Another useful offset found!

Change A$ to be single quote instead of plus will RTS to $286. The current command line is at $270, so be careful not to overwrite yourself. BASIC uses addresses $345-$360 - so avoid!

To help you find more functions you can use from ordinary BASIC, I've attached my sym for DASMx.

Should save you time disassembling ROM.

DASMx Download -http://myweb.tiscali.co.uk/pclare/DASMx/dasmx140.zip

Attached is BASIC playing a tune you all know - using ROM play song! The additional DATA contains this new ASM 03AA: lda #$EB 03AC: sta $04 03AE: lda #$FC 03B0: sta $05 03B2: php 03B3: sei 03B4: lda #$C4 03B6: sta $00 03B8: lda #$03 03BA: sta $01 03BC: ldy #$27 03BE: jsr $FBED ; ROM play song using ...

Today's discovery is ... Sex with strings for BASIC82/83 OK, the BASIC82/3 manual states that strings can only be 32 bytes long. This isn't actually true, you can concatenate strings up to 75 bytes for printing. However, there's a darker, sexier side to our concatenated strings ... they don't like v...

BASIC83H "Speedup" patches The speed up in 83H is to simply STOP the interrupt! ROM:76BA CLI ROM:76BB LDA $C ROM:76BD BPL loc_76BF ROM:76BF ROM:76BF loc_76BF: ROM:76BF SEI ROM:76C0 AND #$7F ROM:76C2 STA $C ROM:76C4 LDA $10 ROM:76C6 CMP #$83 ROM:76C8 BNE sub_76D0 ROM:76CA JSR sub_B380 ROM:76CD JMP lo...

Happy New Year! This update finally brings a function! Note that any new functions must be only 3 characters long, to fit in with the interpreter. This is the final VDP function, VPK , short for VPeeK. I've tried to automate it a little more too, so you'll notice b83p.exe and a patch.txt file. Thes...

Some other VDP functions added. VREG Register, Value - Use this to configure video registers. Be careful - do not change modes! VSAVE - Store VRAM to tape. VLOAD - Go on, guess :) I've attached a sample video showing them in action. VREG 5,38 and VREG 6,1 reset to BASIC82/83 default SAT and SPT. As ...

This update brings sprites to BASIC 83C! By default, BASIC 83 sets the VDP to have a sprite pattern table at $800 (used for DATA temp work) and a sprite attribute table at $1300 (is erased when screen scrolls up!). To allow sprites, the VDP initialisation has been changed to give the sprite pattern ...

The speed up sounds far more impressive than it really is! This was the original subroutine at 9470 (7470 in 83B) ROM:9470 sub_9470: ROM:9470 LDA #0 ROM:9472 STA $D1 ROM:9474 ROM:9474 loc_9474: ROM:9474 ROM:9474 LDX $D6 ROM:9476 LDA $D5 ROM:9478 JSR $FE1F ROM:947B LDX $D1 ROM:947D LDA $230,X ROM:948...

Updates for 27 Dec 2013 * New PRintAT function. * Fixed PEEK, LET and STOP table offsets * Removed address selection each time a line is copied to VRAM. Speed up 41cy per byte transferred. I'll post a kind of lazy changelog as I do them, but the latest code, asm and binary will be in the first post.