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Diffstat (limited to '05/constants.b')
| -rw-r--r-- | 05/constants.b | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/05/constants.b b/05/constants.b index 983bc2a..6a0bba1 100644 --- a/05/constants.b +++ b/05/constants.b @@ -230,6 +230,52 @@ ; types willl be initialized (in main) so that this refers to the type char* #define TYPE_POINTER_TO_CHAR 20 +; STATEMENTS +; In C, note that `if', `while', etc. always have a single statement as their body: +; if (x) { y; z; w; } +; here {y; z; w;} is a single `compound' statement containing three statements. +; our statements don't directly correspond to the C89 standard's notion of statements, in particular, +; labels count as separate statements and declarations count as statements. +; each statement is stored as exactly 40 bytes +; uchar type +; uchar padding +; ushort file +; uint line +; ulong data1 +; ulong data2 +; ulong data3 +; ulong data4 +; a type of 0 indicates the end of the block. +; data layout for particular statements: +; - STATEMENT_EXPRESSION - data1 is a pointer to expression data; data2,3,4 are unused +; - STATEMENT_LOCAL_DECLARATION - declaring a local variable (automatic/"register" storage duration), data1 = total bytes used by all local variables so far in this function including this one; data2,3,4 unused +; - STATEMENT_LABEL - data1 is a pointer to the name of the label; data2,3,4 are unused +; - STATEMENT_BLOCK - data1 is a pointer to an array of statements; data2,3,4 are unused +; - STATEMENT_IF - data1 is a pointer to the condition, data2 is a pointer to the `if' branch statement, data3 is a pointer to the `else' branch statement, or 0 if there is none; data4 is unused +; - STATEMENT_SWITCH - data1 is a pointer to the expression, data2 is a pointer to the body statement; data3,4 are unused +; - STATEMENT_WHILE - data1 is a pointer to the condition, data2 is a pointer to the body statement; data3,4 are unused +; - STATEMENT_DO - data1 is a pointer to the body statement, data2 is a pointer to the condition; data3,4 are unused +; - STATEMENT_FOR - data1,2,3 are pointers to the first, second, and third expressions inside parentheses, data4 is a pointer to the body statement +; - STATEMENT_GOTO - data1 is a pointer to the name of the label; data2,3,4 are unused +; - STATEMENT_CONTINUE - data1,2,3,4 are unused +; - STATEMENT_BREAK - data1,2,3,4 are unused +; - STATEMENT_RETURN - data1 is a pointer to the expression, or 0 if there is none; data2,3,4 are unused +#define STATEMENT_EXPRESSION 1 +#define STATEMENT_LOCAL_DECLARATION 2 +#define STATEMENT_LABEL 3 +#define STATEMENT_BLOCK 4 +#define STATEMENT_IF 5 +#define STATEMENT_SWITCH 6 +#define STATEMENT_WHILE 7 +#define STATEMENT_DO 8 +#define STATEMENT_FOR 9 +#define STATEMENT_GOTO 0xa +#define STATEMENT_CONTINUE 0xb +#define STATEMENT_BREAK 0xc +#define STATEMENT_RETURN 0xd + + + :keyword_table byte SYMBOL_SEMICOLON byte 59 |