To celebrate the BASIC (Beginners' All Purpose Symbolic Instruction Code) turning 60 years old, I'm releasing a big update to my old Bunny Basic from 2019, now called Hare Basic.
Hare Basic is a fast, limited instruction set, integer-only basic interpreter (not a compiler) for Commodore 64 and VIC 20. Requires 32K/35K expansion on VIC 20 (RAM in block 5).
There's a bunch of system calls available through instruction GO that go "beyond basic", such as turn IRQ on/off, copy or fill memory areas very fast, sync to display to avoid flickering, view disk directory, copy character ROM to RAM and move program data higher in RAM to reserve space for graphics, do bit shifts, 16-bit pokes, instantly calculate screen and color memory locations for given coordinates, etc. (See Handbook: GO System Calls)
Mostly everything is at least 6 times faster than CBM BASIC.
- Hare Basic (VIC 20).png (890 Bytes) Viewed 2150 times
- vicraster.png (6.57 KiB) Viewed 2150 times
It's easy to mix Hare Basic code with CBM BASIC code by just treating Hare Basic code as subroutines, called by A=USR(linenumber). Final Hare Basic program, including any data loaded into memory and the interpreter itself, can be linked into a single file (see Handbook: Packacing a final Hare Basic program).
Download: https://bit.ly/harebasic or or Handbook: https://bit.ly/harebasichandbook or
Commands: PRINT, INPUT, GET, POKE, SYS, GOTO, CLR, GOSUB, RETURN, IF/THEN, END, FOR/NEXT, LOAD, SAVE, REM, LET, RND (as command), CMD (repurposed for POKE mode)
Functions: AND, OR, PEEK, VAL, LEN, ASC, <, =, >, <>, <=, >=, +, -
Variables: 26 one-letter variables A-Z, 16-bit unsigned integer (not shared with CBM BASIC)
Arithmetics: 16-bit unsigned integer addition, subtraction, multiplication, division, negation
Limited string functions: CHR$, STR$ (repurposed to display strings), POKE12345,"TEXT"
Hare Basic syntax is very similar to CBM BASIC, but there's quite a few restrictions and some critical differences. You should still feel like at home right away, just dive in!
A=USR(10) in CBM BASIC starts running a Hare Basic program starting from line 10.
If you're writing your entire program in Hare Basic, just type A=USR(10):END on the first basic line before line 10. Start writing Hare Basic code from line 10. This way you can start your program normally with a RUN.
Hare Basic syntax is very similar to CBM BASIC, but there's quite a few restrictions and some critical differences. You should still feel like at home right away, just dive in!
There is no string variables. However, there's simple support for null-terminated strings that can be freely located in the memory. Some commands work a little differently: For example GET gives the PETSCII code of a key and INPUTA uses variable A as a pointer to memory where it stores the user input as a null-terminated string. (You can also type for example INPUT832 to read input to tape buffer).
There is no arrays. Access memory directly with POKE and PEEK to create larger data structures.
All variables are 16-bit unsigned integers. Negative numbers, if entered, are handled as two's complement.
Only one arithmetic operation can be done at once. Arithmetics may only be done as separate instructions and not as regular expressions in command parameters.
See the Handbook for details!
--
Comparison to old Bunny Basic: Bunny Basic was only 1300 bytes in size, while Hare Basic interpreter now takes a whole 4K block. Unexpanded VIC 20 is no longer supported. New commands: INPUT, GET, POKE string, FOR/TO/STEP/NEXT, LOAD, SAVE, RND, CMD, GO (system calls). New functions: VAL, LEN, ASC, variable increment/decrement (A-/A+), STR$ (repurposed to display null-terminated strings from memory). Bunny Basic started with a SYS, but Hare Basic starts by the less often used USR function of CBM BASIC
To dethrone them I need a Vic-20 Super weapon language to kick their behinds. Enter Integer Basic (Hare/Bunny)!
