NAME
IMCC - syntax
VERSION
OVERVIEW
This document describes the imcc syntax.
DESCRIPTION
Comments and empty lines
Comments start with # and last until the following newline. These and empty lines are ignored.
Statements
A valid imcc program consists of a sequence of statements. A statement is terminated by a newline (<NL>).
General statement format
[label:] [instruction] <NL>Labels
Optional label for the given instruction, can stand on its own line. Global labels start with an underscore, local labels shouldn't. A label must conform to the syntax of identifier described below.
INSTRUCTIONS
Terms used here
- <identifier>
-
Start with a letter or underscore, then may contain additionally digits and ::.
Example:
a _a A42 a::b_c - <type>
-
int, float, string or a valid parrot PMC type like PerlArray.
- <reg>
-
A PASM register I0..I31, S0..S31, N0..N31, P0..P31, or a IMCC temporary register $In, $Sn, $Nn, $Pn, where n consists of digit(s) only. The parrot register P31 is reserved for spilling and should not be used in complex code sections, which might need spilling (see operation.pod).
- <var>
-
A local identifier or a reg or a constant (when allowed).
Constants
- "string constants"
-
Are delimited by ". A " inside a string must be escaped by \".
- 'char constant'
-
Are delimited by '.
- numeric constants
-
0x and 0b denote hex and binary constants.
Directive instructions
- .sub <_identifier>
- .end
-
Define a compilation unit with the label _identifier:.
- .emit
- .eom
-
Define a compilation unit containing PASM code.
- .local <type> <identifier>
- .sym <type> <identifier>
-
Define a local name identifier for this compilation unit and of the given type.
- .const <type> <identifier> = <const>
-
Define a named constant of style type and value const.
- .namespace <identifier>
- .endnamespace <identifier>
-
Defines the range of a namespace. Local variables inside a namespace are mangled as <namespaceidentifier::varidentifier>.
- .param <type> <identifier>
-
Like .local and generates PASM restore identifier.
- .param <reg>
- .result <var>
-
restore from stack.
- .arg <var>
- .return <var>
-
save on stack.
- .pcc_*
-
Directives used for Parrot Calling Conventions.
Instructions
Instructions may be a valid PASM instruction or anything listed here below:
- call <identifier>
-
bsr <identifier>.
- goto <identifier>
-
branch <identifier>.
- if <var> goto <identifier>
- unless <var> goto <identifier>
-
Translate to if x, identifier or unless ...
- if <var> <relop> <var> goto <identifier>
-
The relop <, <=, ==, != >= > translate to the PASM opcodes lt, le, eq, ne, ge or gt var, var, identifier.
- unless <var> <relop> <var> goto <identifier>
-
Like above, but branch if condition isn't met.
- <var> = <var>
-
set var, var
- <var> = <unary> <var>
-
The unarys !, - and ~ generate not, neg and bnot ops.
- <var> = <var> <binary> <var>
-
The binarys +, -, *, /, % and ** generate add, sub, mul, div, mod and pow arithmetic ops. binary . is concat and valid for string arguments.
<< and >> are arithmetic shifts shl and shr. >>> is the logical shift lsr.
&&, || and ~~ are logic and, or and xor.
&, | and ~ are binary band, bor and bxor.
- <var> = <var> [ <var> ]
-
This generates either a keyed set operation or substr var, var, var, 1 for string arguments and an integer key.
- <var> [ <var> ] = <var>
-
A keyed set operation or the assign substr op with a length of 1.
- <var> = new <type>
-
new var, .type
- <var> = new <type>, <var>
-
new var, .type, var
- <var> = defined <var>
-
defined var, var
- <var> = defined <var> [ <var> ]
-
defined var, var[var] the keyed op.
- global "string" = <var>
-
store_global "string", var
- <var> = global "string"
-
find_global var, "string"
- <var> = clone <var>
-
clone var, var
- <var> = addr <var>
-
set_addr var, var
SEE ALSO
parsing.pod, calling_conventions.pod
FILES
imcc.l, imcc.y
AUTHOR
Leopold Toetsch <lt@toetsch.at>