FIRSTARG
params = frame->fixreg + FIRSTARG;
rval[1] = frame->fixreg[FIRSTARG + 1];
frame->fixreg[FIRSTARG] = rval[0];
frame->fixreg[FIRSTARG + 1] = rval[1];
frame->fixreg[FIRSTARG + 1] = rval[1];
frame->fixreg[FIRSTARG] = error;
tf->fixreg[FIRSTARG] = 0;