c.sb

Store unsigned byte, 16-bit encoding

Stores a 8-bit value from register xs2 into memory. It computes an effective address by adding the zero-extended offset, to the base address in register xs1. It expands to sb xs2, offset(xs1).

Assembly format

c.sb xs2, imm(xs1)

Decode Variables

Bits<2> imm = {$encoding[5], $encoding[6]};
Bits<3> xs2 = $encoding[4:2];
Bits<3> xs1 = $encoding[9:7];

Execution

if (implemented?(ExtensionName::C) && (CSR[misa].C == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg virtual_address = X[creg2reg(xs1)] + imm;
write_memory(8, virtual_address, X[creg2reg(xs2)][7:0], $encoding);

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction

  • LoadAccessFault

  • StoreAmoAccessFault

  • StoreAmoAddressMisaligned

  • StoreAmoPageFault

Encoding

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Defining extension

Zcb

Access

M

Always

Containing profiles

  • Mandatory: RVA23S64, RVA23U64, RVB23S64, RVB23U64

  • Optional: RVA20S64, RVA20U64, RVA22S64, RVA22U64, RVA23S64, RVA23U64, RVB23S64, RVB23U64, RVI20U32, RVI20U64