void MacExpandStart (Macro* M)
/* Start expanding a macro */
{
MacExp* E;
/* Check the argument */
PRECONDITION (M && (M->Style != MAC_STYLE_DEFINE || DisableDefines == 0));
/* We cannot expand an incomplete macro */
if (M->Incomplete) {
Error ("Cannot expand an incomplete macro");
return;
}
/* Don't allow too many nested macro expansions - otherwise it is possible
* to force an endless loop and assembler crash.
*/
if (MacExpansions >= MAX_MACEXPANSIONS) {
Error ("Too many nested macro expansions");
return;
}
/* Create a structure holding expansion data */
E = NewMacExp (M);
/* Call the apropriate subroutine */
switch (M->Style) {
case MAC_STYLE_CLASSIC: StartExpClassic (E); break;
case MAC_STYLE_DEFINE: StartExpDefine (E); break;
default: Internal ("Invalid macro style: %d", M->Style);
}
}
static void StartExpDefine (Macro* M)
/* Start expanding a DEFINE style macro */
{
/* Create a structure holding expansion data */
MacExp* E = NewMacExp (M);
/* A define style macro must be called with as many actual parameters
* as there are formal ones. Get the parameter count.
*/
unsigned Count = M->ParamCount;
/* Skip the current token */
NextTok ();
/* Read the actual parameters */
while (Count--) {
TokNode* Last;
/* The macro may optionally be enclosed in curly braces */
Token Term = GetTokListTerm (TOK_COMMA);
/* Check if there is really a parameter */
if (TokIsSep (Tok) || Tok == Term) {
ErrorSkip ("Macro parameter #%u is empty", E->ParamCount+1);
FreeMacExp (E);
return;
}
/* Read tokens for one parameter */
Last = 0;
do {
TokNode* T;
/* Get the next token in a node */
T = NewTokNode ();
/* Insert it into the list */
if (Last == 0) {
E->Params [E->ParamCount] = T;
} else {
Last->Next = T;
}
Last = T;
/* And skip it... */
NextTok ();
} while (Tok != Term && !TokIsSep (Tok));
/* One parameter more */
++E->ParamCount;
/* If the macro argument was enclosed in curly braces, end-of-line
* is an error. Skip the closing curly brace.
*/
if (Term == TOK_RCURLY) {
if (TokIsSep (Tok)) {
Error ("End of line encountered within macro argument");
break;
}
NextTok ();
}
/* Check for a comma */
if (Count > 0) {
if (Tok == TOK_COMMA) {
NextTok ();
} else {
Error ("`,' expected");
}
}
}
/* Macro expansion will overwrite the current token. This is a problem
* for define style macros since these are called from the scanner level.
* To avoid it, remember the current token and re-insert it, once macro
* expansion is done.
*/
E->Final = NewTokNode ();
/* Insert a new token input function */
PushInput (MacExpand, E, ".DEFINE");
}
static void StartExpClassic (Macro* M)
/* Start expanding the classic macro M */
{
MacExp* E;
Token Term;
/* Skip the macro name */
NextTok ();
/* Create a structure holding expansion data */
E = NewMacExp (M);
/* Read the actual parameters */
while (!TokIsSep (Tok)) {
TokNode* Last;
/* Check for maximum parameter count */
if (E->ParamCount >= M->ParamCount) {
ErrorSkip ("Too many macro parameters");
break;
}
/* The macro may optionally be enclosed in curly braces */
Term = GetTokListTerm (TOK_COMMA);
/* Read tokens for one parameter, accept empty params */
Last = 0;
while (Tok != Term && Tok != TOK_SEP) {
TokNode* T;
/* Check for end of file */
if (Tok == TOK_EOF) {
Error ("Unexpected end of file");
FreeMacExp (E);
return;
}
/* Get the next token in a node */
T = NewTokNode ();
/* Insert it into the list */
if (Last == 0) {
E->Params [E->ParamCount] = T;
} else {
Last->Next = T;
}
Last = T;
/* And skip it... */
NextTok ();
}
/* One parameter more */
++E->ParamCount;
/* If the macro argument was enclosed in curly braces, end-of-line
* is an error. Skip the closing curly brace.
*/
if (Term == TOK_RCURLY) {
if (Tok == TOK_SEP) {
Error ("End of line encountered within macro argument");
break;
}
NextTok ();
}
/* Check for a comma */
if (Tok == TOK_COMMA) {
NextTok ();
} else {
break;
}
}
/* We must be at end of line now, otherwise something is wrong */
ExpectSep ();
/* Insert a new token input function */
PushInput (MacExpand, E, ".MACRO");
}
