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Thought this would be simple... Z80Hi Folks, Started to read "Beyond simple BASIC, Delving Deeper into your ZX Spectrum" by Dilwyn Jones. This is a great book and I came across the…
...
push bc ; Store BC registers
... ,ATTR_ROW_CHAR
pop bc ; Restore BC registers
pop ... /> 170 LET A=USR 63000
180 ... -
Thought this would be simple... Z80Hi Folks, Started to read "Beyond simple BASIC, Delving Deeper into your ZX Spectrum" by Dilwyn Jones. This is a great book and I came across the…
... /> PAINT_ROW push hl
push bc
; Loop ... reached
pop bc
pop hl
add ...
260 LET Z=USR 63005
270 RETURN < ... -
Is there a way to suppress error R Tape Loading Error in Basic when trying to load only part of fileHi, is there a way to suppress error R Tape Loading Error in Basic when trying to load only part of file. E.g.: I have a Tape-Code-File Start f…
... Two other ideas:
* USR 2221 ($08AD LD_PROG_1) POPs length ... from BASIC?
* USR 1788 ($06FC SA_CODE_4 + 3) will ... for numbers: eg. LET bc=start=length+USR ... will stack start then ... : LET a$=(strexp+STR$ USR ...)(TO 0): puts a ... -
Thought this would be simple... Z80Hi Folks, Started to read "Beyond simple BASIC, Delving Deeper into your ZX Spectrum" by Dilwyn Jones. This is a great book and I came across the…
... ,16
130 LET A=USR 63002
140 STOP
ld bc,8 ; Number of bytes to ... ; INC DE/HL and DEC BC x 8
ldi
Is there a way to suppress error R Tape Loading Error in Basic when trying to load only part of fileHi, is there a way to suppress error R Tape Loading Error in Basic when trying to load only part of file. E.g.: I have a Tape-Code-File Start f…
... /> [code]LET bc=lp=(ll=CODE ("1000bytes"+STR$ USR 1540))[/code]
USR 1540 just does a RET ...Can't Get My Simple Code To RunHello again, I'm trying to run the following simple code: [code] org 32768 main ld b, 21 ; x coordinate is …
... />
has corrupted your BC and DE register pairs so the location ...A Neat Redefine Keys RoutinePreviously, I’ve only shared this routine with a couple of people via PM, but I’ve now decided to make it public. I optimized it for size, so it uses…
...
2$ push bc ;remember counter
ld a ... ; otherwise, use a 16-bit register
;pair, such as ... ;table row
pop bc ;restore counter
djnz 2 ... up (HL will be incremented BC times)
cpir ;while ...Thought this would be simple... Z80Hi Folks, Started to read "Beyond simple BASIC, Delving Deeper into your ZX Spectrum" by Dilwyn Jones. This is a great book and I came across the…
... might execute too quickly, and register the key that you keep ... you run it with RANDOMIZE USR XXXXX, then when you press ...1k Chess (was the 924 bytes thing!)Hi, I've decided to do a major rewrite of large parts of the code for the isometric Chess thing that I've been messing with. It got to the point, …
... counter to 00
push bc ;
... br /> pop bc
get_len:
push bc ;save height ... ;test the data register lo-byte to determine ...1k Chess (was the 924 bytes thing!)Hi, I've decided to do a major rewrite of large parts of the code for the isometric Chess thing that I've been messing with. It got to the point, …
... height
push bc ;
calc_square_addr:< ... current line
push bc ;save height + current ... /> Set the Board: RANDOMIZE USR 64518
Display it: ...Other than using attributes what other ways to detect collisions, when using char based movement?So I'm slowly working out the bits and pieces to write a game completely in assembly. I've been using attributes when writing in BASIC to detect whet…
...
ld c,0 ;BC now holds Y-position * 256 ... b
rr c ;BC now divided by 4
add hl,bc ;Add to attribute address
BC
add hl,bc ;Add to ... the stack into a register you're not using ...Other than using attributes what other ways to detect collisions, when using char based movement?So I'm slowly working out the bits and pieces to write a game completely in assembly. I've been using attributes when writing in BASIC to detect whet…
... same time with an LD BC,(nnnn) instruction. Just remember the ... then Y, when you LD BC,(nnnn) then X ends up ... in A. I could PUSH BC at the start and POP ... BC at the end so that ... or RL'ed into another register.Cubic RevealI just though I'd develop this a little further. Written a while ago on a whim! [img]https://dl.dropbox.com/s/p44y5dda49ucmop/square_reveal_1_1.gi…
... /> ret ;retrieve the result (BC) from BASIC (PRINT USR 40001)
[/code ... 40000,a
20 PRINT USR 40001: GO TO 10
Cubic RevealI just though I'd develop this a little further. Written a while ago on a whim! [img]https://dl.dropbox.com/s/p44y5dda49ucmop/square_reveal_1_1.gi…
... entry point
;0beeah - RAND USR 48874
;
;JES Unknown ... = stored ATTRs address
push bc
call copy
pop ... ;
copy:
ld bc,0ffffh ;ATTRs mask
copy2 ...How can I make a UDG rotate?I designed a set of UDG's that can be used for making shapes or letters. Trouble is that my circle - for example - consists of 4 pieces and it would…
... somewhere and doing a RAND USR to it from BASIC would ... the result of LET x=USR "A" into bytes 04 and ... the rotated UDG
ld bc,0808h ;counters
lp0:
USR"A" etc
lp1:
Why no PLOT, etc. on bottom two lines?I was pondering if there was any way to get PLOT, etc. to address the full screen from BASIC without having to write a few lines of assembler to bypa…
... .):
LET a=x=y+USR Plot191 ... or ... Draw191
23 FLASH x=y+USR p191: REM = PLOT191 (x ... (z-x)=(191-2*Y)+USR d191: REM = DRAW191 ( ... /> pop de
ld bc,(23653) ;BC=(STKEND)
ret
...The I register pointing to $40–$7f causes ULA snow and a crash. Or does it?I have heard it from numerous sources, including a few members of this forum, that 128K/+2 machines crash if the I register points to a range of $40–…
... /> sw or 7
ld bc,$7ffd
ld ($5b5c),a ... /> ld de,$f801
ld bc,256
ld (hl),$fe ... snippet that changes the I register within my ISR (with the ...Loading Images/Screens mid-gameHi all, Looking to get back into a bit of coding and I couldn't figure out a way to do the following: I have an image/SCREEN that I'd like to b…
... /> LD DE,DESTINATION
LD BC,LENGTH
LDIR
RET ... going to
[b]LD BC , 6912[/b] ; how many bytes ... forget!) then do a RANDOMIZE USR 29000 to 'display' the screen ...Making sound using the BEEPER in AssemblyI had a look at the the documentation but it doesn't make sense to me. To make music just the beeper all I have to do is send ones and zeros to one o…
... /> ld a,$17
ld bc,$fffe
loop xor ... the value of the B register, and measured the frequency of ...Passing parameter from BASIC to assembler routineWas there a "clean" way of passing parameter(s) from a BASIC program to an assembler routine? Something like parameterising RANDOMIZE USR call? I fac…
... Z80 routine like this: PRINT USR address,param1,param2 ... etc. This ... parameters one by one in BC.
[code]
;returns ... the next parameter in BC
;at exit, NZ is ... #2DA2 ;calc stack top -> BC
xor a ;set Z ...Passing parameter from BASIC to assembler routineWas there a "clean" way of passing parameter(s) from a BASIC program to an assembler routine? Something like parameterising RANDOMIZE USR call? I fac…
... Z80 routine like this: PRINT USR address,param1,param2 ... etc. This ... parameters one by one in BC.
[code]
;returns ... the next parameter in BC
;at exit, NZ is ... #2DA2 ;calc stack top -> BC
xor a ;set Z ...Passing parameter from BASIC to assembler routineWas there a "clean" way of passing parameter(s) from a BASIC program to an assembler routine? Something like parameterising RANDOMIZE USR call? I fac…
... LET a=10
PRINT USR 32768,a
USR address,param1,param2 ... etc ... parameters one by one in BC.
[code]
BC
;at exit, NZ ... ;calc stack top -> BC
xor a ;set ...
