system/corennnnn
| リビジョン | a96930572c3ef440065a87985ed5f01724bf159b (tree) |
|---|---|
| 日時 | 2009-05-12 06:51:47 |
| 作者 | Frabrice Bellard <fabrice@bell...> |
| コミッター | Jack Palevich |
Document acc language features.
Original text from http://www.ioccc.org/2001/bellard.hint
libacc/FEATURES (diff)| @@ -0,0 +1,65 @@ | ||
| 1 | + | |
| 2 | +Supported C language subset (read joint example 'otccex.c' to have | |
| 3 | + an introduction to OTCC dialect): | |
| 4 | + | |
| 5 | + - Expressions: | |
| 6 | + | |
| 7 | + * binary operators, by decreasing priority order: '*' '/' '%', | |
| 8 | + '+' '-', '>>' '<<', '<' '<=' '>' '>=', '==' '!=', '&', | |
| 9 | + '^', '|', '=', '&&', '||'. | |
| 10 | + | |
| 11 | + * '&&' and '||' have the same semantics as C : left to right | |
| 12 | + evaluation and early exit. | |
| 13 | + | |
| 14 | + * Parenthesis are supported. | |
| 15 | + | |
| 16 | + * Unary operators: '&', '*' (pointer indirection), '-' | |
| 17 | + (negation), '+', '!', '~', post fixed '++' and '--'. | |
| 18 | + | |
| 19 | + * Pointer indirection ('*') only works with explicit cast to | |
| 20 | + 'char *', 'int *' or 'int (*)()' (function pointer). | |
| 21 | + | |
| 22 | + * '++', '--', and unary '&' can only be used with variable | |
| 23 | + lvalue (left value). | |
| 24 | + | |
| 25 | + * '=' can only be used with variable or '*' (pointer | |
| 26 | + indirection) lvalue. | |
| 27 | + | |
| 28 | + * Function calls are supported with standard i386 calling | |
| 29 | + convention. Function pointers are supported with explicit | |
| 30 | + cast. Functions can be used before being declared. | |
| 31 | + | |
| 32 | + - Types: only signed integer ('int') variables and functions can | |
| 33 | + be declared. Variables cannot be initialized in | |
| 34 | + declarations. Only old K&R function declarations are parsed | |
| 35 | + (implicit integer return value and no types on arguments). | |
| 36 | + | |
| 37 | + - Any function or variable from the libc can be used because OTCC | |
| 38 | + uses the libc dynamic linker to resolve undefined symbols. | |
| 39 | + | |
| 40 | + - Instructions: blocks ('{' '}') are supported as in C. 'if' and | |
| 41 | + 'else' can be used for tests. The 'while' and 'for' C constructs | |
| 42 | + are supported for loops. 'break' can be used to exit | |
| 43 | + loops. 'return' is used for the return value of a function. | |
| 44 | + | |
| 45 | + - Identifiers are parsed the same way as C. Local variables are | |
| 46 | + handled, but there is no local name space (not a problem if | |
| 47 | + different names are used for local and global variables). | |
| 48 | + | |
| 49 | + - Numbers can be entered in decimal, hexadecimal ('0x' or '0X' | |
| 50 | + prefix), or octal ('0' prefix). | |
| 51 | + | |
| 52 | + - '#define' is supported without function like arguments. No macro | |
| 53 | + recursion is tolerated. Other preprocessor directives are | |
| 54 | + ignored. | |
| 55 | + | |
| 56 | + - C Strings and C character constants are supported. Only '\n', | |
| 57 | + '\"', '\'' and '\\' escapes are recognized. | |
| 58 | + | |
| 59 | + - C Comments can be used (but no C++ comments). | |
| 60 | + | |
| 61 | + - No error is displayed if an incorrect program is given. | |
| 62 | + | |
| 63 | + - Memory: the code, data, and symbol sizes are limited to 100KB | |
| 64 | + (it can be changed in the source code). | |
| 65 | + |
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