sext.b
Sign-extend byte
This instruction is defined by:
Synopsis
This instruction sign-extends the least-significant byte in the source to XLEN by copying the most-significant bit in the byte (i.e., bit 7) to all of the more-significant bits.
Execution
-
Pruned, XLEN == 64
-
Original
X[rd] = {{56{X[rs1][7]}}, X[rs1][7:0]};
if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
if (xlen() == 32) {
X[rd] = {{24{X[rs1][7]}}, X[rs1][7:0]};
} else if (xlen() == 64) {
X[rd] = {{56{X[rs1][7]}}, X[rs1][7:0]};
}