-
rotating HL left through CarryI've tried this several ways, and it works for a while, then a particular value has a bit set in an inconvenient place and it all goes to pot. Eg: "…
... 256 bytes table for reverse nibbles
[CODE]
ld b, h ;4
ld h, table ... ;7
ld a, (hl) ;7
ld l ... -
assembly optimization: times tenDecimal numbers are not computer friendly :) Anyway, short of saying "sod it - I'll multiply by 8" - and another part of the program does indeed div…
... could consider a look up table (29 t-states) - but ...
[code]
LD H, lookup / 256 ; 7
LD A,(HL) ; 7
INC L ; 4
LD H ... ,(HL) ; 7
LD L,A ; 4< ... (put this on a 256 border)
[/code] -
assembly optimization: times tenDecimal numbers are not computer friendly :) Anyway, short of saying "sod it - I'll multiply by 8" - and another part of the program does indeed div…
... could consider a look up table (29 t-states) - but wasting ... ]
LD H, lookupMSB / 256 ; 7
LD D, lookupLSB / 256 ; 7
LD L,A ... answers (if previous table is in
a 256 border, this will ... -
assembly optimization: times tenDecimal numbers are not computer friendly :) Anyway, short of saying "sod it - I'll multiply by 8" - and another part of the program does indeed div…
... ;643645][code]LD H, lookupMSB / 256 ; 7
LD D, lookupLSB / 256 ; 7
LD L ... 256 border)
lookupLSB: precalculate LSB of all answers (if previous table ... is in
a 256 border, this will ... -
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…
... ldir ; copy initial channel table
ex de, hl ... ldir ; copy initial streams table
ld (iy + _df_sz), 2 ...
ld de, rpt_mesgs - 1 ; address table
... 2
ld h, kstate/256 ; stream address
ld l, a ; ... -
Mirroring UDG'sJust wondered is there a quick an easy way of mirroring UDGs (byte values)? i.e. BIN 11110000 becoming 00001111 etc.
... (not counting the "ld hl, table" because you don ...
[CODE]
ld h, table
... ;a=ABCDEFGH carry ... ;a=0ABCDEFG carry=H
ld l, a ;l ... bytes table instead 256 bytes one -
Mirroring UDG'sJust wondered is there a quick an easy way of mirroring UDGs (byte values)? i.e. BIN 11110000 becoming 00001111 etc.
... cycles (not counting the "ld hl, table" because you don't need ... iteration)
[CODE]
ld h, table
... ;a=ABCDEFGH carry=0 ... is use a 128 bytes table instead 256 bytes one[/QUOTE]
Help with 1-bit sampled soundHi all, I've been sent over this way from the CPC Wiki forums as you guys may be able to help me more specifically with a programming query. Firstly…
... />
get_sample:
...
ld h,codeblock/256
ld l,volume*3 ; volume ... )
...
codeblock: ; jump table
jp volume_0
jp ... and travelling through the jp table to the next volume subroutine ...Multiplying. Again.Is there a faster way of hl=a*32 than doing add hl,hl 6 times?<div><br></div><div>I get the feeling that working with 8 bit registers for most of it …
... look-up table
ld l,a
ld h,MultTable/256
ld a ... ,(hl)
inc h
ld h,(hl)
ld l ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... from the table
ld c, (hl)
inc hl
ld h, (hl ...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... from the table
ld a, (hl)
inc hl
ld h, (hl ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... table NEEDS to be aligned as well because I use
LD H ... , tbl_scraddr/256
and then ... offset for L (adjusting H if L overflows), ... ]ORG $ + (($&255)+255)%256[/s]
might ... br />
#FF00 is -256 as a 16 bit word ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... from the table
ld a, (hl)
inc hl
ld h, (hl ...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... from the table
ld a, (hl)
inc hl
ld h, (hl ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... if > 255
ld h, tbl_scraddr/256 ; this requires tbl_scraddr be aligned ... a 256 byte boundary
adc h ; A = H + carry flag
ld h, a ... up screen address from the table
ld a, (hl)
inc ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... if > 255
ld h, tbl_scraddr/256 ; this requires tbl_scraddr be aligned ... a 256 byte boundary
adc h ; A = H + carry flag
ld h, a ... up screen address from the table
ld a, (hl)
inc ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... can load the table address as LD H, tbl_addr/256. If the table is alsoHow to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... *y-coord
ld h, tbl_scraddr/256 ; this requires tbl_scraddr ... 256 byte boundary
adc h ; A = H + carry flag
ld h ... , a ; write it back
; push table ... screen address from the table
ld a, (hl)< ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... if > 255
ld h, tbl_scraddr/256 ; this requires tbl_scraddr be aligned ... a 256 byte boundary
adc h ; A = H + carry flag
ld h, a ... ; write it back
ld l, b
; push table address ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... now uses a shorter lookup table (one screen address per ... up screen address from the table
ld a, (hl)
... the second row
ld h, tbl_rows/256 ; this requires tbl_scraddr be ... br /> inc l ; using shorter table (just the row screen addresses ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... from the table
ld a, (hl)
inc hl
ld h, (hl ... h ; A = H + carry flag
ld h, a ; write it back
; push table ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... from the table
ld a, (hl)
inc hl
ld h, (hl ... h ; A = H + carry flag
ld h, a ; write it back
; push table ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... from the table
ld a, (hl)
inc hl
ld h, (hl ... h ; A = H + carry flag
ld h, a ; write it back
; push table ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... causes that DJNZ will repeat 256 times
.loop1
setattrib2x2
ld h, 0
ld l, b
; ... attrib
setattrib2x1
ld h, 0
ld l, b
; ... ALIGN 64
; modify this table to be based at #4000 ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... a 256 byte boundary
adc h ; A = H + carry flag
ld h, a ... up screen address from the table
ld a, (hl)
inc ... used a 24x2 byte lookup table to get the starting address ... routine yet. The 192 entry table for the screen address lookup ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
... a 256 byte boundary
adc h ; A = H + carry flag
ld h, a ... up screen address from the table
ld a, (hl)
inc ... used a 24x2 byte lookup table to get the starting address ... routine yet. The 192 entry table for the screen address lookup ...Robospec (new project, hopefully useful as a tutorial as well)Starting a new project after my graphics investigations. * It's gonna be a Robotron clone since that's not too ambitious (although I'd like to hav…
... coord
ld h, tbl_scraddr/256 ; this requires ... 256 byte boundary
adc h ; A = H + carry flag
ld h ... , a ; write it back
; push table ... 256 byte boundary
adc h ; A = H + carry flag
ld h ...How to disable the "scroll?" message?Hello. I'm a beginner Z80 assembly programmer and I decided to make a ZX Spectrum game to practice my skills and gain some more experience. I curr…
...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... from the table
ld a, (hl)
inc hl
ld h, (hl ... h ; A = H + carry flag
ld h, a ; write it back
; push table ...Robospec (new project, hopefully useful as a tutorial as well)Starting a new project after my graphics investigations. * It's gonna be a Robotron clone since that's not too ambitious (although I'd like to hav…
... coord
ld h, tbl_scraddr/256 ; this requires ... 256 byte boundary
adc h ; A = H + carry flag
ld h ... , a ; write it back
; push table ... 256 byte boundary
adc h ; A = H + carry flag
ld h ...Robospec (new project, hopefully useful as a tutorial as well)Starting a new project after my graphics investigations. * It's gonna be a Robotron clone since that's not too ambitious (although I'd like to hav…
... a 256 byte boundary
adc h ; A = H + carry flag
ld h, a ... up screen address from the table
ld a, (hl)
... up screen address from the table
ld a, (hl)
... up screen address from the table
ld a, (hl)
...Robospec (new project, hopefully useful as a tutorial as well)Starting a new project after my graphics investigations. * It's gonna be a Robotron clone since that's not too ambitious (although I'd like to hav…
...
ld h, tbl_scraddr/256
adc h ; A = H + carry flag
ld h, a ; write ... h ; A = H + carry flag
ld h, a ; write it back
; push table ... h ; A = H + carry flag
ld h, a ; write it back
; push table ...
