compiler.c

#include <stdio.h>
#include <stdlib.h>
#include "ast.h"
#include "y.tab.h"

static int lbl;

int ex(nodeType * p) {
    int lbl1, lbl2;
    if(!p)return 0;
    switch(p->type) {
        case typeCon:
            printf("\tpush\t%d\n", p->con.value);
            break;
        case typeId:
            printf("\tpush\t%c\n", p->id.i+'a');
            break;
        case typeOpr:
            switch(p->opr.oper) {
                case WHILE:
                    printf("L%03d:\n", lbl1=lbl++);
                    ex(p->opr.op[0]);
                    printf("\tjz\tL%03d\n", lbl2=lbl++);
                    ex(p->opr.op[1]);
                    printf("\tjmp\tL%03d\n", lbl1);
                    printf("L%03d:\n", lbl2);
                    break;
                case IF:
                    ex(p->opr.op[0]);
                    if(p->opr.nops > 2) {
                        printf("\tjz\t%03d\n", lbl1=lbl++);
                        ex(p->opr.op[1]);
                        printf("\tjmp\tL%03d\n", lbl2=lbl++);
                        printf("L%03d:\n", lbl1);
                        ex(p->opr.op[2]);
                        printf("L%03d:\n", lbl2);
                    } else {
                        printf("\tjz\tL%03d\n", lbl1=lbl++);
                        ex(p->opr.op[1]);
                        printf("L%03d:\n", lbl1);
                    }
                    break;
                case PRINT:
                    ex(p->opr.op[0]);
                    printf("\tprint\n");
                    break;
                case '=':
                    ex(p->opr.op[1]);
                    printf("\tpop\t%c\n", p->opr.op[0]->id.i+'a');
                    break;
                case UMINUS:
                    ex(p->opr.op[0]);
                    printf("neg");
                    break;
                default:
                    ex(p->opr.op[0]);
                    ex(p->opr.op[1]);
                    switch(p->opr.oper) {
                        case '+': printf("\tadd\n"); break;
                        case '-': printf("\tsub\n"); break;
                        case '*': printf("\tmul\n"); break;
                        case '/': printf("\tdiv\n"); break;
                        case '<': printf("\tcompLT\n"); break;
                        case '>': printf("\tcompGT\n"); break;
                        case GE: printf("\tcompGE\n"); break;
                        case LE: printf("\tcompLE\n"); break;
                        case NE: printf("\tcompNE\n"); break;
                        case EQ: printf("\tcompEQ\n"); break;
                    }
            }
    } 
    return 0;
}