rem

Signed remainder

This instruction is defined by:

Encoding

Synopsis

Calculate the remainder of signed division of rs1 by rs2, and store the result in rd.

If the value in register rs2 is zero, write the value in rs1 into rd;

If the result of the division overflows, write zero into rd;

Access

Always

Decode Variables

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

Execution

Pruned, XLEN == 64
Original

XReg src1 = X[rs1];
XReg src2 = X[rs2];
if (src2 == 0) {
  X[rd] = src1;
} else if ((src1 == {1'b1, {63{1'b0}}}) && (src2 == {XLEN{1'b1}})) {
  X[rd] = 0;
} else {
  X[rd] = $signed(src1) % $signed(src2);
}

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] = src1;
} else if ((src1 == {1'b1, {XLEN - 1{1'b0}}}) && (src2 == {XLEN{1'b1}})) {
  X[rd] = 0;
} else {
  X[rd] = $signed(src1) % $signed(src2);
}