NAME

IMCC - syntax

VERSION

0.1 initial

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>

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:
<type>: int, float, string, pmc 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 \". Only 7-bit ASCII is accepted in string constants; to use characters outside thar range, specify an encoding in the way below.
charset:"string constant": Like above with a chracter set attached to the string. Valid character sets are currently: ascii (the default), binary, unicode (with UTF-8 as the default encoding), and iso-8859-1.
charset:encoding:"string constant": Like above with an extra encoding attached to the string. Currently unimplemented.
'char constant': Are delimited by '. They are taken to be ascii encoded.
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. You can define multiple identifiers of the same type by separating them with commas: .sym int i, j
.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

FILES

imcc.l, imcc.y

AUTHOR

Leopold Toetsch <lt@toetsch.at>