commit 36c01fefa0272b5667c2177db464183f342b5f86
parent 248f4c963157080d7b63ef181d66b89b51f0dde3
Author: Roberto E. Vargas Caballero <k0ga@shike2.net>
Date: Thu, 19 Mar 2026 10:54:37 +0100
doc: Update documentation about IR
Diffstat:
6 files changed, 706 insertions(+), 443 deletions(-)
diff --git a/doc/Makefile b/doc/Makefile
@@ -3,6 +3,7 @@
DIRS =\
man1\
man3\
+ man7\
PROJECTDIR = ..
include $(PROJECTDIR)/scripts/rules.mk
diff --git a/doc/man7/Makefile b/doc/man7/Makefile
@@ -0,0 +1,24 @@
+.POSIX:
+
+PROJECTDIR = ../..
+include $(PROJECTDIR)/scripts/rules.mk
+
+PAGES =\
+ scc-ir.7\
+
+.SUFFIXES: .man
+
+NODEP = 1
+
+all: $(PAGES)
+
+.man.7:
+ trap 'rm -f $tmp' EXIT;\
+ trap 'exit 1' HUP INT TERM;\
+ tmp=$$$$.tmp;\
+ sed '/\.TH/ s/VERSION/$(VERSION)/' $< > $$tmp &&\
+ mv $$tmp $@
+ cp $@ $(MANDIR)/man7/
+
+clean:
+ rm -f *.7
diff --git a/doc/man7/scc-ir.man b/doc/man7/scc-ir.man
@@ -0,0 +1,676 @@
+.TH SCC-IR 7 scc\-VERSION
+.SH NAME
+scc-ir \- scc intermediate representation
+.SH DESCRIPTION
+The scc intermediate representation (IR) is a text-based format
+used to communicate between the compiler frontend
+.RB ( cc1 )
+and the compiler backend
+.RB ( cc2 ).
+It is designed to be simple and easily parseable:
+all types and operators are represented by one or two characters,
+so parsing tables can be used to process it.
+.PP
+The language is composed of lines representing statements.
+Each line is composed of tab-separated fields.
+Declarations begin in column 0;
+expressions and control flow statements begin with a tab character.
+When the frontend detects an error,
+it closes the output stream.
+.SH TYPES
+Types are represented with single characters:
+.PP
+.TS
+l l.
+B bool
+C signed 8-bit integer
+K unsigned 8-bit integer
+I signed 16-bit integer
+N unsigned 16-bit integer
+W signed 32-bit integer
+Z unsigned 32-bit integer
+Q signed 64-bit integer
+O unsigned 64-bit integer
+J float
+D double
+H long double
+0 void
+P pointer
+F function
+E function with ellipsis
+V array (vector)
+U union
+S struct
+1 \fI__builtin_va_arg\fR
+.TE
+.PP
+Aggregate and composed types
+.RB ( S ,
+.BR U ,
+.BR V )
+are followed by a numeric identifier
+to distinguish between multiple types of the same kind:
+.BR S3 ,
+.BR V5 ,
+.BR U2 .
+.PP
+The sizes in the table above are nominal.
+Actual sizes depend on the target architecture.
+For example, on amd64-sysv,
+.B int
+is 32-bit and uses
+.BR W ,
+while on z80-scc it is 16-bit and uses
+.BR I .
+.SH STORAGE CLASSES
+Storage classes are represented with uppercase letters:
+.PP
+.TS
+l l.
+A automatic (local variable)
+R register
+G global (public, defined in this module)
+X extern (declared in another module)
+Y private (file-scope static)
+T local (function-scope static)
+M struct/union member
+L label
+.TE
+.PP
+A variable name in the IR is composed of a storage class letter
+followed by a numeric identifier, for example:
+.BR A1 ,
+.BR G2 ,
+.BR T3 ,
+.BR L4 .
+.SH DECLARATIONS
+.SS Variable declarations
+A variable declaration consists of a variable name,
+its type, and a quoted source name:
+.PP
+.RS
+.I var
+.B \et
+.I type
+.B \et "
+.I name
+.RE
+.PP
+For example:
+.PP
+.RS
+.nf
+A4 W "i
+G2 W "g
+X3 P "ptr
+.fi
+.RE
+.SS Function declarations
+Function declarations include the return type
+and use
+.B F
+for the function type
+.RB ( E
+if the function has an ellipsis parameter):
+.PP
+.RS
+.I var
+.B \et
+.I return-type
+.B \et F \et "
+.I name
+.RE
+.PP
+For example:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+G2 W F "main
+X3 W E "printf
+T4 0 F "helper
+.fi
+.RE
+.PP
+.B G
+marks a public function,
+.B T
+a file-scope static function, and
+.B X
+an extern declaration.
+.SS Function definitions
+A function definition starts with the function declaration,
+followed by
+.B {
+on its own line.
+Function parameters are declared inside the body.
+A
+.B \e
+(backslash) on its own line separates
+parameters from local variable declarations.
+The body ends with
+.BR } .
+.PP
+For example, the C source:
+.PP
+.RS
+.nf
+int func(int a, int b) {
+ int c;
+ return a + b;
+}
+.fi
+.RE
+.PP
+generates:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+G2 W F "func
+{
+A3 W "a
+A4 W "b
+\e
+A6 W "c
+ h A3 A4 +W
+}
+.fi
+.RE
+.SS Struct and union declarations
+A struct or union type declaration starts with a header line
+containing the type letter and identifier,
+a quoted tag name,
+a hex-encoded size and a hex-encoded alignment:
+.PP
+.RS
+.I type-id
+.B \et "
+.I tag
+.B \et #
+.IR size-letter size
+.B \et #
+.IR size-letter align
+.RE
+.PP
+Member declarations follow, each including an offset field:
+.PP
+.RS
+.I member-var
+.B \et
+.I type
+.B \et "
+.I name
+.B \et #
+.IR size-letter offset
+.RE
+.PP
+For example, the C source:
+.PP
+.RS
+.nf
+struct point {
+ int x;
+ int y;
+};
+struct point p;
+.fi
+.RE
+.PP
+generates (on amd64-sysv):
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+S3 "point #O8 #O4
+M4 W "x #O0
+M5 W "y #O4
+G6 S3 "p
+.fi
+.RE
+.PP
+Unions use
+.B U
+instead of
+.BR S .
+Members of a union typically share offset 0.
+.SS Array type declarations
+Array types are declared with
+.BR V ,
+the element type,
+and the number of elements in hexadecimal:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+V5 W #OA
+.fi
+.RE
+.PP
+This declares array type V5 with element type
+.B W
+(signed 32-bit integer) and 0xA (10) elements.
+Array variable declarations reference the array type:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+A4 V5 "a
+.fi
+.RE
+.SS Enum declarations
+Enumerations are not emitted as types.
+Enum variables are emitted with their underlying integer type
+(typically
+.BR W ):
+.PP
+.RS
+.nf
+G7 W "c
+.fi
+.RE
+.SH INITIALIZERS
+When a variable has an initializer,
+the declaration line ends without a newline and is followed by
+.B (
+on the same line.
+The initializer expressions follow,
+one per line,
+and the initializer is closed with
+.B )
+on its own line.
+.PP
+For example:
+.PP
+.RS
+.nf
+int g = 42;
+.fi
+.RE
+.PP
+generates:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+G2 W "g (
+ #W2A
+)
+.fi
+.RE
+.PP
+Array and struct initializers list each element:
+.PP
+.RS
+.nf
+int a[3] = {1, 2, 3};
+.fi
+.RE
+.PP
+generates:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+V3 W #O3
+G2 V3 "a (
+ #W1
+ #W2
+ #W3
+)
+.fi
+.RE
+.PP
+String initializers use a quoted form for printable runs
+and individual byte constants for non-printable characters:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n
+ #"hello
+ #C0
+.fi
+.RE
+.SH EXPRESSIONS
+Expressions are emitted in reverse Polish notation (RPN),
+with tab-separated tokens on a single line.
+Every operator is followed by a type letter.
+.SS Constants
+Constants are introduced with
+.BR # ,
+followed by a type letter and a hexadecimal value:
+.PP
+.RS
+.nf
+#W2A
+.fi
+.RE
+.PP
+This represents the integer constant 42 (0x2A) of type
+.BR W .
+.PP
+Floating-point constants are emitted as the hexadecimal encoding
+of their IEEE 754 representation:
+.PP
+.RS
+.nf
+#J3FC00000
+#D4004000000000000
+.fi
+.RE
+.PP
+These represent float 1.5 and double 2.5, respectively.
+.PP
+String constants are emitted using
+.B #"
+for printable character runs:
+.PP
+.RS
+.nf
+#"hello
+.fi
+.RE
+.SS Arithmetic operators
+.TS
+l l.
++ addition
+\- subtraction
+* multiplication
+/ division
+% modulo
+l left shift
+r right shift
+.TE
+.SS Comparison operators
+.TS
+l l.
+< less than
+> greater than
+[ less or equal
+] greater or equal
+\&= equal
+! not equal
+.TE
+.SS Bitwise operators
+.TS
+l l.
+& bitwise and
+| bitwise or
+^ bitwise xor
+~ bitwise complement (unary)
+.TE
+.SS Logical operators
+.TS
+l l.
+a logical and (short-circuit)
+o logical or (short-circuit)
+n logical negation
+.TE
+.SS Unary operators
+.TS
+l l.
+\&_ arithmetic negation
+~ bitwise complement
+n logical negation
+\&' address-of
+@ pointer dereference
+.TE
+.SS Assignment
+.TS
+l l.
+: assignment
+:* multiply and assign
+:/ divide and assign
+:% modulo and assign
+:+ add and assign
+:\- subtract and assign
+:l left shift and assign
+:r right shift and assign
+:& bitwise and and assign
+:^ bitwise xor and assign
+:| bitwise or and assign
+:i post-increment
+:d post-decrement
+.TE
+.SS Other operators
+.TS
+l l.
+, comma
+? ternary (conditional)
+\&. struct/union field access
+g type cast (followed by target type letter)
+.TE
+.SS Function calls
+Function calls use
+.B p
+to push each argument,
+.B c
+for the call itself,
+and
+.B z
+for calls to variadic functions.
+Each is followed by the type of the result:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n 40n 48n
+ X2 Y9 'P pP #W2A pW zW
+.fi
+.RE
+.PP
+This pushes a pointer argument
+.RB ( pP ),
+pushes an integer argument
+.RB ( pW ),
+and calls a variadic function returning
+.BR W
+.RB ( zW ).
+.SS Builtin functions
+Builtin function calls use
+.B m
+as the operator,
+preceded by a quoted builtin name:
+.PP
+.RS
+.nf
+"__builtin_va_arg m
+.fi
+.RE
+.SS Expression example
+The C expression:
+.PP
+.RS
+.nf
+i = j + 2 * 3;
+.fi
+.RE
+.PP
+generates (on amd64-sysv):
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n 40n
+ A4 A5 #W6 +W :W
+.fi
+.RE
+.PP
+Note that constant folding has reduced
+.I 2*3
+to
+.IR 6 .
+The expression is in RPN:
+push A4, push A5, push #W6, add (yielding W), assign (yielding W).
+.SS Type casts
+Casts are emitted as the operator
+.B g
+followed by the target type letter.
+A cast to
+.B void
+is not emitted.
+For example:
+.PP
+.RS
+.nf
+j = (long)i;
+.fi
+.RE
+.PP
+generates (on amd64-sysv):
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n
+ A5 A4 gQ :Q
+.fi
+.RE
+.SH STATEMENTS
+.SS Labels
+Labels begin in column 0 and consist of
+.B L
+followed by a numeric identifier:
+.PP
+.RS
+.nf
+L3
+.fi
+.RE
+.SS Unconditional jumps
+An unconditional jump uses
+.B j
+followed by a label:
+.PP
+.RS
+.nf
+.ta 8n 16n
+ j L3
+.fi
+.RE
+.SS Conditional branches
+A conditional branch uses
+.BR y ,
+followed by a label.
+The expression to evaluate follows on the next line.
+If the expression evaluates to true (non-zero), the branch is taken:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n
+ y L5 A4 #W5 <W
+.fi
+.RE
+.PP
+Note that the frontend negates the condition:
+the C code
+.I "if (i > 5)"
+is emitted as a branch on
+.IR "i <= 5" ,
+jumping past the then-block when the original condition is false.
+.SS Return
+The return statement uses
+.BR h .
+If the function returns a value,
+the expression follows on the same line:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n
+ h A3 A4 +W
+.fi
+.RE
+.PP
+A void return is emitted as
+.B h
+alone, followed by a blank expression line.
+.SS Loops
+Two markers indicate loop boundaries to the backend:
+.PP
+.TS
+l l.
+b beginning of loop body
+e end of loop body
+.TE
+.PP
+For example, a
+.B while
+loop:
+.PP
+.RS
+.nf
+while (i < 10) { ++i; }
+.fi
+.RE
+.PP
+generates:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n
+ j L5
+L4
+ b
+ A4 #W1 :+W
+L5
+ e
+ y L4 A4 #WA <W
+L6
+.fi
+.RE
+.SS Switch statements
+A switch statement is bracketed by
+.B s
+(begin) and
+.B t
+(end).
+The
+.B s
+marker is followed by the switch expression.
+Case entries are emitted with
+.BR v ,
+and the default entry with
+.BR f .
+The
+.B t
+marker takes the label where execution continues after the switch.
+.PP
+For example:
+.PP
+.RS
+.nf
+switch (n+1) {
+case 1:
+case 2:
+case 3:
+default:
+ ++n;
+}
+.fi
+.RE
+.PP
+generates:
+.PP
+.RS
+.nf
+.ta 8n 16n 24n 32n
+ s A3 #W1 +W
+ v L6 #W1
+L6
+ v L7 #W2
+L7
+ v L8 #W3
+L8
+ f L9
+L9
+ A3 #W1 :+W
+ t L5
+L5
+.fi
+.RE
+.PP
+Each
+.B v
+entry is followed by a label and a constant value.
+The
+.B f
+(default) entry is followed by a label only.
+.SH SEE ALSO
+.BR scc-cc (1)
diff --git a/scripts/dirs b/scripts/dirs
@@ -16,3 +16,4 @@ lib/scc/amd64-dragonfly
lib/scc/amd64-darwin
share/man/man1
share/man/man3
+share/man/man7
diff --git a/scripts/proto.all b/scripts/proto.all
@@ -211,11 +211,13 @@ d 755 share/man/man1
f 644 share/man/man1/scc-addr2line.1
f 644 share/man/man1/scc-ar.1
f 644 share/man/man1/scc-cc.1
+f 644 share/man/man1/scc-cpp.1
f 644 share/man/man1/scc-nm.1
f 644 share/man/man1/scc-objdump.1
f 644 share/man/man1/scc-ranlib.1
f 644 share/man/man1/scc-size.1
f 644 share/man/man1/scc-strip.1
+f 644 share/man/man1/scc.1
d 755 share/man/man3
f 644 share/man/man3/asctime.3
f 644 share/man/man3/clock.3
@@ -258,3 +260,5 @@ f 644 share/man/man3/strxfrm.3
f 644 share/man/man3/time.3
f 644 share/man/man3/time.h.3
f 644 share/man/man3/wchar.h.3
+d 755 share/man/man7
+f 644 share/man/man7/scc-ir.7
diff --git a/src/cmd/scc-cc/cc1/ir.md b/src/cmd/scc-cc/cc1/ir.md
@@ -1,443 +0,0 @@
-# scc intermediate representation #
-
-The scc IR tries to be be a simple and easily parseable intermediate
-representation, and it makes it a bit terse and cryptic. The main
-characteristic of the IR is that all the types and operations are
-represented with only one letter, so parsing tables can be used
-to parse it.
-
-The language is composed of lines, representing statements.
-Each statement is composed of tab-separated fields.
-Declaration statements begin in column 0, expressions and
-control flow begin with a tabulator.
-When the frontend detects an error, it closes the output stream.
-
-## Types ##
-
-Types are represented with uppercase letters:
-
-* C -- signed 8-Bit integer
-* I -- signed 16-Bit integer
-* W -- signed 32-Bit integer
-* Q -- signed 64-Bit integer
-* K -- unsigned 8-Bit integer
-* N -- unsigned 16-Bit integer
-* Z -- unsigned 32-Bit integer
-* O -- unsigned 64-Bit integer
-* 0 -- void
-* P -- pointer
-* F -- function
-* V -- vector
-* U -- union
-* S -- struct
-* B -- bool
-* J -- float
-* D -- double
-* H -- long double
-
-This list has been built for the original Z80 backend, where 'int'
-has the same size as 'short'. Several types (S, F, V, U and others) need
-an identifier after the type letter for better differentiation
-between multiple structs, functions, vectors and unions (S1, V12 ...)
-naturally occuring in a C-program.
-
-## Storage classes ##
-
-The storage classes are represented using uppercase letters:
-
-* A -- automatic
-* R -- register
-* G -- public (global variable declared in the module)
-* X -- extern (global variable declared in another module)
-* Y -- private (variable in file-scope)
-* T -- local (static variable in function-scope)
-* M -- member (struct/union member)
-* L -- label
-
-## Declarations/definitions ##
-
-Variable names are composed of a storage class and an identifier
-(e.g. A1, R2, T3).
-Declarations and definitions are composed of a variable
-name, a type and the name of the variable:
-
- A1 I maxweight
- R2 C flag
- A3 S4 statstruct
-
-### Type declarations ###
-
-Some declarations (e.g. structs) involve the declaration of member
-variables.
-Struct members are declared normally after the type declaration in
-parentheses.
-
-For example the struct declaration
-
- struct foo {
- int i;
- long c;
- } var1;
-
-generates
-
- S2 foo (
- M3 I i
- M4 W c
- )
- G5 S2 var1
-
-## Functions ##
-
-A function prototype
-
- int printf(char *cmd, int flag, void *data);
-
-will generate a type declaration and a variable declaration
-
- F5 P I P
- X1 F5 printf
-
-The first line gives the function-type specification 'F' with
-an identifier '5' and subsequently lists the types of the
-function parameters.
-The second line declares the 'printf' function as a publicly
-scoped variable.
-
-Analogously, a statically declared function in file scope
-
- static int printf(char *cmd, int flag, void *data);
-
-generates
-
- F5 P I P
- T1 F5 printf
-
-Thus, the 'printf' variable went into local scope ('T').
-
-A '{' in the first column starts the body of the previously
-declared function:
-
- int printf(char *cmd, int flag, void *data) {}
-
-generates
-
- F5 P I P
- G1 F5 printf
- {
- A2 P cmd
- A3 I flag
- A4 P data
- -
- }
-
-Again, the frontend must ensure that '{' appears only after the
-declaration of a function. The character '-' marks the separation
-between parameters and local variables:
-
- int printf(register char *cmd, int flag, void *data) {int i;};
-
-generates
-
- F5 P I P
- G1 F5 printf
- {
- R2 P cmd
- A3 I flag
- A4 P data
- -
- A6 I i
- }
-
-### Expressions ###
-
-Expressions are emitted in reverse polish notation, simplifying
-parsing and converting into a tree representation.
-
-#### Operators ####
-
-Operators allowed in expressions are:
-
-* \+ -- addition
-* \- -- substraction
-* \* -- multiplication
-* % -- modulo
-* / -- division
-* l -- left shift
-* r -- right shift
-* < -- less than
-* > -- greather than
-* ] -- greather or equal than
-* [ -- less or equal than
-* = -- equal than
-* ! -- different than
-* & -- bitwise and
-* | -- bitwise or
-* ^ -- bitwise xor
-* ~ -- bitwise complement
-* : -- asignation
-* _ -- unary negation
-* c -- function call
-* p -- parameter
-* . -- field
-* , -- comma operator
-* ? -- ternary operator
-* ' -- take address
-* a -- logical shortcut and
-* o -- logical shortcut or
-* @ -- content of pointer
-
-Assignation has some suboperators:
-
-* :/ -- divide and assign
-* :% -- modulo and assign
-* :+ -- addition and assign
-* :- -- substraction and assign
-* :l -- left shift and assign
-* :r -- right shift and assign
-* :& -- bitwise and and assign
-* :^ -- bitwise xor and assign
-* :| -- bitwise or and assign
-* :i -- post increment
-* :d -- post decrement
-
-Every operator in an expression has a type descriptor.
-
-#### Constants ####
-
-Constants are introduced with the character '#'. For instance, 10 is
-translated to #IA (all constants are emitted in hexadecimal),
-where I indicates that it is an integer constant.
-Strings are a special case because they are represented with
-the " character.
-The constant "hello" is emitted as "68656C6C6F. For example
-
- int
- main(void)
- {
- int i, j;
-
- i = j+2*3;
- }
-
-generates
-
- F1
- G1 F1 main
- {
- -
- A2 I i
- A3 I j
- A2 A3 #I6 +I :I
- }
-
-Type casts are expressed with a tuple denoting the
-type conversion
-
- int
- main(void)
- {
- int i;
- long j;
-
- j = (long)i;
- }
-
-generates
-
- F1
- G1 F1 main
- {
- -
- A2 I i
- A3 W j
- A2 A3 WI :I
- }
-
-### Statements ###
-#### Jumps #####
-
-Jumps have the following form:
-
- j L# [expression]
-
-the optional expression field indicates some condition which
-must be satisfied to jump. Example:
-
- int
- main(void)
- {
- int i;
-
- goto label;
- label:
- i -= i;
- }
-
-generates
-
- F1
- G1 F1 main
- {
- -
- A2 I i
- j L3
- L3
- A2 A2 :-I
- }
-
-Another form of jump is the return statement, which uses the
-letter 'y' followed by a type identifier.
-Depending on the type, an optional expression follows.
-
- int
- main(void)
- {
- return 16;
- }
-
-generates
-
- F1
- G1 F1 main
- {
- -
- yI #I10
- }
-
-
-#### Loops ####
-
-There are two special characters that are used to indicate
-to the backend that the following statements are part of
-a loop body.
-
-* b -- beginning of loop
-* e -- end of loop
-
-#### Switch statement ####
-
-Switches are represented using a table, in which the labels
-where to jump for each case are indicated. Common cases are
-represented with 'v' and default with 'f'.
-The switch statement itself is represented with 's' followed
-by the label where the jump table is located, and the
-expression of the switch:
-
- int
- func(int n)
- {
- switch (n+1) {
- case 1:
- case 2:
- case 3:
- default:
- ++n;
- }
- }
-
-generates
-
- F2 I
- G1 F2 func
- {
- A1 I n
- -
- s L4 A1 #I1 +I
- L5
- L6
- L7
- L8
- A1 #I1 :+I
- j L3
- L4
- t #4
- v L7 #I3
- v L6 #I2
- v L5 #I1
- f L8
- L3
- }
-
-The beginning of the jump table is indicated by the the letter 't',
-followed by the number of cases (including default case) of the
-switch.
-
-## Resumen ##
-
-* C -- signed 8-Bit integer
-* I -- signed 16-Bit integer
-* W -- signed 32-Bit integer
-* O -- signed 64-Bit integer
-* M -- unsigned 8-Bit integer
-* N -- unsigned 16-Bit integer
-* Z -- unsigned 32-Bit integer
-* Q -- unsigned 64-Bit integer
-* 0 -- void
-* P -- pointer
-* F -- function
-* V -- vector
-* U -- union
-* S -- struct
-* B -- bool
-* J -- float
-* D -- double
-* H -- long double
-* A -- automatic
-* R -- register
-* G -- public (global variable declared in the module)
-* X -- extern (global variable declared in another module)
-* Y -- private (variable in file-scope)
-* T -- local (static variable in function-scope)
-* M -- member (struct/union member)
-* L -- label
-* { -- beginning of function body
-* } -- end of function body
-* \\ -- end of function parameters
-* \+ -- addition
-* \- -- substraction
-* \* -- multiplication
-* % -- modulo
-* / -- division
-* l -- left shift
-* r -- right shift
-* < -- less than
-* > -- greather than
-* ] -- greather or equal than
-* [ -- less or equal than
-* = -- equal than
-* ! -- different than
-* & -- bitwise and
-* | -- bitwise or
-* ^ -- bitwise xor
-* ~ -- bitwise complement
-* : -- asignation
-* _ -- unary negation
-* c -- function call
-* p -- parameter
-* . -- field
-* , -- comma operator
-* ? -- ternary operator
-* ' -- take address
-* a -- logical shortcut and
-* o -- logical shortcut or
-* @ -- content of pointer
-* :/ -- divide and assign
-* :% -- modulo and assign
-* :+ -- addition and assign
-* :- -- substraction and assign
-* :l -- left shift and assign
-* :r -- right shift and assign
-* :& -- bitwise and and assign
-* :^ -- bitwise xor and assign
-* :| -- bitwise or and assign
-* ;+ -- post increment
-* ;- -- post decrement
-* j -- jump
-* y -- return
-* b -- begin of loop
-* d -- end of loop
-* s -- switch statement
-* t -- switch table
-* v -- case entry in switch table
-* f -- default entry in switch table
