bexti
Single-Bit extract (Immediate)
This instruction is defined by:
Synopsis
This instruction returns a single bit extracted from rs1 at the index specified in rs2. The index is read from the lower log2(XLEN) bits of shamt. For RV32, the encodings corresponding to shamt[5]=1 are reserved.
Decode Variables
Bits<6> shamt = $encoding[25:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];
Execution
-
Pruned, XLEN == 64
-
Original
XReg index = shamt & (63);
X[rd] = (X[rs1] >> index) & 1;
if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg index = shamt & (xlen() - 1);
X[rd] = (X[rs1] >> index) & 1;