binvi
Single-Bit invert (Immediate)
This instruction is defined by:
-
anyOf:
-
B, version >= B@1.0.0
-
Zbs, version >= Zbs@1.0.0
-
This instruction is included in the following profiles:
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RVA22U64 (Mandatory)
-
RVA23U64 (Mandatory)
-
RVB23U64 (Mandatory)
Synopsis
This instruction returns rs1 with a single bit inverted at the index specified in shamt. 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
-
RV32
-
RV64
Bits<5> shamt = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];Bits<6> shamt = $encoding[25:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];Execution
-
IDL
-
Sail
if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg index = shamt & (xlen() - 1);
X[rd] = X[rs1] ^ (1 << index);{
let rs1_val = X(rs1);
let mask : xlenbits = if sizeof(xlen) == 32
then zero_extend(0b1) << shamt[4..0]
else zero_extend(0b1) << shamt;
let result : xlenbits = match op {
RISCV_BCLRI => rs1_val & ~(mask),
RISCV_BEXTI => zero_extend(bool_to_bits((rs1_val & mask) != zeros())),
RISCV_BINVI => rs1_val ^ mask,
RISCV_BSETI => rs1_val | mask
};
X(rd) = result;
RETIRE_SUCCESS
}