Gigatron Hackers • BASIC - Page 4

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Re: BASIC

Posted: 22 Jul 2018, 19:08

by marcelk

Some progress:

FOR-NEXT loops (no STEP)
Arrays. No need for DIM, the arrays grow vertically from top of memory towards the end of the program.
CLS: Clear screen
AT: Position cursor anywhere inside the screen (for Y it performs a lookup in the videoTable)
PUT: write an ASCII value (lacking string variables, this gives some flexibility)
MODE: will switch between video/speed modes (ignored on ROMv1)

It still needs thorough testing. The previous version had a malfunctioning GOSUB/RETURN.

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Some nice POKEs:

POKE 42, x: Change background color for printing
POKE 43, x: Change pen color
POKE 257,200: Observe memory layout of BASIC, program, arrays, variables...

The attachment TinyBASIC.gt1 is no longer available

Re: BASIC

Posted: 23 Jul 2018, 11:08

by marcelk

Code: Select all

1 cls:rem Lines demo
2 a=rnd(160):b=8+rnd(120)
3 c=rnd(160):d=8+rnd(120)
4 x=c-a:y=d-b:q=rnd(64)
5 u=1  :ifx<0x=-x:u=-u
6 v=256:ify<0y=-y:v=-v
7 p=a+256*b:ify<xgoto9
8 t=x:x=y:y=t:t=u:u=v:v=t
9 d=-x:x=x+x:y=y+y
10 fort=dto0:pokep,q
11 d=d+y:ifd>0d=d-x:p=p+v
12 p=p+u:nextt:goto2

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