Search found 350 matches
- Wed May 01, 2024 12:39 am
- Forum: Hardware and Tech
- Topic: How does VIC-20 detect ROM cartridge address?
- Replies: 5
- Views: 701
Re: How does VIC-20 detect ROM cartridge address?
; .ORG $A000 .WORD <cold start vector> .WORD $FEC7 ; default NMI vector .BYTE 'A','0',$C3,$C2,$CD ; "A0CBM" signature The kernel checks for the given byte sequence at $A004 and, when found, takes the contents of $A000 <low byte> and $A001 <high byte> as the address where processing contin...
- Mon Apr 29, 2024 4:57 am
- Forum: Programming
- Topic: 3D Stars
- Replies: 14
- Views: 1712
Re: 3D Stars
Did some more rearrangement here. Curious to know if it still works, and if there is some speed improvement. 1 poke36879,8:poke646,1:@on:@clr:dimx(32),y(32):xc=79:yc=95:n=22:v=1/8:d=3 2 xm=159:ym=191:rx=120:ry=150:zw=20:fz=15:fori=1ton:gosub7:x(i)=xa:y(i)=ya:next 3 fori=1ton:xa=x(i):ya=y(i):@0,xa,ya...
- Fri Apr 26, 2024 3:11 am
- Forum: Programming
- Topic: 3D Stars
- Replies: 14
- Views: 1712
Re: 3D Stars
compacted and renumbered removed spaces removed Z=0 and replaced by . inline replaced D=3 by D=3/8 and removed ABS(V) replace X(I) by XA and Y(I) by YA in appropriate places (prevents array element lookups) remove X2 and Y2 calculations can't test it, unfortunately. after testing this, you could rep...
- Tue Apr 23, 2024 1:09 am
- Forum: Other Systems
- Topic: End of the Z80
- Replies: 3
- Views: 1754
Re: End of the Z80
Hi,
I have a TI-83 Plus, never figured it also has a Z80 aboard. There are instructions and tools (through WikiPedia) on programming assembly on this machine. Have to look into that sometime.
Regards
I have a TI-83 Plus, never figured it also has a Z80 aboard. There are instructions and tools (through WikiPedia) on programming assembly on this machine. Have to look into that sometime.
Regards
- Wed Apr 17, 2024 1:41 am
- Forum: Emulation and Cross Development
- Topic: ASM502 - a new 6502 assembler.. (WIP)
- Replies: 22
- Views: 4651
Re: ASM502 - a new 6502 assembler.. (WIP)
Hello orac81, If I can make a suggestion for a "new" assembler: why not one that optimizes automatically ? During assembly, keep a hold of the state of the machine and comment on instructions that do not affect that state. For example: if it can be known that the carry is set, then do not ...
- Tue Mar 12, 2024 9:05 am
- Forum: Other Systems
- Topic: Hacking old Commodore Calculators.
- Replies: 1
- Views: 1663
Re: Hacking old Commodore Calculators.
This calculator holds the MPS 7561, which is a dedicated processor for calculators...nowhere near a 6502.
- Mon Feb 05, 2024 1:50 am
- Forum: Programming
- Topic: ROM calls and other tricks
- Replies: 33
- Views: 70034
Re: Handy toggle
Sometimes you want to toggle a memory location between two values. This can be done using EOR. The value to use for EOR can be constructed with eor in the assembler (operator ^ in this example) To elaborate on this, consider the following code snippet that I used in WimBasic: EOR #$82 ; token NEXT ...
- Thu Dec 07, 2023 2:24 am
- Forum: Programming
- Topic: Getting a signed multiply working (was: How do I print signed integer numbers?)
- Replies: 6
- Views: 4270
Re: Getting a signed multiply working (was: How do I print signed integer numbers?)
This prints signed integers (-32768 to 32767), including the sign character. It uses Zp $60-$66 and $01FF-$0210.
Code: Select all
LDY <low byte>
LDA <high byte>
JSR $D395 ; convert to float
INY ; eqv. LDY #$01
JMP $DDD7
- Fri Oct 20, 2023 5:32 am
- Forum: Programming
- Topic: File Command Errors
- Replies: 31
- Views: 6251
Re: File Command Errors
Hello chysn, (I believe) the following code queries the device at #8 for the last status text and prints it. Not quite sure as I don't have the resources at hand to check it. Regards, Wim. LDA #$08 JSR $FFB4 LDA #$6F JSR $FF96 LAE3C JSR $FFA5 JSR $E742 CMP #$0D BNE LAE3C JMP $FFAB
- Fri Oct 20, 2023 5:07 am
- Forum: Programming
- Topic: File Command Errors
- Replies: 31
- Views: 6251
Re: File Command Errors
Hello chysn, I looked for this when adding the ' autostart' function to WimBasic. First to check for the existence of the file WBSTART by trying to open and when found, load and run it. Any error (checked in $90) leads to the conclusion that file doesn't exist. So, when trying to scratch a file: jus...
Re: APPLE BUG
APPLE1 needs to run first and then APPLE2
When run from disk you need to modify APPLE1 so that it loads and runs APPLE2 properly.
Regards,
Wim.
- Wed Aug 30, 2023 2:15 am
- Forum: Programming
- Topic: MINIGRAFIK lineart
- Replies: 48
- Views: 22115
Re: MINIGRAFIK lineart
In WimBasic I would use DIVMOD to divide by 150 and then check DQ for oddity. So, check the ML behind DIVMOD.
- Tue Aug 29, 2023 5:16 am
- Forum: Programming
- Topic: MINIGRAFIK lineart
- Replies: 48
- Views: 22115
Re: MINIGRAFIK lineart
Hello Sven If you want yo go ML, then you should consider doing the whole thing in integers and integer calculation. All calculation results will be in the (maybe double) byte range anyway and you wont have the float-to-integer conversions vice versa (which are relatively expensive in terms of CPU)....
- Mon Mar 20, 2023 1:59 am
- Forum: Programming
- Topic: Odd nested FOR loop behaviour
- Replies: 4
- Views: 447
Re: Odd nested FOR loop behaviour
WimBasic actually has a command to resolve issues like this, i.e. DISPOSE NEXT. This drops the most recent FOR/NEXT frame, or can drop multiple frames when the accompanying variable is specified. 10 FORI=1TO4 20 IFI=3THEN DISPOSE NEXT :GOTO40 30 NEXT 40 FORU=1TO2:FORI=1TO2:PRINTI,U:NEXT:NEXT The DIS...
- Mon Mar 13, 2023 5:59 am
- Forum: Games
- Topic: Minesweeper for Commodore 64 and VIC-20
- Replies: 4
- Views: 2432
Re: Minesweeper for Commodore 64 and VIC-20
Hi Rich, Great to have a Minesweeper game on the VIC ! Now, I converted it to a WimBasic version. That makes it no longer dependant on the memory configuration. I brought it back to 36 lines, 1682 bytes. Also, I brought down runtime memory consumption. It can now play in a stock VIC-20 with WimBasic...