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The Structure of I-Code: Difference between revisions

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===I-Code Area===
===I-Code Area===


This is where all of your instruction statements are stored in tokenized post-fix notation form.
This is where all of your instruction statements are stored in tokenized post-fix notation form. In this section I will describe the various structures used in Basic09 coding, including the looping constructs, conditional statements, and the use of literals (constants).
 
====Structures====
* FOR/NEXT
* WHILE/ENDWHILE
* REPEAT/UNTIL
* LOOP/ENDLOOP
 
====Conditional====
* IF-THEN <lref>
* IF-THEN/ENDIF
* IF-THEN/ELSE/ENDIF
* EXITIF-THEN/ENDEXIT
 
====Literals==== (Constants)
* Numeric
** BYTE
** INTEGER
** REAL
** Hexadecimal Integer
* BOOLEAN
* String


===Description Area===
===Description Area===

Revision as of 22:51, 24 July 2013

The 'I' in I-Code stands for Intermediate. Intermediate code is code that is a step between interpreted source statements and fully compiled machine code. Typically, intermediate code uses tokens to represent the instructions to be executed. Basic09 I-Code goes a step further by re-arranging the source code instructions in post-fix notation (also known as Reverse Polish Notation) order.

The tokens used by Basic09 are a single byte ranging from $00 to $FF. See I-Code Token List

Module Format

Basic09 I-Code modules use the same module format as any other OS-9 executable module. However, I-Code modules include optional header extensions not included in other types of memory modules. They also include two very important tables specific to I-Code modules.

Modules are divided into the following sections:

Module Header

Description Size Note
Module Header Space (Sync Bytes) INTEGER 1
Total Procedure Block Size INTEGER
Module Name Offset INTEGER
Module Type/Language BYTE 2
Module Attributes/Revision BYTE 3
Module Header Parity BYTE
I-Code Area Address INTEGER
Runtime Variable Storage Size INTEGER
Symbol Table Address INTEGER
Description Area Address INTEGER
Procedure Link Storage Offset INTEGER 4
First Data Statement Address INTEGER
First Executable Statement Address INTEGER 5
Procedure Status BYTE 6
Procedure Name Size BYTE
Procedure Name Beginning Procedure Name Size BYTEs
Edition Number BYTE 7

NOTES 

 1: Value always $87CD
 2: Value always $22     Sub-Routine / Basic09 I-Code
 3: Value always $81     Re-Entrant,Re-Locatable Object / Revision = 1
 4: Beginning of Subroutine Name Storage
 5: Value always $0000   (Unused, Possible association: <dex> token - $3C)
 6: Value always $80     (I do not know what the use of this BYTE is.)
 7: Always the first byte after the Module Name. This BYTE is actually the
    first byte of I-Code, at the I-Code Area Address location, and not part
    of the header. The OS-9 Level II Manual describes the Edition byte in
    Chapter 6. System Command Descriptions, under the Ident command on page
    6-52,53. The OS-9 Level I Manual Set includes this information in the OS9
    Commands Manual, Chapter 6. System Command Descriptions, Ident command,
    page 87.

I-Code Area

This is where all of your instruction statements are stored in tokenized post-fix notation form. In this section I will describe the various structures used in Basic09 coding, including the looping constructs, conditional statements, and the use of literals (constants).

Structures

  • FOR/NEXT
  • WHILE/ENDWHILE
  • REPEAT/UNTIL
  • LOOP/ENDLOOP

Conditional

  • IF-THEN <lref>
  • IF-THEN/ENDIF
  • IF-THEN/ELSE/ENDIF
  • EXITIF-THEN/ENDEXIT

====Literals==== (Constants)

  • Numeric
    • BYTE
    • INTEGER
    • REAL
    • Hexadecimal Integer
  • BOOLEAN
  • String

Description Area

Symbol Table

CRC

File Access Mode Tokens

READ+WRITE = UPDATE

80 DIR
01 READ 81 READ+DIR
02 WRITE 82 WRITE+DIR
03 UPDATE 83 UPDATE+DIR
04 EXEC 84 EXEC+DIR
05 READ+EXEC 85 READ+EXEC+DIR
06 WRITE+EXEC 86 WRITE+EXEC+DIR
07 UPDATE+EXEC 87 UPDATE+EXEC+DIR

I-Code Instruction Variable Tokens

I have never liked the usage of MIRROR in this instance. I have no better way to describe these tokens at this time. I referred to them as mirror tokens, because in some instances they act as a duplicate of the variable, such as in the case of a:=a+1. Both 'a' variables refer to the same variable, but in the I-Code, each has a separate token, and with the exception of 80-84 (in the instruction area) point to the VDT. 80-83 in the instruction area point to data memory addresses, and 84 points to the DSAT.

VARIABLE FIELD PARAMETER
TYPE TOKEN MIRROR TOKEN MIRROR TOKEN MIRROR
BYTE 80 F2 F6 89 85 F2
INTEGER 81 F2 F6 89 85 F2
REAL 82 F2 F6 89 85 F2
BOOLEAN 83 F2 F6 89 85 F2
STRING 84 F2 F6 89 85 F2
RECORD 85 F2 F6 89 85 F2
VECTOR 85/86 F3 F7 8A 85/86 F3
TABLE 85/87 F4 F8 8B 85/87 F4
MATRIX 85/88 F5 F9 8C 85/88 F5

I-Code Token List

Token Name Used In Description
00 GLOBAL Reserved Global Variable
01 PARAM Editor
01 READ I-Code File Mode
02 TYPE Editor
02 WRITE I-Code File Mode
03 DIM Editor
03 UPDATE I-Code File Mode
04 DATA I-Code/Editor
04 EXEC I-Code File Mode
05 STOP I-Code/Editor
05 READ+EXEC I-Code File Mode
06 BYE I-Code/Editor
06 WRITE+EXEC I-Code File Mode
07 TRON I-Code/Editor
07 UPDATE+EXEC I-Code File Mode
08 TROFF I-Code/Editor
09 PAUSE I-Code/Editor
0A DEG I-Code/Editor
0B RAD I-Code/Editor
0C RETURN I-Code/Editor
0D LET I-Code/Editor
0E <cva> I-Code/Editor Complex Variable Assignment
0F POKE I-Code/Editor
10 IF I-Code/Editor
11 ELSE I-Code/Editor
12 ENDIF I-Code/Editor
13 FOR I-Code/Editor
14 NEXT I-Code/Editor
15 WHILE I-Code/Editor
16 ENDWHILE I-Code/Editor
17 REPEAT I-Code/Editor
18 UNTIL I-Code/Editor
19 LOOP I-Code/Editor
1A ENDLOOP I-Code/Editor
1B EXITIF I-Code/Editor
1C ENDEXIT I-Code/Editor
1D ON I-Code/Editor
1E ERROR I-Code/Editor
1F GOTO Editor Unbound
20 GOTO I-Code/Editor Bound
21 GOSUB Editor Unbound
22 GOSUB I-Code/Editor Bound
23 RUN I-Code/Editor
24 KILL I-Code/Editor
25 INPUT I-Code/Editor
26 PRINT I-Code/Editor ? Becomes PRINT in the Editor
27 CHD I-Code/Editor
28 CHX I-Code/Editor
29 CREATE I-Code/Editor
2A OPEN I-Code/Editor
2B SEEK I-Code/Editor
2C READ I-Code/Editor
2D WRITE I-Code/Editor
2E GET I-Code/Editor
2F PUT I-Code/Editor
30 CLOSE I-Code/Editor
31 RESTORE I-Code/Editor
32 DELETE I-Code/Editor
33 CHAIN I-Code/Editor
34 SHELL I-Code/Editor
35 BASE0 I-Code/Editor
36 BASE1 I-Code/Editor
37 REM Editor ! Becomes REM in the Editor
38 (* Editor
39 END I-Code/Editor
3A <ulrf> Editor Unbound Line Reference
3B <blrf> I-Code/Editor Bound Line Reference
3C <dex> I-Code/Editor Direct Execution (Unimplemented)
3D PROCEDURE Editor Procedure start
3D <erl> Editor/Debug Error Line
3E \ I-Code/Editor End-of-Instruction, Continue Line
3F <eol> I-Code/Editor End-of-Instruction and Line
40 BYTE Editor
40 fbyte I-Code/Editor VDT Entry, Field Byte Variable
41 INTEGER Editor
41 finteger I-Code/Editor VDT Entry, Field Integer Variable
42 REAL Editor
42 freal I-Code/Editor VDT Entry, Field Real Variable
43 BOOLEAN Editor
43 fboolean I-Code/Editor VDT Entry, Field Boolean Variable
44 STRING Editor
44 fstring I-Code/Editor VDT Entry, Field String Variable
45 THEN I-Code/Editor
45 frecord I-Code/Editor VDT Entry, Field Record Variable
46 TO I-Code/Editor
47 STEP I-Code/Editor
48 DO I-Code/Editor
48 fvectorb I-Code/Editor VDT Entry, Field 1 Dimensional Byte Array
49 USING I-Code/Editor
49 fvectori I-Code/Editor VDT Entry, Field 1 Dimensional Integer Array
4A : I-Code/Editor File Mode Operator
4A fvectorr I-Code/Editor VDT Entry, Field 1 Dimensional Real Array
4B , I-Code/Editor Comma Separator
4B fvectorl I-Code/Editor VDT Entry, Field 1 Dimensional Boolean Array
4C : I-Code/Editor Colon
4C fvectors I-Code/Editor VDT Entry, Field 1 Dimensional String Array
4D ( I-Code/Editor Left Parenthesis
4D fvectoru I-Code/Editor VDT Entry, Field 1 Dimensional Record Array
4E ) I-Code/Editor Right Parenthesis
4F [ I-Code/Editor Left Bracket
50 ] I-Code/Editor Right Bracket
50 ftableb I-Code/Editor VDT Entry, Field 2 Dimensional Byte Array
51 ; I-Code/Editor Semi-colon
51 ftablei I-Code/Editor VDT Entry, Field 2 Dimensional Integer Array
52 := I-Code/Editor AssignmentOperator
52 ftabler I-Code/Editor VDT Entry, Field 2 Dimensional Real Array
53 = I-Code/Editor AssignmentOperator
53 ftablel I-Code/Editor VDT Entry, Field 2 Dimensional Boolean Array
54 # I-Code/Editor Channel (Path) Number Operator
54 ftables I-Code/Editor VDT Entry, Field 2 Dimensional String Array
55 <ivgt> I-Code/Editor Invisible GOTO (used in many statements)
55 <ivgt> I-Code/Editor Invisible GOTO (special case in ON var GOTO/GOSUB statements)
55 ftableu I-Code/Editor VDT Entry, Field 2 Dimensional Record Array
56 Unused
57 Unused
58 fmatrixb I-Code/Editor VDT Entry, Field 3 Dimensional Byte Array
59 fmatrixi I-Code/Editor VDT Entry, Field 3 Dimensional Integer Array
5A fmatrixr I-Code/Editor VDT Entry, Field 3 Dimensional Real Array
5B fmatrixl I-Code/Editor VDT Entry, Field 3 Dimensional Boolean Array
5C fmatrixs I-Code/Editor VDT Entry, Field 3 Dimensional String Array
5D fmatrixu I-Code/Editor VDT Entry, Field 3 Dimensional Record Array
5E Unused
5F Unused
60 byte I-Code/Editor VDT Entry, Byte Variable
61 integer I-Code/Editor VDT Entry, Integer Variable
62 real I-Code/Editor VDT Entry, Real Variable
63 boolean I-Code/Editor VDT Entry, Boolean Variable
64 string I-Code/Editor VDT Entry,StringVariable
65 record I-Code/Editor VDT Entry, Record Variable
66 Unused
67 Unused
68 vectorb I-Code/Editor VDT Entry, 1 Dimensional Byte Array
69 vectori I-Code/Editor VDT Entry, 1 Dimensional Integer Array
6A vectorr I-Code/Editor VDT Entry, 1 Dimensional Real Array
6B vectorl I-Code/Editor VDT Entry, 1 Dimensional Boolean Array
6C vectors I-Code/Editor VDT Entry, 1 Dimensional String Array
6D vectoru I-Code/Editor VDT Entry, 1 Dimensional Record Array
6E Unused
6F Unused
70 tableb I-Code/Editor VDT Entry, 2 Dimensional Byte Array
71 tablei I-Code/Editor VDT Entry, 2 Dimensional Integer Array
72 tabler I-Code/Editor VDT Entry, 2 Dimensional Real Array
73 tablel I-Code/Editor VDT Entry, 2 Dimensional Boolean Array
74 tables I-Code/Editor VDT Entry, 2 Dimensional String Array
75 tableu I-Code/Editor VDT Entry, 2 Dimensional Record Array
76 Unused
77 Unused
78 matrixb I-Code/Editor VDT Entry, 3 Dimensional Byte Array
79 matrixi I-Code/Editor VDT Entry, 3 Dimensional Integer Array
7A matrixr I-Code/Editor VDT Entry, 3 Dimensional Real Array
7B matrixl I-Code/Editor VDT Entry, 3 Dimensional Boolean Array
7C matrixs I-Code/Editor VDT Entry, 3 Dimensional String Array
7D matrixu I-Code/Editor VDT Entry, 3 Dimensional Record Array
7E Unused
7F Unused
80 byte I-Code/Editor Instruction, Simple Byte Variable
80 pbyte I-Code/Editor VDT Entry, Parameter Byte Variable
80 DIR I-Code File Mode
81 integer I-Code/Editor Instruction, Simple Integer Variable
81 pinteger I-Code/Editor VDT Entry, Parameter Integer Variable
81 READ+DIR I-Code File Mode
82 real I-Code/Editor Instruction, Simple Real Variable
82 preal I-Code/Editor VDT Entry, Parameter Real Variable
82 WRITE+DIR I-Code File Mode
83 boolean I-Code/Editor Instruction, Simple Boolean Variable
83 pboolean I-Code/Editor VDT Entry, Parameter Boolean Variable
83 UPDATE+DIR I-Code File Mode
84 string I-Code/Editor Instruction, Simple String Variable
84 pstring I-Code/Editor VDT Entry, Parameter String Variable
84 EXEC+DIR I-Code File Mode
85 record/p I-Code/Editor Instruction,Record, Parameter (Simple/Record) Variable
85 vector/p I-Code/Editor Instruction, 1 Dimensional Array, Parameter 1 Dimensional Array Variable
85 table/p I-Code/Editor Instruction, 2 Dimensional Array, Parameter 2 Dimensional Array Variable
85 matrix/p I-Code/Editor Instruction, 3 Dimensional Array, Parameter 3 Dimensional Array Variable
85 precord I-Code/Editor VDT Entry, Parameter Record Variable
85 READ+EXEC+DIR I-Code File Mode
86 vector/p I-Code/Editor Instruction, 1 Dimensional Array
86 WRITE+EXEC+DIR I-Code File Mode
87 table/p I-Code/Editor Instruction, 2 Dimensional Array
87 UPDATE+EXEC+DIR I-Code File Mode
88 matrix/p I-Code/Editor Instruction, 3 Dimensional Array
88 pvectorb I-Code/Editor VDT Entry, Parameter 1 Dimensional Byte Array
89 varm I-Code/Editor Instruction, Simple/Record Variable Mirror
89 pvectori I-Code/Editor VDT Entry, Parameter 1 Dimensional Integer Array
8A fvectorm I-Code/Editor VDT Entry, Field 1 Dimensional Array Mirror
8A pvectorr I-Code/Editor VDT Entry, Parameter 1 Dimensional Real Array
8B ftablem I-Code/Editor VDT Entry, Field 2 Dimensional Array Mirror
8B pvectorl I-Code/Editor VDT Entry, Parameter 1 Dimensional Boolean Array
8C fmatrixm I-Code/Editor VDT Entry, Field 3 Dimensional Array Mirror
8C pvectors I-Code/Editor VDT Entry, Parameter 1 Dimensional String Array
8D <bc> I-Code/Editor BYTE Constant (Literal)
8D pvectoru I-Code/Editor VDT Entry, Parameter 1 Dimensional Record Array
8E <ic> I-Code/Editor INTEGER Constant (Literal)
8F <rc> I-Code/Editor REAL Constant (Literal)
90 " I-Code/Editor STRING Constant (Literal) - Beginning
90 ptableb I-Code/Editor VDT Entry, Parameter 2 Dimensional Byte Array
91 $ I-Code/Editor Hexadecimal Constant (Literal)
91 ptablei I-Code/Editor VDT Entry, Parameter 2 Dimensional Integer Array
92 ADDR() I-Code/Editor
92 ptabler I-Code/Editor VDT Entry, Parameter 2 Dimensional Real Array
93 <addr> I-Code/Editor Second Byte of ADDR()
93 ptablel I-Code/Editor VDT Entry, Parameter 2 Dimensional Boolean Array
94 SIZE() I-Code/Editor
94 ptables I-Code/Editor VDT Entry, Parameter 2 Dimensional String Array
95 <size> I-Code/Editor Second Byte of SIZE()
95 ptableu I-Code/Editor VDT Entry, Parameter 2 Dimensional Record Array
96 POS() I-Code/Editor
97 ERR() I-Code/Editor
98 MOD() I-Code/Editor Byte/Integer
98 pmatrixb I-Code/Editor VDT Entry, Parameter 3 Dimensional Byte Array
99 MOD() I-Code/Editor Real
99 pmatrixi I-Code/Editor VDT Entry, Parameter 3 Dimensional Integer Array
9A RND() I-Code/Editor
9A pmatrixr I-Code/Editor VDT Entry, Parameter 3 Dimensional Real Array
9B PI I-Code/Editor
9B pmatrixl I-Code/Editor VDT Entry, Parameter 3 Dimensional Boolean Array
9C SUBSTR() I-Code/Editor
9C pmatrixs I-Code/Editor VDT Entry, Parameter 3 Dimensional String Array
9D SGN() I-Code/Editor
9D pmatrixu I-Code/Editor VDT Entry, Parameter 3 Dimensional Record Array
9E SGN() I-Code/Editor
9F SIN() I-Code/Editor
A0 COS() I-Code/Editor
A0 <subr> I-Code/Editor Named Subroutine
A1 TAN() I-Code/Editor
A2 ASN() I-Code/Editor
A3 ACS() I-Code/Editor
A4 ATN() I-Code/Editor
A5 EXP() I-Code/Editor
A6 ABS() I-Code/Editor
A7 ABS() I-Code/Editor
A8 LOG() I-Code/Editor
A9 LOG10() I-Code/Editor
AA SQRT() I-Code/Editor
AB SQR() I-Code/Editor Becomes SQRT() in the Code
AC INT() I-Code/Editor Byte/Integer
AD INT() I-Code/Editor Real
AE FIX() I-Code/Editor Byte/Integer
AF FIX() I-Code/Editor Real
B0 FLOAT() I-Code/Editor Byte/Integer
B1 FLOAT() I-Code/Editor Real
B2 SQ() I-Code/Editor Byte/Integer
B3 SQ() I-Code/Editor Real
B4 PEEK() I-Code/Editor
B5 LNOT() I-Code/Editor LogicalNOT
B6 VAL() I-Code/Editor
B7 LEN() I-Code/Editor
B8 ASC() I-Code/Editor
B9 LAND() I-Code/Editor Logical AND
BA LOR() I-Code/Editor Logical OR
BB LXOR() I-Code/Editor Logical XOR
BC TRUE I-Code/Editor
BD FALSE I-Code/Editor
BE EOF() I-Code/Editor
BF TRIM$() I-Code/Editor
C0 MID$() I-Code/Editor
C1 LEFT$() I-Code/Editor
C2 RIGHT$() I-Code/Editor
C3 CHR$() I-Code/Editor
C4 STR$() I-Code/Editor Byte/Integer
C5 STR$() I-Code/Editor Real
C6 DATE$ I-Code/Editor
C7 TAB I-Code/Editor
C8 <ritc> I-Code/Editor Real->Byte/Integer Type Conversion
C8 <fix1> I-Code/Editor Fix Top of Stack
C9 <fix2> I-Code/Editor Fix Second on Stack
CA <fix3> I-Code/Editor Fix Third on Stack
CB <irtc> I-Code/Editor Byte/Integer->Real Type Conversion
CB <flt1> I-Code/Editor Float Top of Stack
CC <flt2> I-Code/Editor Float Second on Stack
CD NOT() I-Code/Editor
CE - I-Code/Editor (Monadic) Negate Byte/Integer
CF - I-Code/Editor (Monadic) Negate Real
D0 AND I-Code/Editor
D1 OR I-Code/Editor
D2 XOR I-Code/Editor
D3 > I-Code/Editor Byte/Integer Comparison Operator
D4 > I-Code/Editor Real Comparison Operator
D5 > I-Code/Editor String Comparison Operator
D6 < I-Code/Editor Byte/Integer Comparison Operator
D7 < I-Code/Editor Real Comparison Operator
D8 < I-Code/Editor String Comparison Operator
D9 <> I-Code/Editor Byte/Integer Comparison Operator >< is converted to <> in the code
DA <> I-Code/Editor Real Comparison Operator >< is converted to <> in the code
DB <> I-Code/Editor String Comparison Operator >< is converted to <> in the code
DC <> I-Code/Editor Boolean Comparison Operator >< is converted to <> in the code
DD = I-Code/Editor Byte/Integer Comparison Operator
DE = I-Code/Editor Real Comparison Operator
DF = I-Code/Editor String Comparison Operator
E0 = I-Code/Editor Boolean Comparison Operator
E1 >= I-Code/Editor Byte/Integer Greater/Equal Operator
E2 >= I-Code/Editor Real Greater/Equal Operator
E3 >= I-Code/Editor String Greater/Equal Operator
E4 <= I-Code/Editor Byte/Integer Less/Equal Operator
E5 <= I-Code/Editor Real Less/Equal Operator
E6 <= I-Code/Editor String Less/Equal Operator
E7 + I-Code/Editor Byte/Integer Add Operator
E8 + I-Code/Editor Real Add Operator
E9 + I-Code/Editor String Concantenate Operator
EA - I-Code/Editor Byte/Integer Subtract Operator (Dyadic)
EB - I-Code/Editor Real Subtract Operator (Dyadic)
EC * I-Code/Editor Byte/Integer Multiply Operator
ED * I-Code/Editor Real Multiply Operator
EE / I-Code/Editor Byte/Integer Divide Operator
EF / I-Code/Editor Real Divide Operator
F0 ^ I-Code/Editor Exponent Operator
F1 ** I-Code/Editor Exponent Operator
F2 varm/p I-Code/Editor Instruction, Simple/Record, Parameter Variable Mirror
F3 vectorm/p I-Code/Editor Instruction, 1 Dimensional Array, Parameter 1 Dimensional Array Mirror
F4 tablem/p I-Code/Editor Instruction, 2 Dimensional Array, Parameter 2 Dimensional Array Mirror
F5 matrixm/p I-Code/Editor Instruction, 3 Dimensional Array, Parameter 3 Dimensional Array Mirror
F6 field I-Code/Editor Instruction, Field Variable
F7 UPDATE Editor File Mode
F7 fvector I-Code/Editor Instruction, Field 1 Dimensional Array
F8 EXEC Editor File Mode
F8 ftable I-Code/Editor Instruction, Field 2 Dimensional Array
F9 DIR Editor File Mode
F9 fmatrix I-Code/Editor Instruction, Field 3 Dimensional Array
FA Unused
FB Unused
FC Unused
FD Unused
FE Unused
FF " I-Code/Editor STRING Constant (Literal) - Terminator
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