#include <stdio.h>
#include "lceb.h"

int eval_cell(pos)
    STACKELT *pos;
{
    STACKELT *prev=pos-1;
    int curop=pos->curop, nop=pos->nop;
    int val1, val2;
    char op;
    int res;

    while (curop<nop) {
        op=pos->op[curop];
        val2=pos->val;
        res=-1;
        printf("eval_cell(%c, %d)\n", op, val2);
        while ((val1=prev->val) == -1)
            prev--;
        switch (op) {
            case Nop:
            case End:
                return val2;
                break;
            case Add:
                res=val1+val2;
                break;
            case Mul:
                res=val1*val2;
                break;
            case Sub:
                if (val1 > val2)
                    res=val1-val2;
                break;
            case Div:
                if (val1 > val2 && (val1 % val2 == 0))
                    res=val1/val2;
                break;
        }
        curop++;
        if (res==-1)
            break;
        pos->val=res;
        printf("\t--> eval=%d\n", res);
    }
    return res;
}

int eval_stack(stack)
    STACK *stack;
{
    int pos, last=stack->last, res;
    STACKELT *pstack=stack->stack;

    printf("+++++ eval_stack: addr=%p\n", pstack);
    for (pos=1; pos<last; ++pos) {
        //printf("eval_stack(%d/%d): addr=%p\n", pos, stack->last, pstack+pos);
        res=eval_cell(stack->stack+pos);
        //printf("  -> val(%d)=%d\n", pos, res);
    }
    return res;
}