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-rw-r--r--gen_code.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/gen_code.c b/gen_code.c
index f3e0232..0026ca3 100644
--- a/gen_code.c
+++ b/gen_code.c
@@ -13,6 +13,7 @@
else yyerror("CAN'T POP");}
#define REG_PUSH {if (reg_cnt < 13) reg_ptr--, reg_cnt++;\
else yyerror("CAN'T PUSH");}
+#define GEN_EXPR(x) {gen_label(x); gen_expr(x);}
char **reg_stack, **reg_ptr;
int reg_cnt;
@@ -45,9 +46,69 @@ ptree *t;
}
+/*Based on Dragon Book gen_code()*/
void gen_expr(t)
ptree *t;
{
+ if (!t) {
+ fprintf(stderr, "GEN_EXPR: NOT T\n");
+ return;
+ }
+
+ /*case 0
+ * t is a left leaf*/
+ if ((!t->r) && (!t->l) && t->label != 0) {
+ switch (t->type) {
+ case ID:
+ fprintf(stdout, "mov\t%s, %s\n",t->attr.nval->name, *reg_ptr);
+ break;
+ case INUM:
+ fprintf(stdout, "mov\t$%d, %s\n",t->attr.ival, *reg_ptr);
+ break;
+ default:
+ fprintf(stdout, "mov OTHER");
+ }
+ }
+ /*case 1
+ * t has a right child with label 0*/
+ else if(t->r && t->r->label == 0) {
+ GEN_EXPR(t->l);
+ if (t->r && t->r->type == INT) {
+ fprintf(stdout, "op\t$%d,\n", t->r->attr.ival);
+ fprintf(stdout, "op\t$%d,%s\n", t->r->attr.ival, *reg_ptr);
+ }
+ }
+ /*case 2
+ * 1 <= t->l->label < t->r->label AND t->l->lable < reg_cnt*/
+ else if ((t->l->label <= 1 && t->l->label < t->r->label)
+ && t->l->label < reg_cnt) {
+
+ REG_SWAP
+ GEN_EXPR(t->l);
+ REG_POP
+ GEN_EXPR(t->r);
+ fprintf(stdout, "op\t%s, %s\n", *(reg_ptr + 1), *reg_ptr);
+ REG_PUSH
+ REG_SWAP
+ }
+ /*case 3
+ * 1 <= t->r->label <= t->l->label */
+ else if (t->r->label <= 1 && t->r->label <= t->l->label) {
+ GEN_EXPR(t->l);
+ REG_POP
+ GEN_EXPR(t->r);
+ fprintf(stdout, "op\t%s, %s\n", *reg_ptr, *(reg_ptr + 1));
+ REG_PUSH
+ }
+ /*case 4
+ *t->l->label, t->r->label >= reg_cnt*/
+ else if (t->l->label >= reg_cnt && t->r->label >= reg_cnt){
+ /*TODO implement case 4*/
+ yyerror("CASE 4 of gen_expr() NOT IMPLEMENTED\n");
+ } else {
+ yyerror("NOT ONE OF DEFINED CASES [gen_expr()]\n");
+ }
+
}
void gen_statement(t)