divu
Unsigned division
This instruction is defined by:
-
M, version >= 0
This instruction is included in the following profiles:
-
RVA20U64 (Mandatory)
-
RVA22U64 (Mandatory)
-
RVI20U32 (Optional)
-
RVI20U64 (Optional)
Synopsis
Divide unsigned values in rs1 by rs2, and store the result in rd.
The remainder is discarded.
If the value in rs2 is zero, rd gets the largest unsigned value.
Decode Variables
Bits<5> rs2 = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];Execution
-
IDL
-
Sail
if (implemented?(ExtensionName::M) && (CSR[misa].M == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg src1 = X[rs1];
XReg src2 = X[rs2];
if (src2 == 0) {
X[rd] = {XLEN{1'b1}};
} else {
X[rd] = src1 / src2;
}{
if extension("M") then {
let rs1_val = X(rs1);
let rs2_val = X(rs2);
let rs1_int : int = if s then signed(rs1_val) else unsigned(rs1_val);
let rs2_int : int = if s then signed(rs2_val) else unsigned(rs2_val);
let q : int = if rs2_int == 0 then -1 else quot_round_zero(rs1_int, rs2_int);
/* check for signed overflow */
let q': int = if s & q > xlen_max_signed then xlen_min_signed else q;
X(rd) = to_bits(sizeof(xlen), q');
RETIRE_SUCCESS
} else {
handle_illegal();
RETIRE_FAIL
}
}