czero.nez

Conditional zero, if condition is nonzero.

This instruction is defined by:

Zicond, version >= 0

This instruction is included in the following profiles:

RVA23U64 (Mandatory)
RVB23U64 (Mandatory)

Encoding

Assembly format

czero.nez rd, rs1, rs2

Synopsis

If rs2 contains a nonzero value, this instruction writes the value zero to rd. Otherwise, this instruction copies the contents of rs1 to rd. This instruction carries a syntactic dependency from both rs1 and rs2 to rd. Furthermore, if the Zkt extension is implemented, this instruction’s timing is independent of the data values in rs1 and rs2.

Access

M	HS	U	VS	VU
Always	Always	Always	Always	Always

Always

Decode Variables

Bits<5> rs2 = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];

Execution

IDL
Sail

X[rd] = (X[rs2] != 0) ? 0 : X[rs1];

{
  let value = X(rs1);
  let condition = X(rs2);
  let result : xlenbits = if (condition != zeros()) then zeros()
						    else value;
  X(rd) = result;
  RETIRE_SUCCESS
}