/****************************************************/ /* File: code.c */ /* TM Code emitting utilities */ /* implementation for the TINY compiler */ /* Compiler Construction: Principles and Practice */ /* Kenneth C. Louden */ /****************************************************/ #include "globals.h" #include "code.h" /* TM location number for current instruction emission */ static int emitLoc = 0 ; /* Highest TM location emitted so far For use in conjunction with emitSkip, emitBackup, and emitRestore */ static int highEmitLoc = 0; /* Procedure emitComment prints a comment line * with comment c in the code file */ void emitComment( char * c ) { if (TraceCode) fprintf(code,"* %s\n",c);} /* Procedure emitRO emits a register-only * TM instruction * op = the opcode * r = target register * s = 1st source register * t = 2nd source register * c = a comment to be printed if TraceCode is TRUE */ void emitRO( char *op, int r, int s, int t, char *c) { fprintf(code,"%3d: %5s %d,%d,%d ",emitLoc++,op,r,s,t); if (TraceCode) fprintf(code,"\t%s",c) ; fprintf(code,"\n") ; if (highEmitLoc < emitLoc) highEmitLoc = emitLoc ; } /* emitRO */ /* Procedure emitRM emits a register-to-memory * TM instruction * op = the opcode * r = target register * d = the offset * s = the base register * c = a comment to be printed if TraceCode is TRUE */ void emitRM( char * op, int r, int d, int s, char *c) { fprintf(code,"%3d: %5s %d,%d(%d) ",emitLoc++,op,r,d,s); if (TraceCode) fprintf(code,"\t%s",c) ; fprintf(code,"\n") ; if (highEmitLoc < emitLoc) highEmitLoc = emitLoc ; } /* emitRM */ /* Function emitSkip skips "howMany" code * locations for later backpatch. It also * returns the current code position */ int emitSkip( int howMany) { int i = emitLoc; emitLoc += howMany ; if (highEmitLoc < emitLoc) highEmitLoc = emitLoc ; return i; } /* emitSkip */ /* Procedure emitBackup backs up to * loc = a previously skipped location */ void emitBackup( int loc) { if (loc > highEmitLoc) emitComment("BUG in emitBackup"); emitLoc = loc ; } /* emitBackup */ /* Procedure emitRestore restores the current * code position to the highest previously * unemitted position */ void emitRestore(void) { emitLoc = highEmitLoc;} /* Procedure emitRM_Abs converts an absolute reference * to a pc-relative reference when emitting a * register-to-memory TM instruction * op = the opcode * r = target register * a = the absolute location in memory * c = a comment to be printed if TraceCode is TRUE */ void emitRM_Abs( char *op, int r, int a, char * c) { fprintf(code,"%3d: %5s %d,%d(%d) ", emitLoc,op,r,a-(emitLoc+1),pc); ++emitLoc ; if (TraceCode) fprintf(code,"\t%s",c) ; fprintf(code,"\n") ; if (highEmitLoc < emitLoc) highEmitLoc = emitLoc ; } /* emitRM_Abs */
