bclri
Single-Bit clear (Immediate)
This instruction is defined by:
Synopsis
This instruction returns rs1 with a single bit cleared 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
Bits<6> shamt = $encoding[25:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];Execution
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Pruned, XLEN == 64
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Original
if ((%%LINK%csr_field;misa.B;CSR[misa].B%% == 1'b0)) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
XReg index = shamt & (63);
X[rd] = X[rs1] & ~(1 << index);if (%%LINK%func;implemented?;implemented?%%(ExtensionName::B) && (%%LINK%csr_field;misa.B;CSR[misa].B%% == 1'b0)) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
XReg index = shamt & (%%LINK%func;xlen;xlen%%() - 1);
X[rd] = X[rs1] & ~(1 << index);