#define OPA ((prvm_eval_t *)&prog->globals.generic[(unsigned short) st->a])
#define OPB ((prvm_eval_t *)&prog->globals.generic[(unsigned short) st->b])
#define OPC ((prvm_eval_t *)&prog->globals.generic[(unsigned short) st->c])
#define OPA ((prvm_eval_t *)&prog->globals.generic[(unsigned short) st->a])
#define OPB ((prvm_eval_t *)&prog->globals.generic[(unsigned short) st->b])
#define OPC ((prvm_eval_t *)&prog->globals.generic[(unsigned short) st->c])