Mercurial > hg > Members > kono > os9 > sbc09

comparison basic/basic.txt @ 57:2088fd998865

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
sbc09 directry clean up
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Mon, 23 Jul 2018 16:07:12 +0900
parents
children
comparison
equal deleted inserted replaced
56:4fa2bdb0c457 57:2088fd998865
1 TINY BASIC SUMMARY
2
3 Editing Standard Basic
4
5 Direct Mode All Verbs Usable
6
7 Statement Types
8
9 PRINT Item List
10 LET Var = Expr (LET is optional)
11 IF Expr Relop Expr Statement
12 INPUT Variable List
13 GOTO Line Number
14 GOSUB Line Number
15 RETURN
16 POKE POKE(Expr) = Expr
17 STOP
18 LIST Line Number, Line Number (Line Numbers are optional)
19 RUN
20 NEW
21
22 Functions
23
24 USR Variable = USR(Expr,Expr)
25 PEEK Variable = PEEK(Expr)
26 MEM Variable = MEM
27
28 Number Integers to _+32767 or Hex Integers preceded by a $ symbol
29
30 Variable Letters A-Z
31
32 Expression Variables, Numbers, and Functions combined with the following
33 operators +, -, *, /, (, ).
34
35 Relop Comparison operators =, <, >, <=, >=, <>.
36
37 Line Number Numbers 1 through 9999
38
39 String "ALPHANUMERICS"
40
41 Item List Expressions and Strings seperated by format control
42 characters , and ;.
43
44 Control Chars. Control H or "Back Space" deletes last input character.
45 Control X or "Cancel" deletes entire input line.
46 Control C Terminates Basic program or List operation and
47 returns control to command mode.
48
49 Memory Usage Tiny Basic V1.37
50
51 $0080 - $009F Tiny Basic interpreter scratch area.
52 $00A0 - $00FD Not used by Tiny Basic interpreter. (usable USR routines)
53 $**** - $**** Pointer to Interrupt Vector Table. (Identical to LILBUG)
54 $D800 - $DFFF Input Buffer, Basic Program storage, Stack Space, and
55 Variables in RAM.
56 $**** - $**** Optional Power Up Basic Program and/or USR functions in ROM.
57 $E800 - $EFFF Tiny Basic interpreter ROM.
58
59 $E800 Cold Start Address.
60 $E803 Warm Start Address.
61
62 Tiny Basic USR Function
63
64 The USR function in Tiny Basic takes 2 arguments and returns a value to a
65 variable. The form of the USR function is "LET V = USR(Expr,Expr)".
66 The USR function can be used in any expression in Tiny Basic as an example
67 "LET V = A * ( B + USR( $EF00, K))". The USR function can also be used with
68 the PRINT statement.
69
70 The first argument of the USR function is evaluated to determine the address
71 or the machine language code to be called. The second argument is evaluated
72 and the value is send to the machine code routine in the D accumulator. The
73 second argument is optional, if it is present the Carry bit in the condition
74 code register will be cleared when the machine code routine is called. If the
75 second argument is not present the Carry Bit will be set when the machine code
76 is called. The machine code routine may return a result to the BASIC program
77 in the D accumulator, the value in the D accumulator on return from the machine
78 code routine will be used by the BASIC program as the value of the function.
79
80 The machine code routine must execute a RTS instruction to return conterol to
81 the BASIC program. The machine code routine may use all the processor registers
82 freely and need not save and restore any registers. It is important that the
83 machine code routine not modify any memory used by the Tiny Basic interpreter.
84 Consult the memory map provided with your version of Tiny Basic to determine
85 which memory areas are not used.
86
87 Tiny Basic handles interrupts with the same interrupt vectoring technique used
88 by LILBUG. Consult the LILBUG manual for details on interrupt vector usage.
89
90
91
92 JPB 12-APR-82