum machine code. Its so frustrating to sit infront of a basic listing w…
... A=99 (and a carry-flag).
The carryflag should be ... can also have a min. negative score of -85
In ... then the ABS of the negative or the true value).
Relative JUMPs use also negative numbers but there bit 7 ...Can a guy that traveled on the short bus learn machine code...Hmmm So after some soul searching I figured it was time to finaly nail spectrum machine code. Its so frustrating to sit infront of a basic listing w…
... ! I meant to say that negative numbers don't exist in ... , in binary, isn't a negative number just the way that ... , though binary certainly does have negative numbers (sometimes). It is entirely ...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…
... xor c ; ones complement if negative
sub c ; add ... , c ; twos complement for negative
xor c ; carry ...
sub c ; if negative
ld (hl), a ... br /> scf ; set carry flag for negative
org ...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…
... br /> ccf ; complement carry flag
ld e, a ... xor a ; clear carry flag
jp test_norm ; immediate ... zero for positive, 255 for negative
ld c, a ... br /> ccf ; complement carry flag
rra ; rotate ...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 a ; clear carry flag
jr count_one ; immediate ... no_rstore:
scf ; set carry flag
org 0x31fa< ... bit 7, d ; test for negative
jr nz, t_numeric ; ... ; sign bit to carry flag
rr h ; ...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…
...
jr c, sl_over ; treat negative slice as null string
res 6, (iy + _flags) ; set flag for string result
scf ; set carry flag
jr z, i_carry ; jump ...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…
... ?
ccf ; complement carry flag
ret c ; return ... br /> ccf ; complement carry flag
ret nc ; return ... br /> ccf ; complement carry flag
adc hl, hl ... br /> inc b ; signal negative
org ...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…
... hl) ; bit 7 to carry flag
dec hl ; point ... reset if positive, set if negative
dec hl ; ...
scf ; set carry flag
jr fp_0_or_1 ; immediate ... /> and a ; reset carry flag
jr fp_0_or_1 ; immediate ...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…
... :
rrca ; update carry flag
push af ; stack ... pop af ; restore carry flag
jr str_test ; ... jr nz, report_bd ; or negative
call bc_1_space ; make ... /> push af ; stack flag
call stk_fetch ; ...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…
...
scf ; set carry flag
rra ; shift right ... /> and a ; clear carry flag
rra ; shift right ... :
call coords_to_bc ; accept negative values as offset
call ... c, (iy + _p_flag) ; p-flag to C
bit 0 ...Z80: ABS(HL) functionI must be very tired but I cannot get my head around whether this function provides a correct implementation of a ABS function for a signed 16-bit va…
... does not alter the carry flag', do you mean between ... with not touching the Carry flag. Of course, you could ... />
I use the carry flag to indicate overflow when doing ... no minus sign
; negative sign found
call ...
