require_rv64;
require_either_extension(EXT_ZBPBO, EXT_XZBT);
int shamt = RS2 & 63;
reg_t a = RS1, b = RS3;
if (shamt >= 32) {
	a = RS3, b = RS1;
	shamt -= 32;
}
int rshamt = -shamt & 31;
WRITE_RD(sext32(shamt ? (b << rshamt) | (zext32(a) >> shamt) : a));