1 2 Supported C language subset: 3 4 - Expressions: 5 6 * binary operators, by decreasing priority order: '*' '/' '%', 7 '+' '-', '>>' '<<', '<' '<=' '>' '>=', '==' '!=', '&', 8 '^', '|', '=', '&&', '||'. 9 10 * '&&' and '||' have the same semantics as C : left to right 11 evaluation and early exit. 12 13 * Parenthesis are supported. 14 15 * Comma operator is supported. 16 17 * Trinary operator (?:) is not supported. 18 19 * Unary operators: '&', '*' (pointer indirection), '-' 20 (negation), '+', '!', '~', '++' and '--'. 21 22 * Pointer indirection ('*') is supported. 23 24 * Square brackets are supported. 25 26 * '=' and <op>= are supported. 27 28 * Function calls are supported with standard Linux calling 29 convention. Function pointers are supported. 30 Functions can be used before being declared. 31 32 - sizeof() is not supported. 33 34 - Types: 35 + int, short, char, float, double 36 + pointers 37 + variables can be initialized in declarations. 38 + Only ANSI-style function declarations are supported. 39 - "..." is not supported. 40 - short is supported 41 - const is not supported 42 - signed and unsigned are not supported. 43 - arrays are supported 44 - long doubles are not supported 45 - structs and unions are supported 46 - typedef is supported 47 - explicit storage class specifiers are not supported: register, auto, static, extern 48 49 - Unknown functions and variables are bound at compile time by calling 50 back to the caller. For the 'acc' command-line tool unknown functions 51 and variables are looked up using dlsym, to allow using many libc 52 functions and variables. 53 54 - Instructions: blocks ('{' '}') are supported as in C. 'if' and 55 'else' can be used for tests. The 'while' and 'for' C constructs 56 are supported for loops. 'break' can be used to exit 57 loops. 'return' is used for the return value of a function. 58 59 - switch / case is not supported. 60 - goto and labels are not supported. 61 - continue is not supported. 62 63 - Identifiers are parsed the same way as C. Local variables are 64 handled, but there is no local name space (not a problem if 65 different names are used for local and global variables). 66 67 - Numbers can be entered in decimal, hexadecimal ('0x' or '0X' 68 prefix), or octal ('0' prefix). 69 70 - Float and double constants are supported. 71 72 - '#define' is supported without function like arguments. 73 - Macro recursion is allowed. 74 - Self-referential macros are handled as in gcc. 75 - '#pragma' is supported. The pragma text is passed to a callback function, 76 and is used to implement meta-information. 77 - Other preprocessor directives are ignored. 78 79 - C Strings and C character constants are supported. All ANSI C 80 character escapes are supported. 81 82 - Both C comments ( /* */ ) and C++ comments ( // ... end-of-line ) are 83 supported. 84 85 - Some syntax errors are reported, others may cause a crash. 86 87 - Memory: the code, data, and symbol sizes are limited to 100KB 88 (it can be changed in the source code). 89 90
