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Assembly - Loops bigger than 255Hi, It looks like it's a bit difficult to make loops with more than 255 cycles on Z80 machine code, since the 16-bit decrements (DEC) do not alter a…
... :
ld (hl), d
cpi
jp pe, loop
CPI, and the tweaking above. At ... -
Assembly - Loops bigger than 255Hi, It looks like it's a bit difficult to make loops with more than 255 cycles on Z80 machine code, since the 16-bit decrements (DEC) do not alter a…
... nice, both the use of CPI, and the tweaking above. At ... -
Assembly - Loops bigger than 255Hi, It looks like it's a bit difficult to make loops with more than 255 cycles on Z80 machine code, since the 16-bit decrements (DEC) do not alter a…
... . Whats the point of exploiting CPI when you do not know ... -
Assembly - Loops bigger than 255Hi, It looks like it's a bit difficult to make loops with more than 255 cycles on Z80 machine code, since the 16-bit decrements (DEC) do not alter a…
... . Whats the point of exploiting CPI when you do not know ... -
Issue 3 board with strange piggy-back boardIn case you are interested. I?ve never seen something like this before. I have an Issue 3 board here. When I opened the case and found a strange pig…
... /> JR Z, a289 ; 0282
CPI ; 0284
JP PE, a262 ... -
mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
This CPI as loop control is a nice thing. I'll add it to my tricks :)mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
This just sorta came up all of a sudden.
[code]InPlaceV2
ld hl,StringAddress
ld bc,StringLength
scf
.loop
rr (hl)
jr nc,.loop
cpi
jp pe,.loop
ret[/code]mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
mirroring bitsIf I have a string of 1408 bytes, each of which has one bit 'b' set, what's the shortest way of mirroring that string, so that each bit set at positi…
Is ESXDOS flexible enough to incorporate e.g. Spectranet commands?I was just discussing the idea with someone about the wish some people have to be able to combine interfaces such as DivIDE (Plus) / DivMMC EnJOY! wi…
... ; length, original position
cpi ; hl++, bc--
ld ...Pac-Land: can be coloured?All versions of this game are full coloured, but not the Spectrum version. It has large sprites, but maybe the scroll is too fine to make a coloured …
... IX
INC DE
CPI ;INC HL,DEC BC no ...
LD (HL),A
CPI ;INC HL,DEC BC no ...Pac-Land: can be coloured?All versions of this game are full coloured, but not the Spectrum version. It has large sprites, but maybe the scroll is too fine to make a coloured …
... idea of how to use CPI and JP PE,nn . A ...LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
... 't work the same as CPI where the flags indicate if ... and Z flags like the CPI instruction does.LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
[QUOTE]Why would it be doing that?
[/QUOTE]
Because LDI and CPI probably share most of the same internal circuitry.
The CPI just disables the part that uses the DE and the LDI dosen't write the subtraction of the A to the flags.LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
[QUOTE=Basher;757328]Because LDI and CPI probably share most of the same internal circuitry.
The CPI just disables the part that uses the DE and the LDI dosen't write the subtraction of the A to the flags.[/QUOTE]
That makes sense! :)LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
... the microcode for LDI and CPI etc. might share the same ...Address bus contents (i.e. PC) during execution of HALTI'm wondering if anyone can tell me what's placed on the address bus during execution of HALT, beyond the initial M1 cycle. The Z80 user manual state…
... behaviour of the LDI and CPI instructions. As in this thread ...LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
... 't work the same as CPI where the flags indicate if ... and Z flags like the CPI instruction does.[/QUOTE]
CPI/CPIR/CPD/CPDR is unchanged ...Address bus contents (i.e. PC) during execution of HALTI'm wondering if anyone can tell me what's placed on the address bus during execution of HALT, beyond the initial M1 cycle. The Z80 user manual state…
... behaviour of the LDI and CPI instructions. As in this thread ...LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
... LDI is HEX A0
CPI is HEX A1
CPI where the flags indicate if ... and Z flags like the CPI instruction does. [/QUOTE]
LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
... 's interesting that LDI and CPI both take 16 T-states ... as the CPI instruction isn't having to ... the final M cycle of CPI. My guess is that they ...LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
[QUOTE=Basher;761210]I will be interested to see if the contents of the DE registers appear on the address bus during the final M cycle of CPI.[/QUOTE]
Contention tests have shown only the HL value on the address bus at that time.LDI questionWhen using LDI (or LDD) is it possible to access the value that is transfered from (HL) to (DE), or does the Z80 use an internal data cache to store …
... 's interesting that LDI and CPI both take 16 T-states ... as the CPI instruction isn't having to ... the final M cycle of CPI. My guess is that they ...Latin-1 font for FZXI'm currently creating some [URL="http://en.wikipedia.org/wiki/Latin-1"]Latin-1[/URL] (ISO 8859-1) characters to be added into [URL="http://www.world…
... =http://www.seasip.info/DOS/CPI/]GSANS and TSANS[/url]) I ... using psftools to generate the .CPI files. Similarly when I did ...Latin-1 font for FZXI'm currently creating some [URL="http://en.wikipedia.org/wiki/Latin-1"]Latin-1[/URL] (ISO 8859-1) characters to be added into [URL="http://www.world…
... =http://www.seasip.info/DOS/CPI/]GSANS and TSANS[/url]) I ... using psftools to generate the .CPI files. Similarly when I did ... out that psftools can generate CPI files. I will convert the ...Latin-1 font for FZXI'm currently creating some [URL="http://en.wikipedia.org/wiki/Latin-1"]Latin-1[/URL] (ISO 8859-1) characters to be added into [URL="http://www.world…
... support a greater range of CPI files, but it seems to ... like to create a Spectrum CPI file to go with GSANS ...Latin-1 font for FZXI'm currently creating some [URL="http://en.wikipedia.org/wiki/Latin-1"]Latin-1[/URL] (ISO 8859-1) characters to be added into [URL="http://www.world…
... support a greater range of CPI files, but it seems to ... like to create a Spectrum CPI file to go with GSANS ...
