小型编译器,可以用于测试使用

				/****************************************************/
				/* File: code.c                                     */
				/* TM Code emitting utilities                       */
				/* implementation for the TINY compiler             */
				/* Compiler Construction: Principles and Practice   */
				/* Kenneth C. Louden                                */
				/****************************************************/
				
				#include 
				#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;
				
				//中间代码
				struct{
					char *op;
					char *a;
					char *b;
					char *c;
				}mcode[512];			//四元式
				
				//生成3地址中间代码
				void emit( char * op, char * a, char * b, char * c )
				{
					mcode[emitLoc].op = (char *)malloc(sizeof(char)*(strlen(op)+1));
					mcode[emitLoc].a = (char *)malloc(sizeof(char)*(strlen(a)+1));
					mcode[emitLoc].b = (char *)malloc(sizeof(char)*(strlen(b)+1));
					mcode[emitLoc].c = (char *)malloc(sizeof(char)*(strlen(c)+1));
					strcpy(mcode[emitLoc].op, op);
					strcpy(mcode[emitLoc].a, a);
					strcpy(mcode[emitLoc].b, b);
					strcpy(mcode[emitLoc].c, c);
					emitLoc++;
					if (highEmitLoc < emitLoc)
						highEmitLoc = emitLoc;
				}
				
				void output()
				{
					int i;
					for(i=0;i					{
						if(strcmp(mcode[i].op, "+")==0 ||
							strcmp(mcode[i].op, "-")==0 ||
							strcmp(mcode[i].op, "*")==0 ||
							strcmp(mcode[i].op, "/")==0 ||
							strcmp(mcode[i].op, "and")==0 ||
							strcmp(mcode[i].op, "or")==0 ||
							strcmp(mcode[i].op, "							strcmp(mcode[i].op, "							strcmp(mcode[i].op, ">")==0 ||
							strcmp(mcode[i].op, ">=")==0 ||
							strcmp(mcode[i].op, "=")==0)
							fprintf(code,"%5d)  %s := %s %s %s\n",i,mcode[i].c,mcode[i].a,mcode[i].op,mcode[i].b);
						else if(strcmp(mcode[i].op, "read")==0)
							fprintf(code,"%5d)  %s %s\n",i,mcode[i].op,mcode[i].c);
						else if(strcmp(mcode[i].op, "write")==0)
							fprintf(code,"%5d)  %s %s\n",i,mcode[i].op,mcode[i].a);
						else if(strcmp(mcode[i].op, ":=")==0)
							fprintf(code,"%5d)  %s %s %s\n",i,mcode[i].c,mcode[i].op,mcode[i].a);
						else if(strcmp(mcode[i].op, "label")==0 ||
							strcmp(mcode[i].op, "goto")==0)
							fprintf(code,"%5d)  %s %s\n",i,mcode[i].op,mcode[i].c);
						else if(strcmp(mcode[i].op, "j=")==0)
							fprintf(code,"%5d)  if %s = %s goto %s\n",i,mcode[i].a,mcode[i].b,mcode[i].c);
					}
				}
				
				//生成临时变量
				char * newtemp()
				{
					static n = 0;
					char tmpn[3]={'\0'};		//临时变量编号
					char * temp = (char *)malloc(sizeof(char)*6);		//临时变量名
					itoa(n++,tmpn,10);
					strcpy(temp,"t");
					strcat(temp,tmpn);
					return temp;
				}
				
				//生成新标签
				char * newlabel()
				{
					static n = 1;
					char * temp = (char *)malloc(sizeof(char)*4);
					char tmpn[3]={'\0'};
					strcpy(temp,"L");
					itoa(n++,tmpn,10);
					strcat(temp,tmpn);
					return temp;
				}
				
				/* 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;}