max
Maximum
This instruction returns the larger of two signed integers.
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Software Hint
Calculating the absolute value of a signed integer can be performed using the
following sequence: neg rD,rS followed by `max rD,rS,rD. When using this
common sequence, it is suggested that they are scheduled with no intervening
instructions so that implementations that are so optimized can fuse them
together.
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Decode Variables
Bits<5> rs2 = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];Execution
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IDL
-
Sail
if (implemented?(ExtensionName::B) && (misa.B == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
X[rd] = ($signed(X[rs1]) > $signed(X[rs2])) ? X[rs1] : X[rs2];{
let rs1_val = X(rs1);
let rs2_val = X(rs2);
let result : xlenbits = match op {
RISCV_ANDN => rs1_val & ~(rs2_val),
RISCV_ORN => rs1_val | ~(rs2_val),
RISCV_XNOR => ~(rs1_val ^ rs2_val),
RISCV_MAX => to_bits(sizeof(xlen), max(signed(rs1_val), signed(rs2_val))),
RISCV_MAXU => to_bits(sizeof(xlen), max(unsigned(rs1_val), unsigned(rs2_val))),
RISCV_MIN => to_bits(sizeof(xlen), min(signed(rs1_val), signed(rs2_val))),
RISCV_MINU => to_bits(sizeof(xlen), min(unsigned(rs1_val), unsigned(rs2_val))),
RISCV_ROL => if sizeof(xlen) == 32
then rs1_val <<< rs2_val[4..0]
else rs1_val <<< rs2_val[5..0],
RISCV_ROR => if sizeof(xlen) == 32
then rs1_val >>> rs2_val[4..0]
else rs1_val >>> rs2_val[5..0]
};
X(rd) = result;
RETIRE_SUCCESS
}