8BASIC theory 6/6: Statements III

8BASIC (C) is a BASIC interpreter developed by manufacturer G.G in 2010 for the homemade Z80/AM95 8 bit NANO COMPUTER.

 

 

 

38 "INPUT A " ; ask the user to enter the numeric value of variable A

39 "INPUT T$" ; ask the user to enter the string value of variable T$

40 " CLS " ; clears (blank) the 16-segment LED displays and reset (0) the 7-segment ones

41 " CLEAR " ; reset variables to their default type value

42 "PRINT A " ; display the numeric value of variable A

43 "PRINT T$" ; display the string value of variable T$

44 "PRINT+T$" ; display and scroll the strings T$ and consecutives till encountering # char

45 "PAUSE T " ; suspend the program execution. Value of T is the time in ms to pause

46 "BEEP T,F" ; generate a tone. T is the tone duration (ms). F is the tone number (max 7)

47 " IN (A) " ; assign to variable A the binary value input from the 8 bit parallel port

48 " OUT (A)" ; output binary value of variable A to the 8 bit parallel port

49 "A=PEEK X" ; assign to variable A the byte value at the X memory location

50 "POKE X,A" ; write byte value of variable A into X memory location

51 "SYS X " ; branch (and jump back) to the machine language program at the X location

 

Each statement is precompiled as much as possible to make the interpreter run faster and it always occupies 16 bytes.

 

Statements allow you extreme flexibility. For example a FOR...TO..NEXT cycle can be easily written as:

 

LET I=+1.00000

LET U=+1.00000

LET T=number of cycles

N:

 

cycle

 

I=I+U

IFT>=I:N

END

 

Due to the internal RAM memory structure, the maximum size of the 8BASIC program has been set to 488 lines, which will fit the first 8K RAM chip.

Done