/*
 stack_functions.c
 Part of ForthBASIC, the BASIC interpreter and menuing system of POWER X Y

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "stack.h"
#include "datatypes.h"

// Discard top value of stack.
// ( value -- )
void basicfn_drop(void) {
	unsigned char t=*stackptr++;
	if(t==BTYPE_NULL) {
		// nothing to do!
	} else if(t==BTYPE_U8) {
		stackptr++;
	} else if(t==BTYPE_U16 || t==BTYPE_S16) {
		stackptr+=2;
	} else if(t==BTYPE_U32 || t==BTYPE_S32) {
		stackptr+=4;
	} else if(t==BTYPE_RAWSTR || t==BTYPE_437STR || t==BTYPE_NKSTR) {
		int L=  *(int *) stackptr; stackptr += sizeof(int); // length of string
		while(L) {
			stackptr++; L--;
		}
		stackptr++; // for the terminating null, used to send BASIC strings to C function calls
	}
	// TODO: Other data types
}