int _zzt_board_limit_links(ZZTboard *brd, int max)
{
int j, board_length;
/* Fix link macro */
#define fixlink(link) if ((link) > max) (link) = 0;
/* Fix board connections */
fixlink(brd->info.board_n);
fixlink(brd->info.board_s);
fixlink(brd->info.board_e);
fixlink(brd->info.board_w);
/* Do the same for passages */
if (!zztBoardDecompress(brd)) {
fprintf(stderr, "Error decompressing board\n");
return 0;
}
board_length = brd->bigboard->width * brd->bigboard->height;
for (j = 0; j < board_length; j++) {
if (brd->bigboard->tiles[j].type == ZZT_PASSAGE && brd->bigboard->tiles[j].param != NULL) {
fixlink(brd->bigboard->tiles[j].param->data[2]);
}
}
return 1;
}
void procedure() {
// assert: allocatedRegisters == 0
// may be global variables but are anyway nicer like that
int callBranches;
int parameters;
int localVariables;
if (symbol == INTEGER) {
getSymbol();
if (symbol == ASTERISK)
getSymbol();
} else if (symbol == VOID)
getSymbol();
else
syntaxError(PROCEDURE); // int expected!
if (symbol == IDENTIFIER) {
callBranches = setProcedureAddress();
getSymbol();
if (callBranches != codeLength)
if (getOpcodeFromCode(callBranches) == BSR)
fixlink(callBranches);
else
// procedure defined more than once!
declarationError(PROCEDURE);
if (symbol == LEFTPARENTHESIS) {
getSymbol();
parameters = 0;
if (symbol != RIGHTPARENTHESIS) {
declaration();
parameters = 1;
while (symbol == COMMA) {
getSymbol();
declaration();
parameters = parameters + 1;
}
// parameter offsets are only known here
// when all parameters have been parsed!
// thus enter offsets in local table now:
// ...
if (symbol == RIGHTPARENTHESIS)
getSymbol();
else
syntaxError(PROCEDURE); // right parenthesis expected!
} else
getSymbol();
} else
syntaxError(PROCEDURE); // left parenthesis expected!
if (symbol == SEMICOLON)
getSymbol();
else if (symbol == LEFTBRACES) {
getSymbol();
localVariables = 0;
while (symbol == INT) {
declaration();
localVariables = localVariables + 1;
if (symbol == SEMICOLON)
getSymbol();
else
syntaxError(PROCEDURE); // semicolon expected!
}
// procedure prologue
// save return address
emit(PSH, LINK, SP, 4);
// save caller's frame
emit(PSH, FP, SP, 4);
// allocate callee's frame
emit(ADD, FP, ZR, SP);
// allocate callee's local variables
emit(SUBI, SP, SP, localVariables * 4);
// create a fixup chain for return statements
returnBranches = 0;
while (symbol != RIGHTBRACES)
statement();
getSymbol();
// procedure epilogue
fixlink(returnBranches);
// deallocate callee's frame and local variables
emit(ADD, SP, ZR, FP);
// restore caller's frame
emit(POP, FP, SP, 4);
// restore return address and deallocate parameters
emit(POP, LINK, SP, parameters * 4 + 4);
// return
emit(RET, 0, 0, LINK);
} else
syntaxError(PROCEDURE); // semicolon or left braces expected!
} else
syntaxError(PROCEDURE); // identifier expected!
// assert: allocatedRegisters == 0
}
